FACE CN V & VII PAROTID GLAND. Jacek Baj, MD, PhD Department of Human Anatomy

Transcription

1 FACE CN V & VII PAROTID GLAND Jacek Baj, MD, PhD Department of Human Anatomy

2 THE FACE THE SCALP The scalp is composed of five layers: Skin ConnecAve Assue Aponeurosis Loose connecave Assue Pericranium

3 THE FACE THE SCALP The scalp is composed of five layers: SKIN: thin, except in the occipital region, containing many sweat and sebaceous glands and hair follicles. CONNECTIVE TISSUE: richly vascularized subcutaneous layer that is well supplied with cutaneous nerves. APONEUROSIS (epicranial aponeurosis): the broad, strong, tendinous sheet that covers the calvaria and serves as the ajachment for muscle LOOSE AREOLAR TISSUE: a sponge-like layer including potenaal spaces that may distend with fluid as a result of injury or infecaon. PERICRANIUM: a dense layer of connecave Assue that forms the external periosteum of the neurocranium

4 THE MUSCLES OF FACE AND SCALP Innervated by the facial nerve CN VII, which emerges from the stylomastoid foramen DerivaAves of the 2nd pharyngeal arch Insert into the skin to provide movement Most muscles of facial expression are localized around the facial orifices There is no deep fascia along the face Facial nerve CN VII supplies the muscles of facial expression CN VII

5 THE MUSCLES OF FACE AND SCALP MUSCLES OF SCALP, FOREHEAD, AND EYEBROWS OCCIPITOFRONTALIS Frontal belly Occipital belly ORIGIN Skin of eyebrows Lateral part of superior nuchal line of occipital bone and mastoid process of temporal bone INSERTION Into galea aponeuroaca Into galea aponeuroaca Frontal belly moves scalp forward and raises the eyebrows Occipital belly moves galea aponeuroaca backward INNERVATION Facial nerve [CN VII]

6 THE MUSCLES OF FACE AND SCALP MUSCLES OF MOUTH, LIPS, AND CHEEKS THE ORBICULARIS ORIS controlling entry and exit through the oral fissure consists of two parts INNERVATION: Facial nerve CN VII

7 THE MUSCLES OF FACE AND SCALP THE BUCCINATOR ajaches laterally to the alveolar processes of the maxillae and mandible, opposite the molar teeth, and to the pterygomandibular raphe, inseraon - angle of mouth (modiolus); orbicularis oris THE BUCCINATOR The paroad duct pierces the buccinator. MUSCLES OF MOUTH, LIPS, AND CHEEKS INNERVATION: Facial nerve CN VII THE BUCCINATOR The paropd duct pierces the buccinator. InnervaAon CN VII Passing deep to the mandible Occupies a deeper, more medially placed plane than the other facial muscles Is more closely related to the buccal mucosa than to the skin of the face

8 THE MUSCLES OF FACE AND SCALP MUSCLES OF MOUTH, LIPS, AND CHEEKS THE PTERYGOMANDIBULAR RAPHE The pterygomandibular raphe, tendinous thickening of the buccopharyngeal fascia separaang and giving origin to the superior pharyngeal constrictor posteriorly. It is connected with: buccinators middle pharyngeal constrictor pterygoid proccess pterygoid hamulus

9 THE MUSCLES OF FACE AND SCALP MUSCLES OF MOUTH, LIPS, AND CHEEKS THE PLATYSMA ORIGIN: Subcutaneous Assue of infraclavicular and supraclavicular regions INSERTION: Base of mandible; skin of cheek and lower lip; angle of mouth (modiolus); orbicularis oris INNERVATION: Facial nerve CN VII THE PLATYSMA Cutaneous muscle occupying an extensive area of the neck. It extends from the lower part of the face to the upper thorax

10 THE MUSCLES OF FACE AND SCALP MUSCLES OF MOUTH, LIPS, AND CHEEKS Depressor anguli oris Depressor labii inferioris Mentalis Risorius ZygomaAcus major ZygomaAcus minor Levator labii superioris Levator labii superioris alaeque nasi Levator anguli oris INNERVATION: Facial nerve CN VII

11 THE MUSCLES OF FACE AND SCALP MUSCLES OF ORBITAL OPENING ORBICULARIS OCULI Palpebral part Orbital part CORRUGATOR SUPERCILII is deep to the eyebrows and the orbicularis oculi muscle and is acave when frowning. INNERVATION: Facial nerve CN VII

12 THE MUSCLES OF FACE AND SCALP MUSCLES OF THE NOSE NASALIS PROCERUS DEPRESSOR SEPTI NASI INNERVATION: Facial nerve CN VII

13 THE NERVES OF FACE AND SCALP All motor nerves are from the facial nerve CN VII and supply the muscles of facial expression Sensory nerves of the face are derived mainly from the 3 divisions of the trigeminal nerve CN V (V 1, V 2, V 3 ) Some sensory branches are from the cervical plexus The muscles of the facial expression the facial nerve CN VII The sensory innervaaon cutaneous innervaaon of the face is by branches of the trigeminal nerve [CN V] The facial nerve CN VII supplies the muscles of facial expression Sensory nerves of the face are derived mainly from the 3 divisions of the trigeminal nerve CN V (V 1, V 2, V 3 ) Muscles of maspcapon are innervated by CN V3 (mandibular nerve, branch of the trigemnal nerve)

14 THE NERVES OF FACE AND SCALP The muscles of the facial expression the facial nerve CN VII The facial nerve (CN VII) exits between the pons and olive and has two divisions: the motor root and the intermediate nerve, passes with the vesabulocochlear nerve into the petrous temporal bone. The larger motor root (facial nerve proper) innervates the muscles of facial expression. The smaller intermediate nerve carries taste, parasympatheac, and somaac sensory fibers. The facial nerve CN VII traverses: the posterior cranial fossa internal acousac meatus facial canal stylomastoid foramen of the temporal bone and paroad gland

15 THE NERVES OF FACE AND SCALP The muscles of the facial expression the facial nerve CN VII The facial nerve [CN VII] exits the posterior cranial fossa through the internal acousac meatus. It passes through the temporal bone, along the medial wall of the tympanic cavity, giving off several branches, and emerges from the base of the skull through the stylomastoid foramen, located between the mastoid and the styloid processes. The larger motor root (facial nerve proper) innervates the muscles of facial expression. The smaller intermediate nerve carries taste, parasympatheac, and somaac sensory fibers.

16 THE NERVES OF FACE AND SCALP THE FACIAL NERVE The muscles of the facial expression the facial nerve CN VII Sensory: special sensory (taste) and somaac (general) sensory. Motor: somaac (branchial) motor and visceral (parasympatheac) motor. It also carries propriocepave fibers from the muscles it innervates. Nuclei: The motor nucleus of the facial nerve is a branchiomotor nucleus in the ventrolateral part of the pons. The cell bodies of the primary sensory neurons are in the geniculate ganglion.

17 THE NERVES OF FACE AND SCALP The muscles of the facial expression the facial nerve CN VII THE FACIAL NERVE THE BRANCHES While traversing the temporal bone within the facial canal, CN VII gives rise to the: Greater petrosal nerve: emerging from the anterior wall of the petrous part of the temporal bone. It incorporates parasympatheac and sensory fibers, and penetrates the covering plate of the foramen lacerum lateral to the internal caroad artery where it is joined by the deep petrosal nerve. Nerve to the stapedius: slender branch supplying the stapedius muscle. Chorda tympani nerve: nerve bundle with parasympatheac fibers for the submandibular gland and sensory fibers from the taste buds occupying the anterior 2/3 of the tongue.

18 THE NERVES OF FACE AND SCALP The muscles of the facial expression the facial nerve CN VII THE FACIAL NERVE THE BRANCHES CN VII emerges from the cranium via the stylomastoid foramen: at this point it gives off the posterior auricular branch - this branch passes upward, behind the ear, to supply the occipital belly of the occipitofrontalis muscle of the scalp and the posterior auricular muscle of the ear the main stem of the facial nerve then gives off another branch, which innervates the posterior belly of the digastric muscle and the stylohyoid muscle at this point, the facial nerve enters the deep surface of the paropd gland; once in the paroad gland, the main stem of the facial nerve usually divides into upper (temporofacial) and lower (cervicofacial) branches they may branch further or take part in an anastomoac network and form the paropd plexus, which gives rise to the five terminal motor branches: temporal, zygomapc, buccal, marginal mandibular, and cervical

19 THE NERVES OF FACE AND SCALP THE FACIAL NERVE The muscles of the facial expression the facial nerve CN VII Temporal branches exit from the superior border of the paroad gland to supply muscles in the area of the temple, forehead, and supra-orbital area. ZygomaPc branches emerge from the anterosuperior border of the paroad gland to supply muscles in the infra-orbital area, the lateral nasal area, and the upper lip. Buccal branches emerge from the anterior border of the paroad gland to supply muscles in the cheek, the upper lip, and the corner of the mouth. Marginal mandibular branches emerge from the anteroinferior border of the paroad gland to supply muscles of the lower lip and chin. Cervical branches emerge from the inferior border of the paroad gland to supply the platysma.

20 THE NERVES OF FACE AND SCALP THE FACIAL NERVE The muscles of the facial expression the facial nerve CN VII SOMATIC (BRANCHIAL) MOTOR The facial nerve supplies mainly the muscles of facial expression and auricular muscles. It also supplies the posterior bellies of the digastric, stylohyoid, and stapedius muscles. VISCERAL (PARASYMPATHETIC) MOTOR CN VII provides presynapac parasympatheac fibers to: the pterygopalapne ganglion via the greater petrosal nerve for innervaaon of the lacrimal glands, and to the submandibular ganglion chorda tympani for innervaaon of the sublingual and submandibular salivary glands. SOMATIC (GENERAL) SENSORY Some fibers from the geniculate ganglion supply a small area of the skin of the concha of the auricle, close to external acousac meatus. SPECIAL SENSORY (TASTE) Fibers carried by the chorda tympani join the lingual nerve to convey taste sensaaon from the anterior two thirds of the tongue and sog palate.

21 THE NERVES OF FACE AND SCALP During development a cranial nerve becomes associated with each of the pharyngeal arches. The trigeminal nerve [CN V] innervates facial structures derived from the first arch. The facial nerve [CN VII] innervates facial structures derived from the second arch.

22 THE NERVES OF FACE AND SCALP The trigeminal nerve CN V FUNCTIONS: SomaAc (general) sensory and somaac (branchial) motor to derivaaves of the 1st pharyngeal arch. NUCLEI: There are 4 trigeminal nuclei one motor (motor nucleus of trigeminal nerve) and three sensory (mesencephalic, principal sensory and spinal nuclei of trigeminal nerve). The trigeminal nerve exits laterally from the pons with two groups of fibers (large posterior sensory and small anterior motor roots of trigeminal nerve), supplies the masacaaon muscles and provides sensory innervaaon to the face. The trigeminal nerve CN V is the principal somaac (general) sensory nerve for the head (face, teeth, mouth, nasal cavity, and dura mater of the cranial cavity). The sensory root leads to the trigeminal ganglion. The motor root runs parallel to the sensory root, then bypasses the ganglion and becomes part of the mandibular nerve (CN V3)

23 THE NERVES OF FACE AND SCALP The trigeminal nerve CN V TRIGEMINAL (SEMILUNAR, GASSERIAN) GANGLION Semilunar ganglion that is equivalent to a spinal ganglion. It is located in an outpockeang of the subarachnoid space (cavum trigeminale) above the foramen lacerum at the medial, anterior border of the petrous part of the temporal bone. The ophtalmic V1 and maxillary V2 divisions are wholly SENSORY. The mandibular V3 division is largely sensory, but also receives the motor fibres that supply the muscles of maspcapon. The trigeminal nerve is divided as follows: ophthalmic V 1 division: exits the skull via the superior orbital fissure maxillary V 2 division: exits the skull via the foramen rotundum mandibular V 3 division: exits the skull via the foramen ovale

24 THE NERVES OF FACE AND SCALP The trigeminal nerve CN V The branches of the ophthalmic nerve V1 that innervate the face include: the supra-orbital and supratrochlear nerves (from frontal nerve), which leave the orbit superiorly and innervate the upper eyelid, forehead, and scalp; the infratrochlear nerve, which exits the orbit in the medial angle to innervate the medial half of the upper eyelid, the skin in the area of the medial angle, and the side of the nose; the lacrimal nerve, which exits the orbit in the lateral angle to innervate the lateral half of the upper eyelid and the skin in the area of the lateral angle; and the external nasal nerve, which supplies the anterior part of the nose.

25 THE NERVES OF FACE AND SCALP The trigeminal nerve CN V The trigeminal nerve is divided as follows: maxillary V 2 division: exits the skull via the foramen rotundum It passes through the foramen rotundum to the pterygopalaane fossa and subsequently through the inferior orbital fissure into the orbit. The trigeminal nerve is divided as follows: maxillary V 2 division: exits the skull via the foramen rotundum Its somaac (general) sensory fibers are generally distributed to skin and mucous membranes associated with the upper jaw.

26 THE NERVES OF FACE AND SCALP The trigeminal nerve CN V The branches of the MAXILLARY NERVE V 2 that innervate the face include: a small zygomapcotemporal branch, which exits the zygomaac bone and supplies a small area of the anterior temple above the zygomaac arch; a small zygomapcofacial branch, which exits the zygomaac bone and supplies a small area of skin over the zygomaac bone; and the large infra-orbital nerve, which exits the maxilla through the infra-orbital foramen and immediately divides into mulaple branches to supply the lower eyelid, cheek, side of the nose, and upper lip

27 THE NERVES OF FACE AND SCALP The trigeminal nerve CN V THE PTERYGOPALATINE (PARASYMPATHETIC) GANGLION is associated with this division of CN V, involved in innervaang the lacrimal gland and glands of the nose and palate. OPHTHALMIC NERVE (CN V1) - SENSORY ONLY MAXILLARY NERVE (CN V2) - SENSORY ONLY MANDIBULAR NERVE (CN V3) - SENSORY AND MOTOR

28 THE NERVES OF FACE AND SCALP The trigeminal nerve CN V THE SOMATIC (BRANCHIOMOTOR) BRANCHES OF THE TRIGEMINAL NERVE THE MANDIBULAR NERVE V3 ONLY (!): masseter temporalis medial and lateral pterygoids mylohyoid anterior belly of digastric tensor tympani

29 THE NERVES OF FACE AND SCALP THE FACIAL NERVE Buccal branches emerge from the anterior border of the paroad gland to supply muscles in the cheek, the upper lip, and the corner of the mouth. VS. THE MANDIBULAR NERVE The branches of the mandibular nerve V 3 innervaang the face include: the buccal nerve, which is on the surface of the buccinator muscle supplying the cheek; BRANCHES NERVE

30 THE NERVES OF FACE AND SCALP The trigeminal nerve CN V The branches of the mandibular nerve V 3 innervaang the face include: the auriculotemporal nerve, which enters the face just posterior to the temporomandibular joint, passes through the paroad gland, and ascends just anterior to the ear to supply the external acousac meatus, the surface of the tympanic membrane (eardrum), and a large area of the temple; the buccal nerve, which is on the surface of the buccinator muscle supplying the cheek; and the mental nerve, which exits the mandible through the mental foramen and immediately divides into mulaple branches to supply the skin and mucous membrane of the lower lip and skin of the chin.

31 THE NERVES OF FACE AND SCALP The trigeminal nerve CN V OPHTHALMIC NERVE (CN V1) - SENSORY ONLY MAXILLARY NERVE (CN V2) - SENSORY ONLY MANDIBULAR NERVE (CN V3) - SENSORY AND MOTOR

32 THE NERVES OF FACE AND SCALP The trigeminal nerve CN V THE SOMATIC (BRANCHIOMOTOR) BRANCHES OF THE TRIGEMINAL NERVE THE MANDIBULAR NERVE V3 ONLY (!): masseter temporalis medial and lateral pterygoids mylohyoid anterior belly of digastric tensor tympani THE TRIGEMINAL NERVE CN V is sensory to: the dura of the anterior and middle cranial fossae skin of the face teeth gingiva mucous membrane of the nasal cavity paranasal sinuses and mouth

33 THE NERVES OF FACE AND SCALP The trigeminal nerve CN V Two parasympatheac ganglia, the opc and submandibular, are associated with the mandibular division V3; both are concerned with the innervaaon of salivary glands.

34 THE NERVES OF FACE AND SCALP The spinal cutaneous nerves Posterior to the ear, the scalp receives cutaneous innervaaon from the spinal cutaneous nerves that originate in the neck (C2, C3): greater occipital nerve (C2) lesser occipital nerve (C2, C3) third occipital nerve (C3)

35 THE VASCULATURE OF FACIAL AND SCALP THE SUPERFICIAL ARTERIES OF FACE THE SUPERFICIAL ARTERIES OF FACE AND SCALP: Facial Inferior labial Superior labial Lateral nasal Angular Occipital Posterior auricular Superficial temporal Transverse facial Mental Supra-orbital Supratrochlear Most superficial arteries of the face are branches or derivaaves of branches of the external caroad artery

36 THE VASCULATURE OF FACIAL AND SCALP THE SUPERFICIAL ARTERIES OF FACE THE FACIAL ARTERY Third anterior branch of external caroad artery. It runs below the stylohyoid muscle, first upward, then lateral, and crosses the mandible at the anterior margin of the masseter. THE FACIAL ARTERY crosses the mandible at the anterior margin of the masseter. THE FACIAL ARTERY The facial artery crosses the mandible, buccinator, and maxilla as it courses over the face to the medial angle (canthus) of the eye, where the superior and inferior eyelids meet. THE FACIAL ARTERY The facial artery provides the major arterial supply to the face.

37 THE VASCULATURE OF FACIAL AND SCALP THE SUPERFICIAL ARTERIES OF FACE THE FACIAL ARTERY The facial artery passes approximately a finger s breadth lateral to the angle of the mouth THE FACIAL ARTERY sends branches to the upper and lower lips (the superior and inferior labial arteries), ascends along the side of the nose. The terminal part of the facial artery is called the angular artery, it anastomoses with the ophthalmic artery.

38 THE VASCULATURE OF FACIAL AND SCALP THE SUPERFICIAL ARTERIES OF FACE THE OCCIPITAL ARTERY Second dorsal branch of external caroad artery. It passes medial to the mastoid process at the occiput and anastomoses with the superficial temporal, vertebral, deep cervical and posterior auricular arteries. THE POSTERIOR AURICULAR ARTERY Third dorsal branch of external caroad artery. It lies under the paroad gland on the styloid process between the mastoid process and the ear. THE SUPERFICIAL TEMPORAL ARTERY One of two terminal branches of the external caroad artery. It passes upward in front of the auricle (pinna) accompanied by the auriculotemporal nerve. THE TRANSVERSE FACIAL ARTERY Branch of the superficial temporal artery, that is covered by the paroad gland and passes below the zygomaac arch to the cheek. Approximately a finger s breadth inferior to the zygomaac arch.

39 THE VASCULATURE OF FACIAL AND SCALP THE SUPERFICIAL ARTERIES OF FACE THE MENTAL ARTERY Terminal branch of inferior alveolar artery. The only superficial branch derived from the maxillary artery, accompanies the nerve of the same name in the chin. THE SUPRAORBITAL and SUPRATROCHLEAR ARTERIES The branches of the ophthalmic artery, accompany nerves of the same name across the eyebrows and forehead. *

40 THE VASCULATURE OF FACIAL AND SCALP THE ARTERIES OF SCALP THE ARTERIES OF SCALP The arterial supply is from the external caroad arteries through: the occipital posterior auricular and superficial temporal arteries And from the internal caroad arteries through: the supratrochlear and supra-orbital arteries THE EXTERNAL VEINS OF FACE Supratrochlear Supra-orbital Angular Facial Deep facial Superficial temporal Retromandibular

41 THE VASCULATURE OF FACIAL AND SCALP THE EXTERNAL VEINS OF FACE OF SCALP THE FACIAL VEINS The facial veins, coursing with or parallel to the facial arteries, are valveless veins that provide the primary superficial drainage of the face. It courses from the medial angle of the eye, behind the facial artery. The facial vein drains directly or indirectly into the internal jugular vein. THE FACIAL VEINS At the medial angle of the eye, the facial vein communicates with the superior ophthalmic vein, which drains into the cavernous sinus. THE ANGULAR VEIN Formed by the union of the supratrochlear and supraorbital veins; it becomes conanuous with the facial vein at the medial angle of the eye and anastomoses with the ophthalmic vein.

42 THE VASCULATURE OF FACIAL AND SCALP THE EXTERNAL VEINS OF FACE OF SCALP THE DEEEP FACIAL VEIN Arises from the pterygoid plexus (drains the pterygoid venous plexus of the infratemporal fossa) and passes anteriorly on the maxilla. THE RETROMANDIBULAR VEIN It drains into the facial vein ager receiving the confluence of many branches in front of the ear. The retromandibular vein divides into an anterior branch that unites with the facial vein and a posterior branch that joins the posterior auricular vein inferior to the paroad gland to form the external jugular vein. This vein passes inferiorly and superficially in the neck to empty into the subclavian vein.

43 THE VASCULATURE OF FACIAL AND SCALP THE VEINS OF SCALP THE VEINS OF SCALP The supra-orbital and supratrochlear veins unite at the medial canthus of the eye to form the facial vein. The superficial temporal vein joins the maxillary vein to create the retromandibular vein just posterior to the neck of the mandible. The posterior auricular vein originates behind the ear and channels venous blood from the posterior of the scalp toward the external jugular vein.

44 THE VASCULATURE OF FACIAL AND SCALP THE VEINS OF SCALP THE VEINS OF FACIAL AND SCALP Some small veins also communicate with the cavernous sinus within the skull. This connecaon of facial venous drainage with intracranial venous drainage accounts for the spread of some infecpons from the face to the brain. The thrombophlebips of the cavernous sinus may be caused by an inflammaaon limited to the: medial angle of the eye upper lip

45 THE VASCULATURE OF FACIAL AND SCALP THE CAVERNOUS SINUS Cranial nerves: oculomotor CN III, trochlear IV and abducent VI and the ophthalmic V 1 and maxillary V 2 divisions of CN V, as well as the internal carotid artery and its periarterial plexus of postganglionic sympathetic fibers traverse the CAVERNOUS SINUS. All of these cranial nerves course in the lateral wall of the sinus except for abducent CN VI, which courses through the middle of the sinus. As a result, CN VI is typically affected first in a cavernous sinus thrombosis or by an aneurysm of the internal caroad artery, with the other nerves being affected later.

46 THE VASCULATURE OF FACIAL AND SCALP THE LYMPHATIC DRAINAGE OF FACE AND SCALP LYMPHATIC DRAINAGE OF FACE AND SCALP There are no lymph nodes in the scalp, and except for the paroad/buccal region, there are no lymph nodes in the face. LYMPHATIC DRAINAGE OF FACE AND SCALP Lymph from the lateral part of the face and scalp, including the eyelids, drains to the superficial paroad lymph nodes. Lymph from the deep paroad nodes drains to the deep cervical lymph nodes. Lymph from the upper lip and lateral parts of the lower lip drains to the submandibular lymph nodes. Lymph from the chin and central part of the lower lip drains to the submental lymph nodes.

47 THE VASCULATURE OF FACIAL AND SCALP THE LYMPHATIC DRAINAGE OF FACE AND SCALP LYMPHATIC DRAINAGE OF FACE AND SCALP The superficial ring (pericervical collar) of lymph nodes: submental submandibular paroad mastoid and occipital Lymph from the scalp, face, and neck drains into the superficial ring of lymph nodes LYMPHATIC DRAINAGE OF FACE AND SCALP All lymphaac vessels from the head and neck drain directly or indirectly into the deep cervical lymph nodes

48 THE PAROTID GLAND THE PAROTID REGION THE PAROTID REGION The paroad region is the posterolateral part of the facial region, bounded by the: ZygomaAc arch superiorly External ear and anterior border of the sternocleidomastoid posteriorly Ramus of the mandible medially Anterior border of the masseter muscle anteriorly Angle and inferior border of the mandible inferiorly THE PAROTID REGION The paroad region includes: the paroad gland and duct the paroad plexus of the facial nerve (CN VII) the retromandibular vein the external caroad artery and the masseter muscle

49 THE PAROTID GLAND THE PAROTID GLAND The paroad gland is enclosed within a tough, unyielding, the paropd sheath (capsule) THE PAROTID GLAND The apex of the paroad gland is posterior to the angle of the mandible, and its base is related to the zygomaac arch. THE PAROTID DUCT The paroad duct passes horizontally from the anterior edge of the gland the duct turns medially pierces the buccinator and enters the oral cavity through a small orifice opposite the 2nd maxillary molar tooth

50 THE PAROTID GLAND THE PAROTID GLAND From superficial to deep there are: the paroad plexus of the facial nerve (CN VII) and its branches the retromandibular vein the external caroad artery The paroadectomy may damage the facial nerve CN VII (the paroad plexus) THE PAROTID GLAND On the paroad sheath and within the gland are paroad lymph nodes.