Tunnels and grooves for supraclavicular nerves within the clavicle: review of the literature and clinical impact

Perforation of the clavicle by supraclavicular nerves is a common anatomical variation. This variation has been reported in several studies based on post-mortem, surgical and radiologic findings, with an overall frequency between 1 and 6.6 %. The penetrating branch passes either through a bony tunnel or a groove on the superior surface of the bone. Entrapment neuropathy of the perforating branch is a documented clinical entity reported in the literature. The intraosseous course of the supraclavicular nerves makes them vulnerable to injury in case of clavicular fractures or during surgical manipulations of these fractures. Furthermore, this variation should be taken into account during the interpretation of chest and shoulder radiographs. The purpose of the current study is to perform an extended review of the relevant literature, highlighting the clinical impact of this variation, as well as to incorporate our own findings into them.