_Head._ The head, or rather the skull, the shape of which is influenced by the cerebral mass it contains, is rarely free from anomalies, and for this reason the careful examination of this part is of the utmost importance. We have no means of studying subtle cranial alterations in the living subject, but we can ascertain the form and capacity of his skull. This is rendered easy and rapid by means of a very convenient craniograph invented by Anfossi (see Fig. 30), which traces the cranial profile on a piece of specially prepared cardboard. =FIG. 31 Pelvimeter= In the absence of a craniometer, measurements may be taken with calipers, the arms of which are curved like the ordinary pelvimeters used in obstetrics (see Fig. 31), and a graduated steel tape. The following are the principal measurements: 1. Maximum antero-posterior diameter, which is obtained by applying one arm of the instrument above the root of the nose just between the eyebrows and sliding the other arm over the vault of the skull till it reaches the occiput. The distance between the two arms furnishes the maximum longitudinal diameter. 2. The maximum transverse diameter or breadth of the skull is measured by placing the arms of the calipers, one on each side of the head on the most prominent spot. 3. The antero-posterior curve is obtained by fixing the graduated tape at zero on the root of the nose (on the fronto-nasal suture) and passing it over the middle of the forehead, vertex, and occiput to the external occipital protuberance. 4. The transverse, or biauricular curve is obtained by applying the steel tape at zero to a point just above the ear, and carrying it over the head in a vertical direction till it reaches the corresponding point on the other side. 5. The maximum circumference is obtained by encircling the head with the steel tape, touching the forehead immediately above the eyebrows, the occiput at the most prominent point, and the sides of the head more or less at the level, where the external ear joins the head, according to whether the position of the occipital protuberance is more or less elevated. (See Figs. 32, 33.) 6. The cranial capacity is obtained by adding together these five measurements, the antero-posterior diameter, maximum transverse diameter, antero-posterior curve, transverse curve, and maximum circumference. For a normal male the capacity is generally 92 inches (1500 c.c). =FIG. 32 FIG. 33 Diagram of Skull= 7. The cephalic index is obtained by multiplying the maximum width by 100 and dividing the product by the maximum length, according to the following formula: W × 100 ------- = X (cephalic index). L If the longitudinal diameter is 200 and the transverse diameter 100, the cephalic index is 10,000 divided by 200 = 50.