Vascular arrangements allowing a bulky transfer of venous blood from the skin of the head and from nasal and paranasal mucous membranes to the dura matter provide an excellent anatomical basis for the convection process of cooling, caused by evaporation of sweat or mucus. The dura mater, with its extraordinarily high vascularization controlled by a potent vasomotor apparatus, may transmit temperature changes to the cerebrospinal fluid (CSF) compartment. Temperature gradients of the CSF may in turn influence the temperature of brain parenchyma (1) directly, along the extensive contact area between the cerebrocortical surface and the CSF-compartment, or (2) indirectly, via brain arteries that extend over long distances and arborize within the subarachnoid space before entering the pial vascular network and brain parenchyma. Numerous subarachnoid and pial arterial branches exposed to the CSF have diameters in the range of the vessels of the retia mirabilia of animals in which selective brain cooling has been clearly established experimentally. It is also shown that the arrangements of venous plexuses within the vertebral canal provide anatomical preconditions for a cooling of the spinal cord via the CSF. The possibility of spinal cord and spinal ganglia cooling by temperature convection via venous blood--cooled in the venous networks of the skin of the back--flowing through numerous anastomoses to the external and internal vertebral plexuses and, finally, into the vascular bed of the spinal dura is discussed on the basis of anatomical facts.

With increased use of anticoagulant agents, femoral neuropathy subsequent to hemorrhage within the iliacus muscle has become a frequent clinical problem. The mechanism for this type of femoral nerve palsy was studied in dissections of the iliac region and by injections of latex into fascial planes in that area. In most dissections, up to four fascial layers, parallel to the iliacus sheath, could be identified. Variable states of fusion of these layers often produced up to three pouches, separated by loose connective tissue or fat. These fasciae (called "lamina peritonealis," "lamina transversalis," "lamina preiliaca," and "lamina iliaca") appear to be variable adult remnants of distinct fascial layers present in the posterior abdominal wall during embryological development, and serve to strengthen the intrinsic fascia of the iliacus muscle. Latex injected into the iliacus sheath spread from the midlumbar region to the femoral triangle, surrounding, compressing, and stretching the femoral nerve in different parts of its course. These observations suggest an anatomical basis for femoral nerve palsy during iliacus hematoma.

Sagittal sections of anatomic specimens and magnetic resonance images well display the individual gyri and sulci along the low-middle convexity. Those familiar with the typical pattern and with the common normal variations will be able to use sagittal magnetic resonance imaging to correctly localize lesions by identifying: (a) the five major rami of the sylvian fissure; (b) the subdivision of the triangular inferior frontal gyrus into the M-shaped partes orbitalis, triangularis, and opercularis by the anterior horizontal and anterior ascending rami of the sylvian fissure; (c) the zig-zag shape of the middle frontal gyrus, which characteristically angles sharply and inferiorly to fuse with the anterior surface of the precentral gyrus; (d) T-shaped bifurcation of the posterior end of the inferior frontal sulcus to form the inferior precentral sulcus; (e) separation of the central sulcus from the sylvian fissure by union of the opercular ends of the precentral and postcentral gyri to form the subcentral gyrus inferior to the central sulcus; (f) narrower sagittal dimension of the postcentral gyrus than the precentral gyrus; (g) horseshoe shape of the supramarginal gyrus perched atop the posterior ascending ramus of the sylvian fissure; (h) similar horseshoe shape of the angular gyrus perched atop the posterior end of the superior temporal sulcus; (i) commonly intercalated accessory presupramarginal and preangular gyri; and (j) the arcuate course of the intraparietal sulcus, which separates the superior from the inferior parietal lobules. The anatomic relationships described are more nearly constant anteriorly than posteriorly. When used as described, they prove helpful in correctly localizing pathology and in planning a surgical approach to lesions that may be difficult to localize on the basis of axial or coronal plane magnetic resonance images.