Superficial perforating fractures.—These formed the next degree; the chief peculiarity in them was the lifting of nearly the whole thickness of the skull at the distal margin of the entry, and the proximal edge of the exit, openings; the flatter the area of skull under which the bullet travelled the more extensive was the comminution. In some cases nearly the whole length of the bone superficial to the track would be raised; in fact, the bullet having once entered, the force is applied from within in exactly the same way that it operates on the inner table in the gutter fractures. A corresponding injury is met with in the case of the bones of the extremities (see fig. 57 of the tibia), and again the resemblance between these injuries of the skull and such perforations of the long bones as are illustrated by skiagrams Nos. III. and XXIII. of the clavicle and fibula is a close one.
Fig. 68.
Superficial Perforating Fracture. Illustrating lifting of roof at both entry and exit openings
I will add here a case of coexistent gutter fracture and perforating wound of the skull, the conditions of the bone in which will illustrate the behaviour of the outer and inner tables respectively, when struck with moderate force.
Fig. 69.
Diagrammatic longitudinal section of Fracture shown in fig. 68
Fig. 70.