Muscles of the Anterior Forearm Anatomy

Antebrachium Or Forearm Question And Answers Introduction

The forearm extends from the elbow joint to the wrist joint.

The forearm has two bones, a radius and an ulna, with their interosseous membrane.

Muscles, arteries, veins, and nerves are present in both the front and back of the forearm.

Muscles of Anterior Forearm – Full Anatomy Notes

Antebrachium Or Forearm Question And Answers

Question 1. Briefly explain the fascial compartments of the forearm.
Answer:

• The deep fascia of the forearm covers it like a sleeve.
• Intermuscular septa extend from this fascial sleeve, and a few of them are attached to the bones, dividing the forearm into anterior and posterior compartments.
• Each compartment has its muscles, nerves, and blood supply.
• The anterior compartment muscles are involved in flexion movement; hence, this compartment is called the flexor compartment.
• Posterior compartment muscles are involved in extension movement; hence, the compartment is called the extensor compartment.
• Near the wrist, deep fascia thickens in both the flexor and extensor compartments and is called the flexor and extensor retinaculum, respectively.

Read And Learn More: Upper Limb

Question 2. List the contents of the front forearm.
Answer:

Contents Of Front Forearm

• 8 Muscles Arranged As:
  • 5 superficial muscles
  • 3 deep muscles.
• 2 Arteries
  • Radial artery
  • Ulnar artery.
• 3 Nerves
  • Medial nerve
  • Radial nerve
  • Ulnar nerve.

Anterior Compartment of Forearm

Question 3. How are the muscles of the anterior compartment of the arm arranged? Enumerate them separately and write the origin, insertion, nerve supply, and actions of them.
Answer:

The anterior compartment of the arm has 8 muscles arranged in superficial and deep layers.

5 Superficial Muscles

• Pronator teres
• Flexor carpi radialis
• Palmaris longus
• Flexor digitorum superfiialis
• Flexor carpi ulnaris.

All the superficial muscles take their common origin from the front of the medial epicondyle of the humerus. This is called the common flexor origin.

Mnemonic

• Elbow: Which side has a common flexor origin?
• FM (as in FM Radio): Flexor Medialis, so the common flexor origin is on the medial side.

Three Deep Muscles

1. Flexor digitorum profundus
2. Flexor pollicis longus
3. Flexor carpi ulnaris.

• Flexor digitorum profundus is a hybrid muscle supplied by both the ulnar nerve and the anterior interosseous nerve (a branch of the median nerve).
• It is the most powerful and bulky muscle of the forearm contributing to the larger portion of the gripping power of hand.

Forearm Flexor Muscles

Question 4. What are the contents of the back of the forearm?
Answer:

This compartment is also known as the extensor compartment as the muscles of this compartment extend the wrist joint.

Contents Of Back Of The Forearm

• Muscles: 12 muscles arranged as 7 superficial and 5 deep muscles
• Nerves: Posterior interosseous nerve
• Artery: Posterior and anterior interosseous arteries.

Median and Ulnar Nerve in Anterior Forearm Muscles

Question 5. How are the muscles of the posterior compartment of the arm arranged? Enumerate them separately and write the origin, insertion, nerve supply, and actions of them.
Answer:

The posterior compartment of the arm has 12 muscles arranged in superficial and deep layers.

Seven Superficial Muscles

• From lateral to medial.
• They are:
  • Brachioradialis
  • Extensor carpi radialis longus
  • Extensor carpi radialis brevis
  • Extensor digitorum
  • Extensor digit minimi
  • Extensor carpi ulnaris
  • Anconeus
• All seven muscles cross the elbow joint.
• They have having common extensor origin from the lateral epicondyle of the humerus.
• Dorsal digital expansion is a small triangular aponeurosis related to each tendon of the extensor digitorum.
• It covers the metacarpophalangeal joint and dorsum of the proximal phalanx.
• A number of muscles are inserted into dorsal digital expansion.

Five Deep Muscles

1. From above downwards, they are:
2. Supinator
3. Abductor pollicis longus
4. Extensor pollicis brevis
5. Extensor pollicis longus
6. Extensor indicis

• In contrast to superficial muscles, none of the deep muscles crosses the elbow joint.

Antebrachium Or Forearm Multiple Choice Questions

Question 1. Which of the following pierces the interosseous membrane?

1. Posterior interosseous artery
2. Anterior interosseous artery
3. Common interosseous artery
4. All the above

Answer: 2. Anterior interosseous artery

Question 2. Which one is not a superficial group muscle of the anterior compartment of forearm?

1. Pronator teres
2. Flexor carpi radialis
3. Palmaris longus
4. Pronator quadratus

Answer: 4. Pronator quadratus

Question 3. Which among these is a hybrid muscle?

1. Flexor digitorum profundus
2. Pronator teres
3. Flexor carpi radialis
4. Palmaris longus

Answer: 1. Flexor digitorum profundus

Anterior Forearm Muscles

Question 4. The anterior interosseous nerve is a branch of:

1. Musculocutaneous nerve
2. Median nerve
3. Radial nerve
4. Ulnar nerve

Answer: 2. Median nerve

Question 5. Allen’s test is performed to ascertain the proper functioning of:

1. Median nerve
2. Ulnar artery
3. Radial artery
4. Flexor digitorum profundus muscle

Answer: 3. Radial artery