Serratus anterior (Musculus serratus anterior)
Educational content only — not medical advice.
Anatomy
A broad muscle with saw-tooth origins on the ribs wrapping the chest wall to the medial border of the scapula, forming the medial wall of the axilla; nicknamed the "boxer’s muscle" because it drives the scapula forward in every punch.
Origin & insertion
Lateral surfaces of ribs 1–8 (sometimes 9) by serrated digitations interdigitating with the external oblique. Anterior surface of the medial border of the scapula along its length.
Action
Protracts the scapula and, with trapezius, rotates its glenoid upward — the true muscle of overhead arm elevation; without it full lifting is impossible.
Innervation
Long thoracic nerve (C5–C7), descending on its external surface along the medial axillary wall.
Clinical notes
Long-thoracic nerve injury (breast and axillary surgery) paralyses it, producing a winged scapula; the patient cannot raise the arm above the horizontal.
Related structures
Educational references
FAQ
What is the role of the Serratus anterior?
A broad muscle with saw-tooth origins on the ribs wrapping the chest wall to the medial border of the scapula, forming the medial wall of the axilla; nicknamed the "boxer’s muscle" because it drives the scapula forward in every punch.
Why is the Serratus anterior clinically important?
Long-thoracic nerve injury (breast and axillary surgery) paralyses it, producing a winged scapula; the patient cannot raise the arm above the horizontal.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details