Background: A thorough understanding of the topographical anatomy of the spinal accessory nerve and the cervical plexus branches is a basic prerequisite for positive results when operating on the neck. Objective: To give an exact description of the topographical and surgical anatomy of the spinal accessory nerve (SAN) and the trapezius branches of the cervical plexus. Design: Anatomic analysis of the SAN and the trapezius branches of the cervical plexus. Setting: The topographical anatomy of the SAN and the cervical plexus branches were studied in the anterior and posterior triangles of the necks of 46 perfusion-fixed human cadavers of both sexes, which ranged in age from 55 to 97 years (mean age, 83 years). Results: The SAN can be identified on the posterior border of the sternocleidomastoid (SCM) muscle, 8.2±1.01 cm cranial to the clavicle. In 37% of cases, the SAN enters the posterior triangle of the neck dorsal to

The data presented in previous literature is well correlated with our own morphologic findings. In comparison of the different techniques applied with the assumptions drawn on the basis of our own anatomic findings, it becomes evident that the SCM flap is only a useful tool in limited indications and under certain precautions.

Our results, especially those involving the descending part of the trapezius muscle, may help to minimize the rate of unexpected trapezius muscle paresis after surgery of the neck.

Background:The knowledge of the exact anatomy of the sternocleidomastoid (SCM) muscle and its nerve and blood supply must be considered a basic prerequisite for its use as a pedicle muscle flap.Objective: To give an exact description of the courses and variability of all vessels supplying the SCM muscle.Design: Anatomic analysis of all arteries supplying the SCM muscle. Setting:The blood supply of the SCM muscle was studied by dissecting bilaterally the anterior regions of the neck of 31 perfusion-fixed human cadavers of both sexes aged 50 to 94 years (mean, 78 years). Results:The blood supply to the SCM muscle can be divided into 3 parts: upper, middle, and lower. The upper third of the SCM muscle was found to be constantly

The results strongly support recent anatomical findings showing that, functionally, the most important descending part of the trapezius muscle is innervated by a fine single branch arising from the spinal accessory nerve in the posterior triangle of the neck. This may help to prevent more patients undergoing modified radical neck dissections from shoulder-arm syndrome.