Brachium to Hand Musculature


Muscle Regions of the Body:

bulletHead and neck
bulletTrunk, front and back
bulletBrachium, antibrachium & hand
bulletThigh, leg & foot

Muscle Groups within this Region:

bulletBrachium
bulletAntibrachial Flexors
bulletAntibrachial Extensors
bulletHand & Wrist



Brachium Musculature

 

Coracobrachialis

bulletOrigin: coracoid process of the scapula
bulletInsertion: medial shaft of the humerus at about its middle
bulletAction:
  1. flexes the humerus
  2. assists to adduct the humerus
bulletBlood: muscular branches of the brachial artery
bulletNerve: musculocutaneous nerve, C5,6,(C7)


Biceps brachii

bulletOrigin:
  1. long head- supraglenoid tubercle and glenohumeral labrum
  2. short head- tip of the coracoid process of the scapula
bulletInsertion:
  1. radial tuberosity
  2. bicipital aponeurosis
bulletAction:
  1. flexes the forearm at the elbow (when supinated)
  2. supinates forearm from neutral
  3. stabilizes anterior aspect of shoulder
  4. flexes shoulder (weak if at all)
bulletBlood: muscular branches of brachial artery
bulletNerve: musculocutaneous nerve, C5,6


Brachialis

bulletOrigin:
  1. lower 1/2 of anterior humerus
  2. both intermuscular septa
bulletInsertion:
  1. ulnar tuberosity
  2. coronoid process of ulna slightly
bulletAction: elbow flexion (major mover)
bulletBlood:
  1. muscular branches of brachial artery
  2. radial recurrent artery
bulletNerve: musculocutaneous nerve, C5,6


Triceps brachii

bulletOrigin:
  1. long head - infraglenoid tubercle of the scapula
  2. lateral head - upper half of the posterior surface of the shaft of the humerus, and the upper part of the lateral intermuscular septum
  3. medial head - posterior shaft of humerus, distal to radial groove and both the medial and lateral intermuscular septum (deep to the long & lateral heads)
bulletInsertion:
  1. posterior surface of the olecranon process of the ulna
  2. deep fascia of the antebrachium
bulletAction:
  1. long - adducts the arm, extends at the shoulder, and a little elbow flexion
  2. lateral - extends the forearm at the elbow
  3. medial - extends the forearm at the elbow
bulletBlood:
  1. muscular branches of the brachial artery
  2. superior ulnar collateral artery
  3. profunda brachii artery
bulletNerve: radial nerve, C6,7


Anconeus

bulletOrigin: posterior surface of the lateral epicondyle of the humerus
bulletInsertion: lateral aspect of olecranon extending to the lateral part of ulnar body
bulletAction:
  1. extends the forearm at the elbow
  2. supports the elbow when in full extension
bulletBlood: middle collateral artery from the profunda brachii artery
bulletNerve: radial nerve, C7,8



Antibrachial Flexor Musculature

 

Pronator teres

bulletOrigin:
  1. humeral head:
    1. upper portion of medial epicondyle via the CFT (common flexor tendon)
    2. medial brachial intermuscular septum
  2. ulnar head - coronoid process of ulna
  3. antebrachial fascia
bulletInsertion: lateral aspect of radius at the middle of the shaft (pronator tuberosity)
bulletAction:
  1. pronates forearm (during rapid or forced pronation)
  2. weakly flexes the elbow
bulletBlood:
  1. muscular branches of ulnar artery
  2. muscular branches of radial artery
bulletNerve: median nerve, C6,7


Flexor carpi radialis

bulletOrigin:
  1. medial epicondyle via the CFT (common flexor tendon)
  2. antebrachial fascia
bulletInsertion: base of the 2nd and sometimes 3rd metacarpals
bulletAction:
  1. flexes the hand at the wrist
  2. radially deviates the wrist
  3. may assist to pronate the forearm
bulletBlood: muscular branches of radial artery
bulletNerve: median nerve, C6,7


Palmaris longus

bulletOrigin:
  1. medial epicondyle via the CFT (common flexor tendon)
  2. antebrachial fascia
bulletInsertion:
  1. central portion of the flexor retinaculum
  2. superficial portion of the palmar aponeurosis
bulletAction: flexes the hand at the wrist
bulletBlood: muscular branches of ulnar artery
bulletNerve: median nerve, C6,7


Flexor carpi ulnaris

bulletOrigin:
  1. humeral head - medial epicondyle via the CFT (common flexor tendon)
  2. ulnar head:
    1. medial aspect of olecranon
    2. proximal 3/5 of dorsal ulnar shaft
    3. antebrachial fascia
bulletInsertion:
  1. pisiform & hamate bones (via the pisohamate ligament)
  2. base of the 5th metacarpal (via the pisometacarpal ligament)
bulletAction:
  1. flexes the hand at the wrist
  2. ulnarly deviates the wrist
  3. stabilizes wrist to permit powerful thumb motion
bulletBlood: muscular branches of ulnar artery
bulletNerve: ulnar nerve, C8,T1


Flexor digitorum superficialis

bulletOrigin:
  1. humeral-ulnar head:
    1. medial epicondyle via the CFT (common flexor tendon)
    2. medial boarder of base of coronoid process of ulna
    3. medial (ulnar) collateral ligament
    4. antebrachial fascia
  2. radial head: oblique line of radius along its upper anterior boarder
bulletInsertion: both sides of the base of each middle phalanx of the 4 fingers
bulletAction:
  1. flexes the proximal and middle phalanges
  2. flexes the wrist if fingers are extended
bulletBlood:
  1. muscular branches of ulnar artery
  2. muscular branches of radial artery
bulletNerve: median nerve, C7,8,T1


Flexor digitorum profundus

bulletOrigin:
  1. anterior & medial surface of upper 3/4 ulna
  2. adjacent interosseous membrane
bulletInsertion: distal phalanx of medial 4 digits (through FDS tunnel)
bulletAction:
  1. flexes the distal IP joints and in so doing flexes the proximal and middle IP joints
  2. flexes the wrist if fingers are extended
bulletBlood:
  1. muscular branches of the ulnar artery
  2. muscular branches of the radial artery
  3. anterior interosseous artery (from ulnar artery)
bulletNerve:
  1. medial portion - ulnar nerve, C8,T1
  2. lateral portion - anterior interosseous branch of median nerve, C8,T1


Flexor pollicis longus

bulletOrigin:
  1. middle anterior surface of the radius
  2. interosseous membrane
  3. (may also originate from lateral boarder of coronoid process
  4. or medial epicondyle)
bulletInsertion: palmar aspect of base of the distal phalanx of thumb (deep to flexor retinaculum)
bulletAction:
  1. flexes the distal phalanx of the thumb (IP joint)
  2. flexes the other joints to the wrist (McP, CMc and weakly at the wrist)
bulletBlood:
  1. muscular branches of radial artery
  2. anterior interosseous artery
bulletNerve: anterior interosseous branch of median nerve, C8,T1


Pronator quadratus

bulletOrigin: distal 1/4 anteriomedial surface of ulna
bulletInsertion: distal 1/4 anteriolateral surface of radius
bulletAction: pronates the forearm and hand
bulletBlood:
  1. anterior interosseous artery
  2. muscular branches of the radial artery
bulletNerve: anterior interosseous branch of median nerve, C8,T1


Antibrachial Extensor Musculature

 

Brachioradialis

bulletOrigin:
  1. upper lateral supracondylar ridge of humerus (between the triceps and brachialis muscles)
  2. lateral intermuscular septum of humerus
bulletInsertion:
  1. superior aspect of styloid process of radius
  2. lateral side of the distal 1/2 to 1/3 of the radius
  3. antebrachial fascia
bulletAction:
  1. flexes the forearm at the elbow
  2. pronates the forearm when supinated
  3. supinates the forearm when pronated
bulletBlood: radial recurrent artery
bulletNerve:
  1. radial nerve, C5,6 OR
  2. deep branch of the radial nerve


Extensor carpi radialis longus

bulletOrigin:
  1. lower lateral supracondylar ridge (below the brachioradialis)
  2. lateral intermuscular septum of humerus
bulletInsertion: base of 2nd metacarpal
bulletAction:
  1. extends the hand at the wrist
  2. radially deviates the hand at the wrist
  3. weakly flexes the forearm at the elbow
  4. weakly supinates the forearm
bulletBlood: radial recurrent artery
bulletNerve:
  1. radial nerve, C5,6 OR
  2. deep branch of the radial nerve


Extensor carpi radialis brevis

bulletOrigin:
  1. lateral epicondyle via the CET (common extensor tendon)
  2. radial collateral ligament
  3. antebrachial fascia
bulletInsertion: base of 3rd metacarpal
bulletAction:
  1. extends the hand at the wrist
  2. radially deviates the hand at the wrist
bulletBlood: radial recurrent artery
bulletNerve: deep branch of the radial nerve, C6,7


Extensor digitorum

bulletOrigin:
  1. lateral epicondyle via the CET (common extensor tendon)
  2. antebrachial fascia
bulletInsertion:
  1. base of middle phalanx of each of the four fingers (central band)
  2. base of distal phalanx of each of the four fingers (2 lateral bands)
bulletAction:
  1. extends the four medial digits
  2. extends the wrist if fingers flexed
  3. abducts the digits (spreads the digits as it extends them)
bulletBlood: posterior interosseous artery
bulletNerve: posterior interosseous nerve of the radial nerve, C6,7,8


Extensor digiti minimi

bulletOrigin:
  1. lateral epicondyl via the CET (common extensor tendon)
  2. antebrachial fascia
  3. ulnar aspect of extensor digitorum
bulletInsertion:
  1. base of middle phalanx of the 5th digit (central band)
  2. base of distal phalanx of the 5th digit (2 lateral bands)
bulletAction:
  1. extends the 5th digit
  2. abducts the 5th digit
bulletBlood: posterior interosseous artery
bulletNerve: posterior interosseous nerve of the radial nerve, C6,7,8


Extensor carpi ulnaris

bulletOrigin:
  1. 1st head - lateral epicondyle via the CET (common extensor tendon)
  2. 2nd head - posterior body of ulna
  3. antebrachial fascia
bulletInsertion: medial side of base of the 5th metacarpal
bulletAction:
  1. extends the hand at the wrist
  2. ulnarly deviates the hand at the wrist
bulletBlood: posterior interosseous artery
bulletNerve: posterior interosseous nerve of the radial nerve, C6,7,8


Supinator

bulletOrigin:
  1. lateral epicondyle of humerus
  2. supinator crest of ulna
  3. radial collateral ligament
  4. annular ligament
  5. antebrachial fascia
bulletInsertion: proximal portion of anteriorlateral surface of the radius
bulletAction: supinates the forearm
bulletBlood: radial recurrent artery
bulletNerve: deep branch of the radial nerve, C6


Abductor pollicis longus

bulletOrigin:
  1. posterior surfaces of ulna and radius
  2. interosseous membrane
  3. antebrachial fascia
bulletInsertion: lateral aspect of base of 1st metacarpal
bulletAction:
  1. abducts the 1st metacarpal
  2. assists to extend & rotate the thumb
  3. radially deviates the hand at the wrist
  4. flexes the hand at the wrist
bulletBlood: posterior interosseous artery
bulletNerve: posterior interosseous nerve of the radial nerve, C6,7,(C8)


Extensor pollicis brevis

bulletOrigin:
  1. posterior surfaces of radius (below abductor pollicis longus)
  2. interosseous membrane
  3. antebrachial fascia
bulletInsertion: base of proximal phalanx of thumb (often a slip inserts into extensor pollicis longus tendon)
bulletAction:
  1. extends the proximal phalanx and 1st metacarpal of the thumb
  2. radially deviates the hand at the wrist
bulletBlood: posterior interosseous artery
bulletNerve: posterior interosseous nerve of the radial nerve, C6,7,(C8)


Extensor pollicis longus

bulletOrigin:
  1. posterior surface of ulna
  2. interosseous membrane
  3. antebrachial fascia
bulletInsertion: distal phalanx of thumb
bulletAction:
  1. extends distal phalanx of thumb
  2. extends proximal phalanx of thumb
  3. assists to extend the hand at the wrist (if fingers flexed)
bulletBlood: posterior interosseous artery
bulletNerve: posterior interosseous nerve of the radial nerve, C6,7,8


Extensor indicis

bulletOrigin:
  1. posterior surface of ulna (distal to extensor pollicis longus)
  2. interosseous membrane
  3. antebrachial fascia
bulletInsertion: base of middle and distal phalanx of the index finger
bulletAction:
  1. extends the 2nd digit (McP & IP joints)
  2. adducts the 2nd digit
  3. assists to extend the hand at the wrist
  4. stabilizes McP joint for flexion of IP solely
bulletBlood: posterior interosseous artery
bulletNerve: posterior interosseous nerve of the radial nerve, C6,7,8


Hand & Wrist Musculature

 

Abductor pollicis brevis

bulletOrigin:
  1. distal border of flexor retinaculum
  2. trapezium (may be variable)
bulletInsertion:
  1. lateral aspect of base of proximal phalanx of the thumb
  2. may also send a slip to the tendon of extensor pollicis longus
bulletAction:
  1. abducts thumb (at the McP joint)
  2. participates to flex the thumb (at the McP joint)
  3. if attached to extensor pollicis longus, it might assist to extend the thumb
bulletBlood: superficial palmar branches of radial artery
bulletNerve: recurrent branch of median nerve, C8,T1


Flexor pollicis brevis

bulletOrigin:
  1. superficial head:
    1. distal border of flexor retinaculum
    2. trapezium
  2. deep head:
    1. floor of carpal tunnel
    2. indirectly to scaphoid & trapezium
bulletInsertion:
  1. base of proximal phalanx of thumb
  2. can also attach to the lateral sesamoid bone at the McP joint
bulletAction: powerfully flexes the thumb (at the McP joint)
bulletBlood: superficial palmar branches of radial artery
bulletNerve:
  1. superficial head - recurrent branch of median nerve, C8,T1
  2. deep head - deep branch of ulnar nerve, C8,T1


Opponens pollicis

bulletOrigin:
  1. distal border of flexor retinaculum
  2. trapezium
bulletInsertion: lateral aspect of the 1st metacarpal
bulletAction: opposes the thumb to the fingers
bulletBlood: superficial palmar branches of radial artery
bulletNerve: recurrent branch of median nerve, C8,T1


Adductor pollicis

bulletOrigin:
  1. transverse head: 3rd metacarpal
  2. oblique head:
    1. base of 1st, 2nd and 3rd metacarpals
    2. floor of carpal tunnel
bulletInsertion:
  1. medial aspect of the base of proximal phalanx
  2. medial sesamoid at McP
bulletAction:
  1. adducts the thumb
  2. may assist to flex the thumb (at the McP joint)
bulletBlood: superficial palmar branches of radial artery
bulletNerve: deep branch of ulnar nerve, C8,T1


Palmaris brevis

bulletOrigin: medial margin of palmar aponeurosis
bulletInsertion:
  1. skin of ulnar border of palm
  2. may insert on the pissiform
bulletAction: tenses the skin on the ulnar side, which is used in a grip action
bulletBlood: superficial palmar branches of ulnar artery
bulletNerve: superficial branch of ulnar nerve, C8,T1


Abductor digiti minimi

bulletOrigin: pisiform & tendon of flexor carpi ulnaris
bulletInsertion:
  1. medial aspect of the base of proximal phalanx of the 5th digit
  2. may send a slip to the ulnar side of the dorsal expansion
bulletAction:
  1. abduct 5th digit (requires pisiform stabilized by FCU)
  2. assists to flex the 5th digit (at McP)
  3. may assist in extension of 5th digit (at IP due to slips to extensor digitorum)
bulletBlood: deep palmar branches of ulnar artery
bulletNerve: deep branch of ulnar nerve, C8,T1


Flexor digiti minimi brevis

bulletOrigin:
  1. distal border of flexor retinaculum
  2. hook of the hamate
bulletInsertion: medial aspect of the base of proximal phalanx
bulletAction: flexes the 5th digit (at the McP joint)
bulletBlood: deep palmar branches of ulnar artery
bulletNerve: deep branch of ulnar nerve, C8,T1


Opponens digiti minimi

bulletOrigin:
  1. distal border of flexor retinaculum
  2. hook of the hamate
bulletInsertion: medial aspect of the 5th metacarpal
bulletAction:
  1. opposes the 5th digit with the thumb
  2. assists to "cup" the palm
bulletBlood: deep palmar branches of ulnar artery
bulletNerve: deep branch of ulnar nerve, C8,T1


Palmar interossei

bulletOrigin: from the side of the metacarpal that faces the midline - to adduct them
bulletInsertion:
  1. on the base of the proximal phalanx of the digit of origin (same side toward the midline)
  2. extensor hood of the same digit(s)
bulletAction:
  1. adducts the fingers (hint: PAD)
  2. flexes the fingers (at the McP while IP joints are extended)
bulletBlood: palmar metacarpal artery of deep palmar arch
bulletNerve: deep branch of ulnar nerve, C8,T1


Dorsal interossei

bulletOrigin: between each metacarpal
bulletInsertion:
  1. directly distal to the origin on the base of the proximal phalanx closest to the midline (to abduct them.)
  2. extensor hood of the same digit(s)
bulletAction:
  1. abducts the fingers (hint: DAB)
  2. flexes the fingers (at the McP while IP joints are extended)
bulletBlood: palmar metacarpal artery of deep palmar arch
bulletNerve: deep branch of ulnar nerve, C8,T1


Lumbricals

bulletOrigin:
  1. tendon of flexor digitorum profundus
  2. 1 & 2 have a single head of origin (from radial aspect of tendon)
  3. 3 & 4 have two heads of origin (each head from an adjacent tendon)
bulletInsertion: extensor hood of digits 2-5
bulletAction:
  1. flexes the fingers (at the McP joints)
  2. extend IPs
bulletBlood: palmar metacarpal arteryof deep palmar arch
bulletNerve:
  1. 1 & 2 - median nerve, C8,T1
  2. 3 & 4 - deep branch of ulnar nerve, C8,T1