THE MUSCULATURE OF THE HEAD

By: Dr. Pamela Josefina T. Fabie

Related mainly to the orbital margins and eyelids, the external nose and nostrils, the cheeks and mouth, the pinna, scalp and cervical skin.

MUSCLES OF FACIAL EXPRESSION

COMMON CHARACTERISTICS:

1) All are inserted into the skin of the face2) All are supplied by the muscular branches

of the facial nerve3) All produce facial expression

The craniofacial ,muscles receive their innervations from the branches of the FACIAL NERVE.

They are grouped as:1. Epicranial2. Circumorbital and Palpebral3. Nasal4. Buccolabial

I. EPICRANIAL MUSCLES

1. OCCIPITOFRONATALIS – covers the dome of the skull

1. Frontalis musclesThe muscle that covers the forehead. It has no bony attachment.

ORIGIN: anterior part of the galea aponeurotica

INSERTION: skin on the lower part of the forehead

ACTION: produce transverse wrinkles on the forehead as in surprise. It raises the eyebrows.

2. Occipitalis musclesA short and narrow muscle that arises from the occipital bone

ORIGIN: lateral 2/3 of the superior nuchal line

INSERTION: posterior part of the galea aponeurotica

ACTION: draw the galea aponeurotica backwards to fix and tense it.

2. TEMPOROPARIETALIS– variably developed sheet of muscle that lies between the frontal parts of the occipitofrontalis and anterior and superior auricular muscles

Temporoparietalis

II. CIRCUMORBITAL AND

PALPEBRAL MUSCLES

1. ORBICULARIS OCULI

A. PALPEBRAL PORTIONORIGIN: medial palpebral ligament and adjacent part of the maxilla

INSERTION: outer surface of the lateral palpebral margin

ACTION: close the eyelids as in sleeping and winkling

B. ORBITAL PORTION

ORIGIN: medial palpebral ligament, frontal bone and maxilla

INSERTION: medial palpebral ligament (no lateral attachment)

ACTION: helps close the eyelids and draw lateral part of lids medially. They are responsible for the “crow’s feet” usually seen at the lateral angles of the eye

C. LACRIMAL PORTION - aka HOMER’S MUSCLE or tensor

tarsi

ORIGIN: posterior lacrimal crest

INSERTION: tarsal plate

ACTION: compress lacrimal sac, forcing the tears into the nasal cavity through the naso-lacrimal duct

TENSOR TARSI

2. CORRUGATOR SUPERCILLI – - deep muscle blending with the upper portion of the orbicularis muscle

ORIGIN: fronto-nasal suture and frontal bone, and medial part of the supercilliary arch

INSERTION: skin on the medial half of the eyebrow

ACTION: throw the skin of forehead into folds as in frowning

3. LEVATOR PALPEBRAE SUPERIORIS

ORIGIN: lesser wing of the sphenoid bone just above the optic foramen

INSERTION: skin of the upper eyelid as well as the superior tarsal plate

ACTION: elevates the upper eyelid thereby opening the eyes

III. NASAL MUSCLES

ORIGIN: nasal bone and lateral nasal cartilage

INSERTION: skin at the root of the nose

ACTION: compress the nostril and depress the cartilage of nose

A. PROCERUS – small muscle overlying the basal bone (frowning)

ORIGIN: side of the bony aperture of the nose and the upper end of the canine eminence of maxilla

INSERTION: the aponeurosis of the cartilaginous part of the nose

ACTION: compress the nostrils and depress the cartilage of the nose

B. NASALIS – aka COMPRESSOR NARES or PARS TRANSVERSUS

ORIGIN: nasal notch of the maxilla and the nasolabial groove

INSERTION: inferior border of the ala of the nose

ACTION: dilate the nostrils

C. DILATOR NARES

ORIGIN: medial fiber of the dilator naris muscle

INSERTION: mobile part of the nasal septum

ACTION: draw the septum downwards and to narrow the nostril

D. DEPRESSOR SEPTI NASI

IV. BUCCOLABIAL

MUSCLES

1.ELEVATORS, RETRACTORS and EVERTORS OF THE UPPER LIP Levator labii superioris alaque nasi Levator labii superioris Zygomaticus major and minor Levator anguli oris Risorius

ORIGIN: frontal nasal process

INSERTION: one slip goes to ala of the nose while the other goes to the orbicularis oris

ACTION: elevate the ala of the nose and the upper lip

A. LEVATOR LABII SUPRIORIS ALAQUE NASI

ORIGIN: infraorbital head, zygomatic head and angular head

INSERTION: upper lip

ACTION: elevate lateral par of upper lip. Contraction of infraorbital head gives expression of sadness. Contraction of infraorbital head gives expression of disdain or doubt

B. LEVATOR LABII SUPRIORIS

ORIGIN: zygomatic bone and arch

INSERTION: angle of the mouth

ACTION: elevate or draw angle of the mouth up and back as in laughing or smiling

C. ZYGOMATICUS MAJOR - Smiling muscle or muscle of

happiness

ORIGIN: zygomatic bone, medial to zygomatic major

INSERTION: skin on the nasolabial groove

ACTION: deepen the nasolabial groove as in sorrow

D. ZYGOMATICUS MINOR- gives the expression of pain or sorrow

ORIGIN: maxilla below the infraorbital foramen and the canine fossa of maxilla

INSERTION: fibers are directed downward, to be inserted to the angle of the mouth

ACTION: elevate angle of the mouth (also a muscle of happiness)

E. LEVATOR ANGULI ORIS OR CANINUS

ORIGIN: superficial fascia over the parotid

INSERTION: skin and mucosa of the angle of the mouth

ACTION: draw the angle of the mouth laterally, giving an expression of strain and stress

F. RISORIUS-lies horizontally across

the cheek. Gives the expression of irony or plasticity

2. DEPRESSORS, RETRACTORS and EVERTORS OF THE LOWER LIP

Depressor labii inferioris Depressor anguli oris mentalis

ORIGIN: base of the mandible, between mental protuberance and mental foramen

INSERTION: skin and mucosa of the lower lip

ACTION: draw the lower lip downward, as in ‘irony”

A. DEPRESSOR LABII INFERIORS

- a quadrilateral muscle; gives the expression of frowning

ORIGIN: oblique line of mandible

INSERTION: angle of the mouth

ACTION: depress the angle of the mouth

B. DEPRESSOR ANGULI ORIS or TRIANGULARIS

- gives the expression of sadness

ORIGIN: mandible below the lower incisor teeth and beneath oral mucosa

INSERTION: skin of chin

ACTION: elevate chin. It also causes trembling of the chin. It wrinkles the skin of the chin as in disdain or doubt.

C. MENTALIS MUSCLE

3.A COMPOUND SPHINCTER Orbicularis oris Accessory muscles to the orbicularis

oris incisivus superior and incisivus inferior

ORIGIN: buccinator muscle

INSERTION: upper lip- angle of the mouth; lower lip - mandible

ACTION: close the mouth in various ways such as closing, pressing against teeth, twisting and protruding

ORBICULARIS MUSCLE

- muscle that forms the sphincter around the mouth

BUCCINATOR MUSCLE

ORIGIN: outer surface of alveolar process of maxilla and mandible in the region of the molar teeth and pterygomandibular ligament

INSERTION: angle of the mouth blending with the orbicularis oris

ACTION: press the cheek against the teeth while chewing. Useful in mastication, whistling, sucking and blowing

PLATYSMA MUSCLE

ORIGIN: skin and superficial fascia of the pectoral and deltoid regions

INSERTION: directed upward and forward to be inserted into the lower border of the mandible

ACTION: retract and depress the angle of the mouth; Depress the mandible.

END