Course and Syntopy of the Brachial Artery
Brachial artery (a. brachialis) is the direct continuation of the axillary artery (a. axillaris). Its initial border is projected at the level of the lower border of the pectoralis major muscle, which anatomically corresponds to the lower boundary of the axilla. The vessel descends along the anterior fascial compartment of the arm, lying in the medial bicipital sulcus (sulcus bicipitalis medialis).
Upon reaching the anterior cubital region, the artery is located at the medial margin of the biceps brachii tendon (m. biceps brachii). Here it lies on the brachialis muscle (m. brachialis) within the splitting of the medial intermuscular septum. Throughout its course, the main trunk is accompanied by two brachial veins (vv. brachiales).
The artery terminates in the cubital fossa (fossa cubiti). At the level of the radial neck, which is approximately 1–2 cm below the elbow crease, it bifurcates into two major branches: the radial (a. radialis) and ulnar (a. ulnaris) arteries. An important topographic feature is that in this zone the vessel is covered by the dense bicipital aponeurosis (lacertus fibrosus).
Projection Line and Practical Landmarks
To accurately determine the position of the vessel in surgery, a projection line is used. It coincides with the direction of the medial bicipital sulcus (when well-defined) and is constructed using two key points:
- Initial point: located at the border of the anterior and middle thirds of the upper boundary of the anterior arm region. Anatomically, this site corresponds to the medial margin of the coracobrachialis muscle.
- End point: located at the midpoint of the elbow crease, strictly 1 cm medial to the m. biceps brachii tendon.
Interestingly, the basilic vein (v. basilica) is projected along this exact same line on the arm.
Knowledge of the projection is critically important for clinical practice. In the medial sulcus of the arm, the artery is easily palpable for pulse assessment. It is also here that digital compression to stop hemorrhage against the humerus is performed. Furthermore, the point at the level of the medial epicondyle at the medial margin of the biceps is the standard placement site for the stethoscope diaphragm during blood pressure measurement. In the cubital fossa, the dense lacertus fibrosus serves as a reliable protective barrier for the artery during venipuncture of the median cubital vein (v. mediana cubiti).
Collateral Circulation and Articular Network of the Elbow
A dense vascular network—the articular network of the elbow (rete articulare cubiti)—is formed around the elbow joint. It is created by multiple anastomoses between descending branches (originating from the brachial artery and its deep branch) and ascending recurrent branches (originating from the forearm arteries).
| Localization | Descending Vessel (Collateral) | Ascending Vessel (Recurrent) |
|---|---|---|
| Lateral Side | a. collateralis radialis (from a. profunda brachii) | a. recurrens radialis (from a. radialis) |
| Posterior Side | a. collateralis media (from a. profunda brachii) | a. interossea recurrens (from a. interossea posterior) |
| Medial (Posterior Bundle) | a. collateralis ulnaris superior (from a. brachialis) | r. posterior a. recurrens ulnaris (from a. ulnaris) |
| Medial (Anterior Bundle) | a. collateralis ulnaris inferior (from a. brachialis) | r. anterior a. recurrens ulnaris (from a. ulnaris) |
Clinical Significance: The architectonics of this network determine the surgeon's tactics in trauma. The most dangerous scenario is the cessation of main blood flow in the segment proximal to the origin of the profunda brachii artery (a. profunda brachii). In such a situation, the limb loses its primary source of upper collaterals. If ligation of the brachial artery becomes necessary distal to the origin of a. profunda brachii, blood supply to the distal forearm is successfully compensated via the ulnar network anastomoses described above.
To remember the syntopy in the cubital fossa, imagine that the artery hides beneath the "hood" of the bicipital aponeurosis (lacertus fibrosus), which protects it from accidental puncture during blood withdrawal from the cubital vein.
Class and exam questions
Where is it safest to ligate the brachial artery during trauma?
Ligation should be performed distal to the origin of the profunda brachii artery (a. profunda brachii). In this case, blood supply to the forearm and hand will be preserved through the well-developed articular network of the elbow.
How to correctly find the projection of the brachial artery on the skin?
The line is drawn from the border of the anterior and middle thirds of the upper arm boundary to a point located 1 cm medial to the biceps tendon at the elbow crease. It corresponds to the medial bicipital sulcus.
Which anatomical structure protects the artery during venipuncture in the elbow crease?
Bicipital aponeurosis (lacertus fibrosus). It lies as a dense lamina between the superficial veins (specifically, v. mediana cubiti) and the deep neurovascular bundle.
What else to study on this topic
- Topography of the Profunda Brachii Artery (a. profunda brachii)
- Syntopy of Vessels and Nerves of the Anterior Cubital Region
- Anatomy of the Radial and Ulnar Arteries in the Forearm
- Venous System of the Arm and Cubital Fossa (v. basilica, v. mediana cubiti)
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