Upper Extremity Week 3 Structure Information: Muscles

Question 1

Abductor digiti minimi

Answer 1

(C8-T1)

attachments- from the pisiform to the ulnar side of the base of the proximal phalanx of the 5th digit

actions- abducts 5th digit

innervation- deep branch of the ulnar nerve

Question 2

Abductor pollicis brevis

Answer 2

(C6-T1)

attachments- from the transverse carpal lig. to the radial side of the base of the proximal phalanx of the thumb and tubercle of trapezium

actions- abducts thumb

innervation- recurrent branch of the median nerve

Question 3

Adductor pollicis

Answer 3

(C8-T1)

attachments- from the capitate & 2nd & 3rd metacarpals (oblique head) & the palmar aspect of the 3rd metacarpal (transverse head) to the base of the proximal phalanx of the thumb

actions- adducts thumb

innervation- deep branch of the ulnar nerve

Question 4

Dorsal interossei

Answer 4

(C8-T1)

attachments- from the adjacent sides of the metacarpals to the proximal phalangeal bases & dorsal digital expansions of digits 2-4

actions- abducts (metacarpophalangeal), flexes (metacarpophalangeal) & extends (interphalangeal) digits 2-4

innervation- deep branch of the ulnar nerve

Question 5

Flexor digiti minimi brevis

Answer 5

(C8-T1)

attachments- from the hamate to the ulnar side of the base of the proximal phalanx of the 5th digit

actions- flexes (metacarpophalangeal) 5th digit

innervation- deep branch of the ulnar nerve

Question 6

Flexor pollicis brevis

Answer 6

(superficial head C6-T1; deep head C8-T1)

attachments- from the transverse carpal lig. & trapezium to the radial side of the base of the proximal phalanx of the thumb; deep head blends with opponens pollicis

actions- flexes (metacarpophalangeal) thumb

innervation- recurrent branch of the median nerve (superficial head) & deep branch of ulnar nerve (deep head)

Question 7

Lumbricals

Answer 7

(C7-T1)

attachments- from the tendons of the flexor digitorum profundus to the radial side of the dorsal digital expansions of digits 2-5

actions- flexes metacarpophalangeal & extends interphalangeal joints of digits 2-5

innervation- deep branch of the ulnar nerve (3rd & 4th lumbricals C8-T1) & median nerve (1st & 2nd lumbricals C7-8-T1)

Question 8

Opponens digiti minimi

Answer 8

(C8-T1)

attachments- from the hook of the hamate to the ulnar margin of the shaft of the 5th metacarpal

actions- opposition of 5th digit to thumb

innervation- deep branch of the ulnar nerve

Question 9

Opponens pollicis

Answer 9

(C6-T1)

attachments- from the transverse carpal lig. & trapezium to the palmar surface of the 1st metacarpal

actions- opposition of thumb to 5th digit

innervation- recurrent branch of the median nerve

Question 10

Palmar interossei

Answer 10

(C8-T1)

attachments- from the palmar aspects of metacarpals 2, 4 & 5 to the dorsal digital expansions of digits 2, 4, 5

actions- adducts (metacarpophalangeal), flexes (metacarpophalangeal) & extends (interphalangeal) digits 2, 4 & 5

innervation- deep branch of the ulnar nerve