Muscles of the Forearm - Anterior Compartment (superficial)

Question 1

List the muscles found superficially in the anterior compartment of the forearm, from lateral to medial

Answer 1

1. Pronator teres
2. Flexor carpi radialis
3. Palmaris longus
4. Flexor digitorum superficialis
5. Flexor carpi ulnaris

Question 2

Origin of pronator teres (3)

Answer 2

has 2 heads

1. Humeral head - (a) lower part of the medial supracondylar ridge + (b) the front of the medial epicondyle (common flexor origin; CFO)
2. Ulnar head - From the medial border of coronoid process of ulna

Question 3

Insertion of pronator teres

Answer 3

Into pronator tuberosity on the middle of lat surface
of radius at the most curved part of the bone
(to give maximal range of pronation).

Question 4

Nerve supply of pronator teres

Answer 4

Median nerve
(It gives a branch to it in the cubital fossa before piercing it)

Question 5

Actions of the pronator teres (2)

Answer 5

1. Helps in pronation of the forearm
2. Helps in the flexion of the forearm at the elbow joint

Question 6

List 3 relations of the pronator teres muscle

Answer 6

1. The median nerve passes between the 2 heads of the pronator teres
2. The lateral border of the pronator teres forms the medial boundary of the cubital fossa
3. The ulnar artery passes deep to the ulnar head of the pronator teres, separating it from the median nerve

Question 7

Origin of the flexor carpi radialis

Answer 7

From the front of the medial epicondyle of the humerus (common flexor origin)

Question 8

Insertion of the flexor carpi radialis

Answer 8

Into the palmar aspects of the bases of the 2nd and 3rd metacarpal bones

Question 9

Nerve supply of flexor carpi radialis

Answer 9

Median nerve (in cubital fossa)

Question 10

Actions of flexor carpi radialis (3)

Answer 10

1. Flexion of elbow
2. Flexion of wrist
3. Abduction (radial deviation of the wrist)

Question 11

Origin of palmaris longus

Answer 11

From the front of the medial epicondyle of the humerus (common flexor origin)

Question 12

Insertion of palmaris longus (2)

Answer 12

1. The superficial part of the tendon is inserted into the apex of the palmar aponeurosis of the palm.
2. The deep part of the tendon blends with the ant. surface of the flexor retinaculum of the wrist.

Question 13

Nerve supply of palmaris longus

Answer 13

Median nerve (by a branch arising from the cubital fossa)

Question 14

Actions of palmaris longus (2)

Answer 14

1. Weak flexor of elbow and wrist joints
2. Protects palm by putting palmar aponeurosis tense

Question 15

What muscle in the superficial group of the anterior compartment of the forearm may be absent?

Answer 15

Palmaris longus

Question 16

Origin of flexor digitorum superficialis (4)

Answer 16

by 2 heads

1. Humero-ulnar head - (a) From the front of the medial epicondyle of the humerus (CFO) + (b) From medial border of coronoid process of ulna + (c) Ulnar collateral ligament
2. Radial head - From anterior oblique line of radius

Question 17

Course and insertion of flexor digitorum superficialis

Answer 17

1. Develops 4 tendons at middle of forearm (the tendons of the middle and ring fingers are superficial to the ones of the index and little fingers)
2. Tendons pass through carpal tunnel, enter palm, and diverge to fibrous flexor sheaths of medial 4 fingers
3. On palmar surface of proximal phalanx, each tendon is divided by the tendon of flexor digitorum profundus into 2 slips which are inserted into the sides of the front of the shaft of the middle phalanx

Question 18

Nerve supply of flexor digitorum superficialis

Answer 18

Median nerve (by a branch arising from the cubital fossa)

Question 19

Actions of the flexor digitorum superficialis (2)

Answer 19

1. Flexes the middle and proximal phalanges
2. Flexes the wrist joint and helps flexion of the elbow

Question 20

Origin of flexor carpi ulnaris (3)

Answer 20

by 2 heads

1. Humeral head - From the front of the medial epicondyle of the humerus (CFO)
2. Ulnar head - (a) Medial border of olecranon process + (b) upper 2/3 of posterior border of ulna

Question 21

Insertion of flexor carpi ulnaris (3)

Answer 21

1. Into pisiform bone
   it then continues distally to:
2. base of 5th metacarpal bone (through pisometacarpal ligament)
3. hamate bone (through pisohamate ligament)

Question 22

Nerve supply of flexor carpi ulnaris

Answer 22

Ulnar nerve (by a branch arising a short distance below the elbow)

Question 23

Actions of the flexor carpi ulnaris (2)

Answer 23

1. Helps flexion of the elbow
2. Flexes and adducts wrist joint

Question 24

3 relations of flexor carpi ulnaris

Answer 24

1. At its origin: the ulnar nerve passes between its 2 heads of origin
2. Along its Course: it overlies flexor digitorum profundus with the ulnar nerve and artery in between.
3. At its insertion: its tendon lies just medial to the ulnar nerve and ulnar artery.