Muscle
Serratus anterior
Boxer's muscle
High-yield
Long thoracic nerve (C5-C7) injury causes medial scapular winging. "C5, 6, 7 raise your arms to heaven."
Overview
A fan-shaped muscle on the lateral thoracic wall that protracts the scapula and anchors it to the ribs, enabling overhead reach.
Reference facts
- Origin
- External surfaces of the lateral parts of ribs 1-8
- Insertion
- Anterior (costal) surface of the medial border of the scapula
- Action
- Protracts and rotates the scapula for overhead abduction; holds the scapula against the thoracic wall
- Innervation
- Long thoracic nerve (C5, C6, C7)
- Blood supply
- Lateral thoracic and superior thoracic arteries
Clinical correlation
Long thoracic nerve palsy → winged scapula and inability to raise the arm above horizontal.
Frequently asked questions
What does the serratus anterior do?
The serratus anterior protracts and rotates the scapula for overhead abduction; holds the scapula against the thoracic wall.
What nerve innervates the serratus anterior?
The serratus anterior is innervated by the long thoracic nerve (C5, C6, C7).
Where does the serratus anterior attach?
The serratus anterior originates from the external surfaces of the lateral parts of ribs 1-8 and inserts on the anterior (costal) surface of the medial border of the scapula.
What is the blood supply of the serratus anterior?
The serratus anterior is supplied by the lateral thoracic and superior thoracic arteries.