Scalp thickness in the temporal region: its relevance to the development of cochlear implants

The thickness of the scalp in the temporal region was measured at two representative points: point 1, over the most laterally prominent part of the mastoid process: and point 2, at the horizontal level of the upper border of the orbit, vertically in line with point 1. Measurements were made directly at autopsy in four patients, then in 50 live patients by magnetic resonance imaging (MRI). The relevance of the methodology and of these measurements to cochlear implant development is discussed. As the term 'scalp' usually includes the periosteum of the skull, the authors have used the term 'scalp' to include the range from the surface of the scalp to the bone shadow as seen on MRI, and the term 'skin' where, at autopsy, the skin is lifted leaving the periosteum intact.