Musculus trapezius

Musculus Trapezius is a large, superficial muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae and laterally to the spine of the scapula. Its functions include moving, rotating, and stabilizing the scapula, a bone that connects the upper arm bone with the collarbone.

Anatomy

The musculus trapezius is broad and triangularly shaped, with the muscle fibers running in three different directions. The upper fibers, or the descending part, runs downward and laterally and are involved in scapular elevation. The middle fibers, or the transverse part, run horizontally and are involved in scapular retraction. The lower fibers, or the ascending part, run upward and medially and are involved in scapular depression.

Function

The musculus trapezius has several functions. It supports the arm and is also involved in a variety of movements of the scapula, including elevation, retraction, and rotation. The upper and lower fibers also work in tandem to cause upward rotation of the scapula, such as when carrying a heavy object on the shoulder.

Clinical Significance

Due to its superficial location, the musculus trapezius is prone to injury. Trapezius strain is a common condition characterized by pain and stiffness in the neck, shoulder, and upper back. It can be caused by a variety of factors, including poor posture, overuse, and stress.

See Also

• Scapula
• Muscle strain
• Posture