NECK (pp.1000~1022) Fascia. 1. Investing layer. 2. Prevertebral layer. 3. Pretracheal layer

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1 NECK (pp.1000~1022) Head Neck Trunk Anterior: lower border of mandible > upper surface of manubrium Posterior: superior nuchal line > intervertebral disc between CVII and TI Four compartments separated by cervical fascia: Visceral compartment digestive, respiratory, and endocrine Vertebral compartment cervical vertebrae, spinal cord, spinal nerves, mm. associated with vertebra Vascular compartments major blood vessels and vagus n. Borders of triangles: Anterior triangle ant. border of SCM m., inf. border of mandible, midline of neck Posterior triangle post. border of SCM m., ant. border of trapezius, middle 1/3 of clavicle Fascia Superficial fascia with platysma m. (from superficial thorax fascia to mandible and mm. on face), innervated by cervical br. of CN VII. Deep cervical fascia 1. Investing layer surrounds neck Ligamentum nuchae, spinous process of CVII > encloses trapezius m. > roof of post. triangle > encloses SCM m. > surrounds infrahyoid mm. attaches to: Superior occipital protuberance, sup. nuchal line Lateral mastoid process, zygomatic arch Inferior spine of scapula, acromion, clavicle, and manubrium of sternum pierced by: ext. and ant. jugular vv., lesser occipital, greater auricular, transverse cervical, and supraclavicular nn., brr. of cervical plexus 2. Prevertebral layer Surrounds: vertebral column, and muscles: prevertebral mm., ant. middle, and post. scalene mm. and deep mm. of back Borders: Superior Anterior basilar part of occipital bone, jugular foramen, carotid canal Lateral mastoid process Posterior superior nuchal line, ext. occipital protuberance Anterior Anterior surface of transverse processes and bodies of CI to CVII vertebrae Fascia splits into two layers, and creates a longitudinal fascial space. Inferior into thorax Lower lateral as axillary sheath extends from anterior and middle scalene mm. to surround brachial plexus and subclavian a. 3. Pretracheal layer surrounds trachea, esophagus, thyroid gland Superior hyoid bone G54-1

2 Anterior trachea, thyroid gland Inferior upper thoracic cavity Posterior buccopharyngeal fascia (from base of skull into thoracic cavity) 4. Carotid sheath surrounds common carotid a., internal carotid a., internal jugular vein, and vagus n. Fascial compartments 1. Investing layer includes other three 2. Prevertebral layer vertebral column, deep mm. and associated structures 3. Pretracheal layer visceral compartment (trachea, esophagus, thyroid gland) 4. Carotid sheath from skull to thorax, with neurovascular structures Fascial spaces As a conduit for spread infection 1. Pretracheal space b/w investing layer of cervical fascia and pretracheal fascia 2. Retropharyngeal space b/w buccopharyngeal fascia and prevertebral fascia 3. Space b/w two split layers of prevertebral layer of cervical fascia Superficial venous drainage 1. External jugular veins formed by posterior auricular v. and posterior division of retromandibular v. 1. Posterior auricular v. drains the scalp behind and above ear 2. Retromandibular v. conjoined by superficial temporal and maxillary vv., splits into: a. Anterior division joined by facial v. as common facial v., drain into internal jugular v. b. Posterior division joined by posterior auricular v. as external jugular v. > crosses SCM m. to subclavian v. 3. Other tributes to external jugular v.: a. Posterior external jugular v. drains superficial area of back of neck b. Transverse cervical v. c. Suprascapular v. drains posterior scapular region 2. Anterior jugular veins variable and inconsistent, from hyoid bone to decent by midline of neck to enter subclavian v. Two anterior jugular vv. are connected by jugular venous arch. Anterior triangle of the neck (pp. 1006~968) 1. Submandibular triangle inferior border of mandible, anterior and posterior bellies of digastric m 2. Submental triangle hyoid bone, anterior bellies of two digastric mm. and midline 3. Muscular triangle hyoid bone, superior belly of omohyoid m., anterior border of SCM, midline 4. Carotid triangle superior belly of omohyoid m., stylohyoid m., posterior belly of digastric m., anterior border of SCM Muscles G54-2

3 Suprahyoid muscles In submental and submandibular triangles; raise the hyoid bone during swallowing 1. Stylohyoid Origin: base of styloid process Insertion: body of hyoid bone Function: pull hyoid posterosuperiorly Innervation: CN VII 2. Digastric Origin: Posterior belly mastoid notch (medial side of mastoid process) Anterior belly digastric fossa (lower inside of mandible) Insertion: tendon between two bellies body of hyoid bone Function: raise hyoid bone (when mandible is fixed) opens mouth (when hyoid is fixed) Innervation: Posterior belly CN VII 3. Mylohyoid Origin: Insertion: Function: Anterior belly CN V 3 mylohyoid line on mandible hyoid bone supports and elevates floor of mouth Innervation: CN V 3 4. Geniohyoid Origin: inferior mental spine of mandible Insertion: body of hyoid bone Function: elevates and pulls hyoid forward (when mandible is fixed) pulls the mandible downward and inward (when hyoid is fixed) Innervation: anterior ramus of C1 (carried by CN XII) Infrahyoid muscles 1. Sternohyoid Origin: posterior aspect of sternoclavicular joint and manubrium of sternum Insertion: body of hyoid Function: depresses the hyoid Innervation: ant. rami of C1 to C3 (through ansa cervicalis) 2. Omohyoid Origin: Inferior belly sup. border of scapula Superior body of hyoid Insertion: Intermediate tendon to clavicle through a fascial sling Function: depresses and fixes hyoid Innervation: ant. rami of C1 to C3 (through ansa cervicalis) 3. Thyrohyoid Origin: oblique line on the thyroid cartilage Insertion: greater horn and body of hyoid Function: depresses hyoid; raises larynx (when hyoid is fixed) G54-3

4 Innervation: anterior ramus of C1 (carried by CN XII) 4. Sternothyroid Origin: post. surface of manubrium of sternum Insertion: oblique line on the thyroid cartilage Function: draws larynx downward Innervation: ant. rami of C1 to C3 (through ansa cervicalis) Vessels Carotid system 1. Common carotid arteries Right common carotid a. from brachiocephalic trunk Left common carotid a. from aorta Both ascend in carotid sheath, lateral to trachea and esophagus, give no branch until bifurcate. Each divides into internal and external carotid aa. near the sup. edge of thyroid cartilage, within carotid triangle. Carotid sinus (dilation in the beginning of int. carotid a.) contains receptor for blood pressure (innervated by CN IX). Carotid body (in the area of bifurcation) contains receptors for blood oxygen (innervated by CN IX and X). 2. Internal carotid arteries give no branch > through carotid canal > enters cranial cavity > supplies cerebral hemisphere, eye, contents of orbit > forehead 3. External carotid arteries Superior thyroid a. 1 st br. > superior pole of thyroid gland Ascending pharyngeal a. 2 nd br. > b/w int. carotid a. and pharynx Lingual a. branches on the level of hyoid bone > deep to CN XII > b/w middle constrictor and hyoglossus m. Facial a. deep to stylohyoid and post. belly of digastric mm. > b/w submandibular gland and mandible > over edge of mandible > face Occipital a. deep to posterior belly of digastic m. > post. aspect of scalp Posterior auricular a. runs posterosuperiorly Superficial temporal a. terminal br. > runs upward > divides into ant. and post. brr. Maxillary a. through parotid gland > infratemporal fossa > pterygopalatine fossa Veins Skull, brain, superficial face, part of neck Inferior petrosal sinus, sigmoid sinus > through jugular foramen > internal jugular vein > Collecting tributes from facial, lingual pharyngeal, occipital, superior thyroid, and middle thyroid vv. > joined by subclavian v. > brachiocephalic v. > superior vena cava (Fig , p.995) Nerves 1. Facial nerve [VII] through stylomastoid f. > post. belly of digastric m. and stylohyoid m. > platysma m. G54-4

5 2. Glossopharyngeal nerve [IX] through jugular f. > b/w int. carotid a. and int. jugular v. > b/w int. and ext. carotid aa. > gives: 1. motor br. to innervate stylopharyngeus m. 2. sensory br. to carotid sinus 3. sensory br. to pharynx > base of tongue and palatine tonsil area 3. Vagus nerve [X] through jugular f. (b/w CN IX and XI) > enters carotid sheath > medial to int. jugular v., int. and common carotid aa. > 1. motor br. to pharynx 2. sensory br. to carotid body 3. superior laryngeal n. ext. br. (to cricothyroid m.) int. br. (for sensation of mucosa above vocal fold) 4. cardiac br. 4. Accessory nerve [XI] through jugular f. > b/w int. carotid a. and int. jugular v. > deep to and innervates SCM m. (Fig , p.1015) 5. Hypoglossal nerve [XII] hypoglossal canal > b/w int. carotid a. and int. jugular v. > lateral to int. and ext. carotid aa. > deep to ant. belly of digastric m. > medial to hyoglossus m. > innervates tongue (Fig , p.1016) 6. Transverse cervical nerve br. of cervical plexus, from ant. rami of C2 and C3; crosses on SCM m. in the middle part; for cutaneous innervation of neck (Fig , p.1016) 7. Ansa cervicalis (Fig , p.1016) a loop formed from two roots: Sup. root C1 ff. carried by CN XII, innervates superior belly of omohyoid m., upper part of sternohyoid and sternothyroid mm. Inf. root C2 and C3 ff. from cervical plexus, innervates inferior belly of omohyoid m., lower part of sternohyoid and sternothyroid mm. Thyroid and parathyroid glands Thyroid gland a large unpaired gland Parathyroid gland 4 of them on posterior surface of thyroid gland Thyroid gland Isthmus connecting two lateral lobes crosses on the 2 nd and 3 rd tracheal rings. The gland is within pretracheal layer of fascia with pharynx, trachea, and esophagus. It is the median pharyngeal outgrowth from foramen cecum on the tongue. Its remains along disappeared thyroglossal duct, including lingual thyroid and pyramidal lobe. Arterial supply 1. Superior thyroid artery the 1 st br. of ext. carotid a., divides into: G54-5

6 Ant. glandular br. along superior border of gland, anastomoses with br. from the other side Post. glandular br. along post. side of gland, anastomoses with br. of inf. thyroid a. 2. Inferior thyroid artery 1 st part of subclavian a. > thyrocervical trunk > inf. thyroid a. > inf. pole of thyroid gland Inf. br. supplies the lower gland Ascending br. supplies parathyroid glands 3. Thyroid ima artery from brachiocephalic trunk or the arch of aorta; ascends on anterior surface of trachea Venous and lymphatic drainage (Fig p.1019) Sup. thyroid v. (primary) > int. jugular v. Middle thyroid vv. (rest) > int. jugular v. Inf. thyroid vv. (rest) > brachiocephalic vv. Lymph > Paratracheal nodes (along trachea) > Deep cervical nodes (along int. jugular v.) Recurrent laryngeal nerves Vagus n. > Recurrent laryngeal n. (left on arch of aorta; right on right subclavian a.) > ascend in the grooves b/w trachea and esophagus > posterior to thyroid gland > enters larynx Consider this relationship while surgically removing or manipulating the thyroid gland. Parathyroid glands Two pairs (sup. and inf.) in deep surface of lateral lobes of thyroid gland; Their levels vary from carotid bifurcation to mediastinum. Inferior parathyroid glands derive from 3 rd pharyngeal pouches; superior from the 4 th pouches. Blood supply is from inferior thyroid a. Location of structures in different regions of the anterior triangle of the neck Subdivisions of anterior triangle: (Fig , p.1011) 1. Submental triangle 1, with submental lymph nodes 2. Submandibular triangle 2, submandibular gland, submandibular lymph nodes, CN XII, mylohyoid n., facial a. and v. 3. Carotid triangle 2 a. and v.: common, internal, and external carotid aa., int. jugular v., Nerves: cervical br. of CN VII, CN X, XI, and XII, transverse cervical n., sup. and inf. roots of ansa cervicalis 4. Muscular triangle 2, sternothyroid, omohyoid, sternohyoid, and thyrohyoid mm., thyroid and parathyroid glands., pharynx G54-6

7 Posterior triangle of the neck (pages ) Connects with upper limb; borders: (Fig , p.1023) Ant posterior edge of SCM m. Post anterior edge of trapezius m. Base middle 1/3 of clavicle Apex posterior to mastoid process Roof investing layer of cervical fascia Floor prevertebral layer of cervical fascia, splenius capitis, levator scapulae, scalene mm. Muscles Omohyoid m., enclosed in investing fascia Origin: superior border of scapula Insert: inferior border of the body of the hyoid bone Intermediate tendon: fascial sling to clavicle Superior belly: in anterior triangle Inferior belly: divides posterior triangle into occipital and subclavian triangles Function: depresses hyoid bone Innervation: ansa cervicalis (anterior rami of C1 to C3) Vessels 1. External jugular vein (Fig , p.1025) Most superficial in posterior triangle, in superficial fascia, crossing on SCM m., Tributes: transverse cervical, suprascapular, anterior jugular vv. 2. Subclavian artery and its branches 1 st part from arch of aorta (left) or brachiocephalic a. (right) 2 nd part passes b/w anterior and middle scalene mm., may have a branch (dorsal scapular a.) 3 rd part crosses the base of posterior triangle, to lateral border of 1 st rib becoming axillary a. Dorsal scapular a. may from 3 rd part, descends on med. border of scapula, post. to rhomboid mm. 3. Transverse cervical and suprascapular arteries (Fig , p.1026) brr. of thyrocervical trunk (from 1 st part of subcalvian a.), Transverse cervical a. divides into: Superficial br. on deep surface of trapezius m. Deep br. (dorsal scapular artery) deep surface of rhomboid mm. Suprascapular a. passes over sup. transverse scapular lig., to post. surface of scapula 4. Veins Subclavian v. receives external jugular, suprascapular, and transverse cervical vv., passes anterior to anterior scalene m. Nerves 1. Accessory nerve through jugular foramen, passes deep to SCM m. and enters posterior triangle, superficially within investing layer of cervical fascia, runs deep to and innervates trapezius m. G55-1

8 2. Cervical plexus Formed by anterior rami of (C1) C2 to C4. Muscular branches a. Phrenic n. from anterior rami of C3, 4, and 5, to diaphragm with sensory and motor innervation On the anterior surface of anterior scalene m. in prevertebral fascia, enters thorax b. Muscular brr. to rectus capitis anterior, rectus capitis lateralis, longus colli, and longus capitis mm. c. Superior and inferior roots of ansa cervicalis from ant. rami of C1 to C3, innervates infrahyoid mm. Cutaneous branches Emerges from posterior border of SCM m. a. Lesser occipital n. from C2, to the skin of neck and scalp posterior to ear b. Great auricular n. from C2 and C3, to the skin of parotid region, ear, and mastoid area c. Transverse cervical n. from C2 and C3, to lateral and anterior part of neck d. Supraclavicular nn. from C3 to 4, to skin over clavicle till rib 2 3. Brachial plexus forms from anterior rami of C5 to T1, its roots run b/w anterior and middle scalene mm. Upper trunk from C5 and C6 Middle trunk from C7 Lower trunk from C8 and T1 In the posterior triangle it gives: Dorsal scapular n. rhomboid mm. Long thoracic n. serratus anterior m. Nerve to subclavius Suprascapular n. supraspinatus and infraspinatus mm. G55-2

9 Root of the neck (pp ) Borders: Ant top of the manubrium of sternum, superior margin clavicle Post top of T1 vertebra, superior margin of scapula to coracoid process Vessels Subclavian arteries (Fig , p.1031) Right subclavian a. from brachiocephalic trunk, anterior to pleural cavity in neck, posterior to anterior scalene m., becomes axillary a. when crosses on lateral border of 1 st rib Left subclavian a. from arch of aorta 1 st part from origin to medial border of ant. scalene m. 2 nd part posterior to ant. scalene m. 3 rd part from lateral border anterior scalene m. to lateral border of rib 1 1. Vertebral artery 1 st br. of subclavian a. entering neck; passes through foramina in transverse processes of CVI to C I vertebrae; turns medially on the posterior arch of CI; enters posterior cranial fossa through foramen magnum. 2. Thyrocervical truck 2 nd br. from 1 st part of subclavian a. > divides into inferior thyroid, transverse cervical, and suprascapular aa Inferior thyroid artery From thyrocervical trunk, posterior to carotid sheath, reaches posterior surface of thyroid gland Ascending cervical a. anterior to prevertebral mm., for these mm. and spinal cord 2-2. Transverse cervical artery From thyrocervical trunk > crosses anteriorly to ant. scalene m. > deep surface of trapezius m. > divides > Superficial br. deep surface of trapezius m. Deep br. deep surface of rhomboid mm., medial to scapula 2-3. Suprascapular a. From thyrocervical trunk > crosses anteriorly to ant. scalene m., phrenic n., brachial plexus > superior border of scapula over superior transverse scapular ligament > suprascapular fossa 3. Internal thoracic artery From subclavian a. > descends posterior to clavicle, large vv. and anterior to pleural cavity > enters thorax > posterior to ribs and anterior to transverse thoracis m. 4. Costocervical trunk Arise from the 1 st part of left subclavian a., and 2 nd part of right subclavian a. > divides into > 4-1. Deep cervical a. ascends in the back of neck 4-2. Supreme intercostal a. descends anterior to root of rib 1, into first two intercostal spaces Veins Axillary v > lateral border of rib 1 > subclavian v. (anterior to ant. scalene m.) > joined by ext. then int. jugular vv. > brachiocephalic v. G56-1

10 Nerves 1. Phrenic nerves Ant. rami of C3 to C5 > lateral then anterior to ant. scalene m. > in prevertebral layer of cervical fascia > between subclavian v. and a. > thorax 2. Vagus nerves [X] In carotid sheath (b/w common carotid a. and int. jugular v.) > gives cardiac br. (posterior to subcalvian a.) > vagus n. anterior to subcalvian a. 3. Recurrent laryngeal nerves From right vagus n. > right recurrent laryngeal n. around subclavian a. > ascends in the groove b/w trachea and esophagus > larynx From left vagus n. > left recurrent laryngeal n. around arch of aorta > ascends in the groove b/w trachea and esophagus > larynx 4. Sympathetic nervous system Cervical part of the sympathetic trunk Anterior to longus colli and logus capitis mm. > posterior to carotid sheath > gray rami communicans to spinal nn. (There is NO white rami communicantes in cervix.) Ganglia 1. Superior cervical ganglion Very large at CI and CII, brr. to: Plexus on int. and ext. carotid aa. C1 to C4 spinal nn. through gray rami communicantes Pharynx Heart as superior cardiac nn. 2. Middle cervical ganglion Second ganglion along sympathetic trunk on CVI level, brr. to: C5 and C6 spinal nn. through gray rami communicantes Heart as middle cardiac nn. 3. Inferior cervical ganglion Combines with T1 ganglion as cervicothoracic ganglion (stellate ganglion) anterior to neck of rib 1 and transverse process of CVII; posterior to 1 st part of subclavian a.; brr. to: C7 and T1 spinal nn. through gray rami communicantes Plexus on vertebral a. Heart as inf. cardiac nn. Lymphatics 1. Thoracic duct Begins at cisterna cyli in abdomen > ascends anterior to vertebral column, posterior to esophagus, thoracic aorta on the left, azygos v. on the right On TV level left to esophagus > posterior to left carotid sheath > Joined by: left jugular trunk from left head and neck left subclavian trunk from left upper limb; terminates at the junction of left int. jugular v. and left subclavian v. G56-2

11 left bronchomediastinal trunk from left half of thoracic structures 2. On the right: Right jugular trunk from head and neck Right subclavian trunk from right upper limb Right bronchomediastinal trunk from right half of thoracic cavity, right upper intercostal spaces Lymphatic of the neck Superficial nodes along ext. jugular v. Deep nodes along int. jugular v. Superficial nodes Superficial nodes > Deep nodes Deep nodes Superficial lymph nodes 1. Occipital nodes along occipital a., drains posterior scalp and neck 2. Mastoid nodes (retroauricular / posterior auricular nodes) along posterior auricular a., drains posterolateral half of scalp 3. Pre-auricular and parotid nodes along superficial temporal and transverse facial aa., drains ant. surface of auricle, anterolateral scalp, upper face, eyelids, and cheeks 4. Submandibular nodes along facial a, along facial a., drains forehead, gingivae, teeth, and tongue 5. Submental nodes inferior and posterior to chin, drains center lower lip, chin, floor of mouth, tip of tongue, lower incisors Lymphatic flow from superficial lymph nodes: Occipital and mastoid nodes > superficial cervical nodes Pre-auricular and parotid, submandibular, and submental nodes > deep cervical nodes Superficial cervical lymph nodes Along ext. jugular v. on the surface of the SCM m. Posterior and posterolateral region of scalp > Occipital and mastoid nodes > Superficial cervical nodes > Deep cervical nodes Deep cervical lymph nodes Along int. jugular v., divided into upper and lower groups 1. Jugulodigastric node most superior, at post. belly of digastric m. on int. jugular v., drains tonsils and tonsillar region 2. Jugulo-omohyoid node lower group, at intermediate tendon on int. jugular v., drains tongue Right to the right lymphatic duct Left to thoracic duct G56-3

12 Gray s Anatomy: by Henry Gray and Peter L. Williams G56-4

13 PHARYNX (pp.1040~1052) Musculofascial half-cylinder, oral and nasal cavities > larynx and esophagus Borders: Base of skull > top of esophagus (CVI) Nasal cavities > choanae + pharyngotympanic tubes > nasopharynx Oral cavity > oropharyngeal isthmus + posterior one-third of tongue > oropharynx Larynx > laryngeal inlet > laryngopharynx Retropharyngeal space > vertebral column Soft palate: Elevate to seal off nasopharynx from oropharynx Depress to seal off oral cavity from oropharynx Skeletal framework Anterior vertical line of attachment for the lateral pharyngeal walls First part Posterior edge of medial pterygoid plate Pterygoid hamulus Pterygomandibular raphe Pterygomandibular raphe: from pterygoid hamulus to mandible (posterior to 3 rd molar tooth) Buccinator superior pharyngeal constrictor Second part Styloid process Stylohyoid ligament Hyoid bone (lesser horn) Hyoid bone (greater horn) Third part Superior tubercle of thyroid cartilage Oblique line Inferior tubercle Cricoid cartilage Pharyngeal wall Muscles Constrictor muscles All the constrictors are innervated by CNX. Superior constrictors Origin: pharyngeal raphe Insertion: hamulus, pterygomandibular raphe, and mandible Palatopharyngeal sphincter: from soft palate, circles inner aspect of pharyngeal wall (blends with superior constrictor) (Fig B, p.1044) Middle constrictors Origin: lower stylohyoid ligament, lesser horn of hyoid bone, upper surface, and greater horn Insertion: pharyngeal raphe Inferior constrictors Origin: oblique line of thyroid cartilage, cricoid cartilage Insertion: pharyngeal raphe The narrowest part of pharyngeal cavity Longitudinal muscles Elevate pharyngeal wall Stylopharyngeus G57-1

14 Origin: medial surface of styloid process Blend with deep surface of pharyngeal wall Innervated by CN IX Salpingopharyngeus Origin: inferior aspect of pharygotympanic tube Blend with deep surface of pharyngeal wall Innervated by CNX Palatopharyngeus Also a muscle of soft palate, forms a mucosal fold (palatopharyngeal arch) Origin: upper surface of palatine aponeurosis Blend with deep surface of pharyngeal wall It closes oropharyngeal isthmus. Palatine tonsil is anterior to the palatopharyngeal arch. Fascia Buccopharyngeal fascia: thinner; coating on outer surface of muscle; as a part of pretracheal layer of cervical fascia Pharyngobasilar fascia: thicker; lining inner surface Gaps in the pharyngeal wall and structures passing through them Provides routes for muscles and neurovascular tissues Gap above the superior constrictor: with pharyngeal fascia Levator veli palatini m. passing through the fascia enters soft palate. Tensor veli palatine m. turning medially around pterygoid hamulus enters soft palate. Gap between superior and middle constrictors, and posterior border of mylohyoid m. Largest and most important aperture; passed by stylopharyngeus m., and the muscles, nerves and vessels to the tongue Gap between middle and inferior constrictors Internal laryngeal vessels and nerves passing through thyrohyoid membrane enter larynx. Gap inferior to inferior constrictor Recurrent laryngeal nn. and vessels Nasopharynx Behind posterior apertures (choanae) of nasal cavity Pharyngeal isthmus (with underlying palatopharyngeal sphincter) mark the separation between oropharynx from nasaopharynx. Pharyngeal tonsil (adenoids): lymphoid tissue at the roof of nasopharynx; occludes nasopharyx while enlarges Lateral wall: pharyngeal opening of pharyngotympanic tube and the covering mucosal elevation and folds Torus tubarius: the tubal elevation or bulge caused by the pharyngotympanic tube Pharyngeal recess: the deep recess posterior to torus tubarius G57-2

15 Salpingopharyngeal fold: overlying salpingopharyngeus muscle Torus levatorius: broad fold continues onto soft palate overlying levator veli palatine muscle Oropharynx Posterior to oral cavity, inferior to soft palate, superior to upper margin of epiglottis Palatoglossal folds (arches) between oropharynx and oral cavity form pharyngeal isthmus. Ant. wall upper part of posterior one-third (pharyngeal part) of tongue, with lymphoid tissue (lingual tonsil) Lat. wall palatine tonsils between palatoglossal and palatopharyngeal arches While holding liquid or solid in the mouth, closing oropharyngeal isthmus, by depression of soft palate, elevation of the back of tongue, moving toward midline of palatoglossal and palatopharyngeal folds While swallowing, oropharyngeal isthmus is opened; and airway is closed at pharyngeal isthmus and larynx. Laryngopharynx Superior margin of epiglottis to top of the esophagus (at CVI) Ant. valleculae (a pair of mucosal pouches) between tongue and epiglottis Lat. piriform fossae (mucosal recesses) between central larynx and lateral lamina of thyroid cartilage for directing food into esophagus Tonsils Pharyngeal tonsil (adenoids when enlarged) at the roof of nasopharynx Palatine tonsils at side of oropharynx between palatoglossal and palatopharyngeal arches Lingual tonsil on the posterior one-third of tongue Small lymphoid nodules occurs in the pharyngotympanic tube and upper surface of soft palate Vessels Arteries Upper part of pharynx is supplied by: Ascending pharyngeal a. Ascending palatine and tonsillar brr. of facial a. Brr. of maxillary and lingual aa. Lower part of pharynx: Pharyngeal brr. from inferior thyroid a. (br. of thyrocervical trunk) Palatine tonsil: Tonsillar br. of facial a. Veins Form a plexus draining to pterygoid plexus (superiorly) and to facial and internal jugular vv. (inferiorly) Lymphatics Drain to deep cervical nodes: including retropharyngeal, paratracheal, and infrahyoid nodes Palatine tonsils to jugulodigastric nodes Nerves Pharyngeal plexus: in the outer fascia; formed by: G57-3

16 Pharyngeal br. of vagus n. (from inf. ganglion of vagus n.) with motor and sensory Brr. of external laryngeal n. (from superior laryngeal br. of vagus n.) Pharyngeal brr. of glossopharyngeal n. All mm. in pharynx are innervated by vagus n. through pharyngeal plexus, except: Stylopharyngeus by a br. of glossopharyngeal n. Sensory function: Nasopharynx by pharyngeal br. of maxillary n. (V 2 ), originating in pterygopalatine fossa through palatovaginal canal Oropharynx by glossopharyngeal n. (IX) via pharyngeal plexus Laryngopharynx by vagus n. (X) via pharyngeal plexus Glossopharyngeal nerve [IX] Exits through jugular foramen > descends on posterior surface of stylopharyngeus m. > lateral surface of stylopharyngeus > gap between superior and middle constrictors > inferior to palatine tonsil > posterior aspect of tongue Motor to stylopharygeus m. Sensory to oropharynx afferent limb of gag reflex G57-4

17 NASAL CAVITIES (pp. 1069~1087) Contains olfactory receptors, with skeletal framework, anterior apertures (nares) and posterior apertures (choanae), a midline nasal septum Lateral wall Conchae: three curved shelves of bone, dividing nasal cavity into four air channels Inferior nasal meatus between inferior concha and nasal floor Middle nasal meatus between inferior and middle conchae Superior nasal meatus between middle and superior conchae Spheno-ethmoidal recess between superior chonca and nasal roof Openings for paranasal sinuses and nasolacrimal duct are on the lateral wall. Regions Nasal vestibule lined by skin and with hair follicles Respiratory region lined by respiratory epithelium with ciliated and mucous cells Olfactory region apex of cavity, lined by olfactory epithelium with olfactory receptors Innervation and blood supply Innervation: Olfaction by olfactory n. (I) General sensation by ophthalmic n. (V 1 ) for anterior region, and maxillary n. (V 2 ) for posterior region Glands by parasympathetic fibers in facial n. (VII) via greater petrosal n. and joined maxillary n. Sympathetic fibers derived from T1 spinal cord; synapse at superior cervical ganglion; postganglionic fibers along with blood vessels or joining brr. of maxillary n. Blood supply: Terminal brr. of maxillary and facial aa. (from external carotid a.) Ethmoidal brr. of ophthalmic a. (from internal carotid a.) Skeletal framework Unpaired ethmoid, sphenoid, frontal, and vomer bones Paired nasal, maxillary, palatine, and lacrimal bones, and inferior conchae Ethmoid bone Contains: two ethmoidal labyrinths united by a cribriform plate, and a perpendicular plate Each ethmoidal labyrinth is with ethmoidal cells between a lateral sheet of bone (orbital plate) and medial sheet of bone (upper lateral wall) Medial sheet superior and middle conchae and a prominent bulge (ethmoidal bulla) Ethmoidal infundibulum connects bulla to frontal sinus Uncinate process on inferior surface of ethmoidal labyrinth Maxillary hiatus between medial wall of maxilla and inferior concha Ethmoidal notch of frontal bone filled by cribriform plate Perforations of cribriform plate are for fibers of olfactory nn. Crista galli on superior surface of cribriform plate, anchors falx cerebri of dura mater G58-1

18 Perpendicular plate forms upper part of medial nasal septum; articulates with: Posterior sphenoidal crest of sphenoid bone Anterior nasal spine of frontal bone Inferior septal cartilage and vomer External nose Bony part nasal bones, and parts of maxillary and frontal bones Cartilage part lateral processes of septal cartilage, major alar and minor alar cartilages Paranasal sinuses Outgrowths of nasal cavities into bones Lined by respiratory mucosa (ciliated and mucus secreting) Open into nasal cavities Innervated by brr. of trigeminal n. (V) Frontal sinuses Most superior of sinuses; drains into lateral wall of middle meatus via frontonasal duct, and continues as ethmoidal infundibulum to semilunar hiatus Innervated by br. of supra-obital n. (from ophthalmic n.); blood supplied by br. of anterior ethmoidal aa. Ethmoidal cells Variable number of air chambers; Anterior ethmoidal cells open into ethmoidal infundibulum or frontonasal duct Middle ethmoidal cells into ethmoidal bulla Posterior ethmoidal cells lateral wall of superior meatus Innervated by: Anterior and posterior ethmoidal brr. (of nasociliary n. from ophthalmic n. V 1 ) Maxillary n. (via orbital brr. from pterygopalatine ganglion) Blood is suppied by the brr. of anterior and posterior ethmoidal aa. Maxillary sinuses Largest paranasal sinus; a pyramidal shape with its base on the medial wall and apex toward lateral Opening is near the top of base in the center of semilunar hiatus. Superolateral surface roof to orbit Anterolateral surface roots of upper molar and premolar teeth Posterior wall infratemporal fossa Sphenoidal sinuses TWO in the body of sphenoid bone Opens on the posterior wall of spheno-ethmoidal recess Superior pituitary gland and optic chiasm Lateral cavernous sinus Below and front nasal cavity Pituitary gland in the hypophyseal fossa can be reached through nasal cavity, its posterior wall, sphenoidal sinus and its top wall. Innervation: posterior ethmoidal br. of ophthalmic n. (V 1 ) G58-2

19 maxillary n. (V2) via brr. of pterygopalatine ganglion Blood supply: brr. of pharyngeal aa. of maxillary aa. Walls, floor, and roof Medial wall Nasal septum separates two nasal cavities; consists of: Septal nasal cartilage, perpendicular plate of ethmoid bone, vomer, nasal spine of frontal bone, and the nasal crest of maxillary and palatine bones, rostrum of sphenoid bone and incisor crest of maxilla Floor Consists of the soft tissue of the ext. nose, upper surface of hard palate (palatine process of maxilla and horizontal plate of palatine bone) Superior aperture of the incisive canal on the floor Roof Consists of: Anteriorly: central region cribriform plate ethmoid bone, nasal spine of frontal bone and nasal bones, lateral processes of septal cartilage and major alar cartilage Posteriorly: anterior surface of sphenoid bone, ala of vomer and adjacent sphenoidal process of palatine bone, and vaginal process of medial plate of pterygoid process Openings of roof: cribriform plate, foramen for anterior ethmoidal n. and vessels, opening of sphnoidal sinus Lateral wall Bony structures: ethmoidal labyrinth and uncinate process; perpendicular plate of palatine bone Cartilages: lateral process of septal cartilage, major and minor cartilages Ethmoidal bulla, semilunar hiatus, and uncinate process Ethmoidal infundibulum on the front end of semilunar hiatus curves up and as frontonasal duct to frontal sinus Nasolacrimal duct lateral wall of inferior meatus Frontal sinus through frontonasal duct, then ethmoidal infundibulum, to lateral wall of middle meatus Middle ethmoidal cells above ethmoidal bulla Posterior ethmoidal cells lateal wall of superior meatus Maxillary sinus semilunar hiatus Nares Anterior openings of nasal cavities Held open by alar cartilages and septal cartilage Can be widened by nasalis m., depressor septi nasi, and levator labii superioris alaeque nasi Choanae Openings between nasal cavities and nasopharynx; with bony margins: Inferior posterior border of horizontal plate of palatine bone Lateal posterior margin of medial plate of pterygoid process Medial posterior border of vomer Roof ala of vomer, vaginal process of medial plate of pterygoid process (anteriorly) G58-3

20 body of sphenoid bone (posteriorly) Gateways Cribriform plate Perforations for the fibers of olfactory nn. (I), anterior ethmoidal n. (from orbit to cranial cavity, then nasal cavities), foramen cecum for connection between nasal vv. to superior sagittal sinus Sphenopalatine foramen On the posterolateral wall of superior meatus Formed by the sphenopalatine notch in palatine bone and body of sphenoid bone Communicates nasal cavity and pterygopalatine fossa, passed by: Sphenopalatine br. of maxillary a. Nasopalatine br. of maxillary n. (V 2 ) Superior nasal brr. of maxillary n. (V 2 ) Incisive canal In the floor of each nasal cavity There are TWO incisive canals. Both opens to a incisive fossa in the roof of oral cavity. It transmits: Nasopalatine nerve from nasal cavity into oral cavity Terminal end of the greater palatine a. form oral cavity into nasal cavity Small foramina in the lateral wall Internal nasal brr. of infra-orbital n. of maxillary n. (V 2 ) and alar brr. of nasal a. (from facial a.) around margin of naris from face Inferior nasal brr. of greater palatine br. of maxillary n. (V 2 ) from palatine canal on lateral wall Vessels Rich vascular supply to increase the humidity and temperature of respired air. Arteries External carotid a. and brr. > Sphenopalatine, greater palatine, superior labial, and lateral nasal aa. Internal carotid a. and brr. > Anterior and posterior ethmoidal aa. 1. Sphenopalatine artery The largest one, the terminal br. of maxillary a., divides into: Posterior lateral nasal brr. large part of lateral wall; anastomose with ant. and post. ethmoidal aa., and lateral nasal brr. of facial a. Posterior septal brr. over roof and then nasal septum, anastomose with terminal end of greater palatine a., and superior labial a. 2. Greater palatine artery Passing through incisive canal form roof of oral cavity into nasal cavity 3. Superior labial and lateral nasal arteries Superior labial artery from facial a., alar br. to lateral aspect of naris, septal br. into nasal cavity Lateral nasal artery from facial a., for supplying external nose. Alar br. for lateral margin of naris and nasal vestibule 4. Anterior and posterior ethmoidal arteries G58-4

21 From ophthalmic a. > medial wall of orbit > between ethmoidal labyrinth and frontal bone > supply paranasal sinus > enter cranial cavity Posterior ethmoidal artery through cribriform plate > upper parts of medial and lateral walls Anterior ethmoidal artery through slit-like foramen lateral to crista galli > medial and lateral walls > deep surface of nasal bones > passing between nasal bone and lateral nasal cartilage > skin of external nose The major sites for nose-bleed (epistaxis) anterior region of medial wall, with extensive anastomoses between greater palatine, sphenopalatine, superior labial, and anterior ethmoidal aa. Veins Brr. originating from maxillary a. drain into pterygoid plexus of veins in infratemporal fossa Vv. from anterior region of nasal cavity join facial v. Nasal v. in some individuals passes through forament cecum, and connects to superior sagittal sinus. It is regarded as an emissary v., by which infection may enter cranial cavity. Ant. and post. ethmoidal vv. are tributes of superior ophthalmic v. draining to carvernous sinus. Innervation Olfactory n. (I) for olfaction Brr. of ophthalmic (V 1 ) and maxillary (V 2 ) for general sensation Secretomotor innervation of mucous glands by parasympathetic fibers. from facial n. (VII) through pterygopalatine ganglion, joining maxillary n. (V 2 ) Olfactory nerve [I] Receptors in olfactory epithelium > through perforations of cribriform plate > synapse with neurons in olfactory bulb of brain Branches from the ophthalmic nerve [V 1 ] Anterior and posterior ethmoidal nerves Originate from nasociliary n. of ophthalmic n.; the nerves travel with vessels Anterior ethmoidal n. supplies mucosa of ethmoidal air cells; nasal cavity, cranial cavity, and passes to external nose, terminates as external nasal n. Posterior ethmoidal n. mucosa of ethmoidal air cells, sphenoidal sinus Branches from the maxillary nerve [V 2 ] Pass through sphenopalatine foramen Posterior superior lateral nasal nerves lateral wall of nasal cavity Posterior superior medial nasal nerves from roof to septum Nasopalatine nerve medial wall of nasal cavity, through incisive canal, to roof of oral cavity Posterior inferior nasal nerves from greater palatine n. in palatine canal, through small foramina on the lateral wall of nasal cavity Small nasal nerve from anterior superior alveolar br. of infra-orbital n., to supply lateal wall near anterior end of inferior concha. Parasympathetic innervation Secretomotor innervation for mucous glands in nasal cavities and paranasal sinuses are carried by: Greater petrosal n. (pregangionic fibers) > synapse at pterygopalatine ganglion in pterygopalatine fossa > Brr. of maxillary n. (postganglionic fibers) > Glands G58-5

22 Sympathetic innervation Regulating blood flow in nasal mucosa Spinal cord level T1 > Spinal nerve > white ramus > Sympathetic trunk (preganglionic fibers) > synapse at superior cervical ganglion > Postganglionic fibers on internal carotid a. > Deep petrosal n. > enters pterygopalatine fossa > hike on brr. of maxillary n. > nasal cavity Lymphatics Anterior region of nasal cavity passing around nares > face > submandibular nodes Posterior region of nasal cavity and paranasal sinuses (retropharygeal nodes >) upper deep cervical nodes G58-6

23 ORAL CAVITY (pages ) Roof: hard and soft palates Floor: muscular diaphragm and tongue Lateral wall: cheeks merge anteriorly with lips surrounding oral fissure (the anterior opening of oral cavity) Posterior aperture: oropharyngeal isthmus (can be closed by soft palate and tongue) Separated by upper and lower dental arches (teeth and alveolar bones) into: Oral vestibule: Oral cavity proper Joint for elevating and depressing the mandible: temporomandibular joint Functions of oral cavity: Inlet for digestive system, processing food Manipulate the sounds Used for breathing and accessing by physician Multiple nerves innervate the oral cavity Predominantly by trigeminal nerve (CN V) Brr. of maxillary nerve (CN V 2 ): sensory for upper part of oral cavity Brr. of mandibular nerve (CN V 3 ): sensory for lower part of oral cavity Brr. of facial nerve (CN VII): taste (special afferent) for oral part and tongue, distributed by brr. of CN V Brr. of facial nerve (CN VII): parasympathetic fibers to glands within oral cavity, distributed by brr. of CN V T1 spinal nerve sympathetic fibers: synapse at superior cervical ganglion, along brr. of CN V or blood vessels All muscles of tongue: by hypoglossal nerve (CN XII); except palatoglossus (by CN X) All muscles of soft palate by vagus nerve (CN X), except tensor veli palatine (by CN V 3 ) Mylohyoid muscle by CN V 3 Skeletal framework Paired maxillae, palatine and temporal bones Unpaired mandible, sphenoid, and hyoid bone Cartilaginous part of pharyngotympanic tubes Maxillae Involved with the formation of the oral cavity Alveolar process Palatine processes: join at midline suture, forms anterior 2/3 of hard palate Incisive fossa: with a incisive canal extends to each of two nasal cavities Incisive canal: passed by greater palatine vessels and nasopalatine nerve Palatine bones L-shaped, horizontal plate and pyramid process form the roof of the oral cavity Posterior nasal spine: at the posterior margin of hard palate Greater palatine foramen: on horizontal plate as the inferior opening of palatine canal Palatine canal: transmitting greater palatine nerve and vessels from pterygopalatine fossa Lesser palatine foramen: inferior opening of lesser palatine canal, transmitting lesser palatine nerve and G59-1

24 vessels to soft palate Pyramidal process: between medial and lateral plates of pterygoid process of sphenoid bone Sphenoid bone Spine of sphenoid bone: posteromedial to foramen spinosum; its medial aspect is attached by tensor veli palatini Pterygoid hamulus: as a pulley of tensor veli palatine (Fig A, p.1107), and attached by pterygomandibular raphe (joined by superior constrictor of pharynx and buccinator muscle of cheek, and attaches inferiorly to mandible) (Fig , p.1092) Scaphoid fossa: medial to foramen ovale and lateral to the root of medial plate of pterygoid process; attached by tensor veli palatini Temporal bone Styloid process: attached by stylohyoid ligament (connects to lesser horn of hyoid bone) attached by styloglossus muscle on anterolateral aspect Petrous part of the temporal bone: by muscle associated to soft palate Stylomastoid foramen: posterior to the root of styloid process Inferior aspect of temporal bone (triangular roughened area): anteromedial to opening of carotid canal; attached by levator veli palatini muscle Cartilaginous part of the pharyngotympanic tube Between (anterior margin of the petrous part of the) temporal bone and (posterior margin of the greater wing of the) sphenoid bone Membranous lamina: inferolateral wall of the tube; attached by tensor veli palatini muscle Medial end of the tube opens into the nasopharynx Mandible Lower jaw; with left and right bodies fusing at midline (mandibular symphysis) and two rami Alveolar arch: anchors the lower teeth Mental foramen: on external surface Superior and inferior mental spines (genial spines): on the posterior surface of mandibular symphysis Mylohyoid line: on the internal surface of body, separates sublingual fossa and submanidbular fossa Retromolar triangle: attached by pterygomandibular raphe (which extends superiorly to pterygoid hamulus) (Fig A, p.1091) Mandibular foramen: on the medial surface of ramus; transmitted by inferior alveolar nerve and vessels Hyoid bone With body, greater horn, and lesser horn (attached by stylohyoid ligament); the key bone in the neck Walls: the cheeks Skin, fascia, skeletal (buccinator) muscle, oral mucosa Buccinator A facial expression muscle; connected with superior constrictor with pterygomandibular raphe Originates from pterygomandibular raphe, alveolar part of mandible, and alveolar process of maxilla Blends with orbicularis oris muscle and inserts to modiolus Innervated by buccal branch of the facial nerve; general sensation is by buccal branch of mandibular n. G59-2

25 Floor 1. Muscular diaphragm composed by paired mylohyoid mm. 2. Geniohyoid mm. above diaphragm 3. Tongue With salivary glands (sublingual glands and oral part of submandibular glands) and ducts Mylohyoid muscles Originates from mylohyoid line to midline raphe, and attaches to hyoid bone Functions: 1. supports floor of oral cavity 2. elevates and pulls forward hyoid bone 3. depress the mandible and open mouth Innervated by the nerve to mylohyoid, from inferior alveolar nerve of mandibular nerve (CN V 3 ) Geniohyoid muscles From inferior mental spines of mandible to hyoid bone Functions: 1. pulls hyoid bone and larynx forward during swallowing 2. depresses mandible to open mouth Innervated by a branch of cervical nerve C1 hiking on hypoglossal nerve (CN XII) Gateway into the floor of the oral cavity Triangular aperture: Formed by the posterior free border of mylohyoid muscle, superior constrictors, and inferior constrictors Infratemporal fossa and upper neck connect to oral cavity Structures passing through: tongue, hyoglossus, styloglossus, lingual a. and v., lingual, hypoglossal, and glossopharyngeal nerves, lymphatics, oral part of submandibular gland Tongue Apex of tongue, root of tongue (attach to mandible and hyoid bone) Anterior 2/3 (horizontal plane) and posterior 1/3 (vertical plane) are separated by terminal sulcus of tongue Foramen cecum of tongue: at the apex of V-shaped sulcus Thyroglossal duct extends from foramen cecum to thyroid gland in some people Papillae Filiform papillae: cone-shaped projections Fungiform papillae: rounder, along the margins Vallate papillae: 8 to 12 blunt-end cylindrical papillae, anterior to terminal sulcus of tongue Foliate papillae: linear folds of mucosa on the side of tongue Inferior surface of tongue Single frenulum of tongue: connect midline sagittal septum to the floor of oral cavity Ligual veins Fimbriated fold Pharyngeal surface With small lymph nodules of lymphoid tissue (lingual tonsils), but no papillae Muscles Intrinsic and extrinsic muscles in pairs are innervated by hypoglossal nerve (CN XII), EXCEPT palatoglossus muscle by vagus nerve (CN X) G59-3

26 Intrinsic muscles Superior longitudinal muscle Inferior longitudinal muscle Transverse muscle Vertical muscle Functions: 1. lengthening and shortening 2. curling and uncurling apex and edges 3. flattening and rounding surface Extrinsic muscles Functions: 1. protrude tongue 2. retract tongue 3. depress tongue 4. elevate tongue Genioglossus Origin: superior mental spine of mandible Insertion: hyoid bone and blends with intrinsic mm. Functions: 1. depress the central part of tongue 2. protrude the anterior part of tongue (stick the tongue out) Clinical: The abnormal CN XII (on the left) causes the tongue sticking toward left. Hyoglossus Origin: greater horn of hyoid Insertion: tongue Innervation: Hypoglossal n. (XII) An important landmark Lingual a. goes medial to hyoglossus m., and lateral to genioglossus m. Hypoglossal n. and lingual n. enter tongue lateral to hyoglossus m. Styloglossus Origin: anterior surface of styloid process Insertion: pass between superior, middle constrictors, and mylohyoid m. To the lateral surface of tongue, blend with hyoglossus m. Function: retract the tongue Innervation: hypoglossal n. Palatoglossus Origin: undersurface of palatine aponeurosis Insertion: lateral side of tongue Functions: elevate the back of tongue; move palatoglossal arch toward the midline; depress soft palate Facilitate closing of the oropharyngeal isthmus Innervation: Vagus n. (X) G59-4

27 Vessels Arteries Lingual artery External carotid a. > Lingual a. > Passes through aperture (superior and middle constrictors, mylohyoid m.) > Runs between hyoglossus and genioglossus mm. > Apex of tongue Supplies: tongue, sublingual gland, and oral mucosa of floor of oral cavity Veins Deep lingual veins On the undersurface of tongue; travels with hypoglossal n. to lateral surface of tongue; joins int. jugular v. Dorsal lingual vein With lingual a. runs between hyoglossus and genioglossus mm.; drains to int. jugular v. Innervation Glossopharyngeal nerve [IX] Taste sensation and general sensation from pharyngeal part of tongue Passes through jugular foramen > Posterior surface of stylopharyngeus m. > Passes through the aperture (superior and middle constrictors, mylohyoid m.) > Below inferior pole of palatine tonsil > Pharyngeal part of tongue and vallate papillae Lingual nerve General sensation from anterior two-third (oral part) of tongue; and mucosa on the floor of oral cavity and gingiva with lower teeth Trigeminal n. (V) > Mandibular n. (V3) > Foramen ovale > Infratemporal fossa > Passes through the aperture (superior and middle constrictors, mylohyoid m.) > Medial surface of mandible at last molar tooth deep to gingival (PALPATABLE) (Fig.258, p.1101) > Under submandibular duct > On lateral surface of hyoglossus m. > Carries: parasympathetic fibers and taste fibers from oral part of tongue (from facial n. VII) Facial nerve [VII] Special sensation (SA, special afferent): from tongue and oral cavity > Lingual n. > Chorda tympani n. > Facial N. (VII) Hypoglossal nerve [XII] All muscles of tongue are innervated by hypoglossal n., EXCEPT palatoglossus m. by vagus n. (X) Passes through hypoglossal canal > At angle of mandible turn forward > Crosses laterally to occipital, external, and internal carotid aa. > Lateral to the hyoglossus m > Carries: anterior ramus of C1 fiber > Gives superior root of ansa cervicalis > Gives: Branch to thyrohyoid m. Branch to geniohyoid m. Lymphatics Drain to deep cervical chain of nodes along internal jugular v. Pharyngeal part of tongue > Pharyngeal wall > Jugulodigastric node of deep cervical chain G59-5

28 Oral part of tongue > Mylohyoid m. > Submental and submandibular nodes > Deep cervical node Submental node between digastric mm. Submandibular node floor of oral cavity along inferior margin of mandible Tip of tongue > Mylohyoid m. > Submental nodes > Jugulodigastric node of deep cervical chain Salivary glands Most are small glands in submucosa or mucosa lining the tongue, palate, cheeks, and lips Three pairs of large glands: Parotid glands Margins of triangular-shaped trench: Sternocleidomastoid m., ramus of mandible, and external acoustic meatus to zygomatic arch Parotid duct crossed masseter m., penetrates buccinator m., open into oral cavity adjacent to 2 nd molar tooth It encloses external carotid a., retromandibular v., and origin of facial n. (VII) Submandibular glands Hook-shaped, larger part below mylohyoid m.; smaller part loops around post. margin of mylohyoid m. Submandibular duct opens at sublingual caruncle (papilla). beside frenulum of tongue. Sublingual glands Smallest, almond shaped, lateral to submandibular duct, on medial surface of mandible, Numerous minor sublingual ducts open to crest of sublingual fold on the floor of oral cavity Vessels Parotid gland supplied by brr. of external carotid a.; drained to ext. jugular v.; lymph drains to parotid node, then to superficial and deep cervical nodes Submandibular and sublingual glands by brr. of facial and lingual aa.; drained to facial and lingual vv.; lymph drains to submandibular node, then to jugulo-omohyoid node Innervation Parasympathetic All salivary glands in oral cavity are innervated by facial n. (VII), whose brr. joining maxillary (V2) and mandibular (V3) nn. Parotid gland is by glossopharyngeal n. (IX), whose br. joining mandibular n. (V3) Greater petrosal nerve For salivary glands above oral fissure, mucus gland in nose, and lacrimal gland Preganglionic parasympathetic fibers in facial n. > Greater petrosal n. > Synapse at pterygopalatine ganglion > Postganglionic fibers > Maxillary n. (V2) > Palatine nn. > Roof of oral cavity Chorda tympani For salivary glands below oral fissure, including the small glands on the floor of oral cavity Preganglionic parasympathetic fibers in facial n. > Chorda tympani n. > Joining lingual n. > Synapse at submandibular ganglion > Postganglionic fibers > Submandibular and sublingual glands G59-6

29 Roof--palate Anterior hard palate and posterior soft palate Hard palate Respiratory mucosa covers upper surface as the floor of nasal cavities Oral mucosa covers lower surface as the roof of oral cavity Bone palatine processes of maxillae; horizontal plate of palatine bones Adjacent with upper alveolar arch and soft palate Transverse palatine folds (palatine rugae) and longitudinal ridge (palatine raphe), which ends as incisive papilla anteriorly Soft palate A valve that: Depress to close oropharyngeal isthmus Elevate to separate nasopharynx from oropharynx Uvula at the center of posterior free margin of soft palate Muscles of the soft palate Four muscles that move the soft palate: Tensor veli palatini m. and levator veli palatini m. (descend into palate) Palatoglossus m. and palatopharyngeus m. (ascend into palate) Musculus uvulae associated with uvula All muscles of palate are innervated by vagus n. (X), EXCEPT tensor veli palatini m. by mandibular n. (V 3 ) 1. Tensor veli palatini and the palatine aponeurosis Muscular part (vertical) descends on the lateral surface of medial pterygoid plate; at the pterygoid hamulus merges as a tendon, and turns medially to form fibrous part (horizontal) as palatine aponeurosis Functions: tenses soft palate; opens pharygotympanic tube (during yawning or swallowing) 2. Levator veli palatini descends from the under surface of the petrous portion of temporal bone; (Fig , p. 1107) attaches to upper surface of palatine aponeurosis Function: elevates the soft palate and close pharyngeal isthmus between masopharyngx and oropharynx Innervation: by vagus n. through pharyngeal br. to pharyngeal plexus Test: Ask patient say Ah ; the palate should elevate at midline; the palate deviates away from abnormal side Posterior View 3. Palatopharyngeus Palatopharyngeal arches: on the pharyngeal wall; posterior and medial to palatoglossal arches G59-7

30 Functions: Innervation: 1. depress palate; move arches toward medline; close oropharyngeal isthmus 2. elevate pharynx during swallowing vagus n. though pharyngeal br. to pharyngeal plexus 4. Palatoglossus From inferior surface of palatine aponeurosis to lateral surface of tongue Underline the palatoglossal arches; define lateral margin of oropharyngeal isthmus Palatine tonsil is between palatoglossal and palatopharyngeal arches Function: depress palate; move palatoglossal arches toward midline, elevate back of tongue; close oropharyngeal isthmus Innervatoin: vagus n. though pharyngeal br. to pharyngeal plexus 5. Musculus uvulae From posterior nasal spine, dorsal to palatine aponeurosis; to connective tissue of uvula Function: retracts uvula; helps closing pharyngeal isthmus Innervation: vagus n. though pharyngeal br. to pharyngeal plexus Vessels Arteries 1. Ascending palatine artery and palatine branch 1-1. Ascending palatine artery: ext. carotid a. > facial a. > ascending palatine a. > soft palate 1-2. Palatine branch of ascending pharyngeal a.: ext. carotid a. > ascending pharyngeal a. > palatine a. > soft palate 2. Greater palatine artery 2-1. Greater palatine artery: ext. carotid a. > maxillary a. > greater palatine a Lesser palatine branch: ext. carotid a. > maxillary a. > lesser palatine a. Veins Drain to: pterygoid plexus of veins in infratemproal fossa > Pharyngeal plexus > Facial v. Lymphatics Deep cervical nodes Innervation Greater and lesser palatine nn. and nasopalatine n. General sensation: maxillary n. (V 2 ) Parasympathetic nerve fibers: from brr. of facial n Sympathetic nerve fibers: from T1 spinal cord to blood vessels mainly 1. Greater and lesser palatine nerves Pterygopalatine fossa > Pterygoid canal > Palate at: Greater palatine foramen > hard palate and gingival (as far as premolar teeth) G59-8

31 Lesser palatine foramen > soft palate 2. Nasopalatine nerves Pterygopalatine fossa > Sphenopalatine foramen > Roof of nasal cavity > Medial wall > Incisive canal > Gingiva and mucosa of incisors and canine Oral fissure and lips Lips: transitional lining of mucosa internally, to skin externally; with thin skin (vermilion) Philtrum vertical shallow groove by fusion of medial nasal processes Median labial frenulum connects lip to gum Orbicularis oris m. sphincter of orifice Contours of oral fissure buccinator, levator labii superioris, zygomaticus major and minor, levator anguli oris, depressor labii inferioris, depressor anguli oris and platysma Oropharyngeal isthmus Lateral palatoglossal arches Superior soft palate Inferior sulcus terminalis of tongue Causes of closure: 1. elevation of back of tongue 2. depression of palate 3. medial movement of palatoglossal arches 4. medial movement of palatopharyngeal arches Teeth and gingivae Alveolar arches mandible (below) and maxillary (above) Gingivae (gums): muscosa covering teeth and adjacent alveolar bone Teeth: Lateral > Molar > Premolar > Canine > Incisor > Midline Teeth (number) M P C I I C P M Superior alveola M P C I I C P M Inferior alveola Adult teeth (32) Baby teeth (20) (Deciduous teeth) Vessels Arteries (from maxillary a. directly or indirectly) 1. Inferior alveolar artery Maxillary a. > Inferior alveolar a. > Mandibular canal > Incisor and mental brr. > Mental foramen 2. Anterior and posterior superior alveolar arteries Maxillary a. > Posterior superior alveolar a. > Small foramina on posterolateral surface of maxilla > Canals in bone > Molar and premolar teeth Maxillary a. > Pterygopalatine fossa > Infraorbital a. > Inferior orbital fissure > Orbit > Infraorbital groove > Infraorbital canal > Anterior superior alveolar a. > Incisor and canine teeth 3. Gingival supply G59-9

32 Side facing oral vestibule or cheek Side facing tongue or palate Inferior alveolar a. > buccal gingiva of lower teeth Lingual a. of tongue > lingual gingiva of lower teeth Ant. and post. superior alveolar aa. > buccal gingival of upper teeth Nasopalatine a. > palatine gingival of incisor and canine teeth Greater palatine a. > palatine gingival of molar and premolar teeth Veins Upper and lower teeth > Superior and inferior alveolar vv. > Pterygoid plexus > 1. Maxillary v. > Retromandibular v. > Jugular system 2. Emissary v. > Cavernous sinus (Infection originating from teeth > cranial cavity) Anterior teeth > Tributes of facial v. > Facial v. Teeth > Mental foramen > Facial v. Gingivae > Facial v. > Pterygoid plexus of vv. Lymphatics Teeth and gingivae > Submandibular, submental nodes > Deep cervical nodes Innervation By brr. of trigeminal nerve (V) 1. Inferior alveolar nerve Mandibular n. (V3) > Inf. alveolar n. > All lower teeth > divides: 1-1. Incisive br. > First premolar, canine, incisor teeth; buccal gingiva 1-2. Mental n. > mental foramen > Chin and lower lip 2. Anterior, middle, and posterior superior alveolar nerves Maxillary n. (V2) > Anterior, middle, and posterior sup. alveolar nn. > Upper teeth 2-1. Maxillary n. > Post. sup. alveolar n. in pterygopalatine fossa > Pterygomaxillary fissure > Superior alveolar plexus > Maxillary sinus and molar teeth 2-2. Maxillary n. > Infraorbital n. > Middle sup. alveolar n. > Superior alveolar plexus > Premolar teeth 2-3. Maxillary n. > Infraorbital n. > Anterior sup. alveolar n. > Superior alveolar plexus > Canine and incisor teeth 3. Innervation of gingivae By trigeminal n. (V) Brr. of maxillary n. (V2) > Anterior, middle, and posterior sup. alveolar nn. > Buccal gingivae of upper teeth Brr. of maxillary n. (V2) > Nasopalatine n. > Palatine gingivae of upper incisor and canine teeth Brr. of maxillary n. (V2) > Greater palatine n. > Palatine gingivae of upper premolar and molar teeth Brr. of mandibular n. (V3) > Mental br. > Buccal gingivae of lower incisor, canine, and premolar teeth Brr. of mandibular n. (V3) > Buccal n. > Buccal gingivae of lower molar teeth Brr. of mandibular n. (V3) > Lingual n. > Lingual gingivae of all lower teeth G59-10

33 LARYNX (pp. 1052~1069) above pharynx and oropharyngeal isthmus below trachea Functions valve to lower respiratory tract and instrument producing sound Composition: Unpaired cartilages cricoid, thyroid, and epiglottis Paired cartilages arytenoids, corniculate, and cuneiform Fibroelastic membrane and intrinsic muscles Swallowing: move larynx upward and forward, closes laryngeal inlet and opens esophagus Motor and sensory by CN X (vagus n.) Laryngeal cartilages 1. Cricoid cartilage Posterior lamina of cricoid cartilage; anterior arch of cricoid cartilage Facets Superolateral surface for arytenoid cartilages Lateral surface for inferior horn of thyroid cartilage 2. Thyroid cartilage Largest one, fusion by right and left laminae, with palpable laryngeal prominence (Adam s apple) Angle between two laminae 90 o (for men); 120 o (for women) Superior thyroid notch palpable Inferior thyroid notch less distinct Superior horn connects to greater horn of hyoid bone through a ligament Inferior horn connects with cricoid cartilage Oblique line for attachments of extrinsic mm. of larynx (sternothyroid, thyrohyoid, and inferior constrictor) Superior and inferior tubercles 3. Epiglottis Leaf-shaped cartilage, connects with thyroid cartilage via thyro-epiglottic ligament Epiglottic tubercle on inferior part of posterior surface 4. Arytenoid cartilages Base of arytenoid cartilage; apex of arytenoid cartilage Base articulates with lamina of cricoid cartilage Apex articulates with corniculate cartilage Medial surface faces each other Anterolateral surface depression for vocalis muscle and vestibular ligament Vocal process anterior angle of base of arytenoid cartilage, for vocal ligament Muscular process lateral angle, for posterior and lateral crico-arytenoid mm. 5. Corniculate On the apex of arytenoid cartilage G60-1

34 6. Cuneiform Club-shaped in fibroelastic membrane (between arytenoid and epiglottis cartilages) Extrinsic ligaments 1. Thyrohyoid membrane A tough fibroelastic ligament, between superior margin of thyroid cartilage and hyoid bone Apertures on lateral surfaces for superior laryngeal aa., nn., and lymphatics Lateral thyrohyoid ligaments thickening in the posterior borders Median thyrohyoid ligament thickening in midline Triticeal cartilage in lateral thyrohyoid ligament 2. Hyo-epiglottic ligament From midline of epiglottis to body of hyoid 3. Cricotracheal ligament From lower border of cricoid cartilage to upper border of 1 st tracheal cartilage Intrinsic ligaments Fibro-elastic membrane of larynx In two parts: lower cricothyroid ligament; upper quadrangular membrane 1. Cricothyroid ligament (cricovocal membrane, cricothyroid membrane) From arch of cricoid cartilage to a upper free margin (from thyroid cartilage to vocal process of arytenoids cartilage) Vocal ligament thickening of the free margin covered in the vocal fold Median cricothyroid ligament on midline between inferior notch of thyroid and arch of cricoid Perforation at median cricothyroid ligament establishes emergency airway. However, occasionally pyramidal lobe of thyroid gland is there. 2. Quadrangular membrane between lateral margin of epiglottis and anterolateral surface of arytenoid, and corniculate cartilages Vestibular ligament free lower margin in vestibular fold A gap is between vestibular ligament and vocal ligament. Laryngeal joints 1. Cricothyroid joints Between inferior horn of thyroid cartilage and cricoid cartilage, Allow thyroid cartilage moving forward and tilting downward, and thus tightening vocal ligaments 2. Crico-arytenoid joints Between the base of arytenoid and cricoid cartilages Movement: rotation of arytenoid, and sliding of arytenoid cartilages toward or away from each other Abduction and adduction of vocal ligaments. Cavity of the larynx Lined with mucosa, supported by fibro-elastic membrane of larynx and laryngeal cartilages Superior aperture (laryngeal inlet) posterior to tongue, can be closed by epiglottis G60-2

35 Ant. border mucosa covering epiglottis Lat. border mucosal folds (aryepiglottic folds), and underlying cuneiform and corniculate cartilges Post. border muscosal fold as a interarytenoid notch Inferior opening lumen of trachea Division into three major regions 1. Vestibule Vestibular folds vestibular ligaments and soft tissues 2. Laryngeal ventricles middle part of laryngeal cavity Vocal folds vocal ligaments and soft tissues 3. Infraglottic space Laryngeal ventricles and saccules b/w vestibular folds and vocal folds Laryngeal saccule extension of ventricle, with mucous glands in wall Rima vestibuli and rima glottidis Rima vestibuli triangular-shaped opening b/w vestibular folds Rima glottidis narrower triangular-space b/w vocal folds, with interarytenoid fold as the base Both rima vestibuli and rima glottidis can be opened and closed. Intrinsic muscles Acting to cricothyroid and crico-arytenoid joints Adjusting the distance b/w epiglottis and arytenoid cartilage Pull vocal ligaments Forcing soft tissues with quadrangular membranes and vestibular ligaments toward midline 1. Cricothyroid muscles Oblique part Origin: arch of cricoid cartilage Insertion: inferior horn of thyroid cartilage Straight part Origin: arch of cricoid cartilage Insertion: posteroinferior margin of thyroid lamina Function: pull thyroid cartilage forward and rotate it down, lengthen vocal folds Innervation: by superior laryngeal n. of CN X (other intrinsic mm. are by recurrent laryngeal n.) 2. Posterior crico-arytenoid muscles Origin: posterior surface of cricoid lamina Insertion: muscular processes of arytenoid cartilages Function: abduct and externally rotate arytenoid cartilages; open rima glottides, primary abductors of vocal folds Innervation: recurrent laryngeal brr. of CN X 3. Lateral crico-arytenoid muscles Origin: upper surface of arch of cricoid cartilage Insertion: muscular processes of arytenoid cartilages Function: adduct and internally rotate arytenoid cartilages G60-3

36 Innervation: recurrent laryngeal brr. of CN X 4. Transverse arytenoids muscle A single muscle connects two arytenoid cartilages Function: adduct arytenoid cartilages Innervation: recurrent laryngeal brr. of CN X 5. Oblique arytenoids muscles Two oblique arytenoid mm. Origin: from muscular process of a arytenoid cartilage Insertion: the apex of the other arytenoid cartilage; some fibers continue to aryepiglottic folds as aryepiglottic part Function: narrow the laryngeal inlet, constricting the distance b/w arytenoids cartilages and epiglottis Innervation: recurrent laryngeal brr. of CN X 6. Vocalis Lateral to and parallel with vocal ligaments Origin: Lateral surface of vocal processes, and anterolateral depression of arytenoid cartilages Insertion: thyroid cartilage Function: adjust the tension of vocal folds Innervation: recurrent laryngeal brr. of CN X 7. Thyro-arytenoid muscles Broad flat mm. lateral to fibro-elastic quadrangular membrane of larynx, laryngeal ventricle, and saccule Insertion: thyro-epiglottic part into aryepiglottic fold, to the margin of epiglottis Function: sphincter of vestibule; pull arytenoid cartilage forward; pull epiglottis toward arytenoid cartilage Innervation: recurrent laryngeal brr. of CN X Functions of the larynx Sphincter of lower respiratory tract; producing sound; change the dimensions of rima glottis, rima vestibule, vestibule, and laryngeal inlet 1. Respiration Quiet respiration: laryngeal inlet, vestibule, rima vestibule, and rima glottidis Force inspiration: posterior crico-arytenoid mm. laterally rotate the arytenoid cartilages, increase the diameter of laryngeal airways 2. Phonation Arytenoid cartilages and vocal folds are adducted; air is forced to pass through closed rima glottidis to produce sound 3. Effort closure Air is retained in thoracic cavity to stabilize the trunk, or to increase the intra-abdominal pressure. Rima glottidis, rima vestibuli and lower vestibule are completely closed. 4. Swallowing Rima glottidis, rima vestibuli and vestibule are closed. Epiglottis closes or narrows laryngeal inlet. Up and forward movement of the larynx opens esophagus. G60-4

37 Prevents the solid and liquid from entry into airway; facilitates the movement through piriform fossae into esophagus. Vessels Arteries 1. External carotid a. superior thyroid a. superior laryngeal a. passes through thyrohyoid membrane with superior laryngeal n. larynx 2. Subclavian a. Thyrocervical trunk inferior thyroid a. ascends in the groove b/w esophagus and trachea deep to margin of inferior constrictor m. passes b/w thyroid and cricoid cartilages Veins 1. Superior laryngeal v. superior thyroid v. internal jugular v. 2. Inferior laryngeal v. inferior thyroid v. left brachiocephalic v. Lymphatics 1. Above vocal folds follows superior laryngeal a. deep cervical nodes associated with bifurcation of common carotid a. 2. Below vocal folds deep nodes associated with inferior thyroid a., or nodes associated with front of cricothyroid ligament Nerves Sensory and motor innervation by CN X brr. 1. Superior laryngeal nerves Inferior vagal ganglion descends medial to int. carotid a. divides at level of greater horn of hyoid: 1. External laryngeal n. along lateral wall of pharynx, to supply and penetrate the inferior constrictor of pharynx and to supply cricothyroid m. 2. Internal laryngeal n. penetrates thyrohyoid membrane for the sensory of laryngeal cavity down to vocal folds 2. Recurrent laryngeal nerves Sensory to laryngeal cavity below level of vocal folds Motor to all intrinsic mm. of larynx except for cricothyroid Left recurrent laryngeal n. originates at arch of aorta in thorax; right at right subclavian a. in the root of neck. Both ascend in the grooves b/w esophagus and trachea deep to the margin of inferior constrictor of pharynx enter larynx G60-5

38 EAR (pp. 953~971) organ of hearing and balance External ear part attached to lateral aspect of head; canal leading inward Middle ear cavity in the lateral part of petrous part of temporal bone; a membrane separating from ext. ear; a narrow tube connecting to pharynx Internal ear cavities within the petrous part of temporal bone b/w middle ear and int. acoustic meatus; with receptors to motion and position Sound to external ear mechanical signals in middle ear electrical signals in internal ear brain External ear 1. Auricle with cartilage covered by skin, to capture the sound, helix with lobule; concha of auricle; external acoustic meatus; tragus; antitragus; antihelix Muscles Intrinsic mm. between cartilaginous parts of auricle Extrinsic mm. anterior, superior, and posterior auricular mm., from skull or scalp to auricle Motor innervation CN VII Innervation Sensory innervation: Outer more superficial surfaces by great auricular and lesser occipital nn. (from cervical plexus) and auriculotemporal n. (of CN V 3 ) Deeper parts of auricle by brr. from CN VII and X Vessels External carotid a. 1. posterior auricular a., 2. superficial temporal a., 3. occipital a. vv. run along with aa. Lymph anteriorly to parotid nodes, posteriorly to mastoid nodes, possibly upper deep cervical nodes 2. External acoustic meatus from the deepest part of concha to the tympanic membrane, an inch (2.5 cm) wall with cartilage (lateral 1/3) and bone (medial 2/3), and covered by skin with hairs and modified sweat glands secreting cerumen To examine pulling auricle superiorly, posteriorly, and laterally Innervation Sensory inputs auriculotemporal n. (CN V 3 ); auricular br. of CN X,; minorly from CN VII 3. Tympanic membrane tilting inferiorly and anteriorly; through a fibrocartilaginous ring attaching to tympanic part of temporal bone Its internal surface attached by lower end of the handle of malleus. Umbo (center) of tympanic membrane; cone (reflection) of light; G61-1

39 Lateral process of malleus; anterior and posterior malleolar folds; pars flaccida thin part above the folds pars tensa rest part Innervation Sensory of skin (outer surface) primarily by CN V; additionally by CN VII and X Sensory of mucous membrane (inner surface) by CN IX Middle ear Air-filled, mucous membrane-lined, in temporal bone, b/w tympanic membrane (lateral) and lateral wall of inner ear (medial); two parts 1. tympanic cavity, 2. epitympanic recess Communicates with: 1. mastoid area (posterior), 2. nasopharynx (through pharyngotympanic tube, anterior) Boundaries Tegmental wall Tegmen tympani roof, separates middle ear from middle cranial fossa Jugular wall Floor, separates middle ear from jugular fossa Small aperture on medial border for tympanic branch from glossopharyngeal n. (IX) Membranous wall Lateral wall tympanic membrane Mastoid wall Lower part of posterior wall separates tympanic cavity (middle ear) from mastoid air cells Aditus to the mastoid antrum locates on posterior wall of epitympanic recess. Pyramidal eminence passed by tendon of stapedius m. Opening for chorda tympani n. (br. of facial n.) Anterior wall Lower part separates tympanic cavity from internal carotid a. Superiorly, opening of pharyngotympanic tube, and opening for canal of tensor tympani muscle Labyrinthine wall Separates middle and internal ear; with promontory produced by basal coil of cochlea Tympanic plexus nerve plexus covering the promontory; consists of: A. Tympanic br. of glossopharyngeal n., with: 1. Parasympathetic nerve fibers to form lesser petrosal n. > across ant. surface of petrous part of temporal bone > middle cranial fossa > foramen ovale > otic ganglion 2. Sensory nerve fibers (for the sensation of mucous membrane of middle ear, mastoid area, and pharyngotympanic tube) B. Brr. from internal carotid plexus, with sympathetic nerve fibers Oval window attached by base of stapes (footplate) Round window attached by secondary tympanic membrane Prominence of facial canal passed by facial n. (VII) Prominence of lateral semicircular canal G61-2

40 Mastoid area Epitympanic recess > Aditus > Mastoid antrum (mastoid air cells) Separates from middle cranial fossa by tegmen tympani Infection of mastoid area spreads from middle ear. Pharyngotympanic tube Connects middle ear with nasopharynx (opening at posterior to inferior meatus of nasal cavity) Bony part lateral one-third Cartilaginous part medial two-thirds Vessels External carotid a. > Ascending pharyngeal a. External carotid a. > Maxillary a. > Middle meningeal a. & Artery of pterygoid canal Drains to pterygoid plexus of veins Innervation Glossopharyngeal n. (IX) > Tympanic br. > Tympanic plexus > Mucous membrane lining pharyngotympanic tube, tympanic cavity, internal surface of tympanic membrane, mastoid antrum, and mastoid cells Auditory ossicles Tympanic membrane > Malleus > Incus > Stapes > Oval window 1. Malleus Head articulates to incus Neck Anterior process attaches to anterior wall Lateral process attaches to anterior and posterior malleolar folds of tympanic membrane Handle attaches to tympanic membrane 2. Incus Body articulates with malleus Short limb to upper posterior wall of middle ear Long limb with the end articulating with stapes 3. Stapes Head articulates with incus Two limbs attach to oval base Base fits into oval window on medial wall of middle ear Muscles associated with the ossicles 1. Tensor tympani Originates in a bony tube above the pharyngotympanic tube; Inserts to handle of malleus; Innervated by mandibular n. (V 3 ); Function: tenses the tympanic membrane, reduces the vibration G61-3

41 2. Stapedius Originates inside the pyramidal eminence Inserts to the neck of stapes Innervated by br. of facial n. (VII) Function: responds to loud noises, prevents excessive oscillation of stapes Vessels 1. Maxillary a. > Tympanic br. 2. Occipital a. or posterior auricular a. > Mastoid br. 3. Smaller brr. from: middle meningeal a., ascending pharyngeal a., a. of pterygoid canal, and tympanic br. (from internal carotid a.) Venous blood to pterygoid plexus of veins, and superior petrosal sinus Innervation Mucous membrane lining middle ear (including mastoid area and pharyngotympanic tube) is by: Tympanic plexus locates on the mucous membrane covering promontory; and is formed by: Glossopharyngeal n. (IX) > Jugular foramen (exits skull) > Tympanic br. > Re-enters skull > Middle ear Internal carotid plexus > Caroticotympanic nn. > Middle ear Tympanic plexus (containing preganglionic parasympathetic ff.) > Lesser petrosal n. > through a hiatus on the anterior surface of petrous part of temporal bone (exits middle ear) > Floor of middle cranial fossa > Foramen ovale (exits skull) > Otic ganglion Internal ear A series of bony cavities (bony labyrinth) and membranous ducts and sacs (membranous labyrinth) Organ of hearing: cochlear duct; by cochlear n. of vestibulocochlear n. (VIII) Organ of balance: semicircular ducts, utricle, and saccule; by vestibular n. of vestibulocochlear n. (VIII) Bony labyrinth Central part: vestibule Posterosuperior: semicircular canals Anterior: cochlea Semicircular canals Anterior, posterior, and lateral semicircular canals; each is at right angle to the other two, and with an ampulla Cochlea Twists into 2 1 / 2 ~2 3 / 4 turns around modiolus, which is entered by cochlear n. The lamina of modiolus (spiral lamina) circles around modiolus. Base of cochlea (posteromedial) and apex (anterolateral) Cochlear duct separates scala vestibule and scala tympani, which connect at apex through helicotrema. Scala vestibule continuous with vestibule G61-4

42 Scala tympani continuous with secondary tympanic membrane covering round window Cochlear canaliculus connects scala tympani (filled with endolymph) with subarachnoid space Membranous labyrinth A continuous system of ducts (semicircular and cochlear ducts) and sacs (utricle and saccule) Cochlear duct (ant.) > Saccule > Utricle (middle in vestibule) > Semicircular ducts (post.) Organs of balance 3 semicircular ducts, utricle and saccule Utricle, saccule, and endolymphatic duct Semicircular ducts (three), each with dilated ampulla, connect to utricle Utriculosaccular duct connects utricle with saccule. Endolymphatic duct, branching from utriculosaccular duct, expands into endolymphatic sac, an extradural pouch on the posterior surface of petrous part of temporal bone (in posterior cranial fossa). Sensory receptors Macula of utricle, macula of saccule, and cristae of ampullae in semicircular ducts Organs of hearing Cochlear duct Spiral duct with triangular-shaped cross section; filled with endolymph; with spiral ligament as outer wall, vestibular membrane as roof, and basilar membrane as floor Vessels Bony labyrinth Maxillary a. > Anterior tympanic br. Posterior auricular a. > Stylomastoid br. Middle meningeal a. > Petrosal br. Membranous labyrinth Basilar a. > (Anterior inferior cerebellar a.) > Labyrinthine a. > Internal acoustic meatus > divides into: 1. Cochlear br. > through modiolus > cochlear duct 2. Vestibular brr. > Vestibular apparatus Venous drainage: Vestibular and cochlear vv. > join into Labyrinthine v. > Inferior petrosal sinus or Sigmoid sinus Innervation Lateral surface of brainstem between pons and medulla > CN VIII > Internal acoustic meatus > divides: Vestibular n. > Vestibular ganglion > Sup. and inf. parts > Semicircular ducts, utricle, and saccule Cochlear n. > Base of cochlea > Modiolus > Base of lamina > Spiral ganglion > Receptors in spiral organ Facial nerve [VII] in the temporal bone Internal acoustic meatus > Facial canal > Geniculate ganglion > Stylomastoid foramen Branches Greater petrosal nerve Facial n. > Preganglionic parasympathetic ff. > Branches from facial n. at geniculate ganglion > Hiatus for the greater petrosal n. (ant. surface of petrous part of temporal bone) > Floor of middle cranial fossa > Foramen lacerum > Pterygoid canal > Pterygopalatine ganglion G61-5

43 Nerve to stapedius and chorda tympani Facial n. > Internal acoustic meatus > Facial canal > Posterior wall of tympanic cavity > gives: Nerve to stapedius > Stapedius m. Chorda tympani n. > enters middle ear from posterior wall > passes between malleus and incus > through petrotympanic fissure > Infratemporal fossa > joins lingual n. Transmission of sound Sound wave > External acoustic meatus > Tympanic membrane > Handle of malleus (medially) > Head of malleus (laterally) > Head of incus (laterally) > Long process of incus (medially) > Stapes (medially) > Base of stapes (medially) > Oval window Wave of perilymph in scala vestibule > through cochlea > Helicotrema > Scala tympani > Vibration of basilar membrane > Stimulation of receptor cells in spiral organ > Secondary tympanic membrane (on round window) Tensor tympani m. (malleus) and/or stapedius m. (to stapes) dampens the vibration of ossicles. G61-6

44 Cranial Nerves Gross Anatomy, Cranial Nerves Cranial Nerves I. Olfactory nerve VII. Facial nerve II. Optic nerve VIII. Vestibulocochlear nerve III. Oculomotor nerve IX. Glossopharyngeal nerve IV. Trochlear nerve X. Vagus nerve V. Trigeminal nerve XI. Accessory nerve VI. Abducent nerve XII. Hypoglossal nerve CN I Olfactory Nerve Smell receptors from olfactory epithelium (in nasal cavity) Olfactory nerves through cribriform plate of ethmoid bone Olfactory bulb (a part of brain) Olfactory tract CN II Optic Nerve Visual receptors from neural layer of retina Optic nerve Optic chiasm Optic tract Lateral geniculate body Optic radiation Visual cortex in occipital lobe CN III Oculomotor Nerve Midbrain between two cerebral peduncle Oculomotor nerve through cavernous sinus through superior orbital fissure Motor levator palpebral superioris, sup. rectus, med. rectus, inf. rectus, inf. oblique mm. Preganglionic parasympathetic fibers Synapse at ciliary ganglion Short ciliary nerve Sphincter pupillae and ciliary muscles CN IV Trochlear Nerve Posterior aspect of midbrain Trochlear nerve through cavernous sinus through superior orbital fissure Superior oblique m. CN V Trigeminal nerve From lateral angle of pons (in posterior cranial fossa) Trigeminal ganglion in middle cranial fossa A. Ophthalmic nerve (CN V 1 ) through superior orbital fissure 1. Lacrimal nerve a. Sensory skin of upper eyelid, conjunctiva b. Carries parasympathetic fibers from CN VII (facial nerve) 2. Frontal nerve sensation from upper eyelid, scalp, and forehead Sensory supraorbital nerve Sensory supratrochlear nerve 3. Nasociliary nerve Short ciliary nerve G62-1

45 Gross Anatomy, Cranial Nerves Sensory Postganglionic parasympathetic fibers from ciliary ganglion, to ciliary muscle and sphincter pupillae Postganglionic sympathetic fibers from superior cervical ganglion, to dilator pupillae Long ciliary nerve Sensory from cornea and iris (2) Postganglionic sympathetic fibers from superior cervical ganglion, to dilator pupillae Infratrochlear nerve (1) Sensory from eyelids, conjunctiva, skin of nose, lacrimal sac Anterior and posterior ethmoidal nerves Sensory from mucous membrane of sphenoidal and ethmoidal sinuses Nasal cavity Skin on the bridge of nose (external nasal n.) B. Maxillary nerve (CN V 2 ) Infraorbital nerve a. Sensory to skin and maxillary teeth and gum Zygomaticotemporal nerve Sensory Communicating branch carrying parasympathetic fibers to lacrimal nerve Zygomaticofacial nerve Posterior superior alveolar nerve Sensory to posterior maxillary teeth, maxillary sinus, Anterior superior alveolar nerve a. Sensory to anterior maxillary teeth C. Mandibular nerve (CN V 3 ) Nerve to masseter Nerves to temporalis Nerve to lateral pterygoid muscle Nerve to medial pterygoid muscle Buccal nerve Sensory to skin on cheek and oral mucosa in cheek Inferior alveolar nerve through mandibular foramen to mandibular teeth and gum through mental foramen Mental nerve Mylohyoid n. Innervates mylohyoid m. Lingual nerve joined by chorda tympani to submandibular ganglion to tongue Sensory nerve general sensation to anterior 2/3 of tongue Sensory nerve special sensation for gustation to anterior 2/3 of tongue Chorda tympani (CN VII) Carries preganglionic parasympathetic nerve fibers from chorda tympani (CN VII) synapse at submandibular ganglion Secretomotor to submandibular and sublingual glands Auriculotemporal nerve sensory to the skin of temporal region G62-2

46 Gross Anatomy, Cranial Nerves carries postganglionic parasympathetic fibers from otic ganglion (from CN IX) Parotid gland CN VI Abducent Nerve Junction of pons and medulla Abducentnerve through cavernous sinus through superior orbital fissure Lateral rectus m. CN VII Facial Nerve From junction of pons and medulla Facial nerve (includes nervus intermedius) through internal acoustic meatus Geniculate ganglion (ganglion for taste sensation) Greater petrosal nerve (with parasympathetic nerve fibers from nervus intermedius) on the floor of middle cranial fossa through foramen lacerum under the base of skull Joined by deep petrosal nerve (sympathetic fibers from nervous plexus around carotid arteries) Nerve of pterygoid canal Pterygopalatine ganglion (parasympathetic fibers synapse at there; sympathetic fibers pass through) Pterygopalatine nerves Maxillary nerve Zygomatic nerve Zygomaticotemporal nerve Communicating branch Lacrimal nerve Lacrimal gland Stapedius muscle Chorda tympani (with preganglionic parasympathetic nerve fibers from nervus intermedius) join lingual nerve Synapse at submandibular ganglion Postganglionic parasympathetic fibers Submandibular and sublingual glands Taste buds of anterior 2/3 of tongue Gustatory sensation Chorda tympani Geniculate ganglion Facial nerve Facial nerve through stylomastoid foramen Temporal, zygomatic, buccal, mandibular, and cervical branches Motor to facial expression muscles CN VIII Vestibulocochlear Nerve From junction of pons and medulla Vestibulocochlear nerve through internal acoustic meatus Vestibular nerve Vestibular ganglion Vestibule Saccule Macula Hair cells Vestibule Utricle Macula Hair cells Semicircular canals Semicircular ducts Cristae ampullares Cochlear nerve Spiral ganglion Cochlea Cochlear duct Organ of Corti Hair cells CN IX Glossopharyngeal Nerve Rootlets from lateral upper medulla Glossopharyngeal nerve Pharyngeal branch (sensory nerve) to mucosa of pharynx Tympanic nerve Preganglionic parasympathetic nerve fibers Promontory in the middle ear Tympanic plexus Lessor petrosal nerve on the floor of middle cranial fossa through foramen ovale Synapse at otic ganglion (medial to the mandibular nerve) Postganglionic parasympathetic fibers join auriculotemporal nerve (of CN V 3 ) Secretomotor to parotid gland G62-3

47 Gross Anatomy, Cranial Nerves Sensory fibers tympanic cavity, auditory tube, mastoid antrum and air cells, inner surface of ear drum Carotid sinus branch (sensory nerve) Stylopharyngeus muscle (motor nerve) Tonsilar branch (sensory nerve) Taste sensation and general sensation to posterior 1/3 of tongue (sensory nerve) CN X Vagus Nerve Rootlets from lateral medulla Vagus nerve through jugular foramen Meningeal branch to dura mater (sensory nerve) Auricular nerve (sensory nerve) Pharyngeal branch to muscles of pharynx and most of soft palate (except tensor veli palatini by CN V 3 ) Enter carotid sheath to give rise to Pharyngeal nn. sensory to valleculae of pharynx (for general sensation and gustation) Sup. laryngeal nn. sensory to larynx; motor to cricothyroid muscle Recurrent laryngeal nn. motor to intrinsic laryngeal mm. Cardiac nn. slow the heart rate Through diaphragm Esophageal branches Gastric branches Pancreatic branches Branches to gallbladder Branches to intestine (Auerbach s plexus) as far as left colic flexure G62-4