SA Head Flashcards
Bones of the hyoid apparatus
Tympanohyoid cartilage, stylohyoid, epihyoid, ceratohyoid, basihyoid, thyrohyoid
4 extrinsic muscles of the hyoid
Geniohyoid, mylohyoid, sternohyoid, thyrohyoid
Geniohyoid muscle
extrinsic muscle. Protractor of the hyoid.
Innervated by CN XII
Mylohyoid muscle
extrinsic muscle. Protractor of the hyoid.
Innervated by CN V
Thyrohyoideus
extrinsic muscle. Retractor of the hyoid. Innervated by CN XI and cervicals.
Also responsible for for protracting the larynx to meet the epiglottis and close the aditus
Sternohyoideus
extrinsic muscle. Retractor of the hyoid. Innervated by CN XI and cervicals
Lingualis proprius
intrinsic muscle of the tongue. Changes shape. Innervated by CN XII
Extrinsic muscles of the tongue
Hyoglossus, genioglossus, styloglossus
Hyoglossus
extrinsic muscle of the tongue, retracts the tongue. Innervated by CN XII
Genioglossus
extrinsic muscle of the tongue. protracts the tongue. Innervated by CN XII
Styloglossus
extrinsic muscle. moves the tongue side to side. Innervated by CN XII
Caudal 1/3rd of the tongue innervation
All by CNIX glossopharyngeal
Rostral 2/3rds of the tongue innervation
Taste: chorda tympani branch (CN VII)
All other sensation: lingual branch of CN V (V3)
Pharyngeal muscles
palatopharyngeus, pterygopharyngeus, stylopharyngeus, hyopharyngeus, thyropharyngeus, cricopharyngeus
Palatopharyngeus + pterygopharyngeus
protractors of the pharynx (bring up to meet food), innervated by CN IX and X
Stylopharyngeus
dilator of the pharynx (open for food), innervated by CN IX and X
hyopharyngeus, thyropharyngeus, cricopharyngeus
constrictor of the pharynx, innervated by CN IX and X
Ranulae
accumulation of fluid due to a blocked salivary duct
Facial nerve
motor to all facial mm. 1 sensory branch = chorda tympani.
Main branches: auriculopalpebral, dorsal buccal, ventral buccal, caudal auricular, coli
Exits the stylomastoid foramen
Platysma m.
O: dorsal median raphe of the neck
I: commissure of the mouth
N: facial
A: keeps the cheek taut, pulls corner of the mouth back
Palpebral group of facial muscles
Orbicularis oculi, frontalis, levator nasolabialis
Orbicularis oculi
found around the eye.
A: blinking
N: auriculopalpebral branch of CNVII
Frontalis m.
found in forehead region
N: auriculopalpebral branch of CNVII
Levator nasolabialis
A: raises upper lip
N: auriculopalpebral branch of CNVII
Aural group of facial muscles
dorsoauricular (pull medially), rostroauricular (pull forward), caudoauricular (pull back), ventroauricular (pull down)
N: caudal auricular branch of the colli n. of CNVII
Oral facial muscles
Maxillonasolabialis, orbicularis oris, mentalis, buccinator
Maxillo-nasolabialis
from nose + maxillary bone to upper lip. Has 2 parts: caninus and levator labii superioris.
A: raises lip, flares nostril
Orbicularis oris
A: closes the mouth
N: dorsal and ventral buccal branches of CNVII
Mentalis
from rostral mandible to orbicularis oris.
A: depresses lower lip
Buccinator
from maxilla and mandible, run along the cheek.
A: keeps food between teeth
N: dorsal and ventral buccal branches of CNVII
Zygomaticus
from commissure of mouth to zygomatic arch.
A: keeps mouth a slit, pulls back corners.
N: auriculopalpebral n. of CNVII
Structures at risk in ear ablation
parotid gland, facial nerve branches, retroarticular vein
muscles of mastication
masseter, temporalis, pterygoids, digastricus
N: innervated by branches of V3 except caudal belly of digastricus (CNVII)
V1
exits orbital fissure. Branches: nasociliary, frontal, lacrimal
100% sensory
V2
exits round foramen. Branches: zygomatic, infraorbital, pterygopalatine
100% sensory
V3
exits round foramen. Branches: buccal, lingual, inferior alveolar (goes through inf. alveolar canal in mandible), mylohyoid, auriculotemporal
Branches of CCA
Cranial thyroid artery
Terminal branches = ECA and ICA
Deep blood supply to the head
Basilar artery - formed by anastomosis of vertebrals, ventral spinal and occipital aa.
ICA trajectory
ascends to TOF and enters the carotid canal, exits the carotid canal via foramen lacerum, does 180 degree turn and reenters to head into the brain
*ICA non functional in cats and ruminants
ECA branches
occipital, ascending pharyngeal, cranial laryngeal, lingual, facial, caudal auricular
Terminal branches: sup. temporal, maxillary
Facial a.
supplies the lips and nose. Used as a facial pulse point
Caudal auricular a.
supplies the external ear
Maxillary a. branches pre-alar canal
inferior alveolar, caudal deep temporal
Maxillary a. branches post-alar canal
rostral deep temporal, external ophthalmic, minor palatine, descending palatine (major and sphenopalatine aa.)
Maxillary a. terminal branch
infraorbital a. upon entering the maxillary foramen
Supplies upper teeth
Inferior alveolar a.
accompanied by inferior alveolar nerve (V3) - both enter mandibular foramen to supply the lower teeth
External ophthalmic a.
first branch of maxillary post-alar canal. Supplies the periorbita
Occipital a.
supplies caudal muscles of the skull
Lingual a.
supplies the tongue
superficial temporal a.
supplies temporalis m.
4 important ligaments of the larynx
hyoepiglottic ligament (basihyoid bone attachment) cranially, crico-tracheal ligament (caudal), cricothyroid ligament (ventral), thyroarytenoid ligament (medial) 2 TA ligaments = vocal lig. and vestibular lig.
Aryepiglottic fold
functions to help seal the aditus during swallowing
Caudal thyroarytenoid fold
aka vocal fold, functions to make sounds
Cranial thyroarytenoid fold
aka vestibular fold
Laryngeal ventricle
b/w vocal and ventricular folds, blind pouch
How to make lower pitched sounds?
loosen the vocal folds by contracting the vocalis part of the thyroarytenoideus m.
How to make higher pitched sounds?
tighten the vocal folds by contracting the cricothyroideus to pull the thyroid down (away from arytenoids)
what muscle closes the airway? (adducts folds)
Lateral cricoarytenoid m. (cricoarytenoideus lateralis)
what muscle opens the airway? (abducts folds)
dorsal cricoarytenoid (cricoarytenoideus dorsalis)
Sternothyroideus m.
responsible for retracting the larynx down the neck to open the aditus
Cranial laryngeal branch of vagus innervates?
sensation to supraglottic cavity, motor to cricothyroideus
caudal laryngeal nerve innervates?
sensory to infraglottic cavity, motor to all intrinsic muscles of the larynx (except cricothyroid)
Glossopharyngeal n.
exits jugular foramen
Sensory: caudal 1/3rd of tongue, carotid body and sinus, pharyngeal mucosa
Motor: pharyngeal muscles, PSNS to salivary glands
Canine dental formula (deciduous)
2x i 3/3 c 1/1 p 3/3
Canine dental formula (permanent)
2x I 3/3 C 1/1 P 4/4 M 2/3
Feline dental formula (deciduous)
2x i 3/3 c 1/1 p 3/2
Feline dental formula (permanent)
2x I 3/3 C 1/1 P 3/2 M 1/1
Equine dental formula
2x I 3/3 C 1/1 P 3-4/3-4 M 3/3
Ruminant dental formula
2x I 0/3 C 0/1 P 3/3 M 3/3
