EPICRANIUS (OCCIPITOFRONTALIS)

Muscles of the face and neck

Greek, epi-, above, upon; cranium, skull.

This muscle is effectively two muscles (occipitalis and frontalis), united by an aponeurosis called the galea aponeurotica, so named because it forms what resembles a helmet upon the skull.

Origin

Occipitalis: Occipital bone. Mastoid process of temporal bone.

Frontalis: Galea aponeurotica.

Insertion

Occipitalis: Galea aponeurotica (a sheet-like tendon leading to frontal belly).

Frontalis: Fascia and skin above eyes and nose.

Action

Occipitalis: Pulls scalp backward.

Frontalis: Pulls scalp forwards.

Nerve

Facial V11 nerve.

Basic functional movement

Example: Raises eyebrows (wrinkles skin of forehead horizontally).

ORBICULARIS OCULI

Orbital and palpebral part

Latin, orbis, orb, circle; oculi, of the eye.

This complex and extremely important muscle consists of three parts, which together form an important protective mechanism surrounding the eye.

ORBITAL PART

Origin

Frontal bone. Medial wall of orbit (on maxilla).

Insertion

Circular path around orbit, returning to origin.

Action

Strongly closes eyelids (firmly ‘screws up’ the eye).

Nerve

Facial V11 nerve (temporal and zygomatic branches).

PALPEBRAL PART

(in eyelids)

Latin, pertaining to an eyelid.

Origin

Medial palpebral ligament.

Insertion

Lateral palpebral ligament into zygomatic bone.

Action

Gently closes eyelids (and comes into action involuntarily, as in blinking).

Nerve

Facial V11 nerve (temporal and zygomatic branches).

LACRIMAL PART

(behind medial palpebral ligament and lacrimal sac)

Latin, pertaining to the tears.

Origin

Lacrimal bone.

Insertion

Lateral palpebral raphe.

Action

Dilates lacrimal sac and brings lacrimal canals onto surface of eye.

Nerve

Facial V11 nerve (temporal and zygomatic branches).



CORRUGATOR SUPERCILII

Latin, corrugator, muscle which wrinkles; supercilii, of the eyebrow.

Origin

Medial end of supercilliary arch of frontal bone.

Insertion

Deep surface of skin under medial half of the eyebrows.

Action

Draws eyebrows medially and downward, so producing vertical wrinkles, as in frowning.

Nerve

Facial V11 nerve (temporal branch).

Basic functional movement

Facilitates facial expression.

PROCERUS

Latin, long, slender.

Origin

Fascia over nasal bone. Lateral nasal cartilage.

Insertion

Skin between eyebrows.

Action

Wrinkles nose. Pulls medial portion of eyebrows downwards.

Nerve

Facial V11 nerve.

Basic functional movement

Example: Enables strong ‘sniffing’ and sneezing.



NASALIS

Latin, nasus, nose.

Origin

Middle of maxilla (above incisor and canine teeth). Greater alar cartilage. Skin on nose.

Insertion

Joins muscle of opposite side across bridge of nose. Skin at tip of nose.

Action

Maintains opening of external nares during forceful inhalation (i.e. flares the nostrils).

Nerve

Facial V11 nerve (buccal branches).

Basic functional movement

Example: Strongly breathing in through the nose.

ORBICULARIS ORIS

Latin, orbis, orb, circle; oris, pertaining to the mouth.

This is a composite sphincter muscle that encircles the mouth. It receives fasciculi from many other muscles.

Origin

Muscle fibres surrounding the opening of mouth, attached to the skin, muscle and fascia of the lips and surrounding area.

Insertion

Skin and fascia at corner of mouth.

Action

Closes lips, compresses lips against teeth, protrudes (purses) lips, and shapes lips during speech.

Nerve

Facial V11 nerve (buccal and mandibular branches).

Basic functional movement

Facial expressions involving the lips.



LEVATOR LABII SUPERIORIS

Latin, levare, to raise; labium, lip; superioris, above.

Origin

Angular head: Zygomatic bone and frontal process of maxilla. Infraorbital head: Lower border of orbit.

Insertion

Angular head: Greater alar cartilage, upper lip and skin of nose. Infraorbital head: Muscles of upper lip.

Action

Raises upper lip. Dilates nares. Forms nasolabial furrow.

Nerve

Facial V11 nerve (buccal branches).

Basic functional movement

Facilitates facial expression and kissing.

LEVATOR ANGULI ORIS

Latin, levare, to raise; angulus, angle; oris, pertaining to the mouth.

Origin

Canine fossa of maxilla.

Insertion

Corner of mouth.

Action



Elevates angle (corner) of mouth.

Nerve

Facial V11 nerve (buccal branches).

Basic functional movement

Helps produce a smiling expression.

ZYGOMATICUS (MAJOR AND MINOR

Greek, zygon, yoke, union; Latin, major, large; minor, small.

Origin

Zygomaticus major: Upper lateral surface of zygomatic bone.

Zygomaticus minor: Lower surface of zygomatic bone.

Insertion

Zygomaticus major: Skin at corner of mouth. Orbicularis oris.

Zygomaticus minor: Lateral part of upper lip lateral to levator labii superioris.

Action

Zygomaticus major: Pulls corner of mouth up and back, as in smiling.

Zygomaticus minor: Elevates the upper lip. Forms nasolabial furrow.

Nerve

Facial V11 nerve (zygomatic and buccal branches).

Basic functional movement

Smiling. Facilitates facial expression.

DEPRESSOR LABII INFERIORIS

Latin, deprimere, to press down; labii, of the lip; inferior, below.

Origin

Anterior surface of mandible, between mental foramen and symphysis.

Insertion

Skin of lower lip.

Action

Pulls lower lip downward and slightly laterally.

Nerve

Facial V11 nerve (marginal mandibular branch).

Basic functional movement

Facilitates facial expression.



DEPRESSOR ANGULI ORIS

Latin, deprimere, to press down; angulus, angle; oris, pertaining to the mouth.

Muscle fibres are continuous with the platysma.

Origin

Oblique line of the mandible.

Insertion

Corner of mouth.

Action

Pulls corner of mouth downwards, as in sadness or frowning.

Nerve

Facial V11 nerve (marginal mandibular and buccal branches).

MENTALIS

Latin, relating to the chin.

This is the only muscle of the lips that normally has no connection with the orbicularis oris.

Origin

Incisive fossa of anterior surface of mandible.

Insertion

Skin of chin.

Action

Protrudes lower lip and pulls up (wrinkles) skin of chin, as in pouting.

Nerve

Facial V11 nerve (marginal mandibular branch).

PLATYSMA muscle

 

Greek, platy, broad, flat.

This muscle may be seen to stand out in a runner finishing a hard race.

Origin

Subcutaneous fascia of upper quarter of chest (i.e. fascia overlying the pectoralis major and deltoideus muscles).

Insertion

Subcutaneous fascia and muscles of chin and jaw. Inferior border of mandible.

Action

Pulls lower lip from corner of mouth downwards and laterally. Draws skin of chest upwards.

Nerve

Facial V11 nerve (cervical branch).

Basic functional movement

Example: Gives expression of being startled or of sudden fright.

BUCCINATOR

Latin, buccina, trumpet; bucca, cheek.

This muscle forms the substance of the cheek.

Origin

Alveolar processes of maxilla and mandible over molars and along pterygomandibular raphe (fibrous band extending from the pterygoid hamulus to the mandible).

Insertion

Orbicularis oris (muscles of lips).

Action

Compresses cheek as in blowing air out of mouth, and caves cheeks in, producing the action of sucking.

Nerve

Facial V11 nerve (buccal branches).



MASSETER

Greek, maseter, chewer.

The masseter is the most superficial muscle of mastication, easily felt when the jaw is clenched.

Origin

Zygomatic arch (cheek bone).

Insertion

Lateral surface of mandible (lower jaw).

Action

Closes jaw. Clenches teeth. Assists in side to side movement of mandible.

Nerve

Trigeminal V nerve (mandibular division).

Basic functional movement

Chewing food.

TEMPORALIS

Zygomatic arch has been removed.

Latin, time (seen by the greying of hairs in this region).

Origin

Temporal fossa including frontal, parietal and temporal bones.

Insertion

Coronoid process and ramus of mandible (area on lower jaw, just below the lateral edge of the zygomatic arch).

Action

Closes jaw. Clenches teeth. Assists in side to side movement of mandible.

Nerve

Anterior and posterior deep temporal nerves from the trigeminal V nerve (mandibular division).

Basic functional movement

Chewing food.

PTERYGOIDEUS LATERALIS (LATERAL PTERYGOID)

Greek, pterygodes, like a wing; Latin, lateral, to the side.

The superior head of this muscle is sometimes called sphenomeniscus, because it inserts into the disc of the temporomandibular joint.

Origin

Superior head: Lateral surface of greater wing of sphenoid.

Inferior head: Lateral surface of lateral pterygoid plate of sphenoid.

Insertion

Superior head: Capsule and articular disc of the temporomandibular joint.

Inferior head: Neck of mandible.

Action

Protrudes mandible. Opens mouth. Moves mandible from side to side (as in chewing).

Nerve

Trigeminal V nerve (mandibular division).

Basic functional movement

Chewing food.

PTERYGOIDEUS MEDIALIS (MEDIAL PTERYGOID)

Greek, pterygodes, like a wing; Latin, medius, middle.

This muscle mirrors the masseter muscle in both its position and action, with the ramus of the mandible positioned between the two muscles.

Origin

Medial surface of lateral pterygoid plate of the sphenoid bone. Pyramidal process of the palatine bone. Tuberosity of maxilla.

Insertion

Medial surface of the ramus and the angle of the mandible.

Action

Elevates and protrudes the mandible. Therefore it closes the jaw and assists in side to side movement of the mandible, as in chewing.

Nerve

Trigeminal V nerve (mandibular division).

Basic functional movement

Chewing food.



SCALENUS ANTERIOR, MEDIUS, POSTERIOR

Greek, skalenos, uneven; Latin, anterior, before; medius, middle; posterior, behind.

Origin

Transverse processes of cervical vertebrae.

Insertion

Anterior and medius: First rib.

Posterior: Second rib.

Action

Acting together: Flex neck. Raise first rib during a strong inhalation.

Individually: Laterally flex and rotate neck.

Nerve

Ventral rami of cervical nerves, C3–C8.

Basic functional movement

The scaleni are primarily muscles of inspiration.

Sports that heavily utilise these muscles

All active sports that require strong respiration (e.g. high pace running).

Common problems when muscles are chronically tight / shortened

Painful conditions of the neck, shoulder and arm because hypertonic muscle puts pressure on a bundle of nerves called the brachial plexus, and the subclavian artery.

STERNOCLEIDOMASTOIDEUS

Greek, sternon, sternum; kleidos, key, clavicle; mastoid, breast-shaped, mastoid process.

This muscle is a long strap muscle with two heads. It is sometimes injured at birth, and may be partly replaced by fibrous tissue that contracts to produce a torticollis (wry neck).

Origin

Sternal head: Anterior surface of upper sternum.

Clavicular head: Medial third of clavicle.

Insertion

Mastoid process of temporal bone (bony prominence just behind the ear).

Action

Contraction of both sides together: Flexes neck (draws head forward). Raises sternum, and consequently the ribs, during deep inhalation. Contraction of one side: Tilts the head towards the same side. Rotates head to face the opposite side (and also upward as it does so).

Nerve

Accessory X1 nerve; with sensory supply for proprioception from cervical nerves C2 and C3.

Basic functional movement

Examples: Turning head to look over your shoulder. Raising head from pillow.

Sports that heavily utilise this muscle

Examples: Swimming. Rugby scrummage. American football.

Movements or injuries that may damage this muscle

Extreme whiplash movements.

Common problems when muscle is chronically tight / shortened

Headache and neck pain.

 

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