Dangerous layer of scalp:

173. Ans. (c) Loose subaponeurotic layerRef: BDC 6th ed. Vol-III/61-63The 5 layers of scalp can be remembered as SCALP:* Skin: consist of hair follicles, sebaceous gland and sweat glands.* Sub Cutaneous layer: contains blood vessels, nerves of the scalp* Aponeurotic layer aka galea aponeurotica It is a tough layer of dense fibrous tissue which runs from the frontalis muscle anteriorly to the occipitalis posteriorly* Loose subaponeurotic tissue containing the emissary veins and allowing free movement of layers 1 to 3 as a unit. Layer 4 is a "dangerous area" because it allows spread of infection even, by way of the emissary veins, to intracranial structures.* Pericranium, is the periosteum of the skull bones providing nutrition.