Muscle Attachments & Actions

Action: frontalis

elevates eyebrows. wrinkles skin of forehead horizontally.

Origin: frontalis

epicranial aponeurosis

Insertion: frontalis

skin of eyebrows

Action: masseter

elevates the mandible

Origin: masseter

zygomatic arch

Insertion: masseter

angle and lateral surface of ramus of mandible

Action: orbicularis oculi

Closes eye. Pulls skin around the eyes, as in blinking and squinting

Origin: orbicularis oculi

orbital portions of the frontal bone and maxilla

Insertion: orbicularis oculi

skin of the orbital area and eyelids

Action: orbicularis oris

Closes and protrudes lips, as in pursing the lips

Origin: orbicularis oris

maxilla and mandible

Insertion: orbicularis oris

skin and connective tissue of the lips

Action: scalene muscles

move head laterally when contracted individually. elevate rib cage with vertebral column fixed. accessory muscles of inspiration

Origin: scalene muscles

tubercles of transverse processes of C 2 through C 7

Insertion: scalene muscles

laterally on the first two ribs

Action: sternocleidomastoid

Together, flex head. Individually, flex and rotate the head toward opposite side. Accessory muscles of inspiration

Origin: sternocleidomastoid

manubrium of sternum, medial portion of clavicle

Insertion: sternocleidomastoid

mastoid process of temporal bone

Action: temporalis

Elevates and retracts the mandible

Origin: temporalis

lateral surface of skull

Insertion: temporalis

coronoid process of the mandible

Action: trapezius (superior section)

Extends the head (raises head from bowed position)

Origin: trapezius (superior section)

external occipital protuberance and cervical vertebrae

Insertion: trapezius (superior section)

lateral portion of clavicle

Action: inferior oblique

Pulls (and helps rotate) anterior eye superiorly and laterally, as when left eye rolls to left and up

Origin: inferior oblique

Maxilla just inside the anterior portion of the orbit

Insertion: inferior oblique

Inferior/ lateral surface of eye

Action: inferior rectus

Depresses (rotates downward) anterior eye, as in looking down, and turns eye medially

Origin: inferior rectus

Common tendinous ring of posterior orbit

Insertion: inferior rectus

Inferior surface of eye

Action: lateral rectus

Pulls anterior eye laterally, as when looking toward the temple

Origin: lateral rectus

Common tendinous ring of posterior orbit

Insertion: lateral rectus

Lateral surface of eye

Action: medial rectus

Pulls anterior eye medially, toward the nose

Origin: medial rectus

Common tendinous ring of posterior orbit

Insertion: medial rectus

Medial surface of eye

Action: superior oblique

Pulls (and helps rotate) anterior eye inferiorly and laterally, as when left eye rolls to left and down

Origin: superior oblique

The posterior orbit

Insertion: superior oblique

Superior/ lateral surface of eye after passing through the trochlea

Action: superior rectus

Elevates (rotates upward) anterior eye, as in looking up and turns eye medially

Origin: superior rectus

Common tendinous ring of posterior orbit

Insertion: superior rectus

Superior surface of eye

Action: deltoid

Abducts the arm; secondarily flexes and extends arm

Origin: deltoid

Acromion and spine of scapula; lateral clavicle

Insertion: deltoid

Deltoid tuberosity of humerus

Action: Latissimus dorsi

Adducts and extends the arm; rotates arm medially

Origin: Latissimus dorsi

Iliac crest, spinous processes of lower thoracic and all lumbar vertebrae

Insertion: Latissimus dorsi

Floor of intertubercular sulcus of the humerus

Action: Pectoralis major

Flexes and adducts the arm; rotates arm medially

Origin: Pectoralis major

Medial clavicle, sternum, costal cartilages 1-7

Insertion: Pectoralis major

Greater tubercle and lateral lip of intertubercular sulcus of humerus

Action: Pectoralis minor

Protracts and depresses scapula

Origin: Pectoralis minor

Anterior part of ribs 3-5

Insertion: Pectoralis minor

Coracoid process

Action: Rhomboid major and rhomboid minor muscles

Retracts scapula

Origin: Rhomboid major and rhomboid minor muscles

Spinous processes of: T2-T5 (major); C7-T1 (minor)

Insertion: Rhomboid major and rhomboid minor muscles

Medial border of scapula

Action: Serratus anterior

Prime mover of scapula in protraction; assists in superior rotation of scapula

Origin: Serratus anterior

First nine ribs

Insertion: Serratus anterior

Medial border of scapula

Action: Teres major

Adducts, extends, and rotates arm medially

Origin: Teres major

Posterior, inferior portion of scapula

Intersection: Teres major

Medial lip of intertubercular sulcus of the humerus

Action: Trapezius muscle (superior section)

Elevates the scapula; rotates scapula superiorly in collaboration with inferior portion

Origin: Trapezius muscle (superior section)

External occipital protuberance and cervical vertebrae

Insertion: Trapezius muscle (superior section)

Lateral clavicle

Action: Trapezius muscle (all sections)

Retracts (via middle portion) and depresses (via inferior section) the scapula; rotates scapula superiorly and elevates scapula (via superior section)

Origin: Trapezius muscle (all sections)

Spinous processes of thoracic vertebrae

Insertion: Trapezius muscle (all sections)

Spine and acromion of scapula

Action: Infraspinatus muscle #

Laterally rotates the humerus; stabilizes shoulder joint

Origin: Infraspinatus muscle #

Infraspinous fossa of scapula

Insertion: Infraspinatus muscle #

Greater tubercle of humerus

Action: Subscapularis muscle

Adducts and rotates the humerus medially: stabilizes shoulder joint

Origin: Subscapularis muscle

Subscapular fossa of scapula

Insertion: Subscapularis muscle

Lesser tubercle of humerus

Action: Supraspinatus muscle

Assists abduction: holds the humerus and stabilizes shoulder joint

Origin: Supraspinatus muscle

Supraspinous fossa of scapula

Insertion: Supraspinatus muscle

Greater tubercle of humerus

Action: Teres minor muscle

Laterally rotates the humerus: stabilizes shoulder joint

Origin: Teres minor muscle

Posterior, lateral border of scapula

Insertion: Teres minor muscle

Greater tubercle of humerus

Action: Biceps brachii muscle

Supinates the forearm; flexes the forearm

Origin: Biceps brachii muscle

Supraglenoid tubercle (long head) and coracoid process (short head)

Insertion: Biceps brachii muscle

Radial tuberosity

Action: Brachialis muscle

Flexes the forearm (prime mover)

Origin: Brachialis muscle

Distal half of the diaphysis of the anterior humerus

Insertion: Brachialis muscle

Coronoid process of ulna

Action: Brachioradialis muscle

Flexes the forearm (synergist)

Origin: Brachioradialis muscle

Ridge proximal to the lateral condyle of the distal humerus

Insertion: Brachioradialis muscle

Distal radius proximal to the styloid process

Action: Extensor carpi radialis brevis muscle

Extends hand; abducts hand

Origin: Extensor carpi radialis brevis muscle

Lateral epicondyle of humerus

Insertion: Extensor carpi radialis brevis muscle

Third metacarpal

Action: Extensor carpi radialis longus muscle

Extends hand; abducts hand

Origin: Extensor carpi radialis longus muscle

Lateral lower diaphysis of humerus

Insertion: Extensor carpi radialis longus muscle

Second metacarpal

Action: Extensor carpi ulnaris muscle

Extends hand; adducts hand

Origin: Extensor carpi ulnaris muscle

Lateral epicondyle of humerus, lateral proximal ulna

Insertion: Extensor carpi ulnaris muscle

Fifth metacarpal

Action: Extensor digitorum muscle

Extends fingers; extends hand