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
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.