Experimental study of traumatic cerebral vascular spasm

Apparent narrowing of cerebral vessels in arterio-grams after subarachnoid haemorrhage of aneurys-mal origin had been described by many authors. It has been accepted by most neurosurgeons as indicating spasm of the vessels secondary to sub-arachnoid haemorrhage, and there has been much discussion about the nature and mechanism of origin of this vascular spasm. In experimental con-ditions, narrowing of cerebral vessels in response to trauma or other forms of stimulation has been produced in cat pial vessels (Echlin, 1942; Lende, 1960) and in primate vessels in the circle of Willi