Muscles: Origin, Insertion, and Actions

Pectoralis minor origin

Sternal end of ribs 3-5

Pectoralis minor insertion

Coracoid process of scapula

Pectoralis minor action

Depression of glenoid fossa

Serratus anterior action

• Adduction of scapula

• Elevation of glenoid fossa

Trapezius origin

• Spinous process of C7 and T1-T12

• External occipital protuberance

Trapezius insertion

• Lateral ⅓ of clavicle

• The acromion and spine of scapula

Trapezius action

• Adduction of scapula

• Elevation of glenoid fossa

Levator scapulae action

• Elevates the scapula (if C vertebrae are fixed

• Flexes the neck laterally (if scapula is fixed)

• Retracts scapula and braces the shoulder

• Rotates scapula and depresses apex of the shoulder

Rhomboid minor action

• Retraction of scapula

• Bracing of shoulder

• Fixation of scapula during other arm movements 

Rhomboid minor action

• Retraction of scapula

• Bracing of shoulder

• Fixation of scapula during other arm movements 

Supraspinatus origin

Supraspinous fossa of scapula

Supraspinatus insertion

Upper surface greater tubercle (humerus)

Supraspinatus action

Humerus abduction (lifting)

Infraspinatus origin

Infraspinous fossa of scapula

Infraspinatus insertion

Middle portion of greater tubercle (humerus)

Infraspinatus action

Lateral rotation of the humerus

Teres minor action

Lateral rotation of humerus

Subscapularis action

Medial rotation of the humerus

Pectoralis major origin

• Medial half of clavicle

• Lateral margin of sternum

• Costal cartilage of ribs 1-6

Pectoralis major insetion

Lateral ridge of the intertubercular groove (humerus)

Pectoralis major action

Humerus:

• Adduction

• Flexion

• Medial rotation

Latissimus dorsi origin

• Spinous process of T7-T12

• L1-L5 by means of thoracolumnar fascia

Latissimus dorsi insertion

Floor of the intertubercular groove (humerus)

Latissimus dorsi action

Humerus:

• Adduction

• Extension

• Medial rotation

Deltoid origin

• Lateral ⅓ of clavicle

• Acromion and spine of scapula

Deltoid insertion

Deltoid tuberosity (humerus)

Deltoid action

Humerus:

• Abduction

• Extension

• Flexion

Teres major action

Humerus:

• Adduction

• Extension

• Medial rotation

Brachialis origin

Distal ½ of anterior surface of humerus

Brachialis insertion

Coronoid process (ulna)

Brachialis action

Elbow flexion

Biceps brachii origin

Coracoid process and supraglenoid tubercle of scapula

Biceps brachii insertion

Radial tuberosity of radius

Biceps brachii action

Elbow and humerus flexion

Triceps brachii origin

Long head:

• Infraglenoid tubercle (humerus)

Lateral and medial head:

• Posterior humerus

Triceps brachii insertion

Olecranon process (ulna)

Triceps brachii action

Elbow extension

Brachioradialis origin

Lateral supracondylar ridge (humerus)

Brachioradialis insertion

Styloid process (ulna)

Brachioradialis action

Elbow flexion

Pronator teres action

Forearm pronation

Flexor carpi radialis action

Flexion and abduction of hand

Flexor carpi ulnaris origin

Medial epicondyle (humerus)

Flexor carpi ulnaris insertion

Pisiform bone

Flexor carpi ulnaris action

Flexion and abduction of hand

Flexor digitorum superficialis action

Flexion of hand and digits

Palmaris longus origin

Medial epicondyle of humerus

Palmaris longus insertion

Flexor retinaculum and palmar aponeurosis

Palmaris longus action

Flexion of hand

Extensor carpi radialis longus action

Hand extension and abduction

Extensor carpi radialis brevis action

Hand extension

Extensor digitorus action

Extension of hand and digits

Extensor digiti minimi action

Extension and hand and digit V

Extensor carpi ulnaris origin

Lateral epicondyle of humerus

Extensor carpi ulnaris insertion

Base of metacarpal V

Extensor carpi ulnaris action

Hand:

• Extension

• Adduction

Iliacus origin

• Iliac crest and fossa

• Superolateral region of sacrum

• Anterior sacroiliac and iliolumbar ligaments

Iliacus insertion

• Lesser trochanter (femur)

• Shaft of femur

Psoas major origin

• Bodies and intervertebral discs of T12-L5

• Transverse processes of L vertebrae

Psoas major insertion

• Lesser trochanter (femur)

• Shaft of femur

Psoas major action

• Hip flexion (when trunk is fixed; as in climbing stairs)

• Waist flexion (when thigh is fixed; as in bending forward in chair or sitting up in bed)

• Balances trunk when sitting

Rectus abdominis origin

Pubic crest

Rectus abdominis insertion

• Xiphoid process (sternum)

• Coastal cartilage of ribs 5-7

Rectus abdominis action

• Flexion of vertebral column

• Compression of the abdomen

External oblique origin

Lower 8 ribs

External oblique insertion

Linea alba

External oblique action

• Lateral flexion of vertebral column

• Rotation of vertebral column

• Compression of abdomen

Internal oblique origin

• Lateral ½ of the inguinal ligament

• Iliac crest

• Thoracolumbar fascia

Internal oblique insertion

• Coastal cartilage of lower 4 ribs

• Linea alba

Internal oblique action

• Lateral flexion of vertebral column

• Rotation of vertebral column

• Compression of abdomen

Transverse abdominis origin

• Lateral part of inguina ligament

• Ilical crest

• Thoracolumbar fascia

Quadratus lumborum action 

• Extension

• Lateral flexion

Tensor fasciae latae origin

Anterior crest of ilium

Tensor fasciae latae insertion

Iliotibial tract of the fascia latae

Tensor fasciae latae action

• Flexion

• Abduction of femur

• Medial rotation of the femur

Gluteus maximus origin

• Dorsal ilium

• Sacrum

• Coccyx

Gluteus maximus insertion

• Iliotibial tract of the fascia latae

• Gluteal tuberosity (femur)

Gluteus maximus action

• Hip extension (as in stair climbing)

• Lateral rotation of the femur

Gluteus medius origin

Between anterior and posterior gluteal lines on ilium

Gluteus medius insertion

Lateral surface on greater trochanter (femur)

Gluteus medius action

Thigh abduction

Gluteus minimus origin

Between anterior and inferior gluteal lines on ilium

Gluteus minimus insertion

Anterior border of greater trochanter (femur)

Gluteus minimus action

• Medial rotation

• Abduction

Adductor longus action

• Medial rotation

• Thigh adduction

• Hip flexion

Adductor magnus action

• Medial rotation

• Thigh adduction

• Hip extension

Gracilis origin

Inferior ramus of pubis

Gracilis insertion

Medial to tibial tuberosity on tibia

Gracilis action

• Thigh adduction

• Knee flexion

• Medial rotation of tibia

Piriformis origin

Anterior surface of sacrum

Piriformis insertion

Superior border of greater tubercle (femur)

Piriformis action

• Thigh abduction

• Lateral rotation

Rectus femoris action

• Extension of knee

• Flexion of thigh

Vastus lateralis action

Extension

Vastus medialis action

Extension

Vastus intermedius action

extension of knee

Sartorius action

• Extension of knee

• Flexion of thigh

• Lateral rotation

Biceps femoris action

• Flexion of knee

• Extension of thigh

Semitendinosus action

• Flexion of knee

• Extension of thigh

Semimembranosus action

• Flexion of knee

• Extension of thigh