Head & Neck Anatomical Dissection Course 8/14/07

Transcription

1 Head & Neck Anatomical Dissection Course 8/14/07 Jason E. Portnof DMD, MD Chief Resident Division of Dentistry, Oral & Maxillofacial Surgery New York Presbyterian Hospital Weill Cornell Medical College

2 Muscles of Facial Expression

3 Muscles of Mouth, Lips, Cheek Circumoral Muscles Orbicularis oris Sphincter of oral aperture. Dilator Muscles Levator labii superioris alaque nasi Elevator of upper lip and alae of nose. Mentalis Raises skin of chin. Mentalis Buccinator Aids mastication by pressing the cheeks against the molar teeth during chewing.

4 Muscles of Mouth, Lips, Cheek Depressor anguli oris Levator anguli oris Zygomaticus major Zygomaticus minor Levator labii superioris Deprssor labii inferioris Risorius Platysma

5 Lymphatic Drainage of Lips Lymph from upper lip and lateral parts of lower lip drains to submandibular LN Lymph from middle part of lower lip drains to submental LN

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7 Facial Nerve Main trunk emerges from Skull Base at Stylomastoid Foramen. Enters the Parotid Gland. 2 trunks emerge from the parotid and radiate anteriorly. Temporofacial Cervicalfacial 5 Terminal Branches Temporal Zygomatic Buccal Marginal Mandibular Cervical

8 Boundaries: Oral Cavity Extends from lips anteriorly to palatoglossal folds posteriorly (i.e., anterior to oropharynx). Structures: Tongue Teeth Alveolar Bone The oral vestibule is the space between the cheeks and the teeth/gums.

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11 Pharynx Nasopharynx Oropharynx Hypopharynx (Laryngopharynx)

12 Pharyngeal Wall 5 Layers Mucosa Submucosa Pharyngobasilar fascia Muscular Layer Buccopharyngeal fascia

13 Oropharynx Boundaries of the oropharynx: Anteriorly: : junction of the hard and soft palate and circumvallate papillae of the tongue base. Superiorly: imaginary line drawn from the hard palate to the posterior oropharyngeal wall. Inferiorly: pharyngoepiglottic folds. Structures: Tonsils, tonsillar fossa, tonsillar pillars, tongue base and a portion of the posterior pharyngeal wall.

14 Oropharynx Structures Folds (or faucial pillars) Folds in the mucous lining of the oral cavity formed by the underlying palatoglossal and palatopharyngeal muscles. Palatoglossal folds run from the wall of the oral cavity to the approximate junction of the posterior 1/3 and anterior 2/3 of the tongue.

15 Oropharynx Structures Tonsils Palatine (faucial( faucial) ) tonsils are located immediately posterior to the palatoglossal folds and anterior to the palatopharyngeal folds; inferior to the soft palate and superior to the tongue; and a medial to the superior constrictors, the styloglossus,, and the glossopharyngeal nerve (IX). Nasopharyngeal (pharyngeal) tonsils are located on the posterior aspect of the nasopharynx. When enlarged these are referred to as the adenoids. Lingual tonsils are lymphoid tissue in the tongue. Continuous with the inferior pole of the palatine tonsil.

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17 Nasopharynx Soft palate separates nasopharynx from oropharynx.

18 Adenoids Pharyngeal tonsils, nasopharyngeal tonsils Mass of lymphoid tissue situated in the roof of the nasopharynx

19 Palate Vasculature: (Bilateral) Greater palatine artery Branch of descending palatine artery Lesser palatine artery Branch of descending palatine artery Ascending palatine artery Branch of Facial Artery Veins of palate Tributaries of pterygoid venous plexus

20 Innervation of Palate Sensory nerves of palate are branches of pterygopalatine ganglion Greater palatine nerve supplies gingiva, mucous membrane, and glands of hard palate Nasopalatine nerve supplies mucous membrane of anterior part of hard palate Lesser palatine nerves supply soft palate

21 Hard Palate Palatine processes of maxilla and horizontal plates of the palatine bones. Periosteum of the hard palate is continuous into the soft palate (palatine aponeurosis), and is the insertion site of the palatal muscles. Landmarks Incisive Foramen Greater Palatine Foramen Lesser Palatine Foramen

22 Soft Palate Muscle Action Innervation Levator veli palatini elevates the soft palate Pharyngeal Plexus Tensor veli palatini Palatoglossus Palatopharyngeus Tenses the palate, opens mouth of auditory tube Elevates posterior tongue, draws soft palate into tongue Tenses soft palate. Pulls the pharynx superiorly, anteriorly, medially Mandibular Nerve V3 (medial pterygoid nerve) Pharyngeal Plexus Pharyngeal Plexus Musculus Uvulae Shortens uvula, pulls it superiorly Pharyngeal Plexus

23 Trigeminal Nerve

24 CN 5 Trigeminal Nerve Originates in Pons. Both motor and sensory nerve. Ophthalmic and maxillary nerves are purely sensory. The mandibular nerve has both sensory and motor functions. Three large trunks originate from the semilunar ganglion (Gasserian( ganglion). Exit Skull at 3 different foramina V1: Superior Orbital Fissure V2: Foramen Rotundum V3: Foramen Ovale

25 Trigeminal Nerve Branches Opthalmic Nerve (V1) Nasociliary nerve Supraorbital nerve Lacrimal nerve Frontal nerve Supratrochlear nerve Infratrochlear nerve Maxillary Nerve (V2) Zygomatic nerve Posterior superior alveolar nerve Middle superior alveolar nerve Anterior superior alveolar nerve Infraorbital nerve Greater Palatine nerve Nasopalatine nerve Mandibular Nerve (V3) Auriculotemporal nerve Lingual nerve Buccal nerve Inferior alveolar nerve (Mental nerve)

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27 CN V Dermatome Distribution

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30 Maxilla Each half of the fused maxilla consists of: The body of maxilla Four processes Zygomatic process Frontal process Alveolar process Palatine process Infraorbital foramen

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32 Mandible Condyle Sigmoid Notch Ramus Angle External Oblique Ridge Symphysis Mental Foramen

33 Mandible Sphenomandibular Ligament Stylomandibular Ligament

34 Muscle Attachments of the Muscles of Mastication Temporalis Masseter Lateral Pterygoid Medial Pterygoid Suprahyoid Muscles Geniohyoid Mylohyoid Digastric (anterior belly) Stylohyoid Genioglossus Mandible

35 Muscle Temporalis Origin Floor of temporal fossa, deep surface of temporal fascia. Insertion Coroniod process, anterior border of mandibular ramus. Function Elevates and retrudes mandible. Masseter Superficial portion- anterior 2/3 of inferior border of zygomatic arch. Deep portion- medial surface of zygomatic arch. Lateral surface of ramus, coronoid process, and angle of mandible. Elevates, protrudes, and retrudes mandible. Lateral Pterygoid Superior head- infratemporal surface of sphenoid greater wing. Inferior head- lateral surface of lateral pterygoid plate. Anterior portion of condylar neck and TMJ capsule. Protrusion of mandible. Lateral movements of mandible. Medial Pterygoid Deep head- Medial surface of lateral pterygoid plate; pyramidal process of palatine bone. Superficial head- maxillary tuberosity. Medial surface of ramus, inferior to mandibular foramen. Protrudes and elevates mandible. Lateral movements of mandible

36 Muscle Geniohyoid Origin Inferior genial tubercle on inner surface of mandibular symphysis. Insertion Body hyoid bone. Function Elevates tongue, FOM, and hyoid. Mylohyoid Line from last molar to mandibular symphysis. (mylohyoid line) Raphe and body of hyoid bone. Elevates base of hyoid bone. Raises floor of mouth and tongue. Digastric Posterior belly- mastoid notch (temporal bone). Anterior belly- digastric fossa (mandible). Intermediate tendon attached to hyoid bone by fibrous loop. Depresses mandible, Elevates the hyoid bone. Stylohyoid Posterior border of the styloid process. Body of hyoid bone. Elevates base of tongue and hyoid bone.

37 Accessory Muscles to the Muscles of Mastication Platysma Buccinator Posterior neck musculature Sternocleidomastoid Trapezius Intrinsic neck muscles

38 Temporomandibular Joint (TMJ)

39 TMJ Classification: Ginglymoarthrodial Joint Translational (gliding) movement Rotational (hinging) movement Synovial Joint

40 TMJ Anatomy Articulation between the condyle of the mandible and the squamous portion of the temporal bone (TMJ fossa). Articular disc lies between condyle and fossa. Condyles Elliptically shaped. Long axis oriented mediolaterally. Articular Surface of Temporal Bone Functional aspect of TMJ. Dense fibrous connective tissue. Concave : Articular fossa (Glenoid Fossa, Mandibular Fossa) Convex : Articular eminence (tubercle)

41 Articular Disc Dense fibrocartilagenous connective tissue. Avascular and aneural. Nutrition of chondrocytes with the movement of synovial fluid is essential for maintenance of structure and function. Biconcave structure is a three dimensional space filler between the two convex surfaces of the condyle and articular eminence. Separates joint into inferior and superior joint spaces. Varies in thickness. Intermediate zone- thin (center of disc) Anterior and Posterior Bands- thick Posterior band is thicker and is attached to retrodiscal tissues (bilaminar( zone, posterior attachment). Anterior band is attached to the capsular ligament, the lateral pterygoid muscle, and the condyle. Retrodiscal Tissues Loose connective tissues. Vascular and Innervated.

42 TMJ Disorders

43 TMJ Reconstruction

44 Boundaries Infratemporal Fossa Laterally: Ramus of Mandible Medially: Lateral Pterygoid Plate Anteriorly: : Posterior Aspect of Maxilla Posteriorly: : Tympanic Plate and the Mastoid and Styloid Processes of the Temporal Bone Superiorly: Inferior Surface of the Greater Wing of the Sphenoid Bone Inferiorly: Where the Medial Pterygoid Muscle Attaches to the Mandibular Angle

45 Infratemporal Fossa Contents: Inferior part of the temporal muscle Lateral and medial pterygoid muscles Maxillary artery Pterygoid venous plexus Mandibular,, Inferior alveolar, lingual, buccal, and chorda tympani nerves, and otic ganglion

46 Arteries of Face Artery Origin Course Distribution Facial External Carotid Artery Ascends deep to submandibular gland, rounds around inferior border of mandible and enters face Muscles of facial expression and face Inferior Labial Facial artery near angle of mouth Runs medially in lower lip Lower lip and chin Superior Labial Facial artery near angle of mouth Runs medially in upper lip Upper lip and ala and septum of nose Lateral nasal Facial artery as it ascends alongside nose Passes to ala of nose Skin on ala and dorsum of nose Angular Terminal branch of facial artery Passes to medial angle (canthus( canthus) ) of eye Superior part of cheek and lower eyelid

47 Arteries of Face Artery Origin Course Distribution Superficial temporal Smaller terminal branch of external carotid artery Ascends anterior to ear to temporal region and ends in scalp Facial muscles and skin of frontal and temporal regions Transverse facial Superficial temporal artery within parotid gland Crosses face superficial to masseter and inferior to zygomatic arch Parotid gland and duct, mauscles and skin of face Mental Terminal branch of Inferior alveolar artery Emerges from mental foramen and passes to chin Facial muscles and skin of chin

48 Maxillary Artery Arises from External Carotid Artery Arises posterior to neck of mandible Passes anteriorly (deep to neck of condyle)- 1 st part Passes superficial or deep to the lateral pterygoid muscle- 2 nd part Passes through pterygomaxillary fissure to enter infratemporal fossa- 3 rd part

49 st (Mandibular)) Part 1 st Deep auricular artery to external acoustic meatus Anterior tympanic artery to tympanic membrane Middle meningeal artery to dura mater and calvaria Accessory meningeal arteries to the cranial cavity Inferior alveolar artery to mandible, gingiva, teeth

50 2nd (Pterygoid Part) Deep temporal arteries,, anterior and posterior (supply temporal muscle) Pterygoid arteries (supply pterygoid muscles) Masseteric artery (supplies deep surface of masseter muscle) Buccal artery (supplies buccinator muscle)

51 rd (Pterygopalatine)) Part 3 rd Posterior superior alveolar artery supplies maxillary molar and premolar teeth, lining of maxillary sinus, gingiva Infraorbital artery supplies inferior eyelid, lacrimal sac, side of nose, superior lip Descending palatine artery supplies maxillary gingiva,, palatine glands, mucous membrane of roof of mouth Artery of pterygoid canal supplies superior part of pharynx, pharyngotympanic tube, tympanic cavity Pharyngeal artery supplies roof of pharynx, sphenoidal sinus, inferior part of pharyngotympanic tube Sphenopalatine artery supplies lateral nasal wall, nasal septum, paranasal sinuses

52 Veins of Face Vein Origin Termination Area Drained Facial Continuation of angular vein past inferior margin of orbit Internal jugular vein opposite or inferior to hyoid bone Anterior scalp and forehead, eyelids, external nose, anterior cheek, lips, chin, submandibular gland Deep facial Pterygoid venous plexus Enters posterior aspect of facial vein Infratemporal fossa (most areas supplied by maxilary artery)

53 Veins of Face Superficial temporal Begins from a widespread plexus of veins on side of scalp and along the zygomatic arch Joins the maxillary vein posterior to the neck of the mandible to form the retromandibular vein Side of scalp, superficial aspect of temporal muscle, external ear Retromandibular Formed anterior to the ear by union of superficial temporal and maxillary veins Unites with posterior auricular vein to form external jugular vein Parotid gland and masseter muscle

54 Salivary Glands Parotid Gland Sublingual Gland Submandibular Gland

55 Parotid Gland Stensen s Duct Pierces the buccal fat, buccopharyngeal fascia and buccinator muscle. Opens into the vestibule of the mouth opposite the maxillary 2nd molar tooth.

56 Floor of Mouth Sublingual Salivary Glands Sublingual folds (plica( sublingualis). Run anteroposterior alongside the frenulum,, one per side, converging just anterior to the root of the frenulum. Overly the sublingual salivary glands from which numerous ducts travel and open onto the top of each fold. Each gland does not have a single duct, but many which open directly into the oral cavity.

57 Floor Of Mouth Submandibular Gland Duct emanates from the posterior aspect of gland and travels deep to mylohyoid on the superficial surface of the hyoglossus and genioglossus muscles. At the anterior most extent of each sublingual fold, the opening for the duct of the submandibular salivary gland. (Wharton s s Duct)

58 Buccal Fat Pad Encapsuled mass of fat in the cheek on the outer side of the buccinator muscle Found in the space between the masseter muscle and the external surface of the buccinator

59 Pterygomandibular Raphe Tendinous band of the buccopharyngeal fascia Attached to: Hamulus of the medial pterygoid plate. Posterior end of the mylohyoid line of the mandible. Boundaries: medial surface is covered by the mucous membrane of the mouth. lateral surface is separated from the ramus of the mandible by adipose tissue. posterior border attaches to the superior pharyngeal constrictor muscle. anterior border attaches to buccinator.

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61 Tongue

62 Surface Anatomy Tongue Sulcus terminalis V-shaped line (with the point facing posteriorly) ) that separates the anterior 2/3 and posterior 1/3 of the tongue. At the point, a shallow pit named the foramen cecum is present (original location of thyroid diverticulum). Located posterior to a row of vallate papillae.

63 Lingual Tonsils Rounded masses of lymphatic tissue that cover the posterior region of the tongue. Located on the dorsal surface at the base of the tongue.

64 Anterior 2/3 Innervation Tongue Lingual Nerve (V3)- general sensation Chorda typmani (CN 7)- taste Posterior 1/3 Lingual branch glossopharyngeal nerve (CN IX)- general sensation, taste Lingual branch facial nerve- taste Internal laryngeal branch Vagus- general sensation, taste

65 Motor Innervation Tongue Palatoglossus- pharyngeal plexus (CN XI, CNX) All other muscles- CN XII (hypoglossal)

66 Extrinsic Muscles of Tongue Genioglossus Hyoglossus Styloglossus Palatoglossus

67 Genioglossus Muscle Origin: Superior part mental spine of mandible. Insertion: Dorsum of tongue, body of hyoid bone. Innervation: : CN 12 (Hypoglossal Nerve). Depresses tongue, posterior part pulls tongue anteriorly for protrusion

68 Hyoglossus Muscle Origin: Body and greater horn of hyoid Insertion: Side and inferior aspect of tongue Innervation: : CN XII Depresses and retracts tongue

69 Styloglossus Muscle Origin: Styloid process and stylohyoid ligament Insertion: Side and inferior aspect of tongue Innervation: : CN 12 Retracts tongue and draws it up to create trough for swallowing

70 Palatoglossus Muscle Origin: Palatine aponeurosis of soft palate Insertion: Side of tongue Innervation: : Cranial root of CN XI via pharyngeal branch of CN X and pharyngeal plexus Elevates posterior part of tongue

71 Intrinsic Muscles Tongue Superior Longitudinal Inferior Longitudinal Transverse Vertical

72 Tongue Vasculature Lingual artery (from external carotid artery) Dorsal lingual arteries Deep lingual artery Sublingual artery All veins terminate in the Internal Jugular Vein Dorsal lingual veins Deep lingual veins (ranine( veins) Sublingual vein

73 Lymph Drainage from Tongue Lymph from posterior 1/3 Superior deep cervical LN Lymph from medial part of anterior 2/3 Inferior deep cervical LN Lymph from lateral anterior 2/3 submandibular LN Apex submental LN Posterior 1/3 & area near midline drain bilaterally

74 Periodontal Anatomy Periodontium Gingiva Periodontal Ligament (PDL) Cementum Alveolar and supporting bone

75 Healthy Gingiva Evaluate Color, Contour, Tone and Consistency of Gingival Tissue

76 Gingiva Masticatory mucosa which cover the alveolar process and surround the cervical portion of teeth. Composed of connective tissue and epithelium. Epithelium can be divided into three histological distinct areas: Oral epithelium Continuous with epithelial lining of the attached gingiva. Composed of keratinized stratified squamous epithelium. Sulcular epithelium Non-keratinized Junctional epithelium Attached to the tooth by hemidesmosomes. Non-keratinized. Larger cells with increased intercellular spaces.

77 Gingival Fibers Composed of type I collagen. Support the gingiva and attach it to the tooth and alveolar bone. Gingival fibers are continuous with the periodontal ligament. Designated by their orientation. Dentogingival fibers Dentoperiosteal fibers Circular fibers Alveologingival fibers Transseptal fibers

78 Principal Fibers of the Periodontal Ligament (PDL) Bundles of collagen fibers grouped according to the direction they extend from the cementum of the root to the alveolar bone. Horizontal Fibers Alveolar Crest Fibers Oblique Fibers Apical Fibers Interradicular Fibers

79 Tooth Anatomy

80 Universal/National System for Permanent (Adult) Dentition (1-32) Maxillary Arch (1-16) 16) Mandibular Arch (17-32) 3 Molars, 2 Premolars, 1 Canine, 1 Lateral Incisor, 1 Central Incisor in each arch quadrant

81 The Universal/National System for the Primary (Baby) Dentition A T Upper case letters A through T No Premolars in the Primary Dentition

82 Sequence of Eruption Deciduous central/ lateral incisiors (6-9 9 months) First deciduous molar ( months) Deciduous canine ( months) Second deciduous molar (24-30 months First permanent molar, central/ lateral incisors (6-9 9 years) Permanent canine, first/ second premolars, second molar ( years) Permanent third molar (17-21 years)

83 Curve of Spee Curvature of the mandibular occlusal plane beginning at the tip of the lower cuspid and following the buccal cusps of the posterior teeth, continuing to the terminal molar. Anterior-posterior curve

84 Lateral curve Curve of Wilson

85 Occlusion Combination of Curve of Spee and Curve of Wilson create the Occlusal Plane Centric Relation Position Anatomic relationship of the TMJ joint. Muscles of Mastication are at rest.

86 Occlusion

87 Angle Classification of Occlusion Class I patient s I profile is characterized as normal. Class II patient s profile is deficient in chin length and characterized as a retruded (retrognathic) profile. Class III patient s profile is excessive in chin length and characterized as protruded (prognathic( prognathic) profile.

88 Overjet / Overbite: Horizontal and Vertical Overlap

89 Occlusal Surface of Teeth Canine= Cuspid Premolar= Bicuspid

90 Normal Cusp Relationship of Posterior Teeth Mesiofacial cusp of the maxillary first molar occludes in the facial groove of the mandibular first molar

91 Orthognathic Surgery Jaw Realignment and Correction of Facial Profile Maxillary (one multiple piece osteotomies) Mandibular osteotomies

92 Orthognathic Surgery

93 Cephalometric Analysis

94 Cepahalometric Analysis

95 Lefort 1 Osteotomy

96 BSR Mandibular ramus sagittal split osteotomy is the most common technique used for mandibular advancement

97 BSR

98 Bilateral Sagittal Split Ramusotomy

99 Vertical Ramus Osteotomy Vertical ramus osteotomy can be used to set the mandible posteriorly.

100 Genioplasty Anterior Mandibular Horizontal Osteotomy

101 Facial Trauma

102 Facial Trauma

103 R Zygomatic Arch Fracture

104 Distribution of Mandible Fractures

105 Mandible Fracture

106 Tx Mandible Fx

107 ORIF Mandible Fx

108 LeFort Fractures

109 Wisdom Teeth

110 Wisdom Teeth (3 rd Molars)

111 Extraction of Mandibular 3 rd Molar Tooth

112 Extraction of Mandibular 3 rd Molar Tooth

113 Thank You!