Pain - Claudication or pain with leg elevation; typically earliest sign
Paraesthesia - May be associated with weakness; preservation of light touch is good guide to viability
Pallor
Paralysis
Pulselessness - May be accompanied by skin changes; late finding
Poikilothermia - Limb is cool to touch when compared to other side; late finding
Acute arterial ischemia
Peripheral artery disease
Venous gangrene
Vascular injury
Wet gangrene
Missile embolus
Atheroembolism 
Dry gangrene