The authors have studied the microvascularization of the intracranial dura mater by microradiographic and histologic examination of 73 injected anatomic specimens. There exists a very abundant superficial arterial plexus which also serves to supply the inner table of the cranial vault. This plexus is continuous, even at the walls of the venous sinuses and the dural septa. The arteries are for the most part tortuous. The veins may be satellites of the arteries or, on the contrary, from a plexiform network passing through crevices in the interior of the dural layer. The walls of these veins consist only of an endothelium to be seen within the fibrous layer of the dura. Often, the arteries compress the venous lumen; this dangerous situation probably explains the frequent occurrence of arteriovenous fistulae of the dura mater, known by the name of dural fistulae.

Most intra-cranial arachnoid cysts are quiescent and remain asymptomatic throughout life. Within the natural course of arachnoid cyst evolution, spontaneous resolution has been known to occur rarely, but its frequency is probably underestimated due to lack of systematic detection and long-term observation. We illustrate the spontaneous regression of arachnoid cysts with a patient which was conjointly diagnosed with an arachnoid cyst and a post-traumatic epidural haematoma. Cyst regression was observed 16 months later, upon examination following a second benign cranial trauma. Mechanisms underlying the resolution of the arachnoid cyst are discussed.

The authors report the case of a 39-year-old man with a common origin of three arteries-the celiac, superior mesenteric, and inferior mesenteric arteries-that has not been described previously in the literature, to their knowledge. This variant, which they call the celiac-bimesenteric trunk, is documented with a selective angiogram, and an embryologic explanation is offered.

Two uncommon anatomical variations of the left renal vein were found on dissected specimens: a circumaortic venous ring and a retro-aortic bifid left renal vein. The first anomaly results from a persistence of the embryonic renal venous collar. The second one would be related to a particular pattern of left inferior vena cava. Both abnormalities have to be known for they may be undetected or be misleading in imaging. Other clinical implications are also considered.

We report a case of vertebral malformation associated with diplomyelia believed to be a type II split cord malformation. Cervicothoracic level cases are exceptional. This article reports the case of an 11-year-old boy with no neurological symptoms who had not undergone surgery. The diagnosis was made during pregnancy by prenatal screening with ultrasound and MRI. Several embryological theories have been offered to provide an explanation for this syndrome. Close follow-up is mandatory. Surgery must only be considered if neurological deterioration occurs.