Human Anatomy

Trapezius

A large, triangular muscle that extends from the back of the neck to the middle of the back and creates a triangular shape.

The trapezius is a major muscle of the upper back and neck, known for its trapezoidal shape. It consists of three distinct parts: the upper fibers, which elevate the shoulders; the middle fibers, which retract the shoulder blades; and the lower fibers, which help in depressing the shoulders. This muscle plays an essential role in various shoulder and neck movements due to its broad attachment points.

Terminologia Anatomica

musculus trapezius

System

Musculoskeletal system

Function

The trapezius muscle is crucial for many movements involving the shoulder girdle and neck. It is responsible for the elevation, retraction, and rotation of the scapula, thereby aiding in the lifting of the shoulders and allowing for arm movements above the head. The upper fibers help in shrugging the shoulders, while the middle fibers pull the shoulder blades together, allowing for actions like pulling or rowing. The lower fibers assist in lowering the shoulder blades and facilitating movements such as reaching behind the back. In addition to its mechanical functions, the trapezius also plays a role in maintaining posture and stabilizing the head and neck during various activities.

Location

The trapezius muscle spans a considerable area of the upper body, originating from the external occipital protuberance and the nuchal ligament at the base of the skull, extending down to the seventh cervical vertebra and all thoracic vertebrae in the spine. The muscles then insert onto the lateral third of the clavicle, the acromion process of the scapula, and the spine of the scapula. This extensive coverage enables the trapezius to control and coordinate movements across the neck and shoulders. It forms a prominent part of the upper back and can be easily palpated, especially when individuals lift their shoulders or perform shoulder-related activities.

Did You Know?

The trapezius muscle is not solely responsible for upper back movement; it also plays a role in stabilizing the head, allowing for efficient neck movement.
The trapezius muscle is often one of the most prominent muscles in individuals who engage in weightlifting or certain sports, due to its involvement in strength training exercises.
In some individuals, muscle tension in the trapezius can lead to tension headaches, showcasing the connection between muscle health and overall well-being.