Forearm Anatomy and Function

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Questions and Answers

Which artery is the larger terminal branch of the brachial artery?

Anterior interosseous artery

Radial artery

Brachial artery

Ulnar artery (correct)

Which of the following branches is NOT from the ulnar artery?

Common interosseous artery

Radial recurrent artery (correct)

Palmar carpal branch

Dorsal carpal branch

What is the role of the median nerve in the forearm?

Has no role in the forearm muscles

Supplies only the medial half of FDP

Supplies all muscles of the forearm

Supplies all muscles except FCU and medial half of FDP (correct)

Which muscle does the radial artery lie deep to in the proximal half of the forearm?

Brachioradialis Signup and view all the answers

Which nerve passes posteriorly around the medial epicondyle of the humerus?

Ulnar nerve Signup and view all the answers

Which of the following correctly describes the location of the radial artery in the distal forearm?

Covered only by deep fascia and skin Signup and view all the answers

Which artery crosses the flexor retinaculum lateral to the ulnar nerve?

Ulnar artery Signup and view all the answers

Which branch provided by the median nerve is responsible for supplying deep structures?

Anterior interosseous nerve Signup and view all the answers

What is the main action of the extensor carpi radialis longus?

Extends and abducts the hand at the wrist joint Signup and view all the answers

Which nerve innervates the brachioradialis?

Radial nerve Signup and view all the answers

What is the primary action of the extensor digiti minimi?

Extends the 5th finger primarily at the metacarpophalangeal joint Signup and view all the answers

Which of the following statements about the ulnar nerve is incorrect?

It has only one cutaneous branch. Signup and view all the answers

What are the components of the posterior compartment muscles?

Extensors of wrist joint and supinator of forearm Signup and view all the answers

Which artery does NOT contribute branches to the posterior compartment?

Ulnar artery Signup and view all the answers

Which deep layer muscle is primarily responsible for supinating the forearm?

Supinator Signup and view all the answers

Which muscle is involved in extending the proximal phalanx of the thumb at the metacarpophalangeal joint?

Extensor pollicis brevis Signup and view all the answers

Which of the following muscles does NOT belong to the superficial layer of the posterior compartment?

Abductor pollicis longus Signup and view all the answers

The action of the extensor carpi ulnaris includes:

Extending and adducting the hand at the wrist joint Signup and view all the answers

The insertion site for the extensor digiti minimi is located on:

The extensor expansion of the 5th finger Signup and view all the answers

The primary action of the extensor pollicis longus is to:

Extend the distal phalanx of the thumb Signup and view all the answers

Which muscle is NOT considered a part of the deep layer of the posterior compartment?

Extensor digitorum Signup and view all the answers

What is the primary action of the muscles in the anterior compartment of the forearm?

Flexion and pronation of the wrist Signup and view all the answers

Which muscle is located in the superficial layer of the anterior compartment?

Palmaris longus Signup and view all the answers

What separates the anterior and posterior compartments of the forearm?

Interosseous membrane Signup and view all the answers

Which nerve innervates the flexor carpi ulnaris?

Ulnar nerve Signup and view all the answers

What is the origin of the flexor digitorum superficialis?

Medial epicondyle of the humerus and radius Signup and view all the answers

Which muscle is responsible for pronation of the forearm?

Pronator teres Signup and view all the answers

Which artery is NOT found in the anterior compartment of the forearm?

Brachial artery Signup and view all the answers

What is the action of the flexor carpi ulnaris?

Adducts the wrist joint Signup and view all the answers

Which nerve innervates the flexor digitorum profundus?

Both ulnar and median nerves Signup and view all the answers

Which muscle is responsible for flexing the distal interphalangeal joints?

Flexor digitorum profundus Signup and view all the answers

What is the primary action of the flexor pollicis longus?

Flexes the thumb Signup and view all the answers

Which of the following muscles is found in the intermediate layer of the forearm?

Flexor digitorum superficialis Signup and view all the answers

Which two bones comprise the forearm?

Radius and ulna Signup and view all the answers

What muscle layer is located deepest in the anterior compartment of the forearm?

Deep layer Signup and view all the answers

Study Notes

The Forearm

The forearm is the distal unit of the upper limb, extending from the elbow to the wrist.
It contains two bones: the radius and ulna, connected by an interosseous membrane.
The forearm is divided into anterior and posterior compartments separated by intermuscular septa and the interosseous membrane.

Facial Compartments of Forearm

The forearm's compartments are divided by intermuscular septa and the interosseous membrane, separating the anterior and posterior compartments.

Anterior Compartment

Muscles: Includes flexors and pronators.
Blood Vessels: Ulnar and radial arteries.
Nerves: Median and ulnar nerves.
The muscles in the anterior compartment are arranged in three layers: superficial, intermediate, and deep. The muscles in each layer are involved in wrist movements, finger flexion, and pronation.

Muscles of the Anterior Compartment

The muscles are responsible for wrist joint movements, finger flexion, and pronation.
They're organised into a superficial, intermediate, and deep layer.

Superficial Layer

Muscles: Pronator teres, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris. These are the four muscles of the superficial layer.
Associated actions: pronation, flexion of the wrist and hand.

Intermediate Layer

Muscle: Flexor digitorum superficialis (FDS). One muscle in the intermediate layer.

Deep Layer

Muscles: Flexor digitorum profundus, flexor pollicis longus, and pronator quadratus. These three muscles make up the deep layer.

Blood Vessels

The main arteries in the forearm are the radial and ulnar arteries.
The arteries pass distally and supply blood to the hand.
These arteries branch into smaller vessels that also supply the posterior compartment.
The terminal branches of the brachial artery in the cubital fossa (elbow pit) are the ulnar and radial arteries.

Ulnar Artery

The ulnar artery is a larger branch of the brachial artery.
It sits deep to pronator teres, flexor carpi radialis, and flexor digitorum superficialis.

Branches of Ulnar Artery

Anterior and posterior recurrent arteries
Common interosseous artery
Cutaneous branches
Muscular branches
Dorsal and palmar carpal branches that supply the wrist.

Radial Artery

The radial artery is smaller than the ulnar artery
It lies deep to the brachioradialis in the proximal half of the forearm.
In the middle third of the forearm, it is lateral to the superficial branch of the radial nerve.
It is covered by deep fascia and skin in the distal forearm.

Branches of Radial Artery

Radial recurrent artery
Cutaneous branches
Muscular branches
Palmar carpal branch
Superficial palmar branch.

Veins of the Forearm

Superficial veins: Basilic vein, cephalic vein, median vein
Deep veins: form venae comitantes (companion veins); ulnar vein and radial vein. Deep veins follow the course of deep arteries.

Median Nerve

The median nerve is the primary nerve of the anterior forearm.
It supplies all the muscles in the anterior compartment, except the flexor carpi ulnaris (FCU) and the medial half of the flexor digitorum profundus (FDP).
It has a straight linear course

Branches of Median Nerve

Anterior interosseous nerve
Articular branch
Muscular branches
Palmar cutaneous branch

Ulnar Nerve

The ulnar nerve enters the anterior compartment posteriorly around the medial epicondyle of the humerus and between the humeral and ulnar heads of the flexor carpi ulnaris muscle (FCU).
It supplies only FCU and the ulnar half of the FDP.

Branches of Ulnar Nerve

Muscular branches
Two cutaneous branches to the hand (palmar and dorsal)
Articular branch to the elbow.

Posterior Compartment

Muscles: Extensors of wrist joint and supinator of forearm
Blood Vessels: Radial artery branches, anterior interosseous artery, and posterior interosseous artery.
Nerves: Radial nerve.

Muscles of the Posterior Compartment - Superficial Layer

Muscles: Brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, anconeus.

Muscles of the Posterior Compartment - Deep Layer

Muscles: Supinator, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis. These are the deep layer muscles.

Blood Vessels of the Posterior Compartment

Posterior Interosseous Artery: Enters the posterior compartment over the proximal margin of the interosseous membrane and gives rise to recurrent interosseous artery. It terminates by joining the dorsal carpal arch of the wrist.
Anterior Interosseous Artery: Has perforating branches that pass directly through the interosseous membrane to supply deep muscles of the posterior compartment.
Radial Artery: Has branches which contribute to the supply of the extensor muscles on the radial side of the forearm.

Radial Nerve

The radial nerve bifurcates into deep and superficial branches beneath the brachioradialis muscle. The deep branch is mainly motor. The superficial branch is mainly sensory. It innervates the skin of the dorsolateral surface of the hand.

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Description

This quiz explores the anatomy of the forearm, focusing on its compartments, bones, and muscles. You'll learn about the structure of the anterior compartment, including its muscles, blood vessels, and nerves, as well as their functions in wrist movements and finger flexion.