Muscles of the Thumb

Question 1

Abductor Pollicis Brevis

Answer 1

O: flexor retinaculum + scaphoid + trapezium

I: base of proximal phalanx of thumb

A: abduction of thumb

In: median nerve

Question 2

Opponens Pollicis

Answer 2

O: flexor retinaculum + trapezium

I: first metacarpal

A: opposition of thumb

In: median nerve

Question 3

Flexor Pollicis Brevis (SUPERFICIAL HEAD)

Answer 3

O: flexor retinaculum and possibly trapezium

I: base of proximal phalanx of thumb

A: flexion of the thumb and aids in opposition and adduction

In: medial nerve

Question 4

Flexor Pollicis Brevis (DEEP HEAD)

Answer 4

O: trapezoid and capitate

I: base of proximal phalanx of thumb

A: flexion of the thumb and aids in opposition and adduction

In: ulnar nerve

Question 5

Adductor Pollicis (TRANSVERSE HEAD)

Answer 5

O: third metacarpal

I: base of proximal phalanx of thumb

A: adduction and flexion of thumb

In: ulnar nerve

Question 6

Adductor Pollicis (OBLIQUE HEAD)

Answer 6

O: bases of first three metacarpals, capitate, trapezoid, and trapezium

I: base of proximal phalanx of thumb

A: adduction and flexion of thumb

In: ulnar nerve