Muscle Action/Origin/Insertion - BIO210 Human Anatomy

orbicularis oculi (muscle of facial expression)

action: close eye

orbicularis Oris (muscle of facial expression)

action: close and purse lips

buccinator (muscle of facial expression)

action: compress cheek (as in sucking)

depressor anguli oris (muscle of facial expression)

action: depress and draw corner of mouth laterally

risorius (muscle of facial expression)

action: draw corner of mouth laterally

zygomaticus major (muscle of facial expression)

action: elevate corner of mouth (as in smile)

origin: zygomatic bone

zygomaticus minor (muscle of facial expression)

action: elevate upper lip

origin: zygomatic bone

platysma (muscle of facial expression)

action: tense skin of neck, depress mandible

lateral rectus (extrinsic muscles of the eye)

action: eyes look laterally

medial rectus (extrinsic muscles of the eye)

action: eye looks medially

insertion: sclera

inferior rectus (extrinsic muscles of the eye)

action: eye looks down

insertion: sclera

superior rectus (extrinsic muscles of the eye)

action: eye looks up

insertion: sclera

superior oblique (extrinsic muscles of the eye)

action: eye rolls: looks down and laterally

insertion: sclera

inferior oblique (extrinsic muscles of the eye)

action: eye rolls: looks up and laterally

insertion: sclera

masseter (muscles of mastication)

action: elevate mandible

origin: zygomatic arch

insertion: mandible, ramus and angle

temporalis (muscles of mastication)

action: elevate mandible

insertion: coronoid process of mandible

sternocloidomastoid (muscles of the neck)

action:

• bilaterally: flex neck

• unilaterally: opposite rotation

origin: 2 heads of origin; manubrium - sternum, sternal end- clavicle

insertion: mastoid process of temporal bone

quadratus lumborum (back muscles that act on vertebral column)

action:

• bilaterally: depresses ribs

• unilaterally: laterally flex vertebral column

erector spinae group: spinalis group, longissimus group, iliocostalis group (back muscles that act on vertebral column)

action:

• bilaterally: extend & hyperextend vertebral column

• unilaterally laterally flex vertebral column

rectus abdominis (muscles of abdomen, some also act on vetebral column)

action: compresses abdomen, flexes vertebral column

external oblique (muscles of abdomen, some also act on vetebral column)

action: compresses abdomen; flexes, laterally flexes or rotates vertebral column to same side

internal oblique (muscles of abdomen, some also act on vetebral column)

action: compresses abdomen; flexes, laterally flexes or rotates vertebral column to same side

transverse abdominis (muscles of abdomen, some also act on vetebral column)

action: compresses abdomen

diaphragm (muscles of the thorax that act in respiration)

action: diaphragm flattens to enlarge thoracic cavity causing inspiration

insertion: central tendon inserts on lumbar vertebrae

external intercostals (muscles of the thorax that act in respiration)

action: elevate ribs & ribcage causing inspiration

origin: inferior border to each rib

insertion: superior border rib above

internal intercostals (muscles of the thorax that act in respiration)

action: depress ribs & ribcage causing expiration

origin: superior border of each rib

insertion: inferior border rib above

pectoralis minor (muscles that act on pectoral girdle)

action: depress scapula

insertion: coracoid process of scapula

rhomboid major & minor (muscles that act on pectoral girdle)

action: abduct and depress scapula

insertion: medial (vetebral) border of scapula

serratus anterior (muscles that act on pectoral girdle)

action: protract and rotate scapula (the punching muscle)

trapezius upper (muscles that act on pectoral girdle)

action: elevate scapulae (as in shrugging shoulders)

origin: occipital bone and ligamentum nuchae

insertion: lateral end of clavicle

trapezius middle (muscles that act on pectoral girdle)

action: adduct (retract) scapulae as in pulling shoulders back

origin: spinous process of thoracic vertebrae

insertion: acromion of scapula

trapezius lower (muscles that act on pectoral girdle)

action: retract and depress scapula (as in pulling shoulders back and down)

origin: spinous process of thoracic vertebrae

insertion: scapular spine

coracobrachialis (muscles that act on the brachium, arm at shoulder joint)

action: flex and adduct brachium

origin: coracoid process of scapula

deltoid anterior (muscles that act on the brachium, arm at shoulder joint)

action: flex and medially rotate the brachium

origin: clavicle - lateral end

insertion: deltoid tuberosity of humerus

deltoid middle (muscles that act on the brachium, arm at shoulder joint)

action: abduct humerus

origin: scapula - acromion

insertion: deltoid tuberosity of humerus

deltoid posterior (muscles that act on the brachium, arm at shoulder joint)

action: extend and laterally rotate brachium

origin: scapular spine

insertion: deltoid tuberosity of humerus

supraspinatus (muscles that act on the brachium, arm at shoulder joint)

action: abduct brachium

origin: supraspinous fossa of scapula

insertion: greater tubercle of humerus

infraspinatus (muscles that act on the brachium, arm at shoulder joint)

action: laterally rotate brachium

origin: infraspinous fossa of scapula

insertion: greater tubercles of humerus

teres minor (muscles that act on the brachium, arm at shoulder joint)

action: laterally rotate and adduct brachium

origin: lateral border of scapula

insertion: greater tubercle of humerus

subscapularis (muscles that act on the brachium, arm at shoulder joint)

action: medially rotate brachium

origin: subscapular fossa of scapula

insertion: lesser tubercle of humerus

teres major (muscles that act on the brachium, arm at shoulder joint)

action: extend and medially rotate brachium

origin: inferior angle of scapula

insertion: intertubercular sulcus of humerus (muscle travels through

latissimus dorsi (muscles that act on the brachium, arm at shoulder joint)

action: extend, adduct, medially rotate brachium

insertion: intertubercular sulcus of humerus

pectoralis major (muscles that act on the brachium, arm at shoulder joint)

action: flex, adduct, medially rotate brachium

insertion: greater tubercle of humerus

biceps brachii, long head (muscles that act on brachium/antebrachium aka arm/forearm)

action: flex brachium; flex and supinate antebrachium

origin: supraglenoid tubercle of scapula

insertion: radial tuberosity

biceps brachii, short head (muscles that act on brachium/antebrachium aka arm/forearm)

action: flex bracium; flex and supinate antebrachium

origin: coracoid process of scapula

insertion: radial tuberosity

brachialis (muscles that act on antebrachium only, forearm/elbow joint)

action: flex antebrachium

insertion: ulnar tuberosity

brachioradialis (muscles that act on antebrachium only, forearm/elbow joint)

action: flex antebrachium

insertion: styloid process of radius

triceps brachii, long head (muscles that act on antebrachium only, forearm/elbow joint)

action: extend antebrachium

origin: infraglenoid tubercle of scapula

insertion: olecranon of ulna

triceps brachii, lateral head (muscles that act on antebrachium only, forearm/elbow joint)

action: extend antebrachium

insertion: olecranon of ulna

triceps brachii, medial head (muscles that act on antebrachium only, forearm/elbow joint)

action: extend antebrachium

insertion: olecranon of ulna

pronator teres (muscles that act on antebrachium only, forearm/elbow joint)

action: pronate antebrachium

origin: medial epicondyle of humerus, coronoid process of ulna

supinator (muscles that act on antebrachium only, forearm/elbow joint)

action: supinate antebrachium

origin: lateral epicondyle of humerus

flexor carpi radialis (muscles that act on carpus, hand/wrist)

action: flex & abduct (radially deviate) carpus

origin: medial epicondyle of humerus

palmaris carpi ulnaris (muscles that act on carpus, hand/wrist)

action: flex & abduct (radially deviate) carpus

origin: medial epicondyle of humerus

palmaris longus (muscles that act on carpus, hand/wrist)

action: flex carpus

extensor carpi radialis (muscles that act on carpus, hand/wrist)

action: extend & abduct (radially deviate) carpus

origin: lateral epicondyle of humerus

extensor carpi ulnaris (muscles that act on carpus, hand/wrist)

action: extend & abduct (ulnar deviate) carpus

origin: lateral epicondyle of humerus

extensor digitorum (muscles that act on both carpus ie hands/wrist and digits, fingers)

action: extend carpus & extend digits of hand

origin: lateral epicondyle of humerus

extensor digiti minimi (muscles that act on both carpus ie hands/wrist and digits, fingers)

action: extend carpus & extend digit V

origin: lateral epicondyle of humerus

gluteus maximus (muscles that act on the femur, thigh at hip joint)

action: extend & laterally rotate thigh

gluteus medius (muscles that act on the femur, thigh at hip joint)

action: abduct & medially rotate thigh

insertion: greater trochanter of femur

tensor fasciae latae (muscles that act on the femur, thigh at hip joint)

action: abduct thigh & laterally support knee by tensing iliotibial tract

origin: iliac crest & anterior superior iliac spine

insertion: iliotibial tract

adductor longus (muscles that act on the femur, thigh at hip joint)

action: adduct thigh

origin: inferior pubic ramus

insertion: linea aspera of femur

adductor magnus (muscles that act on the femur, thigh at hip joint)

action: adduct thigh

origin: inferior pubic ramus & ischial tuberosity

insertion: linea aspera of femur

pectineus (muscles that act on the femur, thigh at hip joint)

action: adduct, flex, medially rotate thigh

origin: superior pubic ramus

iliacus (muscles that act on the femur, thigh at hip joint)

action: flex thigh, or if insertion is fixed as in straight-leg situp: flex vertebral column

origin: iliac fossa

insertion: lesser trochanter of femur

psoas major (muscles that act on the femur, thigh at hip joint)

action: flex thigh, or if insertion is fixed as in straight-leg situp: flex vertebral column

origin: vertebral bodies T12 - L5

insertion: lesser trochanter of femur

piriformis (muscles that act on the femur, thigh at hip joint)

action: laterally rotate thigh

insertion: greater trochanter of femur

gracilis (muscles that act on both femur, thigh @ hip join, and crus, leg @ knee joint)

action: adduct thigh & flex crus

origin: inferior pubic ramus

biceps femoris, long head (muscles that act on both femur, thigh @ hip join, and crus, leg @ knee joint)

action: extend thigh, flex crus, laterally rotate thigh

origin: ischial tuberosity

biceps femoris shorthead (muscles that act on both femur, thigh @ hip join, and crus, leg @ knee joint)

action: flex crus (does not cross hip so can not act on femur)

origin: linea aspera of femur

semimembranosus (muscles that act on both femur, thigh @ hip join, and crus, leg @ knee joint)

action: extend thigh, flex crus, medially rotate thigh

origin: ischial tuberosity

semitendinosus (muscles that act on both femur, thigh @ hip join, and crus, leg @ knee joint)

action: extend thigh, flex crus, medially rotate thigh

origin: ischial tuberosity

sartorius (muscles that act on both femur, thigh @ hip join, and crus, leg @ knee joint)

action: flex & laterally rotate thigh, flex crus

origin: anterior superior iliac spine

rectus femoris (muscles that act on both femur, thigh @ hip join, and crus, leg @ knee joint)

action: flex thigh, extend crus

origin: anterior inferior iliac spine

insertion: tibial tuberosity (via patellar ligament)

vastus intermedius (muscles that act on crus, leg @ knee)

action: extend crus

origin: anterior shaft of femur

insertion: tibial tuberosity

vastus lateralis (muscles that act on crus, leg @ knee)

action: extend crus

origin: greater trochanter & linea aspera of femur

insertion: tibial tuberosity

vastus medialis (muscles that act on crus, leg @ knee)

action: extend crus

origin: linea aspera of femur

insertion: tibial tuberosity

gastrocnemius (muscles that act on both crus, leg @ knee and pes, foot @ ankle)

action: flex crus & plantar flex tarsus

insertion: calcaneus

tibialis anterior (muscles that act on pes, foot @ ankle or toes)

action: dorsiflexion and inversion of pes

extensor digitorum longus (muscles that act on pes, foot @ ankle or toes)

action: dorsiflexion and extend digits II-V

extensor hallucis longus (muscles that act on pes, foot @ ankle or toes)

action: dorsiflexion & extend hallux

fibularis longus & brevis (muscles that act on pes, foot @ ankle or toes)

action: plantar flexion & extend hallux

soleus (muscles that act on pes, foot @ ankle or toes)

action: plantarflexion

insertion: calcaneus

flexor digitorum longus (muscles that act on pes, foot @ ankle or toes)

action: plantarflexion & flex digits II-V

flexor hallucis longus (muscles that act on pes, foot @ ankle or toes)

action: plantarflexion & flex hallux

tibialis posterior (muscles that act on pes, foot @ ankle or toes)

action: plantarflexion & inversion of pes