Trapezius muscle :-
Muscle details :-
- The trapezius (or trapezoid) is a large paired 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.
- medial one – third of superior nuchal line .
– external occipital protuberance .
– ligamentum nuchae .
– t1 – t12 spines .
– corresponding supraspinous ligaments .
- upper fiber into the posterior border of lateral one – third of clavicle .
– middle fibres , into the medial margin of the acromion and upper lip of the crest of spine of the scapula .
– lower fibers , on the deltoid tubercle at the spine , with a bursa intervening .
Nerve supply :-
- spine part of accessory nerve is motor .
– branches from c3,c4 are proprioceptive .
- Upper fibers of trapezius elevate the scapula and rotate during abduction of the arm.
- The middle fibers trapezius retract the scapula
- The lower fibers trapezius pull the scapula inferiorly.