Danger area of scalp: is the layer of Loose areolar tissue of scalp because emissary veins open here which may transmit infection to venous sinuses. Layer ‘C’ (connective tissue layer) is richly vascularised but layer ‘L’ is danger zone as the blood collects here.
Danger area in eye: Ciliary body
Danger area in nose: Olfactory area
Danger area in face: Infection of the lower part of nose and upper lip may be transmitted to cavernous sinus by facial vein & its communications (superior ophthalmic vein and deep facial vein).
Danger space in neck: Space 4 of Grodonsky and Holyoke. It lies in front of prevertebral space and alar fascia.