Trapezius Muscle
Trapezius is a term derived from English word (“trapezium: a diamond shaped quadrilateral”). It’s the superficial skeletal muscle extending from upper back of the neck to the lower thoracic vertebrae. The word spinotrapezius refers to the human trapezius muscle although it’s not commonly used in modern texts. It moves scapulae and supports the arm.
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Trapezius Muscle
It can be divided into three main parts arising from three different sites Superior, upper or descending fibers arising from external occipital protuberance, medial third of superior nuchal lines and ligamentum nuchae. Middle or transverse fibers arise from spinous process last cervical and spinous process of 1st 2nd and 3rd thoracic vertebrae. Inferior ascending part arises from the T4-T12 vertebrae.
Superior fibers proceed downwards and laterally to get inserted into the lateral 1/3rd of clavicle. Transverse fibers get inserted into the medial margin of acromion and superior lip of the posterior border of the spine of scapula. Inferior ascending part proceed upward and laterally to get converge near the scapulae forming an aponeurosis.
Motor part is supplied by accessory nerve, the 11th cranial nerve. Sensory part is supplied by the ventral rami of C3 and C4 cranial nerves.
Superficial branch of transverse cervical artery. Superficial cervical artery.
Helps in following movements at the shoulder region Rotation Retraction Elevation Depression It Perform the cited above movements via three functional regions Superior descending part supports weight of the arm. Intermediate transverse region retracts the scapulae. Inferior ascending portion helps in medial rotation and depression of the scapulae.
Muscle imbalance can result in compromised shoulder health if all the three parts are not fully developed. It affects the posture. It forms the superior and medial boundary of triangle of auscultation by its inferior portion.
ORIGIN
INSERTION
INNERVATION
BLOOD SUPPLY
FUNCTIONS
ANTAGONISED BY
CLINICAL POINTS
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