The Anterior Compartment of the Forearm

Question 1

Answer 1

Question 2

What does the medial epicondyle act as?

Answer 2

The common flexor origin for the superficial and intermediate flexors.

A common tendon arises from here, providing the proximal insertion point for these 4 muscles.

Any overuse injury (such as golfers elbow) is reflected by pain here.

Question 3

What is the palmaris longus?

Answer 3

The palmaris longus (not shown above) is a muscle which is absent in about 20% of people! It is a long thin muscle and is one of the most superficial structures found at the wrist joint – see if you have one by flexing the wrist joint

Question 4

What is the action of pronator teres?

Answer 4

It pronates the forearm turning the hand posteriorly

Question 5

Apart from flexing the wrist, which superficial muscle is involved in adduction (ulnar deviation) of the wrist joint?

Answer 5

Flexor carpi ulnaris and flexor carpi ulnaris

Question 6

Apart from flexing the wrist, which superficial muscle is involved in abduction (radial deviation) of the wrist joint?

Answer 6

Flexor carpi radialis

Question 7

Three superficial muscles of the forearm are supplied by what?

Answer 7

Flexor carpi ulnaris muscle

Question 8

What is the flexor digitorum superficialis?

Answer 8

Lies immediately deep to the superficial group of flexors in the forearm and is seen as the only muscle on the intermediate group of the forearm

Question 9

Explain the distal tendon of FDS

Answer 9

When approaching its insertion point it splits into two loops passing around the back of the phalanx.

This provides a tunnel in which the flexor digitorum profundus tendon can pass through attaching onto the distal phalanx.

Question 10

To which digits (fingers) are the 4 tendons of FDS attached?

Answer 10

Eeveryone but thumb

Question 11

On which phalanx are they inserted?

Answer 11

Middle phalanx

Question 12

What does the flexor digitorum superficialis flex?

Answer 12

Flexes the wrist, metacarpophalangeal and proximal interphalangeal joints.

Question 13

Can this muscle act on the distal interphalangeal joint?

Answer 13

Metacarpophalangeal and prxomal interpahalangeal finger flexion

Question 14

What nerve innervates FDS?

Answer 14

Median nerve (C8-T1)

Question 15

What does the brachioradialis act on?

Answer 15

Although seen as a muscle that lies in the posterior (extensor) compartment of the forearm the brachioradialis acts on the elbow joint with the other anterior muscles.

Question 16

What is the main action of the brachioradialis muscle?

Answer 16

Flexes elbow when forearm is in neutral and acts to stabolise the elbow during rapid flexion and extension

Question 17

Which nerve innervates the brachioradialis muscle?

Answer 17

Radial nerve (C5, C6, C7

Question 18

What rule is the brachioradialis exception to?

Answer 18

The rule that all flexors lie in the anterior compartment, and that the radial nerve only innervates extensor muscles

Question 19

What are the deep group of muscles of the forearm in contact with?

Answer 19

The bones and interosseous membrane.
The flexor digitorum profundus (FDP) is in relation to the ulna, the flexor pollicis longus in in relation to the radius, and the pronator quadratus which is closely related to the distal parts of both bones.

Question 20

The flexor digitorum profundus (FDP) is in relation to what?

The flexor pollicis longus is in relation to what?

The pronator quadratus is in relation to what?

Answer 20

Flexor digitorum profundus- Ulna

Flexor pollicis longus- Radius

Pronator quadratus- Closely related to the distal parts of both bones

Question 21

Answer 21

Question 22

What is the flexor digitorum profundus?

Answer 22

FDP is a long, thick muscle that lies deeply in the front of the forearm. It also lies more superficially on the medial border and back of the forearm.

Question 23

The fleshy mass at the medial side is the FDP covered with the aponeurosis of what?

Answer 23

The fleshy mass at the medial side is the FDP covered with the aponeurosis of flexor carpi ulnaris

Question 24

What is its main action of FDP on the wrist and finger joints?

Answer 24

Finger flexion

Question 25

What is the nerve supply of the FDP like?

Answer 25

Dual nerve supply

Question 26

Which part of the FDP is supplied by ulnar nerve?

Answer 26

Ulnar half

Question 27

Which part of the FDP is supplied by median nerve?

Answer 27

Radial half

Question 28

What is the flexor pollicis longus?

Answer 28

FPL Is the long flexor of the thumb

Question 29

What innervates the flexor pollicis longus?

Answer 29

Anterior interosseous branch of median nerve

Question 30

Where does the pronator quadratus lie?

Answer 30

Lies deeply in the distal part of the forearm, taking origin from the front of the ulna, and passing across to be inserted into the radius.

Question 31

What is the innervation of the pronator quadratus muscle?

Answer 31

Anterior interosseis nerve- a branch of the Median nerve

Question 32

Pronator Quadratus works in synergy with what?

Answer 32

With the pronator teres muscle and form a powerful pair of pronators at both the proximal and distal radioulnar joints