Hand- Hypothenar & Central Hand Muscles

Question 1

Hypothenar muscles

Answer 1

Opponens digiti minimi
Flexor digiti minimi brevis
Abductor digiti minimi

Question 2

Central compartment muscles

Answer 2

Lumbricals

Question 3

Opponens digiti minimi

Answer 3

• Originates on the hook of the hamate and the flexor retinaculum
• Inserts on the medial side of the fifth metacarpal
• Opposes digit 5.

Question 4

Flexor digiti minimi brevis

Answer 4

• Originates on the hook of the hamate and the flexor retinaculum
• Inserts on the medial side of the base of the proximal phalanx of digit 5
• Flexes digit 5.

Question 5

Abductor digiti minimi

Answer 5

Originates on the pisiform (and, in some cases, from the tendon of flexor carpi ulnaris)
• Inserts near flexor opponens digiti minimi on the base of the proximal phalanx of digit 5
• Abducts digit 5.

Question 6

Lumbricals 1 and 2

Answer 6

• Unipennate
• Originate on the lateral sides of their tendons;
Lumbricals insert into the extensor expansions of digits 2-5 (dorsally). Flex the metacarpophalangeal joints (aka, MCP
joints) while extending the interphalangeal joints (aka, IP joints). Contrasting movements at the digit joints allow for fine
motor control, such as in writing

Question 7

Lumbricals 3 and 4

Answer 7

• Bipennate
• Originate on the medial and lateral sides of their tendons
Lumbricals insert into the extensor expansions of digits 2-5 (dorsally). Flex the metacarpophalangeal joints (aka, MCP
joints) while extending the interphalangeal joints (aka, IP joints). Contrasting movements at the digit joints allow for fine
motor control, such as in writing

Question 8

what superficial muscles overlie the lumbricals?

Answer 8

• Palmaris brevis crosses the hypothenar compartment.
• Palmar aponeurosis is a sheet of thick fascia that overlies the central muscles of the hand.
• Both insert into the skin of the palm, and aid with grip; do not act directly on the digits.