The aim of this study is to determine the innervation characteristics and nerve entry points of the musculus semispinalis capitis. This muscle, which is involved in the extension of the head and neck, is a large and long cervico-thoracic muscle innervated by the dorsal rami of the cervical spinal nerves. The study seeks to enhance the effectiveness of procedures like electromyography (EMG) electrode placement and botulinum toxin injections used for diagnosing and treating conditions related to head and neck pain.

Accurately identifying these nerve entry points is crucial for ensuring the safety and efficacy of treatments, particularly for conditions like cervical dystonia and headaches. While existing studies have focused on the innervation and nerve mapping of various muscles, there has been no specific research on the nerve entry points of the musculus semispinalis capitis. This study aims to provide detailed knowledge of these aspects, offering valuable guidance for interventions in this area.

The musculus semispinalis capitis, one of the cervical paraspinal muscles, originates from the transverse processes of the last cervical and the first six to seven thoracic vertebrae. It extends upward along both sides of the posterior midline and inserts between the superior and inferior nuchal lines on the occipital bone. This muscle is innervated by the dorsal rami of the cervical spinal nerves. As a large and long cervico-thoracic muscle, its primary function is the extension of the head and neck.

The aim of this study is to determine the innervation characteristics and nerve entry points of the musculus semispinalis capitis to enhance the effectiveness of procedures such as the placement of electromyography (EMG) electrodes for diagnostic and therapeutic purposes, as well as botulinum toxin injections used for treating conditions associated with head and neck pain.

The innervation characteristics and nerve entry points of the musculus semispinalis capitis need to be precisely identified, particularly in relation to treatments such as botulinum toxin injections for the management of spasms and pain in conditions like cervical dystonia, and for the treatment of headaches. Accurate identification of these points is crucial for ensuring safe and effective injections in this region and for understanding the anatomical variations in the area.

While there are studies in the literature focusing on the innervation characteristics and nerve entry points of various muscles, as well as nerve mapping, there has been no specific research on nerve entry point mapping for the musculus semispinalis capitis. Conducting this study will establish a detailed understanding of the innervation characteristics and nerve entry points of this muscle, providing valuable guidance for interventions in this area.

Previous studies on deep neck muscles have shown that procedures such as injections and EMG measurements have generally been performed using approximate localization methods. This study aims to use the results obtained to make these procedures more effective and less invasive.

Inclusion Criteria:

• Cadavers were preserved using a 10% formalin solution.

Exclusion Criteria:

• neck and back region curvature,
• neck flexion and extension,
• related region muscle or nerve pathology,
• fracture,
• cadavers that have undergone previous surgery

The study was conducted using 10 adult male cadavers, aged between 45 and 75 years, that had been fixed in 10% formalin solution. These cadavers were sourced from the laboratory of the Department of Anatomy at Ege University Faculty of Medicine.