222 Supracondyloid Foramen and Processes in Man 



median nerve arose in the usual manner, but at about the middle of the 

 arm passed behind the brachial artery from without inwards, and at 

 the lower third became separated from it. It passed through the for- 

 amen, lay between the pronator radii teres, and the brachialis anticus, 

 and entered the forearm between the two heads of the pronator. The 

 origin of this muscle was continued into the lower third or more of 

 this process while the brachialis anticus received fibres from about a cor- 

 responding area at the upper end, the middle of the arch having no 

 muscular fibres and appearing as a white line. 



There can be no question that this bony arch represents the process 

 with its fibrous continuation which bounds the occasional opening in 

 man representing the widely distributed supracondyloid foramen of 

 animals. (I may mention in passing that the fibrous band is not con- 

 stant. My experience in this respect agrees with that of Nicholas ( 1 ) ) . 

 In the first place the process that bounds the foramen occurs at the 

 normal point of origin of the supracondyloid process. This, according 

 to Otto (2), is in a line from the inner border of the trochlea to the ante- 

 rior border of the greater tuberosity. Testut (3) accepts this and adds 

 another line of his own from the groove in the trochlea (gorge de la trocli- 

 Ue) to the middle of the articular surface of the head. In point of fact 

 the course of these lines must be far from constant; but if both these 

 statements be correct, as they approximately are, the process must be 

 at the point of intersection of these lines. Although this is true, the 

 process is lower than usual. I have said it arises 62 mm. above the 

 lowest point of the inner border of the trochlea, the measurement being 

 taken from the highest point of the origin of the process. Testut gives 

 the average distance of eight cases as 71 mm. and Nicholas that of six 

 as 73 mm. Moreover, the latter, at least, placed his starting point at 

 the middle of the base of the process. Euge (4) declares that according 

 to all experience the position is a constant one; which is practically 

 in accord with my own less extensive observations. There are, however, 

 certain exceptions to be mentioned later. Another important fact is 

 that the median nerve passes through the foramen, i. e., under the pro- 

 cess. It may be asked whether this is a real foramen; that is to say: 

 Avas the strip of bone bridging it over either laid down in cartilage or 

 formed by the early ossification of the completing band, in contradis- 

 tinction to a quasi-accidental ossification of that band in adult life? In 

 other words, have we at last found the supracondyloid foramen in man ? 

 I incline very strongly to consider it a real foramen, and probably one 

 formed by a cartilage. The process usually, when it is more than a 

 ridge or a tubercle, is thick at its base and narrows to the point which 



