Muscles - Attachment sites and actions

Elaine Laurent

semispinalis action

extends and rotates head

splenius capitis action

extends, rotates and laterally flexes the head

Sternocleidomastoid attachment site

superior= mastoid process of temporal bone

inferior= manubrium and clavicle

sternocleidomastoid action

simultaneous contraction of both heads of muscle= flexion of head

individual contraction= rotates and flexes head to opposite side of contracting muscle

Buccinator action

compresses (pulls forward) cheeks (like whistling and kissing)

Depressor Labii inferioris action

depresses lower lip (frowning or expression of doubt)

Levator Labii Superioris action

elevates upper lip (sneering)

Occipitofrontalis action

elevates eyebrows, wrinkles skin of forehead, draws scalp anteriorly (expressions of surprise or fright)

orbicularis oculi action

closes eye by depressing upper eyelid and elevating lower eyelid (blinking or squinting)

orbicularis oris action

platysma action

depresses mandible, depresses lower lip back and down, tenses skin of neck

zygomaticus action

retracts and elevates upper lip and corner of mouth (smiling)

Temporalis attachment site

superior= temporal lines on parietal and frontal bones

inferior= coronoid process of mandible

temporalis action

elevates and retracts mandible for biting and chewing

masseter attachment site

superior= zygomatic arch

inferior= lateral side of mandible

masseter action

elevates and protracts the mandible

Digastric attachment site

superior= mastoid process (posterior belly), mandible near midline (anterior belly)

inferior= hyoid

Digastric action

Depresses mandible when hyoid is fixed by other muscles, retracts mandible and elevates hyoid

geniohyoid action

protracts and elevates hyoid, depresses mandible

mylohyoid action

elevates floor of mouth and hyoid during swallowing

omohyoid action

depresses hyoid, fixes hyoid for depression of mandible

sternohyoid

depresses hyoid

iliocostalis action

extends and laterally flexes vertebral column

longissimus action

extends and laterally flexes vertebral column

spinalis action

extends vertebral column

interspinales action

extends back and neck

multifidus action

extends and rotates vertebral column

Diaphragm action

depresses floor of thoracic cavity for INHALATION

external intercostals action

elevates ribs for INHALATION

Internal intercostals action

depresses ribs for EXHALATION

External abdominal oblique action

compression of abdomen, flexion (lateral and anterior) and rotation of vertebral column

Internal abdominal oblique action

compression of abdomen, flexion (lateral and anterior) and rotation of vertebral column

Transversus abdominis action

compression of abdomen

rectus abdominis action

compression of abdomen and flexion (anterior) of vertebral column

Pectoralis minor action

depression and protraction of scapula

serratus anterior action

protraction and rotation of scapula

rhomboid action

elevation, retraction and rotation of scapula

levator scapulae action

elevation and rotation of scapula

Trapezius actions (fibers)

Superior fibers - elevation of scapula

middle fibers - retraction of scapula

inferior fibers - depression of scapula

Deltoid action

abduction, flexion, extension and rotation of arm

pectoralis major attachment site

proximal= sternum, clavicle and ribs

distal= intertubercular sulcus of humerus

pectoralis major action

flexion, medial rotation and adduction of arm

latissimus dorsi action

extension, medial rotation and adduction of arm

teres major action

extension, adduction, and medial rotation of arm

Rotator cuff Muscles

S.I.T.S

supraspinatus, infraspinatus, teres minor, subscapularis

Supraspinatus attachment site

proximal= supraspinous fossa of scapula

distal= greater tubercule of humerus

supraspinatus action

abduction of arm

infraspinatus attachment site

proximal= infraspinous fossa of scapula

distal= greater tubercle of humerus

infraspinatus action

adduction and lateral rotation of arm

teres minor attachment site

proximal= lateral edge of scapula

distal= greater tubercle of humerus

teres minor action

adduction and lateral rotation of arm

subscapularis attachment site

proximal= subscapular fossa

distal= lesser tubercle of humerus

subscapularis action

medial rotation of arm

biceps brachii attachment site

proximal= scapula

distal=radial tuberosity

biceps brachii action

flexion and supination of forearm

brachialis action

flexion of forearm

brachioradialis action

flexion of forearm

triceps brachii attachment site

proximal= scapula and humerus

distal= olecranon of ulna

triceps brachii action

extension of forearm

pronator teres action

pronation of forearm

supinator action

supination of forearm

flexor carpi radialis action

flexion of wrist and abduction of hand

flexor carpi ulnaris action

flexion of wrist and adduction of hand

flexor digitorum action

flexion of wrist and digits

extensor carpi radialis action

extension of wrist and abduction of hand

extensor carpi ulnaris action

extension of wrist and adduction of hand

extensor digitorum action

extension of wrist and digits

iliopsoas action

flexion of thigh at hip

gluteus maximus attachment site

proximal= ilium, sacrum and coccyx

distal= posterior side of femur

gluteus maximus action

extension and lateral rotation of thigh at hip

gluteus medius attachment site

proximal= ilium

distal= greater trochanter of femur

gluteus Medius action

abduction of thigh at hip

gluteus minimus attachment site

proximal= ilium

distal= greater trochanter of femur

gluteus minimus action

abduction of thigh at hip

quadriceps femoris attachment site

proximal= ilium, greater trochanter of femur and shaft of femur

distal= tibial tuberosity of tibia

quadriceps femoris action

extension of knee

sartorius action

flexion of thigh and knee and lateral rotation of thigh

adductors action

adduction of thigh

hamstrings action

flexion of knee

Gastrocnemius attachment site

proximal= lateral and medial condyles of femur

distal= calcaneus (gastrocnemius and soleus attach to calcaneus via the calcaneal tendon)

gastrocnemius action

flexion of foot

soleus action

flexion of foot