The effects of single forearm arterial injuries with and without associated neurological injuries were studied. Fifty subjects were evaluated: seven patients with isolated arterial lacerations, 15 patients with isolated nerve lacerations, 13 patients with combined nerve and arterial injuries, and 15 control subjects. A series of noninvasive peripheral vascular studies were correlated with the symptoms produced by a controlled cold-environment exposure. The hemodynamic alterations associated with symptoms of hand ischemia, and particularly with cold intolerance, were studied. Unrepaired single arterial injuries caused modest, consistent alterations in hand vascularity, but few signs of ischemia or symptoms of cold intolerance. The remaining intact artery demonstrated a consistent increase inflow velocity. Combined nerve and artery injuries caused the most significant alterations in hand vascularity, and median nerve and associated artery injuries caused the most disabling symptoms. Single arterial lacerations had no effect on the rate or completeness of recovery from associated nerve injuries.