muscles of the hand

Question 1

what are the thenar muscles of the hand?

Answer 1

• opponens pollicis
• abductor pollicis brevis
• flexor pollicis brevis

Question 2

1. what is the origin of opponens pollicis?
2. what is the insertion of opponens pollicis?
3. what is the action of opponens pollicis?
4. what is the innervation of opponens pollicis?

Answer 2

1. trapezium
2. metacarpal I
3. opposes thumb by medially rotating and flexing the MC on the trapezium
4. median nerve

Question 3

1. what is the origin of abductor pollicis brevis?
2. what is the insertion of abductor pollicis brevis?
3. what is the action of abductor pollicis brevis?
4. what is the innervation of abductor pollicis brevis?

Answer 3

1. scaphoid
2. proximal phalanx of thumb
3. thumb abduction
4. median nerve

Question 4

1. what is the origin of flexor pollicis brevis?
2. what is the insertion of flexor pollicis brevis?
3. what is the action of flexor pollicis brevis?
4. what is the innervation of flexor pollcis brevis?

Answer 4

1. trapezium
2. proximal phalanx of thumb
3. flexes MCP of thumb
4. median nerve

Question 5

what are the muscles of the hypothenar?

Answer 5

• opponens digiti minimi
• abductor digiti minimi
• flexor digiti minimi brevis

Question 6

1. what is the origin of opponens digiti minimi?
2. what is the insertion of opponens digiti minimi?
3. what is the action of opponens digiti minimi?
4. what is the innervation of opponens digiti minimi?

Answer 6

1. hook of hamate
2. metacarpal V
3. rotates metacarpal of little finger towards palm (opposition)
4. ulnar nerve

Question 7

1. what is the origin of abductor digiti minimi?
2. what is the insertion of abductor digiti minimi?
3. what is the action of abductor digitit minimi?
4. what is the innervation of abductor digiti minimi?

Answer 7

1. pisiform
2. proximal phalanx of little finger
3. abducts little finger
4. ulnar nerve

Question 8

1. what is the origin of flexor digiti minimi brevis?
2. what is the insertion of flexor digiti minimi?
3. what is the action of flexor digiti minimi?
4. what is the innervation of flexor digiti minimi?

Answer 8

1. hook of hamate
2. proximal phalanx of little finger
3. flexes MCP of little finger
4. ulnar nerve

Question 9

how many lumbricals are there?

Answer 9

4

Question 10

1. what is the origin of the lumbricals?
2. what is the insertion of the lumbricals?
3. what is the action of the lumbricals?
4. what is the innervation of the lumbricals?

Answer 10

1. each originates from a tendon of flexor digitorum profundas
2. inserts laterally into extensor hood
3. flex MCPJ and extends IPJ
4. medial 2 = ulnar + lateral 2 = median

Question 11

what are the interossei hand muscles?

Answer 11

• dorsal interossei
• palmar interossei

Question 12

1. what is the origin of dorsal interossei?
2. what is the insertion of dorsal interossei?
3. what is the action of dorsal interossei?
4. what is the innervation of dorsal interossei?

Answer 12

1. lateral + medial of each metacarpal fingers II-V
2. extensor hood
3. abduction at MCP
4. ulnar nerve

Question 13

1. what is the origin of palmar interossei?
2. what is the insertion of palmar interossei?
3. what is the action of palmar interossei?
4. what is the innervation of palmar interossei?

Answer 13

1. medial or lateral of each metacarpal fingers II-V
2. extensor hood
3. adduction at MCP
4. ulnar nerve

Question 14

what are the “other” muscles of the hand?

Answer 14

• palmaris brevis
• adductor pollicis

Question 15

1. what is the origin of palmaris brevis?
2. what is the insertion of palmaris brevis?
3. what is the action of palmaris brevis?
4. what is the innervation of palmaris brevis?

Answer 15

1. palmar aponeurosis
2. medial dermis
3. improves grip
4. ulnar nerve