Parotid Fossa Flashcards
Parotid Fossa:
Wedge shaped space with apex medial and base lateral
Anterior and posterior boundaries of the Parotid Fossa are composed of:
Fascia
Posterior Boundary of Parotid Fossa:
Sternocleidomastoid
Posterior Digastric
Stylohyoid muscle
Styloid process
Superior Limit of parotid fossa:
Capsule of TMJ
Floor of external acoustic meatus
Inferior boundary of Parotid fossa:
Angular Tract (Fascia)
Anterior Boundary of Parotid fossa:
Masseter
Ramus and neck of mandible
Stylomandibular fascia (part of deep parotid fascia)
Superficial parotid fascia:
Covering the gland on lateral side
Medial Boundary of Parotid fascia:
Styloid Process
Lateral boundary of fossa:
Superficial parotid fascia (layer of deep fascia)
What forms the angular track?
- Stylomandibular fascia
- Fascia surrounding the stylohyoid and posterior belly of the digastric and connecting to the SCM and Styloid process
What are the contents of the parotid fossa?
- Parotid Gland
- Facial Nerve
- Retromandibular vein and branches
- External carotid artery and branches
Blood supply to Parotid gland:
Transverse Facial Artery,
Superficial temp. ves.
What is the sensory innervation to the gland?
Great auricular Nerve: Runs across SCM. supplies skin overlying the parotid gland. (lower external ear and just in front of ear). Supplies superficial carotid fascia
Auriculotemporal nerve: Branch of V3. Goes posterior and comes out of lateral side of head. Sensory N. comes medial to parotid fossa. supplies sensation to gland
What is the Parasympathetic innervation to the gland?
Fibers from the glossopharyngeal nerve- to secrete saliva, the gland must receive autonomic innervation:
Glossopharyngeal (pre) to tympanic plexus in middle ear to Lesser petrosal N. which goes through foramen ovale (so does trigeminal V3) to synapse in optic ganglion postgalnglionic fibers go with auriculotemporal nerve to supply parotid gland.
What otters structures are passing into and out of the fossa?
External carotid artery:—- Posterior auricular artery: Behind ear. Parallels occipital A. Branches above the posterior digastric
External carotid ends in fossa by splitting into:
- Superficial temporal—- Transvers facial artery: on superficial/more lateral side
- Maxillary artery: Deep straight anteriorly behind ramus
Veins of Parotid Artery:
Superficial temporal vein: Comes down in front of ear. Same pattern as superficial temporal artery
Maxillary vein: under ramus of mandible (deep)
Above will form retromandibular vein:
- Anterior division joins facial to form common facial
- Posterior division joins posterior auricular form external jugular
Common Facial Vein:
Goes under the sternocleidomastoid (deep) so it can empty into the internal jugular vein
Describe path of facial N:
Exits stylomastoid foramen: after exiting its a total motor N.
- It passes anteriorly between and enervates stylohyoid and the posterior digastric muscles. Will give off branches to both of those muscles. Facail N will go right through the facial gland.
Facial Nerve innervates muscles of facial expression
In the gland VII divides into two branches:
Temporofacial
Cervicofacial
What is parotitis (parotiditis)?
Infection of parotid gland (inflammation):
- May result from xerostomia (dry mouth): reduced salivary flow will allow bacteria from oral cavity to move retrograde through the out and infect the gland
Causes: Drugs, Radiation, Illness
What is Mumps? (epidemic or Viral parotitis)
Caused by paramyxovirus: Will target all salivary glands:
- Parotid salivary gland effected and stretching of that gland will be very painful
- Will have some swelling; unilateral or bilateral
KEY ID: Infection will cause a red and swollen parotid papilla
What is Sialolith?
Salivary calculus or stone:
- Parotid gland= 20% of time; 80% in submandibular gland (has higher alkaline content)
- Swelling (more isolated: Usually unilateral) of gland
- Vague pain– when eating will have increased swelling/pain while eating
- Treatment: Increase persons hydration- moist heat- more saliva more it has chance to be removed. Send to ENT
Tumores in Parotid:
85% benign– Pleomorphic adenoma most common
- Will grow quite large
- occurs mainly in superficial lobe
- Will remove gland to prevent reoccurrence
Complication: have to be very careful not to damage facial Nerve
What is Bell’s Palsy
Unilateral facial paralysis due to facial nerve involvement
- Lower eyelid drooping
- NO wrinkles on effected side
- drooping of mouth
- will loose all m of facial expression on effect side
- May result from viral infection… not really sure though– can be caused by dentists
- 3 weeks to several months to return to normal (may not completely go back)
