SURGICAL ANATOMY OF BRACHIAL ARTERY. 485 



The ulnar sometimes arises from the brachial high up, and then occasionally leaves that vessel 

 at the lower part of the arm, and descends towards the inner condyle. In the forearm, it gene- 

 rally lies beneath the deep fascia, superficial to the flexor muscles ; occasionally between the 

 integument and deep fascia, and very rarely beneath the flexor muscles. 



The interosseous artery sometimes arises from the upper part of the brachial or axillary ; as 

 it passes down the arm, it lies behind the main trunk, and, at the bend of the elbow, regains its 

 usual position. 



In some cases of high division of the radial, the remaining trunk (ulnar-interosseous) occa- 

 sionally passes, together with the median nerve, along the inner margin of the arm to the inner 

 condyle, and then passing from within outwards, beneath or through the Pronator Teres, regains 

 its usual position at the bend of the elbow. 



Occasionally, the two arteries representing the brachial are connected at the bend of the elbow 

 by a short transverse branch, and are even sometimes reunited. 



Sometimes, long slender vessels, vasa abtrrantia, connect the brachial or axillary arteries 

 with one of the arteries of the forearm, or a branch from them. These vessels usually join the 

 radial. 



Varieties in Muscular Relations. 1 The brachial artery is occasionally concealed in some part 

 of its course, by muscular or tendinous slips derived from various sources. In the upper third 

 of the arm, the brachial vessels and median nerve have been seen concealed to the extent of three 

 inches, by a muscular layer of considerable thickness, derived from the Coraco-brachialis, which 

 passed round to the inner side of the vessel, and joined the internal head of the Triceps. In the 

 lower half of the arm the artery is occasionally concealed by a broad thin head to the Biceps 

 muscle. A narrow fleshy slip from the Biceps has been seen to cross the artery, concealing it 

 lor an inch and a half, its tendon ending in the aponeurosis covering the Pronator Teres. A 

 muscular and tendinous slip has been seen to arise from the external bicipital ridge by a long 

 tendon, cross obliquely behind the long tendon of the Biceps, and end in a fleshy belly, which 

 appears on the inner side of the arm between the Biceps and Coraco-brachialis, passes down 

 along the inner edge of the former, and crosses the artery very obliquely, so as to lie in front of 

 it three inches, and, finally, gives rise to a narrow flattened tendon, which is inserted into the 

 aponeurosis over, the Pronator Teres. A tendinous slip, arising from the deep part of the ten- 

 don of the Pectoralis Major, has been seen to cross the artery obliquely at or below the Coraco- 

 brachialis, and join the intermuscular septum above the inner condyle. The Brachialis Anticus 

 not unfrequently projects at the outer side of the artery, and occasionally overlaps it, sending 

 inwards, across the artery, an aponeurosis which binds the vessel down upon the Brachialis An- 

 ticus. Sometimes, a fleshy slip from the muscle covers the vessel, in one case to the extent of 

 three inches. In some cases of high origin of the Pronator Teres, an aponeurosis extends from 

 it to join the Brachialis Anticus external to the artery ; a kind of arch being thus formed under 

 which the principal artery and median nerve pass, so as to be concealed for half an inch above 

 the transverse level of the condyle. 



Surgical Anatomy. Compression of the brachial artery is required in cases of amputation 

 and some other operations in the arm and forearm ; and it will be observed, that it may be 

 effected in almost any part of the course of the artery. If pressure is made in the upper part 

 of the limb, it should be directed from within outwards, and if in the lower part, from before 

 backwards, as the artery lies on the inner side of the humerus above, and in front of it below. 

 The most favorable situation is near the insertion of the Coraco-brachialis. 



The application of a ligature to the brachial artery may be required in cases of wounds of the 

 vessel, and in some cases of wound of the palmar arch. It is also sometimes necessary in cases 

 of aneurism of the brachial, the radial, ulnar, or interosseous arteries. The artery may be se- 

 cured in any part of its course. The chief guides in determining its position are the surface- 

 , markings produced by the inner margin of the Coraco-brachialis and Biceps, the known course 

 of the vessel, and its pulsation, which should be carefully felt for before any operation is per- 

 formed, as the vessel occasionally deviates from its usual position in the arm. In whatever 

 situation the operation is performed, great care is necessary, on account of the extreme thinness 

 of the parts covering the artery, and the intimate connection which the vessel has throughout its 

 whole course with important nerves and veins. Sometimes a thin layer of muscular fibre is met, 

 with concealing the artery ; if such is the case, it must be cut across, in order to expose the vessel. 



In the upper third of the arm the artery may be exposed in the following manner : the patient 

 being placed horizontally upon a table, the afiected limb should be raised from the side, and the 

 hand supinated. An incision about two inches in length should be made on the ulnar side of 

 the Coraco-brachialis muscle, and the subjacent fascia cautiously divided, so as to avoid wound- 

 ing the internal cutaneous nerve or basilic vein, which sometimes run on the surface of the artery 

 as high as the axilla. The fascia having been divided, it should be remembered, that the ulnar 

 and internal cutaneous nerves lie on the inner side of the artery, the median on the outer side, 

 the latter nerve being occasionally superficial to the artery in this situation, and that the venae 

 comites are also in relation with the vessel, one on either side. These being carefully Separated, 

 the aneurism needle should be passed round the artery from the ulnar to the radial side. 



If two arteries are present in the arm, in consequence of a high division, they are usually 



1 See STRUTHERS'S Anatomical and Physiological Observations. 



