If we find: Right shoulder, head to the left, the back must be anterior.
64 it right, " " 64 46 • posterior.
Left 46 44 " left " " ti it posterior.
4i it itright, " " " " anterior.
Hence it is sufficient for us to know two terms of the problem to enable us to find the third. If instead of the acromial variety we have to deal with the cubital variety—in other words, if the elbow is the most accessi ble part—its recognition is sufficient to establish the diagnosis. The elbow is characterized by the projecting olecranon, limited on its right and left sides by two other prominences, the epi-condyle and the epi-trochlea. The bend of the elbow is formed by the forearm and the arm, and it is only necessary to follow either one of these parts to convince us that it is the elbow we are touching. ,The forearm will lead to the hand, recognizable by being in the axis of the arm, by the length of the fingers, the apposi tion of the thumb, and the inequality of the fingers. In order to distin guish which hand we are touching, it is best to determine the characteris tics and the situation, and to substitute mentally our own for it. The one we can, as it were, superimpose upon the one felt will indicate whether it is the right or the left hand. This gives us the shoulder, or the elbow indicates the situation of the axilla; in either case the diagnosis is com plete. Pajot advises, in doubtful cases, to make traction on the hand felt externally and compare it with one's own; this will show whether it is right or left.
If the hand is outside the vulva, it is sufficient to compare it with either one of ours to show whether it is the right or the left; but there is a more scientific and equally reliable procedure. Take the protruding hand and turn it palm upward, the border inferior to the symphysis pubis; the thumb will always be turned to the thigh homonymous to the hand, to the right thigh in the case of the right hand and vice versa. When the shoulder is known, we need but follow the arm to reach the axilla, and thus the situation of the head and the diagnosis is complete.
When the hand depends freely from the vulva, the arm in its natural attitude, simple inspection of the hand will complete the diagnosis.
The hand gives us the shoulder; besides, the back of the hand always turns away from the side where the head is. This gives us two terms of the problem, and we can find the third without difficulty and complete the diagnosis. But examination of the hand suffices.
The hand gives us the shoulder; the dorsum of the hand, the situation of the bead; the direction of the thumb indicates the direction of the back; for when the back is posterior, the thumb points upward from the symphysis. When the back is anterior, the thumb is directed downward toward the anus.