Facial muscles, Eyes, Ears

Question 1

Platysma muscle

Answer 1

cutaneous muscle that passes from the dorsal median raphe of the neck to the angle of the mouth, where it radiates into the orbicularis oris in the lips; most superficial muscle, covering the ventrolateral surface of the face

action: Draws lips caudally
innervation: Facial n.

Question 2

Orbicularis oris muscle

Answer 2

near the free borders of the lips and extends from one lip to the other around the angle of the mouth; fibers of each side at the median plane in the incisor region of both jaws

action: Closes mouth
innervation: Dorsal and ventral buccal branches of the facial n.

Question 3

Buccinator muscle

Answer 3

thin, wide muscle that forms the foundation of the cheek; attaches to the alveolar margins of the mandible and the maxilla and the adjacent buccal mucosa; may be found between the rostral border of the masseter muscle and the orbicularis oris; portion lies deep to the orbicularis oris

action: Tenses cheek to compress the oral vestibule
innervation: Dorsal and ventral buccal branches of the facial n.

Question 4

Levator nasolabialis muscles

Answer 4

flat muscle lying beneath the skin on the lateral surface of the maxillary bone; arises from the maxillary bone, courses rostroventrally, and attaches to the edge of the superior lip and on the naris, the external opening of each half of the nasal cavity

action: dilates the nostril and raises the superior lip
innervation: Auriculopalpebral branch of the facial n.

Question 5

Eyelids

Answer 5

aka palpebrae; superior and inferior

Question 6

Palpebral fissure

Answer 6

space between the palpebrae

Question 7

Palpebral commissures

Answer 7

lateral and medial; joining at either end of the palpebral fissure

Question 8

Medial palpebral ligament

Answer 8

well developed and attaches the medial commissure to the frontal bone near the nasomaxillary suture

Question 9

Palpebral conjunctiva

Answer 9

posterior or inner surface of the palpebrae covered by a mucous membrane

Question 10

Bulbar conjunctiva

Answer 10

reflection of conjunctiva onto the globe of the eye

Question 11

Fornix

Answer 11

angle formed by the reflection of the palpebral conjunctiva onto the globe of the eye

Question 12

Conjunctiva sac

Answer 12

bounded posteriorly by the bulbar conjunctiva (where it covers the sclera) and anteriorly by the palpebral conjunctiva

Question 13

Lacrimal caruncle

Answer 13

covers the lacrrimal duct; triangular prominence of finely haired skin

Question 14

Plica semilunaris

Answer 14

aka third eyelid; concave fold of palpebral conjunctiva and cartilage that protrudes from the medial angle of the eye; cartilage is T shaped, with an expanded portion in the medial canthus and a stem that extends ventrally into the orbit; surrounded by the superficial gland of the third eyelid

Question 15

Orbicularis oculi muscle

Answer 15

lies partly in the eyelids and is attached medially to the medial palpebral ligament; laterally the fibers of the muscle blend with those of the retractor anguli oculi lateralis

action: close the palpebral fissure
innervation: Auriculopalpebral branch of the facial n.

Question 16

Helix

Answer 16

slightly folded medial and lateral margin of the ear

Question 17

Antihelix

Answer 17

located on the internal, concave wall at the level of the beginning of the external acoustic meatus; transverse ridge

Question 18

Tragus

Answer 18

opposite the antihelix the rostral boundary of the initial part of the ear canal; thick, quadrangular plate of auricular cartilage

Question 19

Antitragus

Answer 19

thin, elongate piece of cartliage; projects caudally from the tragus, completes the lateral boundary of the external ear canal

Question 20

Marginal cutaneous sac

Answer 20

pouch formed by proximal incisure on lateral portion of the helix