Vessel course and syntopy
The artery begins its course at the lower border of the pectoralis major muscle (m. pectoralis major). Initially, it lies anterior to the coracobrachialis muscle (m. coracobrachialis), and then descends along the medial sulcus on the surface of the brachialis muscle (m. brachialis), heading towards the cubital fossa.
Reaching the cubital fossa (fossa cubiti), the vascular trunk lies in the groove between the brachialis muscle and the round pronator (m. pronator teres). In this zone, the vessel is reliably covered by the aponeurosis of the biceps brachii (aponeurosis m. bicipitis brachii). It is right here, under the protection of the aponeurosis, that bifurcation—division into terminal branches—occurs:
- Radial artery (a. radialis);
- Ulnar artery (a. ulnaris).
In some cases, an anatomical variant is found — the superficial brachial artery (a. brachialis superficialis). In this case, the division into terminal branches occurs high up, even before entering the elbow region, and the vascular trunk is located superficially.
Neurovascular bundle of the arm
Along its course, the artery is accompanied by two brachial veins (vv. brachiales) and the median nerve (n. medianus). The relationship between the artery and the median nerve changes depending on the level:
- In the upper third of the arm, the nerve runs laterally to the vascular trunk.
- In the middle third, the nerve trunk crosses the vessel anteriorly.
- In the lower third, the nerve lies medially to the artery.
Branches of the brachial artery
Several significant collaterals branch off from the main trunk, supplying the muscles, bone, and forming the articular network.
Deep artery of the arm (a. profunda brachii) This is the largest branch, originating in the upper third from the posterolateral wall of the main trunk. It runs posteriorly, accompanying the radial nerve (n. radialis), and spirals around the posterior surface of the humerus. The deep artery of the arm gives off the following branches:
- Deltoid branch (r. deltoideus) — passes under the coracobrachialis and biceps muscles to the deltoid muscle, also supplying the anterior zone of the bone.
- Nutrient arteries of the humerus (aa. nutritiae humeri) — penetrate the bone foramina (sometimes may arise directly from the main trunk).
- Middle collateral artery (a. collateralis media) — descends between the medial and lateral heads of the triceps brachii muscle, participating in the elbow network.
- Radial collateral artery (a. collateralis radialis) — is the distal continuation of the deep artery, anastomosing with the radial recurrent artery.
Ulnar collateral arteries
- Superior (a. collateralis ulnaris superior): originates just below the deep artery of the arm (sometimes they share a common trunk). It runs downward together with the ulnar nerve (n. ulnaris) toward the medial epicondyle.
- Inferior (a. collateralis ulnaris inferior): branches off already in the area of the cubital fossa, heading downward and forward, piercing the medial intermuscular septum.
Participation in the elbow joint network
All collateral vessels of the brachial system weave into the articular network of the elbow (rete articulare cubiti), forming robust anastomoses with the branches of the forearm:
- a. collateralis radialis connects with a. recurrens radialis;
- a. collateralis media anastomoses with a. interossea recurrens;
- a. collateralis ulnaris superior connects with the posterior branch of a. recurrens ulnaris;
- a. collateralis ulnaris inferior anastomoses with the anterior branch of a. recurrens ulnaris.
Practical landmarks: Knowledge of the artery's projection in the medial sulcus is critically important for pulse palpation and temporary hemorrhage control (compression against the bone). In the region of the fossa, the bicipital aponeurosis serves as a protective layer safeguarding the artery during venipuncture of the median cubital vein (v. mediana cubiti).
Briefly: answers to topical questions
Which muscles bound the cubital fossa and form the groove for the brachial artery?
The cubital fossa is bounded by three muscular elevations: the lateral one is formed by the brachioradialis muscle, the middle one by the biceps brachii muscle, and the medial one by the flexor muscles from the medial epicondyle. Within the fossa itself, the brachial artery lies in the groove between the pronator teres and the brachialis muscle, located beneath the bicipital aponeurosis.
Which nerves accompany the superior and inferior ulnar collateral arteries?
The superior ulnar collateral artery is accompanied by the ulnar nerve, with which it passes into the posterior fascial compartment and heads toward the medial epicondyle. The inferior ulnar collateral artery branches off in the area of the cubital fossa and weaves into the elbow network, however, specific accompanying nerves for it are not specified in the sources.
The median nerve "crosses the path" of the artery from top to bottom: Laterally — Anteriorly — Medially (L-A-M).
Class and exam questions
Where and into what branches does the brachial artery divide?
Bifurcation occurs in the cubital fossa, where the trunk divides into two terminal branches: the radial (a. radialis) and ulnar (a. ulnaris) arteries.
Which nerve accompanies the deep artery of the arm?
It is accompanied by the radial nerve (n. radialis), with which it spirals around the posterior surface of the humerus.
How is the artery protected in the cubital fossa?
Anteriorly, it is covered by the bicipital aponeurosis, which reduces the risk of its injury during vein puncture.
What else to study on this topic
- Topography of the cubital fossa (fossa cubiti)
- Radial nerve canal (canalis nervi radialis)
- Structure of the elbow joint network (rete articulare cubiti)
- Radial artery and its branches
- Ulnar artery and its branches
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