155. Subcutaneous veins.—The veins on the back of the hand, and their arrangement in the form of arches which receive the digital veins, is sufficiently obvious. The number and arrangement of the arches may vary, but in all hands it is interesting to notice that the veins from the fingers run up between the knuckles and are out of harm’s way.
156. Interosseous arteries.—Since the dorsal interosseous arteries, like the palmar, run along the interosseous spaces, incisions to let out pus should always be made along the lines of the metacarpal bones.
157. Digital bursæ.—Small subcutaneous bursæ are sometimes developed over the knuckles and the backs of the joints of the fingers. They often become enlarged and unseemly in persons of a rheumatic or gouty tendency.
158. Knuckles and digital joints.—The three rows of projections called ‘the knuckles’ are formed by the proximal bones of the several joints: thus the first row is formed by the ends of the metacarpals; the second by the ends of the first phalanges, and so forth. In amputations of the fingers it is well to remember that in all cases the line of the joints is a little in advance of the knuckles, that is, nearer the end of the fingers.
Long and graceful fingers, coupled with thickness and breadth of the sentient pulp at their ends, and too great arching of the nails, have been regarded, ever since the days of Hippocrates, as not unlikely indications of a tendency to pulmonary disease.
PALPATION BY THE RECTUM.
The following report is from Mr. Walsham, of St. Bartholomew’s Hospital, who, having a small hand (somewhat less than seven and a half inches round), has had opportunities of introducing it up the rectum, in the living subject, for the purpose of diagnosis:—
‘It is possible to introduce the hand (if small) into the rectum; in many cases into the sigmoid flexure, and in rare instances into the descending colon.
‘Once beyond the sphincter, the hand enters a capacious sac, and the following important parts can be felt through its walls:—
‘Through the anterior wall the hand first recognises the prostate, which feels like a moderately large chestnut. Immediately behind the prostate, the vesiculæ seminales may be distinguished as two softish masses situated one on either side of the middle line. Internal to them, the whipcord-like feel of the vasa deferentia can be readily traced over the bladder to the sides of the pelvis.