Hand

Question 1

Abductor Pollicus Brevis

Answer 1

Thenar Eminence

Origin: flexor retinaculum, trapezium, and scaphoid tubercles

Insertion: base of proximal phalanx of thumb

Action: abduct thumb, assist in opposition of thumb

Nerve: median nerve C6, 7, 8, T1

Question 2

Flexor Pollicus Brevis

Answer 2

Thenar Eminence

Origin:

• Superficial head: flexor retinaculum
• Deep head: trapezium, trapezoid, and capitate

Insertion: base of proximal phalanx of thumb

Action: flex thumb, assist in opposition

Nerve:

• Superficial head: median nerve C6, 7, 8, T1
• Deep head: ulnar nerve C8, T1

Question 3

Opponens Pollicis

Answer 3

Thenar Eminence

Origin: flexor retinaculum and tubercle of trapezium

Insertion: entire 1st length of metacarpal bone, radial surface

Action: opposition of thumb at carpometacarpal joint (CMC)

Nerve: median nerve C6, 7, 8, T1

Question 4

Adductor Pollicis

Answer 4

Origin: capitate, second and third metacarpals

Insertion: base of proximal phalanx of thumb

Action: adduct thumb, assist to flex thumb

Nerve: ulnar nerve C8, T1

Question 5

Abductor Digiti Minimi

Answer 5

Hypothenar Eminence

Origin: pisiform and tendon of FCU

Insertion: base of proximal phalanx of 5th finger, ulnar surface

Action: abduct 5th finger, assist in opposition of 5th finger toward thumb

Nerve: ulnar nerve C7, 8, T1

Question 6

Flexor Digiti Minimi Brevis

Answer 6

Hypothenar Eminence

Origin: hook of hamate and flexor retinaculum

Insertion: base of proximal phalanx of 5th finger, palmar surface

Action: flex 5th finger, assist in opposition of 5th finger toward thumb

Nerve: ulnar nerve C7, 8, T1

Question 7

Opponens Digiti Minimi

Answer 7

Hypothenar Eminence

Origin: hook of hamate and flexor retinaculum

Inserion: shaft of 5th metacarpal, ulnar surface

Action: opposition of 5th finger at CMC joint

Nerve: ulnar nerve C7, 8, T1

Question 8

Lumbricals

Answer 8

Origin: surfaces of flexor digitorum profundus tendons

Insertion: extensor aponeurosis on dorsal side of phalanges 2-5

Action:

• Extend 2nd through 5th fingers at interphalangeal joints
• Flex 2nd through 5th fingers at metacarpophalangeal joints

Nerve:

• 2nd-3rd fingers: median nerve C6, 7, 8, T1
• 4th-5th fingers: ulnar nerve C7, 8, T1

Question 9

Palmar Interossei

Answer 9

Origin: base of 1st, 2nd, 4th, and 5th metacarpals

Insertion: base of proximal phalanx of related finger and extensor aponeurosis

Action:

• Adduct thumb, 2nd, 4th, 5th, fingers toward 3rd finger
• Assist to flex thumb, 2nd, 4th, 5th, fingers at metacarpophalangeal joints and extend them at interphalangeal joints

Nerve: ulnar nerve C8, T1

Question 10

Dorsal Interossei

Answer 10

Origin: adjacent sides of all metacarpals

Insertion: base of proximal phalanx of 2nd, 3rd, 4th fingers and extensor aponeurosis

Action:

• Abduct 2nd, 3rd, 4th fingers at metacarpophalangeal joints
• Assist to flex 2nd, 3rd, 4th fingers at metacarpophalangeal joints and extend them at interphalangeal joints

Nerve: ulnar nerve C8, T1