Anatomy & Organs

Trapezius muscle – structure, function & diseases

Trapezius muscle

The trapezius muscle , the trapezius muscle , is also known as the hood muscle due to its location and anatomical shape . It consists of three parts in total.

What is the trapezius muscle?

The trapezius muscle (musculus trapezius) is located in the area of ​​the neck and upper back . It is divided into three different sections, each with a different function. Paralysis of the trapezius muscle leads to shoulder tilt and pain . Various movements are also no longer possible with paralysis of the trapezius muscle.

Anatomy & Structure

The human trapezius muscle consists of three parts. The descending part (pars descendens) is above the scapula . This part of the trapezius muscle originates from the occipital bone (Os occipitale) and the neck ligament.The nuchal ligament is a paired ligament that runs from the occiput to the spinous process of the seventh cervical vertebra. The upper cervical vertebrae also serve as the point of origin for the pars descendens of the trapezius muscle. This part of the muscle attaches to the lateral third of the collarbone . The pars transverse, the crossing part of the trapezius muscle, is located between the thoracic vertebrae and is called the middle trapezius muscle. Origin is the seventh cervical vertebra and the first three vertebrae of the thoracic spine. Muscle attachment is the acromion. The acromion is also known as the fish bone. It forms the highest point of the shoulder blade in humans.

The third part of the trapezius muscle is the ascending part. This ascending part is below the shoulder blade. The lower trapezius muscle originates from the fourth to twelve thoracic vertebrae. The starting point, however, is the spina scapulae. The spina scapulae is the shoulder bone that runs across the dorsal surface of the scapula and divides the scapula into the infraspinous and supraspinous fossa. Occasionally the trapezius muscle is also fused with the sternocleidomastoid muscle.

This muscle is also known as the head nod or head turner. It is located between the breastbone , collarbone and base of the skull . Both muscles develop from a common system and are also supplied by the same nerve (Nervus accessorius). The typical lateral cervical triangle (Regio cervicalis lateralis) is only formed when the joint system of the muscles is separated.

Function & Tasks

The individual sections of the trapezius muscle have almost opposite directions of action, so that the muscle can fulfill different functions. The pars descendens, the descending part, is responsible for turning the head. Raising the shoulders is also part of the task of this muscle section. The pars descendens is mainly trained during strength training and bodybuilding. A well-trained descending part of the trapezius muscle means that the shoulders remain stable and do not sag even when carrying heavy loads.

A contraction of the middle trapezius muscle (pars transversea) leads to contraction of the shoulders by contraction of the shoulder blades. The pars ascendens, i.e. the ascending part of the trapezius muscle, lowers the shoulders. It is also possible to raise the torso with fixed arms thanks to the ascending trapezius muscle.

Diseases

Pain in the neck and upper back is often due to a tightening of the trapezius muscle. The most common cause of this tension is sitting for long periods in unergonomic postures. Impairments of the trapezius muscle are particularly common in people who work a lot on the computer or often sit at a desk.An unfavorable sleeping position, incorrect posture and heavy strain during sports can also lead to tension in the trapezius muscle area. It is not uncommon for mental stress and psychosomatic causes to cause tension and muscle hardening . Another risk factor for trapezius muscle tension is shoulder bags. Anyone who carries bags on one shoulder often pulls up the affected shoulder so that the strap of the bag does not slip off the shoulder. As a result, one half of the pars descendens works permanently, so that tension can quickly arise.

Impairments of the trapezius muscle are expressed by pain in the neck area, pain in the upper back and shoulders and often also by headaches . The muscles tire quickly, so raising your arms or shoulders is only possible for a short period of time. Sooner or later, the constant tension also leads to signs of wear and tear in the cervical and thoracic spine. The vertebrae, the intervertebral joints and the intervertebral discs are particularly affected. One possible consequence is acute or chronic neck-arm or shoulder-arm syndrome. In the vernacular, these phenomena are also known as lumbago.

If the impairment of the trapezius muscle appears as a head-and-neck syndrome, symptoms such as dizziness , flickering eyes and ringing in the ears are also possible. The so-called cervical cord syndrome develops less frequently. Due to the degenerative changes resulting from the tension in the trapezius muscle, the intervertebral disc in the area of ​​the cervical spine protrudes. This narrows the spinal canal and presses the cervical cord. An acute contusion can lead to paralysis of the arms and legs. However, it is rather rare. More often, the damage develops more slowly. Gait disturbances, tingling and disturbances of fine motor movements are typical.

When the trapezius muscle is paralyzed by an illness, this paralysis is reflected in a depression in the affected shoulder. The middle edge of the shoulder blade stands out obliquely and points from the top outside inwards below. If the arm is to be raised to the side, this is only possible for a small section. Raising to the horizontal is not possible. The attachment of the shoulder blade to the spine is also severely impaired.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.