Intrinsic Muscles

Question 1

What are the insertions of the lumbricals?

Answer 1

Proximal: FDP tendons
Distal: Extensor hoods

Question 2

What is the function of the lumbricals?

Answer 2

Flex the MCPJs, Extend the IPJs

Question 3

How many dorsal and palmar interossei are there?

Answer 3

4 dorsal, 3 palmar

Question 4

What is the function of the dorsal interossei?

Answer 4

Abduct the digits away from the 3rd digit (axial line)

Question 5

What is the function of the palmar interossei?

Answer 5

Adduct the digits towards the 3rd digit (axial line)

Question 6

What is the mnemonic that helps us remember the action of the dorsal and palmar interossei?

Answer 6

PAD-DAB
Palmar Adduct
Dorsal Abduct

Question 7

Name the Thenar Muscles, and describe their function.

Answer 7

Abductor Pollicis Brevis - abducts the thumb, superficial
Flexor Pollicis Brevis - flexes the thumb into the palm. Lies above the APB.
Opponens Pollicis - opposes the thumb (brings it to fingers). Lies deep to the APB.

Question 8

Name the Hypothenar Muscles, and describe their function.

Answer 8

Abductor Digiti Minimi - abducts the LF at the MCPJ. located on the ulnar border of the palm of the hand
Flexor Digiti Minimi Brevis - flexes the LF at the MCPJ. lies lateral to the ADM.
ODM - flexes and laterally rotates the 5th MC around the CMCJ, as well as opposing the LF.

Question 9

What are the two other intrinsic muscles?

Answer 9

Palmaris Brevis - tenses the skin on the ulnar side of the palm during a grip action.
Adductor Pollicis - Adducts the thumb