The musculus scalenus medius, commonly known as the middle scalene muscle, is a slender muscle located in the neck region. It is one of the three scalene muscles, situated between the anterior scalene and the posterior scalene muscles.
The musculus scalenus medius originates from the transverse processes of the cervical vertebrae, specifically from the posterior tubercles of the fifth, sixth, seventh, and sometimes the first thoracic vertebra. It then courses downward and laterally, inserting onto the first rib.
This muscle is characterized by its triangular shape, with its apex attaching to the first rib and its base extending upward. The musculus scalenus medius contributes to various movements and functions in the neck and upper limb region. It acts to elevate the first rib during inspiration, aiding in the expansion of the thoracic cavity.
Additionally, the musculus scalenus medius assists in bending the neck laterally when acting individually, and when contracted bilaterally, it helps in extending the cervical spine. This muscle also plays a role in stabilizing and supporting the neck during movements involving lifting and carrying heavy objects.
In summary, the musculus scalenus medius is a slender triangular muscle located in the neck region that functions in elevating the first rib, aiding in neck movements, and providing stabilization for the upper limb area.
