Serratus anterior muscle

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The serratus anterior muscle is a muscle that originates on the surface of the 1st to 8th or 9th ribs at the side of the chest and inserts along the entire anterior length of the medial border of the scapula. It is innervated by the long thoracic nerve and receives its blood supply from the lateral thoracic artery.

Structure

The serratus anterior muscle is divided into three parts:

• The superior part, which originates from the 1st and 2nd ribs and inserts into the superior angle of the scapula.
• The intermediate part, which originates from the 2nd and 3rd ribs and inserts along the medial border of the scapula.
• The inferior part, which originates from the 4th to 8th or 9th ribs and inserts into the inferior angle of the scapula.

Function

The primary function of the serratus anterior muscle is to protract and stabilize the scapula. It also assists in the upward rotation of the scapula, which is essential for the full abduction of the arm. This muscle plays a crucial role in movements such as pushing and punching, earning it the nickname "boxer's muscle."

Clinical significance

Weakness or paralysis of the serratus anterior muscle can lead to a condition known as winged scapula, where the medial border of the scapula protrudes posteriorly. This condition can result from damage to the long thoracic nerve, which may occur due to trauma, surgical procedures, or certain medical conditions.

See also

• Scapula
• Rhomboid muscles
• Trapezius muscle
• Long thoracic nerve