Hand (Palmar)

Question 1

Palmaris brevis

Answer 1

Origin: Palmar aponeurosis, flexor retinaculum

Insertion: Dermis (medial border of palm)

Action: Deepens hollow of hand, assists/improves grip

Innervation: Ulnar nerve - superficial branch (C8, T1)

Question 2

Adductor Pollicis

Answer 2

Origin:
Oblique head = capitate + 2nd and 3rd MC
Transverse head = 3rd MC

Insertion: Base of 1st proximal phalanx + extensor hood of thumb

Action: Adducts thumb

Innervation: Ulnar nerve - deep branch (C8, T1)

Question 3

Palmar interossei

Answer 3

Origin: Sides of metacarpals 2, 4, and 5

Insertion: Extensor hoods of digits 2, 4, 5

Action: Adduction of 2nd, 4th, 5th digits towards axial line of hand (3rd digit) + MCP flexion + IP extension

Innervation: Ulnar nerve - deep branch (C8, T1)

Question 4

Dorsal interossei

Answer 4

Origin: Adjacent sides of two metacarpal bones

Insertion: Extensor hoods of digits 2-4

Action: Abduct digits from axial line of hand (3rd
digit) + MCP flexion + IP extension

Innervation: Ulnar nerve - deep branch (C8, T1)

Question 5

Lumbricales, first and second

Answer 5

Origin: Lateral two FDP tendons

Insertion: Lateral/radial sides of 2nd and 3rd extensor hood

Action: MCP flexion + IP extension

Innervation: Ulnar nerve - deep branch (C8, T1)

Question 6

Lumbricales, third and fourth

Answer 6

Origin: Medial three FDP tendons

Insertion: Lateral/radial sides of 4th and 5th extensor hoods

Action: MCP flexion + IP extension

Innervation: Ulnar nerve - deep branch (C8, T1)