Anatomy: Posterior Forearm and Hand

Question 0

Abductor Pollicis Brevis

Answer 0

N: Recurrent Branch of Median N.
A: Abducts thumb, aids in opposition of thumb
O: Posterior surface of proximal ulna, radius and interosseuos membrane
I: lateral side of base of proximal phalanx of thumb

Question 1

Abductor Digiti Minimi

Answer 1

N: deep branch of ulnar
A: abducts 5th digit, assists in flexion of proximal phalanx
O: pisiform
I: medial side of base of proximal phalanx of 5th digit

Question 2

Abductor Pollicis Longus

Answer 2

N: Posterior interosseus N. from deep branch of radial
A: abduct thumb, extend thumb at carpometacarpal joint
O: posterior surface of proximal ulna, radius and interosseous membrane
I: base of 1st metacarpal

Question 3

Adductor Pollicis

Answer 3

N: deep branch of ulnar n.
A: adducts thumb toward lateral border of palm
O: oblique head: bases of 2nd and 3rd metacarpals, capitate and adjacent carpals; transverse head: shaft of 3rd metacarpal
I: middle side of base of proximal phalanx of thumb

Question 4

Brachioradialis

Answer 4

N: radial
A: flex forearm
O: supraepicondylar ridge of humerus
I: distal end of radius proximal to styloid process

Question 5

Dorsal Interossei

Answer 5

N: deep branch of ulnar n.
A: abduct 2nd-4th digits, aid lumbricals in flexing MCP joint and extending the IP joints
O: adjacent sides of two metacarpals
I: bases of proximal phalanges; extensor expansion of 2nd-4th digits

Question 6

Extensor Carpi Radialis Brevis

Answer 6

N: deep branch of radial n.
A: extend and abduct hand
O: lateral epicondyle of humerus
I: base of 3rd metacarpal

Question 7

Extensor Carpi Radialis Longus

Answer 7

N: radial n.
A: extend and abduct hand
O: lateral supraepicondylar ridge of humerus
I: base of 2nd metacarpal

Question 8

Externsor Carpi Ulnaris

Answer 8

N: posterior interosseous n. (from deep branch of radial)
A: extend and adduct hand
O: lateral epicondyle of humerus
I: base of 5th metacarpal

Question 9

Extensor Digit Minimi

Answer 9

N: posterior interosseous n. (from deep branch of radial)
A: extends 5th digits at MCP joint and secondarily at IP joint
O: lateral epicondyle of humerus
I: extensor expansion of 5th digit

Question 10

Extensor Digitorum

Answer 10

N: posterior interosseous n. (from deep branch of radial)
A: extends medial four digits primarily at MCP joints and secondarily at IP joints
O: lateral epicondyle of humerus
I: extensor expansions of medial four digits

Question 11

Extensor Indicis

Answer 11

N: posterior interosseous
A: extends 2nd digit, aid in extension of hand
O: distal third of ulna, and interosseous membrane
I: extensor expansion of the 2nd digit

Question 12

Extensor Pollicis Brevis

Answer 12

N: posterior interosseous
A: extends proximal phalanx of thumb at MCP joint, extends carpometacarpal joint
O: distal third of radius and interosseous membrane
I: base of proximal phalanx of thumb

Question 13

Extensor Pollicis Longus

Answer 13

N: posterior interosseous
A: extends distal phalanx of thumb at IP joint, extends MCP and carpometacarpal joints
O: middle third of ulna and interosseous membrane
I: base of distal phalanx of thumb

Question 14

Flexor Digit Minimi

Answer 14

N: deep branch of ulnar
A: flexes proximal phalanx of 5th digit
O: hook of hamate, flexor retinaculum
I: base of proximal phalanx of 5th digit

Question 15

Flexor Pollicis Brevis

Answer 15

N: superficial head: recurrent branch of median; deep head: deep branch of ulnar
A: superficial head: flexes thumb; deep head: adducts thumb toward lateral border of palm
O: flexor retinaculum, tubercles of scaphoid, and trapezium
I: base of proximal phalanx of thumb

Question 16

Lumbricals

Answer 16

N: 1, 2: median; 3, 4: ulnar
A: flex MCP joints, extend IP joint of 2-5 digits
O: 1-2: lateral two tendons of flexor digitorum profundus; 3-4: medial three tendons of flexor digitorum profundus
I: lateral sides of extensor expansion of digits 2-5

Question 17

Opponens Digiti

Answer 17

N: deep branch of ulnar
A: draws 5th metacarpal anterior and rotates it for opposition
O: hook of hamate and flexor retinaculum
I: 5th metacarpal

Question 18

Opponens Pollicis

Answer 18

N: recurrent branch of median
A: draws 1st metacarpal medially to center of palm and rotates it medially
O: flexor retinaculum and tubercles of scaphoid and trapezium
I: lateral side of 1st metacarpal

Question 19

Palmar Interossei

Answer 19

N: deep branch of ulnar
A: adducts digits, assists lumbricals in flexing MCP joints and extending IP joint
O: 2, 4, 5 metacarpals
I: bases of proximal phalanges, extensor expansion of 2, 4, 5

Question 20

Supinator

Answer 20

N: deep branch of radial
A: supinate a forearm
O: lateral epicondyle, radial collateral and anular ligaments, supinator fossa, crest of ulna
I: proximal third of radius

Question 20

Supinator

Answer 20

N: deep branch of radial
A: supinate a forearm
O: lateral epicondyle, radial collateral and anular ligaments, supinator fossa, crest of ulna
I: proximal third of radius