Thenar Muscles

Question 1

Opponens Pollicis

Answer 1

O: Flexor retinaculum and tubercles of scaphoid and trapezium
I: Lateral side of 1st Metacarpal
N: Recurrent branch of median nerve (C8, T1)
A: To oppose thumb; it draws 1st metacarpal medially to center of palm and rotates it medially

Question 2

Abductor Pollicis Brevis

Answer 2

O: Flexor retinaculum and tubercles of scaphoid and trapezium
I: Lateral side of base of proximal phalanx of thumb
N: Recurrent branch of the median nerve (C8, T1)
A: Abducts thumb; helps oppose it

Question 3

Flexor Pollicis Brevis (Superficial Head)

Answer 3

O: Flexor retinaculum and tubercles of scaphoid and trapezium
I: Lateral side of base of proximal phalanx of thumb
N: Recurrent branch of the median nerve (C8, T1)
A: Flexes Thumb

Question 4

Flexor Pollicis Brevis (Deep Head)

Answer 4

O: Flexor retinaculum and tubercles of scaphoid and trapezium
I: Lateral side of base of proximal phalanx of thumb
N: Deep branch of Ulnar Nerve (C8, T1)
A: Flexes Thumb

Question 5

Adductor Pollicis (Oblique Head)

Answer 5

O: Bases of 2nd and 3rd Metacarpals, Capitate, and adjacent Carpals
I: Medial Side of base of proximal phalanx of thumb
N: Deep branch of Ulnar Nerve (C8, T1)
A: Adducts thumb toward lateral border of palm

Question 6

Adductor Pollicis (Transverse Head)

Answer 6

O: Anterior surface of shaft of 3rd Metacarpal
I: Medial Side of base of proximal phalanx of thumb
N: Deep branch of Ulnar Nerve (C8, T1)
A: Adducts thumb toward lateral border of palm