Thenar Muscles

Question 1

Adductor Pollicis

Origin

Insertion

Answer 1

Origin:

• Transverse head: M3
• Oblique head: M2-3 bases and trapezoid + capitate

Insertion:

• Medial base of proximal phalanx of D1
• Ulnar sesamoid

Question 2

Adductor Pollicis

Action

Innervation

Answer 2

Action:

• Thumb adduction

Innervation:

• Deep branch of ulnar n.

Question 3

Abductor Pollicis Brevis

Origin

Insertion

Answer 3

Origin:

• Scaphoid and trapezium

Insertion:

• Radial sesamoid and radial base of proximal phalanx of D1

Question 4

Abductor Pollicis Brevis

Action

Innervation

Answer 4

Action:

• Thumb abduction

Innervation:

• Recurrent branch of median n.

Question 5

Flexor Pollicis Brevis

Origin

Insertion

Answer 5

Origin:

• Trapezium
• Flexor retinaculum

Insertion:

• Proximal phalanx of D1

Question 6

Flexor Pollicis Brevis

Action

Innervation

Answer 6

Action:

• Thumb flexion

Innervation:

• Recurrent branch of median n.

Question 7

Opponens Pollicis

Origin

Insertion:

Answer 7

Origin:

• Trapezium

Insertion:

• Radial side of M1

Question 8

Opponens Pollicis

Action

Innervation

Answer 8

Action:

• Thumb flexion aiding in opposition

Innervation:

• Recurrent branch of median n.