First things first. It is essential to understand the meaning of collateral and recurrent arteries. Recurrent arteries turn back so as to reverse direction. Collateral arteries refer to side branches of the major arteries.
Mnemonic: M.R. Deep
On the posterior aspect of the shaft of the humerus:
Profunda brachii (Deep branch of brachial artery) branches into a middle and a radial collateral artery.
Brachial artery gives off a superior ulnar collateral artery (about 1-2 cm below profunda brachii) and an inferior ulnar collateral artery (about 1 cm above the medial supracondylar ridge).
Mnemonic: SIMR – PAIR
- Superior ulnar collateral artery ↔ Posterior ulnar recurrent artery (Deep antecubital fossa)
- Inferior ulnar collateral artery ↔ Anterior ulnar recurrent artery (Deep antecubital fossa)
- Middle collateral artery ↔ Interosseous recurrent artery from posterior interosseous artery (Lateral supracondylar ridge)
- Radial collateral artery ↔ Radial recurrent artery (Deep antecubital fossa)
About 1 inch below antecubital fossa, brachial artery divides into radial & ulnar artery.
About 1 inch below the origin of the ulnar artery, the common interosseous artery arises and subsequently divides into an anterior and posterior branch. Posterior branch gives off interosseous recurrent artery.
Risk of amputation is 50% with ligation of brachial artery proximal to profunda brachii artery and 25% with that below the profunda brachii artery.