Muscles of the Head Flashcards
Epicranial aponeurosis
strong tendinous sheet covering the calvarium
What cranial nerve innervates the muscles of facial expression?
CN VII - facial nerve
Describe the 5 major motor branches of the facial nerve
temporal
zygomatic
buccal
mandibular
cervical
Occipitofrontalis
origin
insertion
function
innervation
- origin:
Frontal belly (frontalis): epicranial aponeurosis
Occipital belly (occipitalis): superior nuchal line of the occipital bone
- insertion:
Frontal body (frontalis): skin and subcutaneous tissue of eyebrows and forehead
Occipital belly (occipitalis): epicranial aponeurosis
- function:
Frontal belly: protracts scalp
Occipital belly: opposes the frontal belly to achieve the same facial expression
total function: Elevates eyebrows and produces horizontal forehead wrinkles
(surprised expression)
innervation: facial nerve CN VII
Orbicularis occuli:
origin
insertion
function
innervation
- origin:
Orbital part: frontal bone; lacrimal bone
Palpebral part: medial palpebral ligament
- insertion:
Skin around the orbital margin. Superior and inferior tarsal plates, lateral palpebral ligament - function:
Palpebral part: closes eyelids gently like during sleeping and blinking;
Orbital part:
Forcefully closes the eyes such as during winking and squinting.
innervation: facial nerve CN VII
Orbicularis oris
origin
insertion
function
innervation
- origin: Medial maxilla and mandible; peri-oral skin; angle of the mouth
- insertion: Mucous membrane of the lips
- function: Compresses and protrudes lips (kissing) or resists the distension (when blowing)
- innervation: facial nerve CN VII
Define palpebral fissure
Gap between eyelids; controlled by the orbicularis oculi
Buccinator
origin
insertion
function
innervation
- origin: Alveolar process of maxilla and mandible of the molars
- insertion: Angle of mouth; orbicularis oris
- function: Active when smiling; keeps cheeks taught; prevents biting of teeth during chewing
Presses cheeks against teeth resists tension when blowing
- innervation: facial nerve CN VII
Levator anguli oris
origin
insertion
function
innervation
- origin: Infra-orbital maxilla
- insertion: Angle of mouth
- function: elevates the angle of the mouth. Widens oral fissure (grinning or grimacing)
- innervation: facial nerve CN VII
Zygomaticus minor and major
origin
insertion
function
innervation
- origin: lateral aspect of zygomatic bone
- insertion: angle of mouth
- function:
Zygomatic minor: elevates the lips
Zygomatic major: pulls the angles of the mouth upwards and, with risorius, contributes to laughing
- innervation: facial nerve CN VII
Minor resides superior to major
Zygomatic minor spans from zygomatic bone to upper lip
Depressor anguli oris
origin
insertion
function
innervation
- origin: anterolateral base of mandible
- insertion: Angle of mouth
- function: Active during frowning; depresses commissures of lips
- innervation: facial nerve CN VII
Platysma
origin
insertion
function
innervation
- origin: Subcutaneous tissue, infraclavicular and supraclavicular regions
- insertion: Base of mandible; skin of cheek and lower lip; angle of mouth; orbicularis oris
- function: depresses mandible against resistance; tenses skin of inferior face and neck (as in stress or shaving)
- innervation: facial nerve CN VII
Most superficial
Thin sheet; covers anterolateral aspect of neck
Temporalis
origin
insertion
function
innervation
- origin: temporal fossa
- insertion: Coronoid process of the mandible
- function: Elevate and retracts the mandible at the temporomandibular joint to close the jaw
- innervation: mandibular branch of trigeminal nerve
Masseter
origin
insertion
function
innervation
- origin: Zygomatic arch
- insertion: Lateral surface of the angle and ramus of the mandible
- function: Elevates and protracts/protrudes mandible to elevate the jaw
- innervation: Mandibular branch of trigeminal nerve
Sternocleidomastoid
origin
insertion
function
innervation
- origin: Sternal head: manubrium of sternum
Clavicular head: medial third of clavicle
- insertion: Mastoid process of temporal bone
- function: Unilateral contraction of the SCM laterally flexes the neck and rotates the head, rotating the chin to the contralateral side
Forced inspiration
- innervation: accessory nerve CNXI
Risorious
origin
insertion
function
innervation
- origin: parotid fascia
- insertion: modiolus and overlying skin of angle of mouth
- function: pull angle of mouth laterally (mewing muscle)
- innervation: facial nerve CNVII
Depressor labii inferioris
origin
insertion
function
innervation
- origin: Oblique line of mandible
- insertion: Middle portion of lower lip
- function: Depress lower lip infero-laterally
- innervation: facial nerve CNVII
Mentalis
origin
insertion
function
innervation
- origin: Incisive fossa of mandible
- insertion: Subcutaneous tissue of chin
- function: Elevates and protrudes lower lip (pouting)
- innervation: facial nerve CNVII
Corrugator supercilii
origin
insertion
function
innervation
- origin: Medial portion of superciliary arch
- insertion: Skin of eyebrow
- function: Draws eyebrow downward and medially - vertical wrinkling on nose bridge
- innervation: Facial nerve CNVII
Procerus
origin
insertion
function
innervation
- origin: Fascia covering nasal bone
- insertion: Skin of forehead
- function: Pull the part of skin between the eyebrows inferiorly
Assists with nostril flaring; wrinkles nose
- innervation: Facial nerve CNVII
Nasalis
origin
insertion
function
innervation
- origin: Transverse part: area of maxilla superolateral to incisive fossa
Alar part: area of maxilla superior to lateral incisor and canine teeth
- insertion: Transverse part: Aponeurotic fascia crossing bridge of nose; skin overlying lateral crus of major alar cartilage
Alar part: skin overlying lateral crus of major alar cartilage
- function: Transverse part: compresses nostrils
Alar part: dilates nostril
- innervation: facial nerve CNVII
Medial pterygoids
origin
insertion
function
innervation
- origin: Medial surface of lateral pterygoid plate of sphenoid
- insertion: Medial surface of ramus and angle of mandible
- function: Laterally moves and protracts mandible. Elevates jaw
- innervation: CNV3 mandibular branch of trigeminal nerve
Lateral pterygoids
origin
insertion
function
innervation
- origin: Lateral surface of lateral pterygoid plate of sphenoid bone
- insertion: Neck of mandible
- function: Depress mandible
Only one that depresses mandible
- innervation: CNV3
Scalene muscles
origin
insertion
function
innervation
- origin: Transverse process of cervical vertebrae
- insertion: Anterior scalene and middle scalene: first rib
Posterior scalene: second rib
- function: Accessory muscles for inspiration
Flexion, lateral flexion, rotation of head at neck
- innervation: Cervical nerves C3-C8
Levator Scapulae
origin
insertion
function
innervation
- origin: Transverse vertebral processes of C1-C4
- insertion: Medial border of scapula
- function: Scapulae elevation
And
Lateral flexion and extension of the neck (when scapulae are stabilized on the posterior thorax)
- innervation: Anterior rami of third and fourth cervical nerves. Dorsal scapular nerve (C5)
Descending trapezius
origin
insertion
function
innervation
- origin: Spinous process of T5-T12 vertebrae
- insertion: Medial end of spine of scapula
- function: Elevates pectoral girdle
- innervation: Accessory nerve and anterior rami of third and fourth cervical nerves
