Stefan Kubik

An atlas devoted exclusively to the anatomical descriptions and relationships of the cortical sulci has not previously been published. Ostensibly, it would seem an insurmountable task to classify the myriad sulcal patterns that exist upon the cortical surface. However, basic recurring themes can be identified in general terms, and trends in individual variabilities can be categorized...Chad D. Abernathey, M.D.</p

The pterional craniotomy as described previously by the first author requires creation of a special flap over the temporalis muscle for increased visibility. Topographical variations of the course taken by the frontal branches of the facial nerve were studied and are described in this report.

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.

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.