As a continuation of the axillary artery, it begins at the inferior border of the teres major tendon and it ends at the level of the neck of the radius about 1cm distal to the elbow joint. At this point, it divides into the ulnar and radial arteries. The brachial artery runs medial to the humerus proximally, before moving more anteriorly to lie between the epicondyles of the humerus.
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| Brachial artery |
Relationships of the brachial artery to other structures in the arm can be important in clinical practice. The brachial artery is a superficial vessel and is only covered by the layers of the skin, as well as the superficial and deep fasciae, with a few exceptions:
The first exception to this is at the cubital fossa, where the bicipital aponeurosis, which is the aponeurosis of the biceps brachii muscle, covers the artery, and separates it from the median cubital vein.
The second exception is when the median nerve crosses the brachial artery near the distal attachment of the coracobrachialis.
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| Brachial artery |
Posteriorly, the brachial artery is separated from the long head of the triceps brachii muscle by the profunda brachii artery and the radial nerve. The attachments of the coracobrachialis and the brachialis muscles, as well as the medial head of the triceps brachii muscle, also lie posterior to the brachial artery.
The median nerve and coracobrachialis muscle lie laterally to the brachial artery at its proximal aspect whereas the medial cutaneous nerve of the forearm and the ulnar nerve lie medially to the artery proximally.
📖 Clinically Oriented Anatomy 7th Edition
At the distal aspect of the brachial artery, the basilic vein and median nerve lie medially. Two venae comitantes, or accompanying veins, run with the brachial artery, and are connected together by transverse and oblique branches.
Branches
The brachial artery forms 8 branches including the:
- Profunda brachii artery
- Nutrient artery of the humerus
- Superior ulnar collateral artery
- Middle ulnar collateral artery
- Inferior ulnar collateral (supratrochlear) artery
- Deltoid (ascending) artery
- Radial artery
- Ulnar artery
The profunda brachii artery is a large posteromedial branch of the brachial artery, distal to the teres major muscle. It accompanies the radial nerve in its course. The profunda brachii artery runs initially posteriorly between the medial and long heads of the triceps brachii muscle before continuing within the spiral groove of the humerus. It then divides into two branches, the middle collateral (posterior descending) branch and the radial collateral (anterior descending) branch.
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| The brachial artery forms 8 branches |
The middle collateral branch is the larger of the two branches and arises posterior to the humerus before descending posterior to the lateral intermuscular septum to the elbow. Proximally, this branch runs between the brachialis and the lateral head of the triceps brachii. Distally, it runs posterior to the brachioradialis and anterior to the lateral head of the triceps brachii. The middle collateral branch then either remains deep to the fascia or crosses it to become cutaneous before reaching the interosseus recurrent artery posterior to the lateral epicondyle. It gives off five fasciocutaneous perforators, which are small arteries that pass through the fascia between muscles and supply the skin.
The radial collateral branch runs with the radial nerve and crosses the lateral intermuscular septum to descend anteriorly to the lateral epicondyle, between the brachialis and brachioradialis. It then joins the radial recurrent artery and supplies the radial nerve, the brachioradialis and brachialis muscles, as well as some fasciocutaneous perforators.
The nutrient artery arises from the brachial artery around the middle level of the arm before entering the nutrient canal, which is essentially a large foramen or hole in the humerus. It enters this canal posterior to the deltoid tuberosity, near the attachment of coracobrachialis.
The superior ulnar collateral artery arises from the brachial artery slightly distal to the mid-level of the arm but can occasionally arise as a branch of the profunda brachii artery. Along the ulnar nerve, it passes through the medial intermuscular septum into the posterior compartment of the arm to supply the medial head of the triceps brachii muscle. It then runs between the medial epicondyle of the humerus and the ulnar epicondyle. Deep to the flexor carpi ulnaris muscle, it joins the inferior collateral artery and the posterior branch of the posterior ulnar recurrent artery. Sometimes, a branch anastomoses with the anterior ulnar recurrent artery after it travels anteriorly to the medial epicondyle.
The middle ulnar collateral artery is present in some people to supply the triceps brachii muscle, in which case it arises from the brachial artery between the superior and inferior ulnar collateral arteries and travels anteriorly to the medial epicondyle before anastomosing with the anterior branch of the anterior ulnar recurrent artery. Similar to the middle collateral branch of the profunda brachii artery, it gives off some small fasciocutaneous perforators.
The inferior ulnar collateral (supratrochlear) artery arises from the brachial artery about 5cm proximal to the elbow joint. It runs medially between the brachialis muscle and the median nerve before crossing the medial intermuscular septum. It then spirals round the humerus between the bone and the triceps brachii muscle until it anastomoses with the middle collateral branch of the profunda brachii artery to form an arch located proximally to the olecranon fossa, a depression on the posterior aspect of the humerus. Anterior to the brachialis muscle, the inferior ulnar collateral artery divides into a few branches, which either run anteriorly to the medial epicondyle to anastomose with the anterior ulnar recurrent artery or run posteriorly to it to anastomose with the posterior ulnar recurrent artery and superior ulnar collateral artery.
The deltoid artery is a muscular branch of the brachial artery, which lies between the lateral and long heads of the triceps brachii until it reaches the descending branch of the posterior humeral circumflex artery.
The radial artery runs deep to the brachioradialis to give off the radial recurrent artery distal to the elbow joint. It runs between the superficial and deep branches of the radial nerve before it passes, in a superior direction, posteriorly to the brachioradialis muscle and anteriorly to the supinator and brachialis muscles. It supplies the brachioradialis, supinator and brachialis muscles as well as the elbow joint, before anastomosing with the radial collateral branch of the profunda brachii artery.
The ulnar artery is the largest of the terminal branches of the brachial artery. Its earliest branch is the ulnar recurrent artery, which subsequently divides into its anterior and posterior branches. Proceeding down the forearm, the ulnar artery gives off the common interosseous artery, dorsal, palmar and deep carpal branches, as well as the superficial palmar arch; all of which contribute to the blood supply of the forearm and hand together with the branches of the radial artery.
References
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