180 



MR WM. TURNER ON VARIABILITY IN HUMAN STRUCTURE. 



Fig. 2 * 



cases the connecting slip was in great measure, though not altogether, formed 

 of the fibres of the rounded head of the flexor longus pollicis, which arose from 

 the coronoid process of the ulna. In one case the connecting slip received almost 



one-half the fibres of the long flexor muscle, a specimen 

 which illustrates how large and important this inter- 

 muscular tendon may at times become. In one very 

 remarkable specimen the bond of union passed in the 

 opposite direction from those above described — viz., 

 from the index tendon of the flexor profundus to the 

 tendon of the flexor longus pollicis (fig. 2). 



Amongst the intermuscular structures which not 

 unfrequently connect together the superficial and deep 

 flexor muscles of the forearm, I am disposed to place 

 that rounded musculo-tendinous band, which is so 

 often met with, as a second head of origin of the 

 flexor longus pollicis, for it arises along with the 

 flexor sublimis from the coronoid process of the ulna, 

 and ends inferiorly in the inner part of the long flexor of the thumb. But the 

 superficial is also not unfrequently connected to the deep flexor of the fingers 

 by intermuscular bands. For I have frequently seen a slip of muscle arise from 

 the coronoid process, along with, and apparently forming a part of, the flexor 

 sublimis, which, after it became tendinous, blended in five specimens with the 

 tendon of the flexor profundus going to the little finger {e.g. fig. 2), in one with 

 the tendon passing to the ring-finger, in four with the tendon of the same 

 muscle going to the middle finger, and in one it divided into three slips which 

 joined the deep tendons for the middle, ring, and little fingers. The blending 

 usually occurred opposite, or slightly below, the carpal articulations. f 



The lumbricales muscles exhibit many forms of variation in size, number, 

 extent, surface of origin, and mode of insertion ; but as both Theile and Henle 

 have entered fully into these varieties, I need do no more than state that I have 

 seen, in addition to most of the forms which they have described, a variety in 

 which an accessory first lumbricalis arose tendinous from the flexor sublimis. 



* Fig. 2, t, flexor longus pollicis ; p, flexor profundus digitorura ; s, flexor sublimis digitorum. 

 The connection of the first and second muscles by a tendinous band passing from the index tendon 

 of the latter to the long flexor of the thumb, is shown ; also a tendon connecting the ulnar side of 

 the superficial with the tendon of the deep flexor for the little finger ; also a close connection low 

 down the limb between the ring and little finger tendons of both the superficial and deep flexor muscles. 



f The presence of slips proceeding between the flexor sublimis and F. profundus, though with- 

 out precise statement as to their connections, has been recognised by Cowper (Myotomia reformata), 

 Theile. and Wood. 



I may in this place also refer to an arrangement which I saw on one occasion in the left fore- 

 arm. A slender fasciculus of muscular fibres proceeded from the flexor sublimis immediately to the 

 inner side of the palmaris longus. It ended on a tendon which passed beneath the palmaris, and 

 joined the tendon of the supinator radii longus at the lower end of the forearm. 



