The acromiohumeral muscle, also known as the deltoid muscle or simply the deltoid, is a large, triangular muscle located in the upper arm and shoulder region. Named after its shape, the deltoid muscle originates from the outer third of the clavicle (collarbone), the acromion (bony process of the shoulder blade), and the spine of the scapula (shoulder blade). It then inserts into the deltoid tuberosity of the humerus (upper arm bone).
Functionally, the acromiohumeral muscle plays a crucial role in various movements of the shoulder joint. It acts as the primary muscle responsible for shoulder abduction, which is the movement of lifting the arm away from the body to the side. It also assists in shoulder flexion, extension, and rotation. Additionally, the deltoid muscle provides stability to the shoulder joint and helps prevent dislocation.
The acromiohumeral muscle is innervated by the axillary nerve, a branch of the brachial plexus. This nerve supplies the muscle with the necessary motor signals for contraction. In terms of blood supply, the deltoid muscle receives blood from the deltoid branch of the thoracoacromial artery and the posterior circumflex humeral artery.
Regular strengthening exercises targeting the acromiohumeral muscle can help improve overall shoulder function, stability, and range of motion. These exercises may include shoulder presses, lateral raises, front raises, and upright rows. Strengthening the deltoid muscle can be beneficial for athletes, individuals involved in manual labor, or those seeking to improve their upper body strength and aesthetics.
