Introduction

The forearm is a region of the upper limb that consists of two segments: the proximal (nearer to the body) and distal (farther from the body). This anatomical structure houses several arteries that supply blood to the forearm muscles, bones, skin, and other tissues. The primary arterial network in the forearm includes the brachial, radial, and ulnar arteries, which arise from the axillary artery and branch out to deliver oxygenated blood to specific regions.

Understanding the anatomy of the arteries in the forearm is essential for medical professionals as they may encounter injuries or diseases that require prompt diagnosis and treatment. This course provides a comprehensive overview of the arterial network in the forearm, delving into their origins, branches, and functions.

The Brachial Artery

The brachial artery is the continuation of the axillary artery as it passes through the inferior border of the teres major muscle. It runs along the anterior aspect of the humerus and divides into its terminal branches near the elbow joint: the radial and ulnar arteries.

Origin

The brachial artery originates from the axillary artery, which itself is a continuation of the subclavian artery at the outer border of the first rib. The axillary artery descends through the axilla and enters the arm by passing beneath the teres major muscle.

Branches

1. The profunda brachii artery: This branch supplies the deep muscles of the arm, including the triceps brachii, as well as the elbow joint capsule.
2. The superior ulnar collateral artery: This vessel travels along the medial border of the humerus and anastomoses with the inferior ulnar collateral artery to form the common interosseous artery, which supplies the interosseous membrane between the radius and ulna.
3. The inferior ulnar collateral artery: This branch descends along the posterior aspect of the humerus and also anastomoses with the superior ulnar collateral artery to form the common interosseous artery.
4. The anterior ulnar recurrent artery: This vessel loops back towards the anterior surface of the brachial artery, supplying the anterior aspect of the ulna and its muscles.
5. The superior and inferior radial collateral arteries: These branches supply the lateral humeral condyle and the posterior surface of the radius, respectively.
6. The superior and inferior intercostobrachial arteries: These small vessels pass through the anterior and posterior intermuscular septa, respectively, to enter the axilla. They provide blood flow to the overlying skin and subcutaneous tissues.

The Radial Artery

The radial artery is a continuation of the brachial artery after it gives off the ulnar artery. It courses along the radius, anterior to the interosseous membrane, and terminates by anastomosing with the ulnar artery at the wrist.

Branches

1. The posterior interosseous artery: This branch supplies the muscles of the posterior compartment of the forearm, such as the supinator, pronator teres, and extensor carpi radialis longus and brevis.
2. The superficial palmar arch: The radial recurrent artery (a branch from the radial artery) joins with the ulnar artery to form the superficial palmar arch. This arch provides blood flow to the dorsum of the hand, wrist, and thumb.
3. The deep palmar arch: The anterior interosseous artery (a branch from the common interosseous artery) anastomoses with the radial artery to form the deep palmar arch. This arch supplies the thenar muscles, the hypothenar muscles, and the adductor pollicis.
4. The dorsal carpal branches: These small vessels supply the carpal bones and joints of the wrist.
5. Muscular branches: The radial artery provides numerous smaller branches to the muscles of the forearm, such as the brachioradialis, extensor carpi radialis longus and brevis, and the extensor digitorum communis.

The Ulnar Artery

The ulnar artery is a continuation of the brachial artery after it divides from the radial artery. It runs along the medial aspect of the forearm and continues into the hand, where it anastomoses with the radial artery to form the deep palmar arch.

Branches

1. The common interosseous artery: This vessel originates from the confluence of the superior and inferior ulnar collateral arteries and runs along the interosseous membrane between the radius and ulna.
2. The anterior ulnar recurrent artery: This branch loops back towards the anterior surface of the brachial artery, supplying the anterior aspect of the ulna and its muscles.
3. The posterior ulnar recurrent artery: This branch courses along the posterior surface of the humerus before passing anteriorly to join the common interosseous artery.
4. The palmar carpal branches: These vessels supply the carpal bones and joints of the wrist, as well as the palm of the hand.
5. Muscular branches: The ulnar artery provides numerous smaller branches to the muscles of the forearm, such as the flexor carpi ulnaris, the pronator teres, and the flexor digitorum superficialis.
6. The terminal branch: The ulnar artery terminates by anastomosing with the radial artery at the wrist to form the deep palmar arch.

Conclusion

Understanding the arterial network of the forearm is crucial for medical professionals, as injuries or diseases in this region may require prompt diagnosis and treatment. In this course, we have discussed the origin, branches, and functions of the brachial, radial, and ulnar arteries, providing a comprehensive overview of the vascular system in the forearm.