AGE 37 The laryngeal and costal cartilages become ossified, and the greater cornua of the hyoid bone are firmly joined to the body by bony union ; the lesser cornua which are usually connected to the body by fibrous tissue throughout life, may occasionally become ankylosed in advanced life. Fig, 11.—The lower jaw showing angles at various ages. In infancy the mandible (lower jaw) has a short oblique ramus, which forms an obtuse angle with the body. The mental foramen opens near the lower margin, the condyloid process is nearly in line with the body, and the coronoid process projects above the condyle. In adult life the ramus joins the body almost at a right angle, and the mental foramen opens mid- way between the upper and lower borders of the body. The condyle is elongated and projects above the coronoid process. In old age the ramus forms an obtuse angle with the body which is reduced in size owing to the loss of the teeth and the absorption of the alveolar processes. The mental foramen is closer to the alveolar (upper) border. Minor Signs.—The growth of hair appears first on the pubes and then in the axillae (armpits). In the case of girls it commences with the appearance of soft and pale coloured downy hair on the pubes at the age of about 13 years, and a few sparse dark hairs appear at about 14 years. The growth becomes thicker in the course of a year or two, when hair commences to grow in the axillse. In the case of boys downy hair appears on the pubes at about 14 years, and a few dark hairs appear at about 15, when downy hair begins to grow in the axillae. A thick growth of dark hairs is well marked on the pubes, scortum and in the axillse at about 16 or 17 years. Hair begins to appear on the chin and upper lip between 16 and 18 years. The development of the breasts in girls commences from thirteen to fourteen years, but it is liable to be affected by loose habits and social environments. Boys develop a deep voice between 16 and 18 years when Pomum Adami becomes more prominent. Hair on the head tends to become grey usually after forty years of age and silvery white in advanced old age. Grey hair is sometimes seen among young people. In a few cases it is a hereditary peculiarity. Cases have occurred in which the hair of the head has suddenly changed to grey from extreme terror, grief, shock or some unaccountable reason. A case is recorded in which hair turned snowwhite a day or two after an automobile accident.-5 Circumscribed patches of grey hair on the head may also be due to trophic changes produced by neuralgia or other diseases affecting the fifth nerve. Pubic hair begins to turn grey usually after the age of fifty. Atheromatous arteries, and an opaque zone in the cornea, known as arcus senilisy are rarely seen before forty. Wrinkles on the face begin to appear after this age; but no reliance can be placed on these signs inasmuch 25. Medico-Legal Jour., Vol. 49, No. 2, 1932, p. 50.