Skull fractures are detected by skull x-rays and computed tomography (CT Scans). These tests allow the classification of skull fractures into three basic categories:
Linear, Comminuted, and Depressed. The skull in composed of three layers. The outer layer is dense cortical bone, the middle layer is cancellous bone filled with marrow, and the inner table is second layer of cortical bone.
Linear fractures consist of a crack through the skull resulting from a traumatic blow to the head. These linear fractures heal in infants. Adult linear fractures heal by fibrosis and will always show on x-ray studies. High
impact injuries to the skull are capable of splitting the sutures that join two skull plates together (Fig. 1)
Figure
1
Comminuted fractures occur when an impact breaks the skull into several small pieces. If the fractured pieces remain in the original position of the skull bone this fracture is called non-displaced. If bone fragments are
driven blow the normal position to compress the brain tissue, this type of fracture is called depressed. Some depressed skull fractures cut the dura (protective covering of the brain) and may lacerate the brain tissue.
Tearing the dural coverings of the brain often allows spinal fluid to leak through the fracture line to cause leakage from areas such as the nasal sinuses and ears. Air may leak into the skull (pneumocephalus ) from the outside world through a skull fracture and dural tear.
Basal skull fractures are a special category of linear fractures extending through the petrus portion of the temporal bone that leak spinal fluid from an ear. There may be associated hearing loss, instability of gait, and vertigo.
Treatment of spinal fluid leaks or pneumocephalus is a conservative management approach waiting to see if the leak stops. If the leak continues, the risk of meningitis (a brain infection) may force the surgeon to repair the dural tear and seal the site of the original leak.
