Deltoid muscle
muscle of the upper limb
The deltoid muscle (or musculus deltoideus) is the muscle forming the rounded contour of the human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle is made up of three distinct sets of muscle fibers, namely the
anterior deltoid or clavicular part (pars clavicularis)
posterior or scapular part (pars scapularis)
intermediate or acromial part (pars acromialis)
The deltoid's fibres are pennate muscle. However, electromyography suggests that it consists of at least seven groups that can be independently coordinated by the nervous system.
It was previously called the deltoideus (plural deltoidei) and the name is still used by some anatomists. It is called so because it is in the shape of the Greek capital letter delta (Δ). Deltoid is also further shortened in slang as "delt".
A study of 30 shoulders revealed an average mass of 192 grams (6.8 oz) in humans, ranging from 84 grams (3.0 oz) to 366 grams (12.9 oz).
Structure
Origin
The anterior or clavicular fibers arise from most of the anterior border and upper surface of the lateral third of the clavicle. The anterior origin lies adjacent to the lateral fibers of the pectoralis major muscle as do the end tendons of both muscles.
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This entry incorporates text from “Deltoid muscle” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.