Anatomy-Physiology: Head & Neck Muscle Images

Corrugator supercilii

Draws eyebrows together and inferiorly; wrinkles skin of forehead vertically (as in frowning).

O - arch of frontal bone above nasal bone.
I - skin of eyebrow.

Nerve Supply - Facial (Cranial VII)

Orbicularis oculi

Sphincter muscle of eyelid; surrounds rim of the orbit.

Various parts can be activated individually; produces blinking, squinting, and draws eyebrows inferiorly.

O - frontal and maxillary bones and ligaments around the orbit.
I - tissue of the eyelid.

Nerve Supply - Facial (Cranial VII)

Levator labii superioris

Opens lips; raises and furrows the upper lip.

O - zygomatic bone and infraorbital margin of maxilla.
I - skin and muscle of upper lip.

Nerve Supply - Facial (Cranial VII)

Zygomaticus minor and major

Raises lateral corners of the mouth upward (smiling muscle)

O - zygomatic bone.
I - skin and muscle at corner of mouth.

Nerve Supply - Facial (Cranial VII)

Buccinator

Principal muscle of the cheek; draws corner of the mouth laterally; compresses cheek; holds food between teeth during chewing.

O - molar region of maxilla and mandible.
I - orbicularis oris.

Nerve Supply - Facial (Cranial VII)

Risorius

Draws corner of lip laterally; tenses lips; synergist of zygomaticus.

O - lateral fascia associated with masseter muscle.
I - skin at angle of mouth,

Nerve Supply - Facial (Cranial VII)

Orbicularis oris

Complicated, multilayered muscle with fibers running in many directions.

Closes lips; purses and protrudes lips.

O - arises indirectly from maxilla and mandible.
I - encircles mouth; inserts into muscle and skin at angles of mouth.

Nerve Supply - Facial (Cranial VII)

Mentalis

One of a pair of muscles on chin.

Protrudes lower lip; wrinkles chin,

O - mandible below incisors.
I - skin of chin.

Nerve Supply - Facial (Cranial VII)

Depressor labii inferioris

Draws lower lip inferiorly (as in a pout).

O - body of mandible later to its midline.
I - skin and muscle of lower lip.

Nerve Supply - Facial (Cranial VII)

Depressor anguli oris

Zygomaticus antagonist; draws corners of mouth downward and laterally.

O - body of mandible below incisors.
I - skin and muscle at angle of mouth below insertion of zygomaticus.

Nerve Supply - Facial (Cranial VII)

Frontalis (Frontal Belly of Epicranius)

No bony attachments.

Raises and lowers eyebrows; wrinkles the forehead.

O - galea aponeurotica.
I - skin of eyebrows and root of nose.

Nerve Supply - Facial (Cranial VII)

Masseter

Prime mover of jaw closure; elevates mandible.

O - zygomatic arch and maxilla.
I - angle and ramus of mandible.

Nerve Supply - Trigeminal (Cranial V)

Galea aponeurotica

Cranial aponeurosis between frontalis and occipalis muscles of the epicranius.

Occipitalis (Occipital Belly of Epicranius)

Fixes aponeurosis; pulls scalp posteriorly.

O - occipital and temporal bones.
I - galea aponeurotica.

Nerve Supply - Facial (Cranial VII)

Temporalis

Closes jaw; elevates and retracts mandible; synergist of pterygoids in side-to-side movements; maintains position of mandible at rest.

O - temporal fossa.
I - coronoid process of mandible.

Nerve Supply: Trigeminal (Cranial V)

Sternocleidomastoid

Key muscular landmark in the neck.

Prime mover of active head flexion.

O - manubrium of sternum and medial portion of clavicle.
I - mastoid process of temporal bone and superior nuchal line of occipital bone.

Nerve Supply - Accessory (Cranial XI) and branches of C-2, C-3 spinal nerves (ventral rami).

Trapezius

Stabilizes, raises, and rotates scapula.

O - occipital bone, ligamentum nuchae, and spines of C-7 and all thoracic vertebrae.
I - continuous insertion along acromion and spine of scapula and lateral third of clavicle.

Nerve Supply - Accessory (Cranial XI), and C-3, C-4.

Splenius capitis

Extends or hyperextends head; when muscles on one side of head are activated, head is rotated and bent laterally toward the same side.

O - ligamentum nuchae and spinous processes of C-7 through T-6 vertebrae.
I - mastoid process of temporal bone and occipital bone.

Nerve Supply - cervical spinal nerves (dorsal rami).

Platysma

Plays a role in facial expression; helps depress mandible; pulls lower lip back and down.

O - fascia of chest.
I - lower margin of mandible, as well as skin and muscle at corner of mouth.

Nerve Supply - Facial (Cranial VII)

Buccinator

Principal muscle of the cheek; draws corner of the mouth laterally; compresses cheek; holds food between teeth during chewing.

O - molar region of maxilla and mandible.
I - orbicularis oris.

Nerve Supply - Facial (Cranial VII)

Masseter

Prime mover of jaw closure; elevates mandible.

O - zygomatic arch and maxilla.
I - angle and ramus of mandible.

Nerve Supply - Trigeminal (Cranial V)

Temporalis

Closes jaw; elevates and retracts mandible; synergist of pterygoids in side-to-side movements; maintains position of mandible at rest.

O - temporal fossa.
I - coronoid process of mandible.

Nerve Supply: Trigeminal (Cranial V)

Lateral pterygoid

Protrudes mandible (pulls it anteriorly); provides forward sliding and side-to-side grinding movements of the lower teeth.

O - greater wing and lateral ptergoid plate of sphenoid bone.
I - condyle of mandible and capsule of temporomandibular joint.

Nerve Supply - Trigeminal (Cranial V)

Medial pterygoid

Synergist of temporalis and masseter muscles in elevation of the mandible; acts with lateral pterygoid to protrude mandible and to promote side-to-side movements.

O - medial surface of lateral pterygoid plate of sphenoid bone, maxilla, and palatine bone.
I - medial surface of mandible near its angle.

Nerve Supply - Trigeminal (Cranial V)

Styloglossus

Retracts (and elevates) tongue.

O - styloid process of temporal bone.
I - interolateral tongue.

Nerve Supply - Hypoglossal (Cranial XII)

Hyoglossus

Depresses tongue and draws its sides downward.

O - body and greater horn of hyoid bone.
I - inferolateral tongue.

Nerve Supply - Hypoglossal (Cranial XII)

Stylohyoid

Elevates and retracts hyoid, thereby elongating floor of mouth during swallowing.

O - styloid process of temporal bone.
I - hyoid bone.

Nerve Supply - Facial (Cranial VII)

Thyrohyoid

Appears as a superior continuation of sternothyroid muscle.

Depresses hyoid bone and elevates larynx if hyoid is fixed.

O - thyroid cartilage.
I - hyoid bone.

Nerve Supply - First cervical nerve via hypoglossal nerve (Cranial XII).

Genioglossus

Forms the bulk of inferior part of tongue; attachment to mandible prevents from falling backwards; primarily protrudes tongue, but can depress or act in concert with other extrinsic muscles to retract tongue.

O - internal surface of mandible near symphysis.
I - inferior aspect of the tongue and body of hyoid bone.

Nerve Supply - Hypoglossal (Cranial XII)

Geniohyoid

Pulls hyoid bone superiorly and anteriorly, shortening floor of mouth and widening pharynx for receiving food.

O - inner surface of mandibular symphysis.
I - hyoid bone.

Nerve Supply - First cervical spinal nerve via hypoglossal nerve (Cranial XII)

Mylohyoid

Muscle pair; elevates hyoid bone and floor of mouth, which forces food bolus into the pharynx.

O - medial surface of mandible.
I - hyoid bone and median raphe.

Nerve Supply - Mandibular branch of trigeminal nerve (Cranial V)

Stylohyoid

Elevates and retracts hyoid bone, thereby elongating the floor of the mouth during swallowing.

O - styloid process of temporal bone.
I - hyoid bone.

Nerve Supply - Facial (Cranial VII)

Omohyoid

Depresses and retracts hyoid bone,

O - superior surface of scapula.
I - hyoid bone, lower border.

Nerve Supply - Cervical spine nerves C-1 to C-3, through ansa cervicalis (slender nerve root in cervical plexus).

Sternohyoid

Depresses larynx and hyoid bone if mandible is fixed; may also flex skull.

O - manubrium and medial end of clavicle.
I - lower margin of hyoid bone.

Nerve Supply - Cervical spine nerves C-1 to C-3, through ansa cervicalis (slender nerve root in cervical plexus).

Sternocleidomastoid

Key muscular landmark in the neck.

Prime mover of active head flexion.

O - manubrium of sternum and medial portion of clavicle.
I - mastoid process of temporal bone and superior nuchal line of occipital bone.

Nerve Supply - Accessory (Cranial XI) and branches of C-2, C-3 spinal nerves (ventral rami).

Omohyoid

Depresses and retracts hyoid bone.

O - superior surface of scapula.
I - hypoid bone, lower border.

Nerve Supply - Cervical spine nerves C-1 to C-3, through ansa cervicalis (slender nerve root in cervical plexus).

Anterior belly of digastric muscle

Elevate hyoid bone and steady it during swallowing and speech; open mouth and depress mandible.

O - lower margin of mandible.
I - connective tissue loop to hyoid bone.

Nerve Supply - mandibular branch of trigeminal nerve (Cranial V)

Posterior belly of digastric muscle

Elevate hyoid bone and steady it during swallowing and speech; open mouth and depress mandible.

O - mastoid process of the temporal bone.
I - connective tissue loop to hyoid bone.

Nerve Supply - Facial (Cranial VII)

Thyrohyoid

Appears as a superior continuation of sternothyroid muscle.

Depresses hyoid bone and elevates larynx if hyoid is fixed.

O - thyroid cartilage.
I - hyoid bone.

Nerve Supply - First cervical nerve via hypoglossal nerve (Cranial XII).

Sternothyroid

Pulls thyroid cartilage (including larynx and hyoid bone) interiorly.

O - posterior surface of manubrium of sternum.
I - thyroid cartilage.

Nerve Supply - Cervical spine nerves C-1 to C-3, through ansa cervicalis (slender nerve root in cervical plexus).

Tensor veli palatini

Associated with mastication and opening of the Eustachian tube through its function of tensing the palate.

O - medial pterygoid plate of the sphenoid bone.
I - palatine aponeurosis.

Nerve Supply - medial pterygoid nerve, a branch of mandibular nerve, the third branch of the trigeminal nerve (Cranial V).

Levator veli palatini

Elevates soft palate to help prevent food from entering the nasopharynx.

O - temporal bone and Eustachian tube.
I - palatine aponeurosis.

Nerve Supply - Vagus (Cranial X).

Superior pharyngeal constrictor

Contracts upon food bolus, sending it down the esophagus.

O - medial pterygoid plate, pterygomandibular raphé, and alveolar process.
I- pharyngeal raphe, pharyngeal tubercle.

Nerve Supply - Vagus (Cranial X)

Middle pharyngeal constrictor

Contracts upon food bolus, sending it down the esophagus.

O - hyoid bone.
I - pharyngeal raphe.

Nerve Supply - Vagus (Cranial X)

Inferior pharyngeal constrictor

Contracts upon food bolus, sending it down the esophagus.

O - cricoid and thyroid cartilages.
I - pharyngeal raphe.

Nerve Supply - Vagus (Cranial X)

Buccinator

Principal muscle of the cheek; draws corner of the mouth laterally; compresses cheek; holds food between teeth during chewing.

O - molar region of maxilla and mandible.
I - orbicularis oris.

Nerve Supply - Facial (Cranial VII)

Geniohyoid

Pulls hyoid bone superiorly and anteriorly, shortening floor of mouth and widening pharynx for receiving food.

O - inner surface of mandibular symphysis.
I - hyoid bone.

Nerve Supply - First cervical spinal nerve via hypoglossal nerve (Cranial XII)

Hyoglossus

Depresses tongue and draws its sides downward.

O - body and greater horn of hyoid bone.
I - inferolateral tongue.

Nerve Supply - Hypoglossal (Cranial XII)

Sternocleidomastoid

Key muscular landmark in the neck.

Prime mover of active head flexion.

O - manubrium of sternum and medial portion of clavicle.
I - mastoid process of temporal bone and superior nuchal line of occipital bone.

Nerve Supply - Accessory (Cranial XI) and branches of C-2, C-3 spinal nerves (ventral rami).

Middle Scalene

Elevates first two ribs (assists in respiration); flex and rotate neck.

O - transverse processes of cervical vertebrae.
I - anterolaterally of first two ribs.

Nerve Supply - cervical spine nerves.

Anterior Scalene

Elevates first two ribs (assists in respiration); flex and rotate neck.

O - transverse processes of cervical vertebrae.
I - anterolaterally of first two ribs.

Nerve Supply - cervical spine nerves.

Posterior Scalene

Elevates first two ribs (assists in respiration); flex and rotate neck.

O - transverse processes of cervical vertebrae.
I - anterolaterally of first two ribs.

Nerve Supply - cervical spine nerves.

Splenius capitis

Extends or hyperextends head; when muscles on one side of head are activated, head is rotated and bent laterally toward the same side.

O - ligamentum nuchae and spinous processes of C-7 through T-6 vertebrae.
I - mastoid process of temporal bone and occipital bone (capitalis), and transverse process of C-2 through C-4 vertebrae (cervicis).

Nerve Supply - cervical spinal nerves (dorsal rami).

Splenius cervicus

Extends or hyperextends head; when muscles on one side of head are activated, head is rotated and bent laterally toward the same side.

O - ligamentum nuchae and spinous processes of C-7 through T-6 vertebrae.
I - transverse process of C-2 through C-4 vertebrae.

Nerve Supply - cervical spinal nerves (dorsal rami).