3 basic functions
o    protection of respiratory tract during swallowing food/air pathways cross.
    epiglottis provides protection
o    control intra-thoracic pressure (in coughing) -    close off airway to build pressure then rapidly open to release stuff
o    production of sound (in speaking, singing, laughing)

Important structures

o    hyoid bone
o    thyroid cartilage
o    arytenoids cartilage: vocal and muscle process
    sits on slope on posterior side of cricoid - spin and slide
o    cricoid cartilage: signet ring
o    thyroepiglottic ligament

Membranes and ligaments

o    membrane: general; ligament: thickening of membrane
o    folds: free edges of membranes or ligaments
o    names: tell you where located

Important membranes:
    quandrangular/vestibular membrane—from epiglottis to arytenoids
•    inferior edge: false vocal fold
    thyrohyoid membrane
    conus elasticus = cricothyroid = cricovocal
•    superior/medial edge = vocal fold
•    vocal ligaments: true folds, top of cricothyroid membrane

The Parotid Glands

• The parotid glands are the largest of the three pairs of salivary glands.
• Each gland is wedged between the mandible and the sternocleidomastoid muscle and partly covers them.

• The parotid gland is wrapped with a fibrous capsule (parotid fascia) that is continuous with the deep investing fascia of the neck.

• Viewed superficially, the parotid gland is somewhat triangular in shape.
• Its apex is posterior to the angle of the mandible and its base is along the zygomatic arch.
• The parotid gland overlaps the posterior part of the masseter muscle.

• The parotid duct (Stensen's duct) is about 5 cm long and 5 mm in diameter.
• It passes horizontally from the anterior edge of the gland.
• At the anterior border of the masseter muscle, the parotid duct turns medially and pierces the buccinator muscle.
• It enters the oral cavity opposite the second maxillary molar.

Blood Vessels of the Parotid Gland

• This gland is supplied by branches of the external carotid artery.
• The veins from the parotid gland drains into the retromandibular vein, which enters the internal jugular vein.

Lymphatic Drainage of the Parotid Gland

• The lymph vessels of this gland end in the superficial and deep cervical lymph nodes.

Nerves of the Parotid Gland

• These nerves are derived from the auriculotemporal nerve and from the sympathetic and parasympathetic systems.

• The parasympathetic fibres are derived from the glossopharyngeal nerve (CN IX) through the otic ganglion.
• Stimulation of these fibres produces a thin watery (serous) saliva to flow from the parotid duct.

• The sympathetic fibres are derived from the cervical ganglia through the external carotid plexus.
• Stimulation of these fibres produces a thick mucous saliva.

Superior Constrictor Muscle

• Origin: Hamulus, pterygo-mandibular raphe, and mylohyoid line of the mandible.
• Insertion: Median raphe of the pharynx.
• Nerve Supply: Vagus nerve via the pharyngeal plexus.
• Arterial Supply: Ascending pharyngeal artery, ascending palatine artery, tonsillar branch of the facial artery, and dorsal branch of the lingual artery.
• Action: Constricts the wall of the pharynx during swallowing.

Extrinsic Muscles of the Tongue (p. 746)

The Genioglossus Muscle

• This is a bulky, fan-shaped muscle that contributes to most of the bulk of the tongue.
• It arises from a short tendon from the genial tubercle (mental spine) of the mandible.
• It fans out as it enters the tongue inferiorly and its fibres attach to the entire dorsum of the tongue.
• Its most inferior fibres insert into the body of the hyoid bone.
• The genioglossus muscle depresses the tongue and its posterior part protrudes it.

The Hyoglossus Muscle

• This is a thin, quadrilateral muscle.
• It arises from the body and greater horn of the hyoid bone and passes superoanteriorly to insert into the side and inferior aspect of the tongue.
• It depresses the tongue, pulling its sides inferiorly; it also aids in retrusion of the tongue.

The Styloglossus Muscle

• This small, short muscle arises from the anterior border of the styloid process near its tip and from the stylohyoid ligament.
• It passes inferoanteriorly to insert into the side and inferior aspect of the tongue.
• The styloglossus retrudes the tongue and curls its sides to create a trough during swallowing.

The Palatoglossus Muscle 

• Superior attachment: palatine aponeurosis.
• Inferior attachment: side of tongue.
• Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.

• This muscle, covered by mucous membrane, forms the palatoglossal arch.

• The palatoglossus elevates the posterior part of the tongue and draws the soft palate inferiorly onto the tongue.

The Temporomandibular Joint

• This articulation is a modified hinge type of synovial joint.
• The articular surfaces are: (1) the head or condyle of the mandible inferiorly and (2) the articular tubercle and the mandibular fossa of the squamous part of the temporal bone.

• An oval fibrocartilaginous articular disc divides the joint cavity into superior and inferior compartments. The disc is fused to the articular capsule surrounding the joint.

• The articular disc is more firmly bound to the mandible than to the temporal bone.

• Thus, when the head of the mandible slides anterior on the articular tubercle as the mouth is opened, the articular disc slides anteriorly against the posterior surface of the articular tubercle

The Ear

• The ear contains the vestibulocochlear organ and consists of three main parts: external, middle, and internal.
• It has two functions, balance and hearing.

• The tympanic membrane (eardrum) separates the external ear from the middle ear.
• The auditory tube joins the middle ear or tympanic cavity to the nasopharynx.