Deep Brachial Artery

The deep brachial artery, also known as the profunda brachii artery, is the largest and most significant branch of the brachial artery in the arm. It arises proximally from the brachial artery and travels posteriorly through the arm, accompanying the radial nerve in the radial groove of the humerus. It supplies the posterior compartment of the arm, including the triceps brachii, and plays a crucial role in collateral circulation around the elbow.

Location

The deep brachial artery originates from the posteromedial aspect of the brachial artery, usually just below the lower border of the teres major muscle. It enters the posterior compartment of the arm by passing through the triangular interval, along with the radial nerve, and courses in the radial groove of the humerus. It terminates near the lateral epicondyle by dividing into collateral branches that contribute to the arterial anastomoses of the elbow.

Branches

The deep brachial artery gives off several important branches during its course:

• Deltoid branch: Occasionally present; supplies deltoid muscle.
• Nutrient branch to humerus: A small branch entering the humerus to supply the bone.
• Middle collateral artery: Descends posterior to the elbow joint; anastomoses with interosseous recurrent artery.
• Radial collateral artery: Runs anterior to the lateral epicondyle; anastomoses with radial recurrent artery.

Relations

• Accompanies the radial nerve as it travels through the radial groove of the humerus.
• Initially lies posterior to the brachial artery and brachial vein in the proximal arm.
• Passes between the long and lateral heads of the triceps brachii muscle.
• Runs along the posterior surface of the humerus before emerging near the lateral epicondyle.

Function

• Vascular supply to the posterior arm: Provides blood supply to the triceps brachii and other extensor muscles of the arm.
• Contributes to the elbow anastomosis: Through its terminal branches (radial and middle collateral arteries), it ensures continued blood flow to the forearm and hand even when the elbow is flexed or brachial flow is compromised.

Physiological Role(s)

• Maintains perfusion of the posterior upper arm musculature during dynamic movement.
• Provides key components of the periarticular arterial anastomosis of the elbow joint, which helps maintain circulation during joint flexion and compression.

Development

The deep brachial artery forms during embryological vascular remodeling from the axial artery system that supplies the developing upper limb. The radial nerve and deep brachial artery maintain a close embryological relationship as they course together through the limb bud into the posterior compartment. This proximity is retained in postnatal anatomy and is clinically relevant in trauma and surgery.

Clinical Significance

• Humeral shaft fractures: The radial groove, where the deep brachial artery lies, is a common site for fractures. This puts the artery at risk of injury, which can result in hemorrhage or compromise to distal perfusion.
• Radial nerve injury: Because the artery runs alongside the radial nerve, vascular damage is often associated with radial neuropathy (e.g., wrist drop).
• Collateral circulation importance: In cases of brachial artery occlusion or clamping during surgery, the profunda brachii provides an important collateral route to maintain forearm perfusion via the elbow anastomoses.
• Vascular claudication or ischemia: Though rare in young patients, occlusion or trauma to the deep brachial artery can contribute to upper limb ischemia symptoms.

Imaging

• CT angiography: Used to visualize the course of the artery in cases of trauma or suspected vascular compromise.
• Doppler ultrasound: Can assess patency and flow characteristics in patients with suspected arterial injury.
• MRI: May show surrounding soft tissue involvement in cases of hematoma or muscle injury related to deep brachial artery trauma.

Surgical and Procedural Relevance

• Fracture management: In midshaft humerus fractures, the deep brachial artery must be preserved or repaired to prevent distal ischemia.
• Ligation safety: Due to rich collateralization, the deep brachial artery can sometimes be ligated without catastrophic consequences, but only with intact collateral pathways.
• Posterior arm surgeries: Surgeons must be cautious when dissecting between the heads of the triceps or during nerve decompression procedures to avoid arterial injury.

Anatomical Variations

• May arise higher or lower than usual from the brachial artery.
• In rare cases, it may give rise to the radial artery (high bifurcation variant).
• Accessory profunda brachii arteries may exist, which can be mistaken for variant radial or ulnar branches during surgery or angiography.

Collateral Circulation

The deep brachial artery participates in important collateral anastomoses around the elbow. This includes:

• Middle collateral artery → Interosseous recurrent artery
• Radial collateral artery → Radial recurrent artery
• These ensure continued perfusion during elbow flexion and are especially important during surgical ligation or traumatic injury to the main brachial trunk.