key facts

Origins

Lateral 1/3 of Clavicle (clavicular part), Acromion (acromial part), Spine of Scapula (spinal part)

Insertion

Deltoid tuberosity of humerus

Innervation

Axillary nerve (C5, C6)

Blood supply

Deltoid and acromial branches of thoracoacromial artery, subscapular artery, anterior and posterior circumflex humeral arteries, deltoid branch of deep brachial artery

Function

Clavicular part: flexion and internal rotation of the arm,

Acromial part: abduction of the arm beyond the initial 15°

Spinal part: extension and external rotation of the arm.