Trapezius muscle

Trapezius muscle
Trapezius muscle
origin
Protuberantia occipitalis externa , neck ligament , spinous processes of the cervical and thoracic vertebrae
approach
Collarbone ( clavicle ), shoulder blade ( acromion and spina scapulae )
function
Movement of the shoulder blade (scapula) : lifting (supports elevation), lowering, rotation in the medial direction and retraction in the dorsal direction Lateral flexion of the neck in a contralateral direction (on one side) , dorsiflexion of the neck (on both sides) Retraction of the clavicle in a dorsal direction
Innervation
Accessor nerve and branches of the cervical plexus
Spinal segments
C2-C4

The trapezius muscle ( lat. Musculus "muscle"; trapezius "trapezoidal") or trapezoid muscle is a muscle that is present on both sides of the upper spine and extends from the occiput to the lower thoracic vertebrae and laterally to the shoulder blade .

Because of its location in the neck area , it is also called the hood muscle or cap muscle . It owes its name as trapezius to the fact that the two triangular individual muscles together form a square . " Trapeze " is to be understood here in a generalized sense of "square", according to the ancient Greek etymology: τράπεζα trápeza is originally a "table with four feet".

Shares

In humans, the muscle consists of three parts:

• The pars descendens (Latin for "descending part") is the part above the shoulder blade ("upper hood muscle").
  Origin: occiput , neck ligament and cervical vertebra , attachment: lateral third of the collarbone .
  Function: turns your head, lifts your shoulders.
• The pars transversa (Latin for "crossing part") is the part between the thoracic vertebrae and the shoulder joint ("middle hood muscle").
  Origin: 7th cervical vertebra to 3rd thoracic vertebra , insertion: acromion .
  Function: contracts the shoulders.
• The pars ascendens (Latin for "ascending part") is the part below the shoulder blade ("lower hood muscle").
  Origin: 4th to 12th thoracic vertebrae, insertion: spina scapulae .
  Function: lowers the shoulders.

In animal anatomy, a distinction is made between a pars cervicalis (neck part) and a pars thoracica (chest part).

function

The three parts of the trapezius muscle are responsible for different movements. The descending and ascending parts turn the shoulder blade to the side and up, which allows the arm to be raised above the horizontal. The descending part alone turns the shoulder blade upwards. The pars transversa turns the shoulder blade towards the middle when it acts alone. All three parts together turn the head and cervical spine to the opposite side with one-sided action, with both-sided action the cervical spine is stretched.

clinic

In the case of paralysis of the trapezius muscle , the affected shoulder stands a little forward and lower. The middle edge of the shoulder blade ( Margo medialis scapulae ) protrudes obliquely from the top outside to the bottom from the back. If the arm is raised to the side, it cannot be brought horizontally. The hold of the shoulder blade on the spine is severely weakened and no longer secured.

Varieties

Occasionally the trapezius muscle can grow together with the sternocleidomastoideus muscle . This adhesion is explained by the joint attachment of the muscles, which are therefore both supplied by the eleventh cranial nerve ( accessory nerve ). The triangular gap between the trapezius muscle and the sternocleidomastoideus muscle , the lateral cervical triangle ( regio cervicalis lateralis ), is only created when the common muscle anus is separated.

Web links

Commons : Trapezius muscle  - Collection of images, videos and audio files

Individual evidence

1. ↑ U. Bommas-Ebert et al .: Short textbook anatomy and embryology. Thieme, 2011, p. 89
2. ↑ L. Richard Drake et al .: Gray's Anatomy for Students with Studentconsult Access . Elsevier, Urban & Fischer Verlag, 2007, pp. 51–52. ISBN 978-3-437-41231-8