Professor Harvey Littlejohn's collection.)]

[Illustration: FIG. 189.--Depressed and Comminuted Fracture of Right
Parietal Bone: Pond Fracture. The patient sustained the injury twenty
years before death.]

[Illustration: FIG. 190.--Pond Fracture of Left Frontal Bone, produced
during delivery.

(From a photograph lent by Mr. J. H. Nicoll.)]

As a rule the whole thickness of the skull is broken, and, as usual,
the inner table suffers most. In infants the bones may be merely
indented, the fracture being of the greenstick variety. All degrees of
severity are met with, from a simple, localised indentation of the
bone, to complete smashing of the skull into fragments.

_Diagnosis._--When compound, the nature of these fractures is readily
recognised on exploring the wound, but their extent is not always easy
to determine, and it is not uncommon for extensive fissures to pass
into the base.

A haematoma of the scalp may readily be mistaken for a depressed
fracture. The condensation of the tissues round the seat of impact and
the soft coagulum in the centre, closely simulate a depression in the
bone; but if firm pressure is made with the finger, the irregular edge
of the bone can be recognised, and the depressed portion is felt to be
on a lower level. On the other hand, a depression in the bone is
sometimes obscured by an overlying haematoma, and unless great care is
taken the fracture may be overlooked.

_Treatment._--All are agreed that compound depressed and comminuted
fractures--whether associated with cerebral symptoms or not--should
be operated on to enable the wound to be purified, and the normal
outline of the skull to be restored by elevating or removing depressed
or separated fragments. Except in young children, in whom considerable
degrees of depression are frequently righted by nature, most surgeons
recommend operative interference even in simple fractures with the
object of elevating the depressed bone, and to anticipate subsequent
complications such as persistent headache, attacks of giddiness,
traumatic epilepsy, or insanity. Others, including von Bergmann and
Tilmanns, consider that the risk of such sequelae ensuing is not
sufficient to justify a prophylactic operation of such severity as
trephining.

The operation is described in _Operative Surgery_, p. 93.

FRACTURES OF THE BASE

The base of the skull may be fractured by a pointed object, such as a
fencing foil, a knitting pin, or the end of an u