BRACHIAL 529 



elliiiw ill tlie usual situatitm of the brat-liial, whence one follows the normal course of the radial 

 artery through tlie iorearni, and tlie other takes the noruial course of the ulnar artery, givini^ off 

 as usual tiie coniiuon interosseous artery. This aiTangeiuent may be consideied a simple high 

 division of the brachial. At other times the disposition of the two vessels is different : thus (i) 

 tlu' two arteries may communicate at the elbow by a cross branch, or reunite, and then again 

 divide in the usual manner, (ii) One ve.«sel may follow the course of the ulnar artery in the 

 forearm, and the other divide into the radial and common interosseous. This condition is spoken 

 of as a high origin of the ulnar, (iii) One artery may divide into tlie radial and ulnar as usual, 

 and the other take the course of the common interosseous and divide into the anterior and jios- 

 terior interosseous arteries ; or, much more rarely, take the course of the posterior interosseous 

 artery, the anterior intero-sseous coming from the ulnar, (iv) The vessels may follow a course in 

 the upper arm different from that of the normal brachial. Thus (A) the branch rei)re.senting 

 the radial may (a) cross over or under the other branch ; (b) perforate the deep fascia above the 

 elbow, and run beneath the skin to its place in the forearm ; or(c) pass behind the tendon of the 

 biceps. (B) The branch representing the ulnar may (a) run to the front of the inner condyle 

 with the meilian nerve, and thence reach its u.sual situation by descending from within outwards 

 beneath the fascia and jironator teres, or, more rarely, beneath some of the flexor mu.scles, or 

 merely beneath the skin ; or (b) it may run with the ulnar nerve behind the inner condyle, and 

 thence beneath the muscles to its u.sual place in the forearm. (2) An enlarged vas aberrans may 

 be present. This is a long slender A'essel, which arises from the brachial usually near the origin 

 of the superior profunda, and joins most commonly the radial artery, or, more rarely, one of its 

 branches, or the ulnar. It is said to be usually present, though not admitting of complete injec- 

 tion, and to descend over the median nerve to the biceps muscle. At times this vessel takes the 

 jilace of the bracliial ; the median nerve will then be found behind the artery. (3) The brachial 

 may run with the median nerve towards the inner condyle, where it then usually turns round a 

 supracondyloid process after the course normally taken by the artery in the Felidfe, in which 

 it runs through a supracondyloid foramen. Thence it descends to its normal situation beneath 

 the pronator teres, which then usually arises from a fibrous expansion from the process. 

 (4) The brachial may be covered 'by various nni.scular slips derived from the adjacent muscles. 

 (.5) Certain abnormalities in the giving off of its collateral branches. These are referred to 

 under each branch. 



Branches of the Brachi.\l Artery 



The branches of the brachial artery are: — (1) The superior profunda; (2) 

 tlie inferior profunda; Co) the anastornotica magna; (4) the nutrient; (5) the 

 muscular; and (G; tlie terminal branches — the radial and ulnar arteries. 



d) The Superior Profunda Artery 



Tlic superior profunda is the largest of the branches of the brachial. It arises 

 from the inner and hinder aspect of that artery, a little below the inferior liorderof 

 the tendon of the teres major. It at first lies to the inner side of the lirachial, but 

 soon passes behind that vessel, and, sinking between the inner and long heads of tlie 

 triceps with the musculo-spiral nerve, curves round the humerus in the musculo- 

 spiral groove, lying in contact with the bone between the inner and outer heads 

 of the triceps. On reaching the external supracondyloid ridge of the humerus, it 

 perforates the external intermuscular septum, and. continuing forward between the 

 supinator longus and brachialis anticus to the front of the external condyle, ends 

 by anastomosing with the radial recurrent artery. 



It gives off the following Itranches: — 



(a) The ascending branch, which runs upwards behind the tendon of the 

 teres major in the sul)Stance of the triceps, or between the outer and inner heads of 

 that muscle, to anastomose with the tricipital brancli of the posterior circumflex 

 artery. The importance of this anastomosis in carrying on the collateral circula- 

 tion after ligature of the third part of the axillary artery below the circumHex. or 

 the brachial above the profunda, has already been mentioned (page 526). 



(6) The cutaneous branch, which runs with the external cutanef)us branch of 

 the musculo-s])iral nerve to supjily the skin of the outer side of the arm. 



(c) Tlie articular branch, which is often larger than the continued trunk of the 

 superior profunda itself, is given off from the artery just before it ])erforates the 

 intermuscular sei)tum. runs downwards in the sub.stance of the triceps to the l)ack 

 of the external condyle, Avhere it anastomoses with the interosseous recvuTent, and 

 forms an arterial arch bv anastomosing with the anastornotica magna across tlie 

 34 ■ " 



