In Figs. 20 and 21 the inner and outer views of the thumb shape are shown ; the same outline could be used for both positions, but reversed in drawing.
The wrist is separate from the hands, being composed of an assortment of small bones called " bones of the carpus," situated between the hand and the arm, Fig. 15. They form a connecting link between the two (see Fig. 16, shaded space showing position). Joining these are the metacarpal bones forming the body of the hand (Fig. 12, A), followed by three sets of phalanges at B, except the thumb, which has only two sets.
The ulna and radius bones connect the wrist with the arm, the heads of these bones showing prominently. The ulna bone is small and round, standing high on the little finger side (Figs. 14 and 16, U).
The radius bone is long and flat, being on the thumb side in the same figures at R.
In some positions of the hands prominent bones of the carpi will show, but it is unnecessary to emphasize them in a work of this kind.
Owing to the webbing between the fingers, the first
phalanges appear to be of the same length as second phalanges, but in reality they are longer (Fig. 12).
Shafts are held together by cartilages which are very elastic, it being possible to bend the finger into the palm of hand at right angles, except the last phalange which bends at about 45° (Plate 12, Fig. 10).
When the fingers are bent at this angle, the back view of the knuckles will indicate the shape of the bone, the flesh creases being on the inside. Creases on the inside of finger vary in size and quantity according to the angle of the bend, taking double crease when very intense (see Plate 12, Figs. 9 and 10).
Shafts (or phalanges) become smaller and thinner towards the nail tip, giving a tapering appearance.
They are convex on back, concave on front (Plate 12, Fig. 5, and shown in the blocking form).
In the case of side view of fingers, the shafts will sometimes show their shape (Fig. 17, S), the side being on a different plane. Light and shade help to define the line.
Back ligaments are held down at the middle joint, causing a flatness on that point with the creases of flesh running round, then taking a curve forward to the next joint (Plate 12, Fig. 7, L).