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The trapezius [4] is a large paired trapezoid-shaped surface muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae of the spine and laterally to the spine of the scapula. It moves the scapula and supports the arm. The trapezius has three functional parts: an upper (descending) part which supports the weight ...
The trapezius muscle controls the action of shrugging the shoulders, and the sternocleidomastoid the action of turning the head. [8] Like most muscles, control of the trapezius muscle arises from the opposite side of the brain. [8] Contraction of the upper part of the trapezius muscle elevates the scapula. [13]
There are several options of treatment when iatrogenic (i.e., caused by the surgeon) spinal accessory nerve damage is noted during surgery. For example, during a functional neck dissection that injures the spinal accessory nerve, injury prompts the surgeon to cautiously preserve branches of C2, C3, and C4 spinal nerves that provide supplemental innervation to the trapezius muscle. [3]
trapezius, descending part Upper limb, Vertebral column, Right/Left down midline, external occipital protuberance, nuchal ligament, medial part of superior nuchal line, spinous processes of vertebrae C7-T12: at shoulders, lateral third of clavicle, acromion of scapula, spine of scapula: transverse cervical artery: motor: accessory nerve [CNXI]
Secondary to serratus anterior palsy, a winged scapula is also caused by trapezius and rhomboid muscle palsy involving the accessory nerve and the dorsal scapular nerve, respectively. [ 1 ] Though the most common causes of a winged scapula is due to serratus anterior palsy, and less commonly trapezius and rhomboid palsy, there are still other ...
Compression of a trigger point may elicit local tenderness, referred pain, or local twitch response. The local twitch response is not the same as a muscle spasm. This is because a muscle spasm refers to the entire muscle contracting whereas the local twitch response also refers to the entire muscle but only involves a small twitch, no contraction.
Fasciculations arise as a result of spontaneous depolarization of a lower motor neuron leading to the synchronous contraction of all the skeletal muscle fibers within a single motor unit. An example of normal spontaneous depolarization is the constant contractions of cardiac muscle, causing the heart to beat. Usually, intentional movement of ...
Downward rotation would be prevented by co-contraction of other muscles that elevate the spine, the upper fibers of the trapezius, which is an upward rotator. When the shoulder is fixed, levator scapulae rotates to the same side and flexes the cervical spine laterally.