The deltoid muscle is thick, triangular shaped muscle which arises from the lateral third of the clavicle, the superior acromion process and the spine of the scapular. It attaches to the deltoid tubercle of the lateral proximal humeral shaft.
Origin
- Clavicle
- Acromion process
- Spine of scapula
Insertion
- Deltoid tuberosity
Action
- Anterior fibres: flexion of arm
- Middle fibres: abduction of arm
- Posterior fibres: extension of arm
Innervation
- Axillary nerve: C5, 6
Blood Supply
- Deltoid branch of thoracoacromial artery