Brachial artery
Arteria brachialis
Definition
The brachial artery (arteria brachialis) is the principal artery of the arm and the direct continuation of the axillary artery, beginning at the inferior border of the teres major muscle. It courses along the ventral (anteromedial) surface of the arm, lying initially medial to the humerus, and descends through the arm in close relation to the median nerve — which crosses it from lateral to medial — to reach the cubital fossa, where it terminates by bifurcating into the radial artery (laterally) and the ulnar artery (medially), typically at the level of the neck of the radius, slightly distal to the elbow joint.
Course and relations. In the arm, the brachial artery lies in the medial bicipital groove (sulcus bicipitalis medialis), superficial to the brachialis muscle and deep to the bicipital aponeurosis distally. It is accompanied by two venae comitantes (brachial veins). The median nerve is its most important neurovascular companion, initially lateral to the artery proximally and crossing anterior to it at mid-arm to lie medially in the cubital fossa. The ulnar nerve lies medial to the artery in the proximal arm before piercing the medial intermuscular septum posteriorly. The radial nerve separates from the artery early, passing posteriorly with the profunda brachii artery into the radial (spiral) groove of the humerus.
The average diameter of the brachial artery above the antecubital fossa is approximately 3.9 ± 0.5 mm in adults.
Anatomical variations. Typical brachial artery anatomy is observed in approximately 90% of individuals, while variations occur in about 10% of limbs. The most common variant is the brachioradial artery (high take-off radial artery), comprising approximately 66% of all brachial artery variations, followed by the superficial brachial artery and the accessory brachial artery. High brachial artery bifurcation (HiBAB) may occur in the proximal, middle, or distal third of the arm. These variations show a right-side predominance (~65%) and are predominantly unilateral (~71%).
Origin | Continuation of the axillary artery at the inferior border of the teres major muscle |
Branches | |
1. Profunda brachii (deep brachial) artery | First and largest branch; accompanies the radial nerve in the spiral groove; gives off the radial collateral artery and middle collateral artery |
2. Superior ulnar collateral artery | Arises from the proximal brachial artery; accompanies the ulnar nerve behind the medial epicondyle; participates in the medial periarticular anastomosis of the elbow |
3. Inferior ulnar collateral artery | Arises just above the elbow; contributes to the medial periarticular anastomosis and vascularizes the ulnar nerve at the cubital tunnel |
4. Muscular branches | Variable unnamed branches to the biceps brachii, brachialis, and coracobrachialis muscles |
5. Nutrient artery of the humerus | Enters the nutrient foramen of the humeral shaft |
6. Cutaneous perforators | Average of ~4.5 perforating arteries per arm supplying the skin of the medial arm (mean diameter ~0.68 mm) |
Terminal branches | Radial artery (lateral) and ulnar artery (medial), bifurcating in the cubital fossa |
Territory of supply | |
— Arm | Anterior and posterior compartment muscles (biceps brachii, brachialis, coracobrachialis, triceps brachii via profunda brachii); humeral diaphysis; skin of the medial arm |
— Elbow | Medial, lateral, and posterior periarticular anastomotic arcades (capitellum, trochlea, olecranon, radial head); ulnar nerve vascularization |
— Forearm, hand (via terminal branches) | Entire forearm musculature, radius and ulna, and hand via the radial and ulnar arteries and their palmar arches (superficial and deep) |
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