Muscles of the Hand

Question 1

Instrinsic muscles of the hand are responsible for

Answer 1

Fine motor functions of the hand

Question 2

Instrinsic Muscles of the hand

Answer 2

Adductor pollicus
Palmaris Brevis
Interossei
Lumbricals
Thenar
Hypothenar muscles

Question 3

Thenar Muscles

Answer 3

These are three short muscles located at the base of the thumb. The muscle bellies produce a bulge, known as the thenar eminence. They are responsible for the fine movements of the thumb.

Question 4

Nerve innervation of the thenar muscles

Answer 4

Median Nerve

Question 5

Opponens Pollicus

Answer 5

The largest of the thenar muscles. This lies underneath the other two thenar muscles.

Question 6

Opponens Pollicus Attachements

Answer 6

Originates from the tubercle of the trapezium and the associated flexor retinaculum. It inserts into the lateral margin of the metacarpal of the thumb

Question 7

Opponens Pollicus Action

Answer 7

Opposes the thumb, by medially rotating and flexing the metacarpal on the trapezium

Question 8

Aductor Pollicus Brevis

Answer 8

This muscle is found anteriorly to the opponens pollicus and proximal to the pollicus brevis

Question 9

Attachments of Abductor Pollicus Brevis

Answer 9

Originates from the tubercles of the scaphoid and the trapezium, and from the associated flexor retinaculum. Attache to the lateral side of the proximal phalanx of the thumb.

Question 10

Action of Abductor Pollicus Brevis

Answer 10

Abducts the thumb

Question 11

Flexor Pollicus Brevis

Answer 11

This is the most distal of the thenar muscle

Question 12

Attachements of Flexor Pollicus Brevis

Answer 12

Originates from the tubercle of the trapezium and the associated flexor retinaculum. Attaches to the base of the proximal phalanx of the thumb.

Question 13

Actions of Flexor Pollicus Brevis

Answer 13

Flexes the metacarpophalangeal joint of the thumb.

Question 14

Hypothenar Eminence

Answer 14

This is is produced by the hypothenar muscles and is a muscular protrusion on the medial side of the palm, at the base of the little finger.

Question 15

Innervation of Hypothenar Muscles

Answer 15

The Ulnar Nerve

Question 16

Opponens Digiti Minimi attachments

Answer 16

Originates from the hook of the hamate and associated flexor retinaculum, inserts into the medial margin of metacapral 5.

Question 17

Actions of opponens digiti minimi

Answer 17

It rotates the metacarpal of the little finger towards the palm, producing opposition.

Question 18

Abductor Digiti Minimi attachments

Answer 18

Originates from the pisiform and the tendon of the flexor carpi ulnaris. It attaches to the base of the proximal phalanx of the little finger.

Question 19

Actions of abductor digiti minimi

Answer 19

Abducts the little finger

Question 20

Flexor Digiti Minimi Brevis attachments

Answer 20

Originates from the hook of hamate and adjacent flexor retinaculum, and inserts into the base of the proximal phalanx of the little finger

Question 21

Actions of Flexor Digiti Minimi Brevis attachments

Answer 21

Flexes the MCP joint of the little finger

Question 22

Lumbricals

Answer 22

These are four lumbricals in the hand, each associated with a finger. They are very crucial to finger movement, linking the extensor tendons to the flexor tendons

Question 23

Attachments of the lumbricals

Answer 23

Each lumbrical originates from a tendon of the flexor digitorum profundus. They pass dorsally and laterally around each finger, and inserts into the extensor hood.

Question 24

Actions of the Lumbrical muscles

Answer 24

The flex at the MCP joint, and extend at the interphalangeal (IP) joints of each finger.

Question 25

Innervation of the Lumbrical Muscles

Answer 25

The lateral two lumbricals (of the index and middle fingers) are innervated by the median nerve. The medial two lumbricals (of the little and ring fingers) are innervated by the ulnar nerve.

Question 26

Interossei

Answer 26

The interossei muscles are located between the metacarpals. They can be divided into two groups: the dorsal and palmar interossei

Question 27

Dorsal Interossei Attachments

Answer 27

Each interossei originates from the lateral and medial surfaces of the metacarpals. They attach into the extensor hood and proximal phalanx of each finger.

Question 28

Actions of the dorsal interossei

Answer 28

Abduct the fingers at the MCP joint

Question 29

Innervation of the dorsal interossei

Answer 29

Ulnar nerve

Question 30

Attachments of the Palmar Interossei

Answer 30

Each interossei originates from a medial or lateral surface of a metacarpal, and attaches into the extensor hood and proximal phalanx of same finger.

Question 31

Actions of the Palmar Interossei

Answer 31

Adducts the fingers at the MCP joint

Question 32

Innervation of the palmar interossei

Answer 32

Ulnar nerve

Question 33

Palmaris Brevis

Answer 33

A small thin muscles, found in the subcutaenous tissue of the hypothenar eminence

Question 34

Attachments of Palmaris Brevis

Answer 34

Originates from the palmar aponeurosis and flexor retinaculum, attaches to the dermis of the skin on the medial margin of the hand.

Question 35

Actions of Palmaris Brevis

Answer 35

Wrinkles the skin of the hypothenar eminence and deepens the curvature of the hand, improving grip.

Question 36

Innervation of Palmaris Brevis

Answer 36

Ulnar Nerve

Question 37

Adductor Pollicus

Answer 37

This is large triangular muscle with two heads. The radial artery passes anteriorly through the space between the two heads, forming the deep palmar arch

Question 38

Attachments of Adductor Pollicus

Answer 38

One head originates from metacarpal III. The other head originates from the capitate and adjacent areas of metacarpals II and III. Both attach into the base of the proximal phalanx of the thumb

Question 39

Actions of Adductor Pollicus

Answer 39

Adductor of the thumb

Question 40

Innervation of adductor pollicus

Answer 40

Ulnar nerve

Question 41

Radial artery

Answer 41

contributes mainly to supply of the thumb and the lateral side of the index finger. As it tends to enter the hand dorsally it contributes mainly to the deep palmar arch.

Question 42

Ulnar Artery

Answer 42

contributes mainly to the supply of the rest of the digits, and the medial side of the index finger. The main contributor of the superficial arch.