Brachial Artery: Anatomy, Branches, Clinical Significance, and Variations

The brachial artery is the principal arterial supply to the upper limb. Its superficial course and predictable anatomy make it vital for clinical procedures and a key landmark in vascular surgery, trauma, and regional anesthesia.

Gross Anatomy

• Origin: Continuation of the axillary artery at the inferior border of the teres major muscle (or ~2.5 cm distal to the lateral clavicle border).
• Course: Runs distally on the medial aspect of the arm, in the medial bicipital groove (between biceps brachii and triceps brachii), deep to the bicipital aponeurosis (lacertus fibrosus) in the cubital fossa.
• Termination: Bifurcates at the level of the radial neck (just distal to the elbow crease) into the radial artery (lateral) and ulnar artery (medial).
• Relations:
  • Medial: Median nerve (crosses anterior mid-arm), basilic vein, ulnar nerve (distal)
  • Lateral: Biceps brachii tendon, brachioradialis
  • Posterior: Brachialis, medial head of triceps, coracobrachialis insertion

Branches

Branch	Origin	Distribution
Profunda Brachii (Deep Brachial Artery)	Posteromedial, just distal to teres major	Accompanies radial nerve in spiral groove; supplies triceps, humerus (nutrient), anastomoses at elbow (middle collateral, radial collateral)
Superior Ulnar Collateral Artery	Mid-arm, opposite coracobrachialis insertion	Runs with ulnar nerve; anastomoses with posterior ulnar recurrent at elbow
Inferior Ulnar Collateral Artery	5-7 cm proximal to elbow	Anastomoses with anterior ulnar recurrent
Nutrient Artery to Humerus	Variable (often from profunda brachii)	Enters nutrient foramen (anteromedial mid-shaft)
Muscular Branches	Multiple	Biceps, brachialis, coracobrachialis, triceps
Radial Artery (Terminal)	Bifurcation in cubital fossa	Lateral forearm, wrist, hand (deep palmar arch)
Ulnar Artery (Terminal)	Bifurcation in cubital fossa	Medial forearm, wrist, hand (superficial palmar arch)

Clinical Significance

• Blood Pressure Measurement: Standard site (auscultatory/oscillometric). Cuff bladder encircles 80% of arm; artery palpable medial to biceps tendon.
• Arterial Access:
  • Arterial line (ICU, OR) – radial preferred (collateral flow via palmar arches); brachial alternative.
  • Cardiac catheterization (transbrachial) – larger sheaths, direct aortic access.
• Pulse Palpation: Medial bicipital groove; assess volume, rhythm, symmetry.
• Compartment Syndrome Monitoring: Brachial artery pressure vs. compartment pressure (ΔP <30 mmHg = fasciotomy).
• Trauma: Humeral shaft fractures (proximal 1/3) risk brachial artery injury. Hard signs → exploration.
• Supracondylar Fracture (Pediatric): Brachial artery injury/occlusion → Volkmann ischemic contracture if missed.
• Thoracic Outlet Syndrome: Subclavian/axillary compression; Adson's test, imaging.

Anatomic Variations (Clinical Relevance)

Variation	Frequency	Significance
High Bifurcation	5-10%	Radial/ulnar origin proximal to elbow; risk during venipuncture, surgery; radial may run superficial
Low Bifurcation	2-5%	Bifurcation in forearm; affects catheterization, flap planning
Common Interosseous Origin	Rare	Single trunk → radial + ulnar + common interosseous
Superficial Brachial Artery	Rare	Runs superficial to bicipital aponeurosis; high injury risk (venipuncture, laceration); palpable pulsation
Radial Artery Origin from Axillary	Rare	Separate origin; "high radial"
Persistent Median Artery	1-3%	Accompanies median nerve; can be dominant hand supply

Imaging

• Ultrasound (Duplex): First-line for access, stenosis, trauma, pseudoaneurysm.
• CT Angiography: Trauma, preoperative mapping, thoracic outlet syndrome.
• MR Angiography: No radiation/contrast; vascular anomalies.
• Conventional Angiography: Gold standard; therapeutic intent.

Summary

The brachial artery's anatomy underpins essential clinical skills (BP measurement, arterial access, trauma assessment). Knowledge of variations prevents iatrogenic injury and guides surgical/interventional planning.