A patient develops a chronic subdural haematoma. The haematoma accumulates in the potential space between the dural border cell layer and the arachnoid membrane. Which meningeal layer is actually split to create this subdural space, and why does it bleed slowly?

• A The arachnoid mater is torn, allowing CSF to mix with blood in the true subarachnoid space
• B The dura mater is split at the falx cerebri level, with arterial bleeding from the middle meningeal artery
• C The dural border cell layer (inner dural layer) is where the plane forms; bleeding from bridging veins in this layer is venous and low-pressure, accumulating over weeks ✓
• D The arachnoid granulations rupture, causing venous hypertension and bilateral subdural collections

Explanation

Modern meningeal anatomy describes the 'subdural space' as a potential space within the inner lamina of the dura itself — the dural border cell layer, which lacks tight junctions and has fragile cell-to-cell connections. Bridging veins traversing from the brain cortex to the venous sinuses pass through this layer and are prone to slow venous tearing with minor trauma, accumulating a chronic subdural haematoma over weeks to months. Because the bleeding is venous and low-pressure, patients may be asymptomatic for weeks. This explains why the 'subdural space' is more accurately described as an intrameningeal plane.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.