524 



REGIONS OF THE HAND. 



the base of the little finger; this traverses the 

 hand about two lines above the metacarpo- 

 phalangeal articulations. Opposite the joints 

 of the fingers there are also transverse lines ; 

 the two first have double, the last joint but a 

 single line ; an incision made perpendicular 

 to it would fall about a line above the articula- 

 tion. Of the middle joint, the superior trans- 

 verse line is the most constant, and is placed 

 about half a line above its articulation. 



Of the lines corresponding to the first joint 

 of the fingers, the superior is on a level with 

 the termination of the interdigital web, and from 

 ten lines to an inch below the articulation, 

 excepting that of the thumb, which resembles 

 the middle joint of the fingers, its line nearly 

 corresponding to the articulation. There are 

 many other inconstant folds, or markings of the 

 skin, in this region, which, to the surgeon, are 

 of little import, but which present a book of 

 mystic lore to the gipsy and the cheirornancer, 

 wherein (when opened by the necessary charms) 

 they discern the future destinies of all that seek 

 to be enlightened by them. 



We shall now proceed to examine the various 

 structures found in this region, and, for con- 

 venience of description, shall consider them as 

 -constituting the following layers : 1, skin ; 

 2, subcutaneous cellular tissue, vessels, and 

 nerves ; 3, aponeurosis ; 4, deep vessels and 

 nerves ; 5, muscles and tendons. 



1. The skin. The integument on the front 

 of the wrist resembles that on the anterior sur- 

 face of the fore-arm ; but, on reaching the palm, 

 it suddenly changes its character, and instead of 

 the fine, smooth, yielding skin, we find it dense, 

 resisting, exceedingly vascular, and covered 

 with a very strong and thick cuticle ; on the 

 thenar, however, it preserves some degree of 

 suppleness and elasticity. In those accustomed 

 to hard manual labour, and in the aged, the 

 cuticle becomes so thick and callous as to en- 

 able them to handle even hot coals without 

 inconvenience ; but in them, from this increased 

 resistance, and from the difficulty of getting at 

 matter, or freeing the parts by incisions, inflam- 

 mations of the palm are the more dangerous. 

 Corns are sometimes developed at the roots of 

 the fingers, on the prominences formed by the 

 heads of the metacarpal bones. There are no se- 

 baceoifs follicles to be discovered in this region ; 

 but M. Velpeau thinks, from the fact of the 

 occasional appearance of variolous pustules on 

 the front of the fingers, that follicles there exist. 

 The physical conditions of the skin of the 

 hand, as to coolness or warmth, as to moisture 

 or dry ness, often furnish valuable signs in dis- 

 ease. 



2. Subcutaneous cellular tissue is dense and 

 serrated, more fibrous than cellular, enclosing 

 in its meshes small rounded pellets of fat. On 

 the wrist it binds the skin so closely to the 

 subjacent parts, that, in cases of serous or other 

 infiltration above this point, the effused fluids 

 are arrested, and prevented from passing into 

 the palm of the hand ; also, in very fat and 

 flabby people, and in young children, a kind of 

 strangulation is observable at the wrist from 



the same cause. On the thenar this layer is 

 laxer and less compact, permitting the skin to 

 play freely. On the centre of the palm and 

 hypothenar it is very dense and fibrous, enclos- 

 ing larger pellets of fat, binding the skin very 

 firmly to the palmar aponeurosis and sheaths 

 of the fingers, towards the extremities of which 

 it becomes more fatty, increases in thickness, 

 forming a soft elastic cushion called the pulp of 

 the fingers. This tissue is the seat of that painful 

 phlegmonous inflammation, the true whitlow. 

 The unyielding natureof the thick consistent skin 

 on the one hand, and of the bones and sheaths 

 on the other, whereby the swollen and inflamed 

 pulp, together with its great number of vessels 

 and the nervous expansion it encloses, are vio- 

 lently compressed, easily account for the violent 

 symptoms, and call loudly for the prompt relief 

 of the strangulation by means of the knife, and 

 also indicate the great advantage of emollients. 



The subcutaneous nerves are few, and derived 

 from the palmar cutaneous branch of the median 

 and some terminal branches of the internal and 

 musculo-cutaneous nerves. The veins are also 

 veiy few, and give rise to the median, and are 

 accompanied by the superficial lymphatics. 



3. The aponeurosis. At the wrist the apo- 

 neurosis, derived from that of the front of the 

 forearm, is interwoven with and inseparable 

 from the anterior annular ligament, from the 

 lower border of which, and from the tendon of 

 the palmaris longus, the palmar fascia proceeds. 

 Above the annular ligament the aponeurosis is 

 attached to the extremity of the ulna, and the 

 pisiform and the styloid process of the radius ; 

 it furnishes sheaths to the tendons that do not 

 pass under the annular ligament, one to the ul- 

 nar and its nerve, and another to the radial 

 trunk and its volar branch. The anterior annu- 

 lar ligament is exceedingly strong, attached 

 internally to the pisiform and unciform, and ex- 

 ternally to the scaphoid and trapezium. It con- 

 sists of two layers, the one superficial, of diver- 

 gent fibres, derived from the tendon of the 

 palmaris longus when it exists, or belonging to 

 the origin of the palmar fascia when it does 

 not; the other deep, of transverse fibres, con- 

 tinuous with the fascia of the forearm. It 

 forms, together with the concavity of the pal- 

 mar aspect of the carpal bones, a sort of ellipti- 

 cal ring about two inches in its transverse, and 

 one inch in its antero-posterior diameter, and 

 gives passage to the common flexor tendons and 

 median nerve, which are enveloped by a com- 

 mon synovial bursa which binds them together, 

 and terminates in a common cul-de-sac above 

 and below the ligament; also to the long flexor 

 tendon of the thumb, which has a distinct 

 bursa. This ligament, from its great strength, 

 presents an insurmountable obstacle to the pro- 

 gress of tumours developed beneath it, forcing 

 them to protrude on the forearm above the liga- 

 ment in the hand below it. Thus, when the 

 common synovial bursa of the tendons is dis- 

 tended, it forms two tumours, the one above, 

 the other below the ligament ; and upon com- 

 pressing the fluid from one the other will be 

 found to enlarge. Ganglia rarely occur here. 



