Variation of prevertebral musculature in cadaveric studies

Background: This case report documents muscular variation observed in a detailed dissection of the prevertebral region of multiple cadavers. The prevertebral region contains the muscles lying between the prevertebral layer of cervical fascia and the vertebral column. The deep location of these muscles means that they are often understudied during routine dissections. The prevertebral muscles lie in close proximity to numerous important neurologic and vascular structures, including the contents of the carotid sheath and the jugular foramen. The rectus capitis lateralis muscle, in particular, is used as a landmark in the microsurgical anatomy in certain extracranial approaches to the jugular foramen. The anatomical variations described in this report have little previous documentation in the literature, and their characterization here adds to the current understanding of variation in the region and its impact on surgical anatomy. Case Information: Detailed dissection of the prevertebral region of multiple embalmed cadavers revealed differing variations in the muscular anatomy. One such variation involved accessory muscles running in superolateral fashion over the anterior portion of the transverse processes of the atlas bilaterally. Conclusions: The muscular variation detailed in this report has implications in surgical approaches to surrounding structures, including the jugular foramen and its contents. Various approaches rely on specific landmarks, which have the possibility to be mistaken or obscured by anatomic variation in the region. Continued study and reporting of variation discovered in the prevertebral region can help characterize common deviations from normal anatomy and aid in surgical planning.