Applied anatomy study of C2 nerve root and its surrounding venous plexus

Abstract

Objective To study the anatomical structure of cervical 2 nerve root and its surrounding venous plexus at the lateral joint of atlantoaxial joint, and to explore the optimal operation mode of atlantoaxial dislocation and fixation with cervical screws. Methods Six adult head and neck specimens were perfused. The bilateral C2 nerve roots and their surrounding venous plexuses were dissected and observed under microscope. Measurement and analysis of related anatomical structures were performed. Results Atlantoaxial lateral posterior joint was rich in venous plexus. The medial part of the venous plexus covered the normal dura mater and had a clear membrane boundary. The C2 nerve root coursed inside the venous plexus from the medial superior side towards lateral inferior direction. The total width of the plexus was 21.1±2.1 mm. The distance from the medial border of the venous plexus to the posterior median line was 5.7±1.3 mm. After sufficient dissection of plexus from the dura mater, the distance was increased to 14.1±1.0 mm. The distance from the middle line of C2 pedicle to the lateral and median side of venous plexus was 10.7±2.1 mm and 5.9±1.2 mm, respectively. The upper and lower distances between C2 nerve root and lateral margin of plexus were 6.3±1.3 mm and 2.6±0.6 mm, respectively. Atlantoaxial lateral facet joint was exposed after cleaning of venous plexus and dissection of C2 nerve root. The height and width of exposed C1 lateral joint were 6.6±0.3 mm and 13.7±0.5 mm, respectively. The height of exposed superior articular process of C2 was 4.9±0.3 mm, and the width of C2 pedicle was 8.2±0.3 mm. Conclusions It is of significance in instructing surgical operations to clearly understand the anatomy of C2 nerve root and its surrounding venous plexus. During implantation of C1 lateral mass screw and C2 pedicle screw, the incision along the middle line of C2 pedicle to dissect the C2 nerve root could provide maximal exposure and help reduce venous bleeding. Key words: C2 nervous root; Venous plexus; C1/2 lateral facet; Anatomy