Muscles: Wrist Joint and Hand

Question 1

What are the 2 groups of muscles in the hand?

Answer 1

• Intrinsic mucles: located in the hand
• Extrinsic muscles: in the forearm and their tendons pass into the hands

Question 2

What do the extrinsic muscles of the hand consist of in the anterior and posterior compartments?

Answer 2

• Anterior compartment: superficial and deep flexors
• Posterior compartment: superficial and deep extensors

Question 3

How do the extrinsic muscles of the forearm move the wrist and fingers?

Answer 3

• The muscles attach proximally to the bones in the arm or forearm and have **long tendons ** which cross the joints of the wrist and fingers or thumb

Question 4

1. How are the tendons of the extrinsic muscles in the forearm held in place at the wrist joint?
2. What movements can be done at the wrist?

Answer 4

1. The tendons are held in place by a band of connective tissue (flexor/extensor retinaculum)
2. Movements: flexion, extension, abduction, adduction and circumducition.

*The hand can also change position by movements at the radio-ulnar joints (pronation and supination) *

Question 5

What are the muscles in the anterior compartment of the forearm? (flexor compartment)

Answer 5

• Flexor carpi ulnaris
• Flexor carpi radialis
• Flexor digitorium superficialis

Question 6

What are the muscles in the posterior compartment of the forearm? (extensor compartment)

Answer 6

• Extensor carpi radialis longus and brevis
• Extensor carpi ulnaris
• Brachioradialis
• Pronator teres
• Palmaris longus

Question 7

Name the muscles

Answer 7

Question 8

Where does the flexor digitorium of the anterior compartment of the forearm attach and how does it allow movement?

Answer 8

• Attaches from the medial condyle of the humerus and splits into 4 tendons which connect to the middle phalanx of each finger
• It acts to flex the fingers at the metacarpophalangeal joints (MCPJs) and the proximal interphalangeal joints (PIPJs)

Question 9

Where does the pronator teres attach and how does it allow movement?

Answer 9

• Attaches to the shaft of the radius
• Acts to pronate the forearm

Question 10

Where does the flexor carpi radialis attach and how does it allow movement?

Answer 10

• Attaches to the metacarpals 2 and 3
• Acts to flex and abduct at the wrist

Question 11

Where does the flexor carpi ulnaris attach and how does it allow movement?

Answer 11

• Attaches to the pisiform bone in the hand
• Allows wrist flexion and adduction

Question 12

What nerve innovates the pronator teres, flexor carpi radialis and plamaris longus?

Answer 12

Median nerve

Question 13

What nerve innovates the flexor carpi ulnaris

Answer 13

Ulnar nerve

Question 14

What nerve innovates the posterior compartment (extensor compartment) of the forearm?

Answer 14

The radial nerve

Question 15

Where does the brachioradialis of the posterior forearm attach and how does it allow movement?

Answer 15

• Originates from lateral humerus and attaches to distal radius
• Flexion at the elbow

Question 16

Where does the extensor carpi radialius longus and brevis attach and what movements does it allow?

Answer 16

• From the lateral aspect of the humerus
• Longus attaches to metacarpal 2
• Brevis attaches to metacarpal 3
• Both extend the wrist and abduct

Question 17

Where does the extensor digitorium attach and how does it allow movement?

Answer 17

• Attaches at the lateral epicondyle of humerus, splits into 4 tendons and attaches at the distal phalanx of each finger
• Allows extension of fingers at MCPJs and IPJs

Question 18

Where does the extensor digiti minimi attach and how does it allow movement?

Answer 18

• The lateral epicondyle of the humerus and extends to distal phalanx of the little finger
• Extension of little finger

Question 19

Where does the extensor carip ulnaris attach and what movement does it allow?

Answer 19

• Attaches from lateral epicondyle of humerus and attaches to metacarpal 5
• Extension and adduction of wrist

Question 20

Where does the aconeus attach and what movement does it allow?

Answer 20

• originates from lateral epicondyle of humerus and attaches at the olecranon process
• It extends the elbow joint

Question 21

Label the muscles in the posterior compartment of the forearm

Answer 21