Skin landmarks to main cerebral structures: how to identify the main cerebral sulci? An anatomical study.

Abstract

Neuronavigation is used in neurosurgical practice to locate the cortical structures. If this tool is unavailable, basic anatomical knowledge should be used. Craniometry has been rarely detailed in recent literature, systematically using bony landmarks. The aim of this study is to describe skin landmarks for neurosurgical practice. Dissection of 10 hemispheres with insertion of radio-opaque markers within the limits of lateral sulcus, central and pre-central sulci, and preoccipital notch. Computed tomography was performed in all cases and multiplanar reconstructions were performed. Maximal intensity projection (MIP) fusion images were used for measurements between known skin landmarks and sulci of interests. The Anterior Sylvian Point is measured 31.8 ± 2.8mm behind the orbital wall, 36.9 ± 3mm above the zygomatic arch. The horizontal part of the lateral sulcus is measured 59 ± 6mm above the tragus. The Superior Rolandic Point is measured 190.7 ± 4.5mm behind the nasion. The Pre-occipital Notch is measured 37.0 ± 6.9mm above the tragus and 67.1 ± 6.4mm behind. The Ideal Entry Points (IEP) for ventricular punctures are measured 120.2 ± 7mm behind the nasion and 33.8 ± 3mm laterally for the frontal IEP, and 61.3mm ± 2.5mm above and 64.7 ± 6.8mm behind the tragus for the parieto-occipital IEP. In this study, we described simple skin landmarks for lateral sulcus, central sulcus, preoccipital notch, and an IEP for ventricular drainage. Precise knowledge of brain sulcal anatomy will guide patient's positioning, skin incision, and craniotomies; and permits checking of imaging data provided by neuronavigation systems.