ANATOMY OF THE NUCHAL LIGAMENT AND ITS SURGICAL APPLICATIONS

Abstract

Although considered a basic maneuver for neurosurgical procedures, dissection of the musculature of the posterior cervical spine can be a source of complications during surgery. These complications include excessive blood loss, a loss of the plane of dissection, and injury to important structures such as the vertebral artery and nerve roots. Inappropriate closing of the muscular plane might also contribute to leakage of spinal fluid and postoperative deformation of the cervical spine. We review the anatomy of the nuchal ligament and describe a technical nuance based on the characteristics of the ligament's components, which can be used to assure the midline for a bloodless and atraumatic dissection. We set out to determine whether or not the nuchal ligament could be used as a natural plane of dissection for splitting the posterior cervical musculature. We studied the anatomy of the nuchal ligament in five cadavers. The nuchal ligament extends from the external occipital protuberance to the spinous process of the seventh cervical vertebra (C7). It is covered by layers of cervical fascia and the aponeurosis of the trapezius muscle. It is composed of two portions: 1) the lamellar portion, an anterior double-layered portion with fatty areolar tissue interposed between its layers that inserts into the medial side of the bifid spinous process of the cervical vertebra; and 2) the funicular portion, a posterior fibrous portion that corresponds to the fusion of the layers of the lamellar portion. Several steps can assure that the midline plane is respected, thereby decreasing risk and reducing trauma and blood loss during dissection: 1) dissection of the nuchal ligament within the fatty areolar tissue of the lamellar portion, 2) isolation and incision of the funicular portion from inside to outside, and 3) retrograde dissection of the cerviconuchal muscles attached to the occipital bone in a subperiosteal plane.