Padalecki 5 Flashcards
Anterior and Posterior Boundaries of the Parotid Region
A. Anterior - anterior border of the mandibular ramus
B. Posterior - mastoid process of temporal bone
Superior and Inferior Boundaries of the Parotid Region
C. Superior - zygomatic arch
D. Inferior - posterior belly of the digastric muscle
Medial and Lateral Boundaries of the Parotid Region
E. Medial - to the styloid process and beyond
F. Lateral - superficial layer of parotid fascia
Location of the Parotid Gland
- Inferior and anterior to the auricle
- Lateral and posterior to masseter muscle
- Lateral, posterior, and medial to the mandibular ramus
Shape of the Parotid Gland
- Roughly triangular
2. Apex points inferiorly
Parotid gland is sometime described as _______.
Bilobate
a. Constricted between _____ and _____.
b. Deep “lobe” expands into the ________.
c. Lobes demarcated by courses of ______; there is fatty tissue between the lobes to allow for movement
a. mandible and styloid process
b. lateral pharyngeal space
c. facial nerve branches
Embedded within the parotid from superficial to deep:
- parotid plexus and branches
- retromandibular vein
- external carotid artery
The parotid space location is ________.
encompasses parotid gland
a. Extension of investing cervical fascia
b. Thick superficial lamina
c. Thin deep lamina - abuts medially on the lateral pharyngeal space
d. Septa penetrate gland
Parotid fascia
Attachments of Parotid fascia
(1) Superior - zygomatic arch
(2) Inferior - fascia on sternocleidomastoid
(3) Anterior - masseteric fascia
- Arises from anterior surface of gland
- Course - 1 to 2 cm inferior to zygomatic arch
a. Curves around anterior border of masseter muscle
b. Pierces buccinator muscle - Empties into buccal cavity
a. At parotid papilla
b. Opposite maxillary second molar tooth
Parotid Duct
Arteries are branches of…
a. Maxillary artery
b. Superficial temporal artery
c. Transverse facial artery
Veins & location of drainage
a. Maxillary vein
b. Superficial temporal vein
c. Transverse facial vein
d. Drain into retromandibular vein
Lymphatics
a. Parotid nodes
b. Superficial cervical nodes
c. Superior deep cervical nodes
Afferent fiber innervation
a. Great auricular nerve (1) From C2&3
(2) Cell bodies in dorsal root ganglia
b. Auriculotemporal nerve
(1) From V3
(2) Cell bodies in trigeminal ganglion
Parasympathetic fiber innervation - Postganglionic
(1) Within auriculotemporal branch of V 3
(2) Cell bodies in otic ganglion
(3) Stimulation increases rate of parotid salivary flow
(4) Parotid salivary flow is also stimulated by chewing
Parasympathetic fiber innervation - Preganglionic
(1) Cell bodies in inferior salivatory nucleus
(2) Peripheral course
(a) Tympanic branch of IX
(b) Tympanic plexus on medial wall of tympanic cavity
(c) Lesser petrosal nerve
(i) Through foramen ovale (ii) To otic ganglion
Sympathetic postganglionic fiber innervation
a. Through external carotid plexus
b. Cell bodies in superior cervical ganglion
c. Stimulation increases glycoprotein and viscosity of parotid salivary flow
Clinical correlates
- Mumps: viral infection resulting in swelling of the parotid gland; causes severe pain due to the parotid sheath limiting swelling
- Parotid tumors
a. 80% are benign
b. cancer rare but sometimes in parotid
c. surgical intervention is risky CN VII.
Origin of facial nerve:
- From lateral aspect of brainstem at junction of ____ and _____.
- This is a complex structure with a peculiar course through the ______.
- pons and medulla
2. temporal bone
In addition to the branchiomeric efferent fibers found in the branches on the face, the facial nerve contains _______ and _______ fibers. The distribution of these fibers within the visceral parts of the head will be considered in detail later.
- Afferent (mainly taste) fibers
2. Preganglionic parasympathetic (secretomotor) fibers
Fiber types of branches of the face
a. Efferent to branchiomeric muscle
b. Afferent
(1) Muscles derived from second branchial arch
(a) Muscles of facial expression
(b) Three other muscles
(i) Posterior belly of the digastric
(ii) Stylohyoid
(iii) A small muscle of the middle ear (stapedius)
(2) Cell bodies in facial motor nucleus
Efferent to branchiomeric muscle
(1) To auricular skin
(2) Cell bodies in geniculate ganglion
Afferent
Course of branches of the face
a. Exits skull at stylomastoid foramen
b. Branches within parotid gland (parotid plexus)
Peripheral branches
a. Two small branches below auricle
b. Temporofacial division
c. Cervicofacial division
Two small branches below auricle
(1) Posterior auricular
(2) Branch to posterior digastric and stylohyoid muscles
Temporofacial division
(1) Temporal branches
(2) Zygomatic branches
(3) Buccal branch
Cervicofacial division
(1) Buccal branch
(2) Marginal mandibular branch
(3) Cervical branch
Connections with cutaneous branches of the trigeminal nerve
a. Occur in areas of overlap
b. Mechanism to supply afferent fibers to facial muscles
- Raise the eyebrows
- Close both eyelids tightly
- Whistle
- Smile to show the teeth
- Pull down the corners of the mouth and raise (wrinkle) the skin of the neck
Test for function of the facial nerve
Lesions resulting in facial paralysis
- Peripheral lesions
2. Central lesions (i.e. stroke)
Paralysis of muscles of the lower face only; forehead is usually not affected.
Central lesions (i.e. stroke)
Peripheral lesions are usually _____.
Unilateral
(1) Smoothing of wrinkles and folds
(2) Drooping of eyebrow
(3) Sagging of lower eyelid
(4) Sagging of corner of mouth
(5) Deviation of mouth to unaffected side
(6) Interference with normal facial movements (e.g., asymmetry)
(a) Frowning or wrinkling forehead skin
(b) Elevating eyebrow
(c) Closing eye tightly
(d) Pursing lips
(e) Laughing, smiling, or showing teeth
(f) Control of cheek in chewing
(g) Wrinkling skin of neck
(7) Depending on level of lesion, other manifestations may occur (e.g., changes in taste, dry mouth, etc.)
Results of peripheral lesions
- Trauma
- Tumor
- Inflammatory disorders
- Bell’s palsy
Etiology of peripheral lesions
(a) Parotid neoplasms
b) Acoustic neuroma (benign sheath - cell tumor of VIII
Tumors
(a) Idiopathic
(b) Often preceded by mild upper respiratory illness
(c) Progresses steadily to affect half of face
(d) Thought to result from ischemic or pressure effects of nerve edema within narrow bony canal
(e) Uncomplicated cases demonstrate some regeneration and varying degrees of functional recovery
Bell’s palsy: characteristics
