Your Monday Muscle: #2 the Deltoid

The Deltoid

The deltoid muscle is a rounded, triangular muscle located on the uppermost part of the arm and the top of the shoulder. It is named after the Greek letter delta, which is shaped like an equilateral triangle.

The deltoid is attached by tendons to the skeleton at the clavicle (collarbone), scapula (shoulder blade), and humerus (upper arm bone). The deltoid is widest at the top of the shoulder and narrows to its apex as it travels down the arm.

Contraction of the deltoid muscle results in a wide range of movement of the arm at the shoulder due to its location and the wide separation of its muscle fibres… (Read more at InnerBody.com)

The deltoid muscle has three parts; the front or anterior, middle, and back or posterior.

The muscle lifts the arm up sideways. The front part helps to lift the arm up forwards, known as shoulder flexion and the back part helps to lift the arm up backwards, known as shoulder extension.

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