LAB 22 Introduction
Superficial Structures of the Head
and the Oral Cavity & Pharynx
(Guide to the Dissection of the Dog, pp. 225-235)
Lab Objectives:
•Dissect muscles of facial expression on the left half of head:
- cutaneous muscles, e.g., platysma muscle
- muscles in walls of lips, cheeks, and eyelids
- superficial muscles that move ear and nose & upper lip
• Examine eyelid features and the conjunctival sac.
• Examine oral cavity, tongue, and salivary glands.
• Identify regions of the pharynx:
- oropharynx (contains palatine tonsil)
- nasopharynx (contains auditory tube opening)
- laryngopharynx
• Optionally, examine osseous features of the nasal cavity.
Anatomical Terms:
Superficial Structures of the Head
philtrum
platysma m.
orbicularis oris m.
buccinator m.
levator nasolabialis m.
superior & inferior palpebrae
palpebral fissure
medial & lateral palpebral commissures
orbicularis oculi m.
retractor anguli oculi m.
levator palpebrae superioris m.
conjunctival sac
palpebral conjunctiva
bulbar conjunctiva
fornix
lacrimal caruncle
lacrimal puncta (dorsal & ventral)
lacrimal duct
lacrimal sac
nasolacrimal duct
plica semilunaris (third eyelid)
superficial gland of the third eyelid
rostral auricular muscles
scutiform cartilage
caudal auricular muscles
Oral Cavity and Pharynx
vestibule
parotid & zygomatic duct openings
oral cavity proper
tongue (root, body, apex)
papillae: (filiform, conical, fungiform, foliate & vallate)
lingual frenulum
lyssa
sublingual caruncle
sublingual fold
mandibular salivary duct
major sublingual salivary duct
mandibular salivary gland
sublingual salivary gland (monostomatic gland)
parotid salivary gland
parotid duct
buccal salivary gland (cat only)
palate
incisive papilla & duct
vomeronasal organ
Pharynx:
oropharynx
palatoglossal arch
palatine tonsil
semilunar fold
nasopharynx
palatopharyngeal arch
auditory tube
laryngopharynx
pharyngoesophageal limen (border)
Pharyngeal Muscles:
cricopharyngeus m.
thyropharyngeus m.
hyopharyngeus m.
Note:
palpebra [Latin = eyelid] = eyelid
buccal [from Latin: bucca = cheek] = pertaining to cheek
buccinator [Latin = trumpeter] = muscle of the cheek
scutiform [Latin: scutum = shield & forma = form] flat cartilage in the rostral muscles of the ear
Instructor Commentary:
In quadrupeds such as domestic mammals, directional terms are different in the head compared to the rest of the body. The term "cranial" is replaced with "rostral" (Latin: rostrum = beak) because the cranium is situated in the caudal part of the head.
While you may continue to use "dorsal/ventral", you can also use "superior/inferior" in the head because, in the head, the terms mean the same in humans and quadrupeds. (In the human trunk, "superior/inferior" equates to "cranial/caudal" in quadrupeds.)
You can also use "anterior/posterior" in the head because the terms are consistent in humans and quadrupeds. (In the human trunk, "anterior/posterior" equates to "ventral/dorsal" in quadrupeds.)
Human anatomists use "superior/inferior" and "anterior/posterior" throughout the body. In veterinary anatomy we refrain from using these terms because their meanings are different, except in the head where human and veterinary meanings are the same.
The term "mouth" [Latin: os & oris] is commonly used to refer to the opening of the oral cavity (as in "close your mouth"). Anatomically, however, "mouth" refers to the oral cavity, which contains the tongue and teeth.
Dissection Images:
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