Bevelling of the skull is seen in the:
**Core Concept**
Bevelling of the skull refers to the thinning and inward curving of the inner table of the skull, typically seen in cases of increased intracranial pressure. This phenomenon is a result of the compensatory mechanism to accommodate the expanding intracranial contents.
**Why the Correct Answer is Right**
Bevelling of the skull is a characteristic radiological finding in conditions such as chronic subdural hematoma, where the inner table of the skull becomes thinned and concave due to the gradual accumulation of blood. This process is mediated by the underlying osteoclasts, which resorb the bone in response to the increased intracranial pressure. The bevelled appearance is a result of the uneven resorption of the inner and outer tables of the skull.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because bevelling of the skull is not typically associated with traumatic brain injury, which more commonly results in fractures or lacerations of the skull.
**Option B:** This option is incorrect because craniostenosis, a condition characterized by abnormal skull development, typically presents with abnormal skull shape or size, but not bevelling.
**Option C:** This option is incorrect because hyperostosis frontalis interna, a condition characterized by thickening of the frontal bone, is not associated with bevelling of the skull.
**Clinical Pearl / High-Yield Fact**
Bevelling of the skull is a radiological sign that should raise suspicion for increased intracranial pressure, particularly in the context of chronic subdural hematoma. This sign can be an important clue in the diagnosis of conditions that require prompt medical attention.
**Correct Answer:** D.