|Henry Gray (18251861). Anatomy of the Human Body. 1918.|
|divides opposite the neck of the radius into the radial and ulnar arteries; it is covered, in front, by the integument, the superficial fascia, and the vena mediana cubiti, the last being separated from the artery by the lacertus fibrosus. Behind it is the Brachialis which separates it from the elbow-joint. The median nerve lies close to the medial side of the artery, above, but is separated from it below by the ulnar head of the Pronator teres. The tendon of the Biceps brachii lies to the lateral side of the artery; the radial nerve is situated upon the Supinator, and concealed by the Brachioradialis.|
Peculiarities of the Brachial Artery as Regards its Course.The brachial artery, accompanied by the median nerve, may leave the medial border of the Biceps brachii, and descend toward the medial epicondyle of the humerus; in such cases it usually passes behind the supracondylar process of the humerus, from which a fibrous arch is in most cases thrown over the artery; it then runs beneath or through the substance of the Pronator teres, to the bend of the elbow. This variation bears considerable analogy with the normal condition of the artery in some of the carnivora; it has been referred to in the description of the humerus (p. 212).
As Regards its Division.Occasionally, the artery is divided for a short distance at its upper part into two trunks, which are united below. Frequently the artery divides at a higher level than usual, and the vessels concerned in this high division are three, viz., radial, ulnar, and interosseous. Most frequently the radial is given off high up, the other limb of the bifurcation consisting of the ulnar and interosseous; in some instances the ulnar arises above the ordinary level, and the radial and interosseous form the other limb of the division; occasionally the interosseous arises high up.
| Sometimes, long slender vessels, vasa aberrantia, connect the brachial or the axillary artery with one of the arteries of the forearm, or branches from them. These vessels usually join the radial.|
FIG. 525 The brachial artery. (See enlarged image)
Varieties in Muscular Relations.The brachial artery is occasionally concealed, in some part of its course, by muscular or tendinous slips derived from the Coracobrachialis, Biceps brachii, Brachialis, or Pronator teres.
Collateral Circulation.After the application of a ligature to the brachial artery in the upper third of the arm, the circulation is carried on by branches from the humeral circumflex and subscapular arteries anastomosing with ascending branches from the profunda brachii. If the artery be tied below the origin of the profunda brachii and superior ulnar collateral, the circulation is maintained by the branches of these two arteries anastomosing with the inferior ulnar collateral, the radial and ulnar recurrents, and the dorsal interosseous.
Branches.The branches of the brachial artery are:
||Superior Ulnar Collateral.
||Inferior Ulnar Collateral.|