The musculus scalenus posterior, also known as the posterior scalene muscle, is a triangular-shaped muscle located in the neck region. It is one of three scalene muscles, alongside the musculus scalenus anterior and medius.
Originating from the posterior tubercles of the transverse processes of the cervical vertebrae (C5-C7), the musculus scalenus posterior inserts onto the second rib. It runs diagonally across the posterior compartment of the neck, extending obliquely upward and laterally.
This muscle plays a crucial role in various movements and functions. It acts to elevate the second rib during deep inhalation, contributing to the expansion of the thoracic cavity. Additionally, it works synergistically with other muscles to facilitate lateral bending and rotation of the neck.
The musculus scalenus posterior receives innervation from the ventral rami of the cervical nerves (C5-C7). Alongside the surrounding scalene muscles, it also assists in stabilizing the neck and maintaining its proper alignment.
Pathologies associated with the musculus scalenus posterior include overuse injuries, nerve entrapment syndromes (such as thoracic outlet syndrome), and muscle spasms. These conditions can cause pain, restricted range of motion, and other discomforts in the neck, shoulder, and arm.
Understanding the anatomy and function of the musculus scalenus posterior is essential in diagnosing and treating various neck-related conditions and in maintaining overall musculoskeletal health.
