64 



REGION OF THE ELBOW. 



the other division of the median vein, called 

 median cephalic, passes obliquely upwards 

 and outwards, external to the prominence 

 formed by the biceps, and joins the cephalic at 

 an acute angle above the external condyle. 



The cephalic, the basilic, and the two divi- 

 sions of the median vein joining them, form a 

 figure which somewhat resembles the Roman 

 capital letter M. 



The superficial lymphatic vessels follow the 

 course of the veins ; those on the internal side 

 are larger and enter small ganglions, varying 

 in number from two to five, which are situated 

 in the subcutaneous cellular tissue, above and 

 in front of the internal condyle, where they 

 are sometimes seen swollen and inflamed in 

 consequence of inflammatory affections of the 

 hand or fore- arm. 



The subcutaneous nerves are : branches of 

 the internal cutaneous, usually three or four in 

 number, the external cutaneous, and some 

 twigs from the radial and ulnar nerves. The 

 branches of the internal cutaneous pass down 

 to the fore-arm, generally superficial to the 

 basilic and median basilic veins, while the 

 external cutaneous lies deeper than the ce- 

 phalic and median cephalic, with the latter of 

 which it is more intimately connected. Some 

 twigs from both the internal and the external 

 cutaneous nerves are distributed to the inte- 

 guments behind the elbow. 



Aponeurosis. The aponeurosis of the region 

 of the elbow is continuous with the brachial 

 aponeurosis above, and with that of the fore- 

 arm inferiorly ; it is strong behind the elbow, 

 where it receives an expansion from the tendon 

 of the triceps, and has an intimate adhesion to 

 the margin of the olecranon : on each side it 

 is firmly attached to the condyles of the hu- 

 merus, sending off several layers from its 

 internal surface, which form septa between the 

 origins of the muscles of the fore-arm which 

 arise from these processes : anteriorly it is 

 spread over the triangular depression, where 

 its strength is considerably increased by ex- 

 pansions which it receives from the tendons of 

 the biceps and the brachiseus anticus ; the ex- 

 pansion from the brachiaeus anticus comes 

 forward on the external side of the tendon of 

 the biceps, and is lost over the external mus- 

 cular prominence of the fore-arm in front of 

 the external condyle ; the expansion from the 

 biceps forms a narrow band about half an inch 

 in breadth where it is first detached from the 

 tendon of that muscle ; it then descends 

 obliquely to the inner side of the fore-arm, on 

 the aponeurosis of which it is lost about two 

 inches below the inner condyle. Superiorly 

 this expansion crosses over the brachial artery, 

 and its superior margin is defined by a lunated 

 border to which the brachial aponeurosis is 

 attached, while its inferior margin is con- 

 founded with the aponeurosis of the fore- 

 arm. 



From the above described attachments of 

 the tendons of the biceps and brachiaeus an- 

 ticus to the aponeurosis of this region, it fol- 

 lows as a necessary consequence that the con- 



tractions of these muscles must have the effect 

 of rendering it more tense. 



The aponeurosis of the arm assumes the 

 form of a very thin fascia as it approaches the 

 superior margin of the expansion of the biceps ; 

 at this place it often appears to degenerate 

 into cellular tissue which covers an oval space 

 placed obliquely, the broader extremity of 

 which is below, being bounded by the expan- 

 sion of the biceps externally and inferiorly, 

 and by a sort of defined border terminating 

 the lower margin of the brachial aponeurosis 

 superiorly and internally : in this oval space 

 the brachial artery and the median nerve which 

 lies to its inner side are more thinly covered 

 than in any other part of their course. The 

 aponeurosis is also very weak on the external 

 side of the expansion of the biceps, where it 

 is pierced by the deep branch of the median 

 vein, and by the external cutaneous nerve 

 which comes from beneath the aponeurosis at 

 this place. 



The brachial artery terminates by dividing 

 into the radial and ulnar arteries in the tri- 

 angular depression, which is bounded exter- 

 nally by the supinator longus and internally by 

 the pronator radii teres. 



This artery enters the region of the elbow on 

 the internal side of the tendon of the biceps 

 included in a common sheath with its two 

 vena? comites, one of which lies on either side 

 of it ; it lies on the surface of the brachiaeus 

 anticus, and, becoming deeper as it descends, 

 it divides into the radial and ulnar arteries at 

 about an inch below the level of the internal 

 condyle. The median nerve lies internal to it, 

 separated from it at first by cellular tissue ; 

 lower down, where this nerve pierces the pro- 

 nator teres, the external origin of that muscle 

 arising from the coronoid process is interposed 

 between it and the artery : the radial and ulnar 

 arteries, while still in this region, give off their 

 recurrent branches, which pass upwards, encir- 

 cling the condyles of the humerus, to anasto- 

 mose with the profundae and anastomotic 

 branches of the brachial, as described in the 

 article BRACHIAL ARTERY. The venae comites 

 of the brachial, radial, and ulnar arteries are 

 double : these vessels are also accompanied by 

 a deep set of lymphatics. The nerves which 

 traverse this region beneath the aponeurosis 

 are, the median on the internal side of the 

 brachial artery; the radial, which, descending 

 between the brachiseus anticus and the supinator 

 radii longus, then between the biceps and ex- 

 tensor carpi radialis, divides into two branches, 

 the posterior of which passes between the supi- 

 nator brevis and extensor carpi radialis brevior 

 to the muscles on the back part of the fore-arm, 

 while the anterior branch or proper radial 

 nerve descends in the fore-arm under the su- 

 pinator radii longus. The trunk of the ulnar 

 nerve passes behind the internal condyle, and 

 entering between the two heads of the flexor 

 carpi ulnaris follows that muscle down the 

 fore-arm. 



Development. In early life the condyles of 

 the humerus are not so well marked, nor is 



