Muscle Origins and Insertions

Trapezius Origin

Origin: superior nuchal line (on occipital bone), external occipital protuberance (EOP), ligamentum nuchae, C7-T12 spinous processes (SPs)

Trapezius Insertion

Insertion: Lateral 1/3 of clavicle, acromion, and spine of scapula.

Action: upper- elevate scapula, middle- retract scapula, lower- depress scapula

Latissimus Dorsi Origin

Origin: spinous processes from T7 to sacrum, iliac crest, lower ribs, posterior lamella of thoracolumbar fascia

Latissimus Dorsi Insertion

Insertion: Floor of intertubercular sulcus on humerus

Action: extend, adduct, medially rotate humerus

Levator Scapulae Origin

Origin: C1-C4 Transverse processes (TPs)

Levator Scapulae Insertion

Insertion: Vertebral border of scapula above scapula’s spine

Action: elevate scapula

Rhomboid Minor Origin

Origin: C7-T1 spinous processes (SPs), ligamentum nuchae

Rhomboid Minor Insertion

Insertion: Vertebral border of scapula at the root of the scapula’s spine

Action: retraction of scapula, movement of shoulder girdle (clavicle + scapula)

Rhomboid Major Origin

Origin: T2-T5 spinous processes (SPs)

Rhomboid Major Insertion

Insertion: vertebral border of the scapula below the scapula’s spine

Action: retraction of scapula, movement of shoulder girdle (clavicle + scapula)

Serratus Posterior Superior Origin

Origin: Ligamentum nuchae, C7-T3 spinous processes (SPs)

Serratus Posterior Superior Insertion

Insertion: Ribs 2-5

Action: elevate ribs (inspiration)

Serratus Posterior Inferior Origin

Origin: T11-L3 spinous processes (SPs)

Serratus Posterior Inferior Insertion

Insertion: Ribs 9-12

Action: depress ribs (expiration)

Splenius Capitis Origin (part of spinotransversales group)

Origin: spinous processes of CV7 vertebrae, upper thoracic vertebrae (TV), and ligamentum nuchae

Splenius Capitis Insertion (part of spinotransversales group)

Insertion: superior nuchal line of occipital bone, mastoid process of temporal bone

Action: extend vertebral column bilaterally, laterally flex and rotate vertebral column to same side unilaterally (same as splenius cervicis)

Splenius Cervicis Origin (part of spinotransversales group)

Origin: spinous processes of middle TVs

Splenius Cervicis Insertion (part of spinotransversales group)

Insertion: transverse processes of upper CVs

Action: extend vertebral column bilaterally, laterally flex and rotate vertebral column to same side unilaterally (same as splenius capitis)

Semispinalis Capitis Origin (part of transversospinales muscles)

Origin: transverse processes of lower CVs and upper TVs

Semispinalis Capitis Insertion (part of transversospinales muscles)

Insertion: occipital bone

Action: extend vertebral column bilaterally, laterally flex and rotate vertebral column to opposite side unilaterally (same as semispinalis cervicis, multifidus, rotatores)

Semispinalis Cervicis Origin (part of transverseospinales muscles)

Origin: transverse processes of upper TVs

Semispinalis Cervicis Insertion (part of transverseospinales muscles)

Insertion: spinous processes of CVS up to CV2

Action: extend vertebral column bilaterally, laterally flex and rotate vertebral column to opposite side unilaterally (same as semispinalis capitis, multifidus, rotatores)

Obliquus Capitis Inferior Origin (part of suboccipital triangle)

Origin: CV2 spinous process

Obliquus Capitis Inferior Insertion (part of suboccipital triangle)

Insertion: CV1 transverse process

Action: extend head bilaterally, rotates head to same side at atlantoaxial joint unilaterally (all suboccipital triangle)

Obliquus Capitis Superior Origin (part of suboccipital triangle)

Origin: CV1 transverse process

Obliquus Capitis Superior Insertion (part of suboccipital triangle)

Insertion: inferior nuchal line of occipital bone

Action: extend head bilaterally, rotates head to same side at atlantoaxial joint unilaterally (all suboccipital triangle)

Rectus Capitis Posterior Major Origin (part of suboccipital triangle)

Origin: CV2 spinous process

Rectus Capitis Posterior Major Insertion (part of suboccipital triangle)

Insertion: inferior nuchal line of occipital bone

Action: extend head bilaterally, rotates head to same side at atlantoaxial joint unilaterally (all suboccipital triangle)

Rectus Capitis Posterior Minor Origin (does not border suboccipital triangle)

Origin: CV1 posterior tubercle

Rectus Capitis Posterior Minor Insertion (does not border suboccipital triangle)

Insertion: inferior nuchal line of occipital bone

Action: extend head bilaterally, rotates head to same side at atlantoaxial joint unilaterally

Pectoralis Major Origin

Origin: medial part of clavicle, sternum, costal cartilages of ribs 2-5

Pectoralis Major Insertion

Insertion: crest of greater tubercle of humerus

Action: adduction, medial rotation, and flexion of arm at shoulder joint

Pectoralis Minor Origin

Origin: ribs 2-4 or ribs 3-5

Pectoralis Minor Insertion

Insertion: coracoid process of scapula

Action: protract and depress scapula

Subclavius Origin

Origin: junction of first rib and its cartilage

Subclavius Insertion

Insertion: inferior surface of clavicle

Action: depresses clavicle

Serratus Anterior Origin

Origin: upper 8 ribs

Serratus Anterior Insertion

Insertion: vertebral border of scapula

Teres Major Origin

Origin: inferior angle of scapula, axillary border of scapula

Teres Major Insertion

Insertion: crest of lesser tubercle of humerus

Action: medially rotate and adduct arm

Deltoid Origin

Origin: lateral 1/3 of clavicle, acromion, spine of scapula (this is the same as the insertion of the trapezius)

Deltoid Insertion

Insertion: deltoid tuberosity

Action: abducts the arm 15-90 degrees

Supraspinatus (part of rotator cuff group) Origin

Origin: supraspinous fossa of scapula

Supraspinatus (part of rotator cuff group) Insertion

Insertion: greater tubercle of humerus (same as infraspinatus and teres minor)

Action: abducts arm 15 degrees (assists deltoid)

Infraspinatus (part of rotator cuff group) Origin

Origin: infraspinous fossa of scapula

Infraspinatus (part of rotator cuff group) Insertion

Insertion: greater tubercle of humerus (same as supraspinatus and teres minor)

Action: laterally rotate arm at 0 degrees of abduction

Teres Minor (part of rotator cuff group) Origin

Origin: lateral (axillary) border of scapula

Teres Minor (part of rotator cuff group) Insertion

Insertion: greater tubercle of humerus (same as supra and infraspinatus)

Action: laterally rotates arm at 90 degrees of abduction

Subscapularis (part of rotator cuff group) Origin

Origin: subscapular fossa

Subscapularis (part of rotator cuff group) Insertion

Insertion: lesser tubercle of humerus (only one in rotator group with this insertion)

Action: medially rotates and adducts arm

Coracobrachialis Origin

Origin: coracoid process of scapula

Coracobrachialis Insertion

Insertion: middle third medial aspect of humerus

Action: adducts and flexes arm

Biceps Brachii Origin

Origin: supraglenoid tubercle of scapula (long head), coracoid process of scapula (short head)

Biceps Brachii Insertion

Insertion: radial tuberosity of radius

Action: flex shoulder joint, flex forearm at elbow, supinate forearm

Brachialis Origin

Origin: distal anterior half of humerus

Brachialis Insertion

Insertion: ulnar tuberosity of ulna

Action: Flex forearm at elbow

Triceps Brachii Origin

Origin: infraglenoid tubercle of scapula

Triceps Brachii Insertion

Insertion: olecranon of ulna

Action: extend elbow and shoulder joints

Pronator teres (1st layer) Origin

Origin: medial epicondyle (superficial head) + coronoid process of ulna (deep head)

Pronator teres (1st layer) Insertion

Insertion: midway lateral surface of radius

Action: pronate hand

Flexor carpi radialis (1st layer) Origin

Origin: medial epicondyle of humerus

Flexor carpi radialis (1st layer) Insertion

Insertion: bases of 2nd and 3rd metacarpals

Action: flex, abduct wrist

Palmaris Longus (1st layer) Origin

Origin: medial epicondyle of humerus

Palmaris longus (1st layer) Insertion

Insertion: flexor retinaculum + palmar aponeruosis

Action: flex hand

Flexor carpi ulnaris (1st layer) Origin

Origin: medial epicondyle + olecranon and posterior border of ulna

Flexor carpi ulnaris (1st layer) Insertion

Insertion: pisiform- through pisohamate and pisometacarpal ligaments, hamate, base of 5th metacarpal

Action: flex and adduct wrist

Flexor digitorum superficialis muscle (2nd layer) Origin

Origin: humero-ulnar head- medial epicondyle + coronoid process of ulna

Flexor digitorum superficialis muscle (2nd layer) Insertion

Insertion: bases of middle phalanges of medial 4 fingers

Action: flex wrist joint, metacarpophalangeal joints, proximal interphalangeal joints (same as FDP)

Flexor digitorum profundus (3rd layer) origin

Origin: medial + anterior surface of ulna, interosseous membrane

Flexor digitorum profundus (3rd layer) Insertion

Insertion: bases of distal phalanges of medial 4 fingers

Action: flex wrist joint, metacarpophalangeal joints, interphalangeal joints (PIPs and DIPs)

Flexor Pollicis Longus (3rd layer) origin

Origin: anterior surface of radius, interosseous membrane

Flexor Pollicis Longus (3rd layer) Insertion

Insertion: base of distal phalanx of thumb

Action: flex metacarpophalangeal joint of 1st digit, flex interphalangeal joint of 1st digit, flex wrist (weak)

Pronator Quadratus (4th layer) Origin

Origin: distal anterior surface of ulna

Pronator Quadratus (4th layer) Insertion

Insertion: distal anterior surface of radius

Action: pronation

Abductor Pollicis Brevis, Flexor Pollicis Brevis, Opponens Pollicis Origin (thenar compartment)

Origin: Lateral flexor retinaculum

Abductor Pollicis Brevis, Flexor Pollicis Brevis Insertion (thenar compartment)

Insertion: lateral side of base of proximal phalanx

Action: APB- abduct thumb, FPB- flex thumb

Opponens Pollicis Insertion (thenar compartment)

Insertion: shaft of 1st metacarpal

Action: oppose thumb

Abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi Origin (hypothenar compartment)

Origin: medial end of flexor retinaculum

Abductor digiti minimi, flexor digiti minimi brevis Insertion (hypothenar compartment)

Insertion: medial side of base of proximal phalanx

Action: ADM- abduct, FDMB- flex

Opponens Digiti minimi Insertion (hypothenar compartment)

Insertion: medial side of 5th metacarpal

Action: oppose pinky

Lumbricals Origin (central compartment)

Origin: tendons of flexor digitorum profundus

Lumbricals Insertion (central compartment)

Insertion: tendon wraps to lateral side of digit to insert on extensor expansion

Action: Flex metacarpal phalangeal joint (MCP’s), Extend interphalangeal joints (IP’s)

Palmar interosseous Action (interosseous compartment)

3 muscles, adduction

Dorsal Interosseous muscles (interosseous compartment) Action

4 muscles, abduction

Adductor Pollicis Origin (interosseous compartment)

Origin: oblique head- capitate, transverse head- 3rd metacarpal

Adductor Pollicis Insertion (interosseous compartment)

Insertion: medial side of proximal phalanx of thumb

Action: adduct thumb

Brachioradialis (Superficial layer of posterior forearm) Origin

Origin- lateral supracondylar ridge of humerus

Brachioradialis (Superficial layer of posterior forearm) Insertion

Insertion: distal radius near styloid process

Action: flex forearm at elbow

Extensor Carpi radialis longus (ECRL) (Superifical layer of posterior forearm) (Compartment 2) Origin

Origin: lateral supracondylar ridge and lateral epicondyle

Extensor Carpi radialis longus (ECRL) (Superifical layer of posterior forearm) (Compartment 2) Insertion

Insertion: base of 2nd metacarpal

Action: extend forearm

Extensor carpi radialis brevis (ECRB) (Superifical layer of posterior forearm) (Compartment 2) Origin

Origin: lateral epicondyle

Extensor carpi radialis brevis (ECRB) (Superifical layer of posterior forearm) (Compartment 2) Insertion

Insertion: base of third metacarpal

Action: extend forearm

Extensor Digitorum (Superifical layer of posterior forearm) (Compartment 4) Origin

Origin: lateral epicondyle (all superficials except brachioradialis)

Extensor Digitorum (Superifical layer of posterior forearm) (Compartment 4) Insertion

Insertion: extensor hood of digits 2-5

Action: extend digits and wrist

Extensor Digiti Minimi (superficial layer of posterior forearm) (5th compartment) Origin

Origin: lateral epicondyle

Extensor Digiti Minimi (superficial layer of posterior forearm) (5th compartment) Insertion

Insertion: extensor hood of 5th digit (pinky)

Action: extend pinky

Extensor Carpi Ulnaris (superficial layer of forearm) (6th compartment) Origin

Origin: lateral epicondyle

Extensor Carpi Ulnaris (superficial layer of forearm) (6th compartment) Insertion

Insertion: base of 5th metacarpal

Action: extend wrist on ulnar side

Anconeus (superficial layer of forearm) Origin

Origin: lateral epicondyle

Anconeus (superficial layer of forearm) Insertion

Insertion: upper ulna

Action: extend elbow