Lecture 23 - Face and Parotid Region Flashcards
What do the parotid glands lay caudal to?
Masseter and temporomandibular join, will expand cranially over masseter
What are the parotid glands associated with dorsally?
External auditory meatus and base of ear
What part of the vertebrae does the parotid gland associated with?
Wing of the atlas
What is the ventral limit of the parotid gland in dogs?
Maxillary vein
What is the ventral limit of the parotid gland in equine?
Convergence of maxillary and linguofacial veins
What does the facial n. pass out of?
Stylomastoid foramen and ramifies with the gland
What procedure can commonly cause harm to the parotid gland?
Ventral displacement when working with the external auditory meatus of the dog
What is the blood supply of the parotid gland?
Parotid artery
What is the parotid artery a branch of in dogs?
External Carotid a.
What is the parotid artery a branch of in horses?
Common carotid a.
What type of gland is the parotid gland, in most animals?
Serous gland
What is different about the dog’s parotid gland?
Seromucous gland
What is the general function of the parotid gland?
Moistening and softening food
What is the path of the parotid duct in dogs?
Crosses the lateral surface of the masseter, shorter and less protected
Where does the parotid duct of a dog enter into the mouth?
Vestibule of the mouth opposite of the fourth upper premolar
What is the path of the parotid duct in larger domestic animals?
Medial to the angle of the jaw and winds below the mandible, longer more protected route
Where does the parotid duct enter in the mouth of a larger domestic animal?
Along rostral margin of the masseter
What are the subdivisions of the muscles innervated by the facial nerve?
Deep and superficial
What are the deep division of muscles that are innervated by the facial nerve?
Scattered, muscles that act on hyoid, stapedius, part of digastric
What are the superficial division of muscles that are innervated by the facial nerve?
Cutaneous muscles of face and head, muscles that move lips, eyelids, external ear, nostrils, and cheeks
What are the four branches of the facial nerve? (dorsal to ventral)
Auriculopalpebral - Dorsal buccal branch - Ventral buccal branch - Cervical branch
How many layers are there in the superfical division of facial muscles?
Three
What are the three layers of the superficial division of the facial muscle derived from?
Deep sphincter in the neck
What is the outermost superficial layer of the facial muscles?
Missing in most domestic animals
Spincter colli in the DOG is remnant
What is the middle superficial layer of facial muscles?
Platysma
What is the deep superficial layer of facial muscles?
Origin of most muscles of facial expression
What are the seven prinicipal muscles of the lips and cheeks?
Orbicularis oris Caninus Levator nasolabialis Levator labii superiorsis Buccinator Depressor labii inferioris
What is the location of the obicularis oris?
Surrounds the mouth opening and is closely attached to skin and mucosa of the lip
What is the function of the obicularis oris?
Closes the opening of the mouth by pursing lips - important to sucking
What is the location of the canius?
Arises ventral to infraorbital foramen and radiates into the wing of the nostril and upper lip
What is the function of the caninus?
Dilates the nostril and elevates the corner of the mouth
Snarling in dogs
What is the location of the levator nasolabialis?
Arises over the dorsum of the nose and inserts on the wing of the nostril and lateral part of the upper lip
What does the levator nasolabialis do?
Dilate the nostril and to elevate and retract the upper lip
What is the location of the levator labii superoris?
Arises on the lateral aspect of the face
Runs dorsorostrally, forms with its fellow a common tendon that interests into the lip between the nostrils
What is the function of the levator labii superoris?
Elevate medial part of the upper lip
What is the flehman response?
Elevation of the nostrils to allow pheromones or other chemical cues to enter vomeronasal organ
What is another name for the vomeronasal?
jacobson’s organ
What is the behavioral reason’s for the flehman response?
Territorial or sexual behavior
What is the location of the buccinator?
Passes between the margins of upper and lower jaws, partly covered by masseter, forms basis of the cheeks
What is the function of the buccinator?
Acts in opposition to tongue preventing food from collecting in vestibule by returning it to the central cavity of the mouth
What gland does the buccinator associate with?
Buccal salivary gland
What does the buccinator do in regards to the salivary gland?
Discharging secretions into the mouth, glands scattered amoung fascicles of Buccinator
What muscle is the lips and cheeks is present in horses but NOT dogs and cats?
Depressor labii inferioris
Where is the depressor labii inferioris present?
Lower lip
What muscle is the labii inferioris associate with?
Buccinator
What are the muscles of the eyelid?
Obicularis oculi, Levator/retractor anguli oculi medialis/lateralis, and malaris
What is location of the orbicularis oculi?
Surrounds the palpebral fissue
Anchored at the medial and lateral commissures
What is the palpebral fissure?
Opening between the lids
What is the function of the obicularis oculi?
Narrows the opening to a horizontal slit
What is the function of the retractor anguli oculi lateralis?
Raise the upper eyelid
What is the function of the malaris?
Depress the lower lid, enlarging the eye opening
What are the three muscles of the dorsal face?
Frontalis, occipitalis, and zygomaticus
What happens with a centrally located lesion of the facial n.?
Affected whole facial field
Loss of secretory activity by lacrimal gland and salivary
Mimetic muscular paralysis
Loss of taste sensation from anterior 2/3 of tongue
What is the only salivary gland not affected by a central lesion of the facial nerve?
Parotid
What happens when there is a lesion of the facial nerve at the stylomastoid foramen?
Paralyze the entire mimetic musculature
What happens a lesion occurs more peripherally on the facial nerve?
Will depend on the certain branch of the nerve
What happens if the auriculopalpebral n. is severed?
Drooping of external ear
Narrowing of palpebral fissure with inability to close the eye
What is the clinical use of auriculopalpebral n.?
Some times blocked in horses to aid in an eye examination
What is the path of the auriculopalpebral n. in horses and cattle?
Detached from facial n. prior to face
Take independent course across the zygomatic arch
What happens when there is a lesion in the buccal branch of the facial n.?
Paralysis of the muscles of the lips and cheeks
Deformation of the muzzle
Unopposed activity of the muscles on the sound side
