deltoid (muscle)


del·toid (mus·cle)

[TA] intrinsic (scapulohumeral) muscle of shoulder joint; origin, lateral third of anterior border of clavicle, lateral and posterior border of acromion process, lower border of spine of scapula; insertion, lateral side of shaft of humerus (deltoid tuberosity) a little above its middle; action, its anterior, middle, and posterior portions act independently to produce abduction, flexion, extension, and rotation of the humerus at the shoulder joint; nerve supply, axillary (fifth and sixth cervical spinal cord segments via the brachial plexus). Synonym(s): musculus deltoideus [TA]