
Serratus Anterior Muscle
Origin: Attaches to the outer surface of the upper 8 to 9 ribs
Insertion: Attaches to the anterior surface of the vertebral margin of the scapula
Actions: Rotation, protraction, and depression of the scapula
Innervation: Long thoracic nerve (C5, C6, C7)
Blood Supply: Lateral thoracic branch of the axillary artery
Primary Actions of the Serratus Anterior
1. Upward rotation of the scapula
Agonists:
- Trapezius (upper and lower parts)
Antagonists:
- Levator Scapulae
- Serratus Anterior (upper fibers)
- Rhomboid Major
- Rhomboid Minor
- Pectoralis Minor
The middle part of the trapezius is a stabilizer.
2. Downward rotation of the scapula
Agonists:
- Levator Scapulae
- Rhomboid Major
- Rhomboid Minor
- Pectoralis Minor
- Trapezius (middle part)
Antagonists:
- Trapezius (upper and lower fibers)
- Serratus Anterior (lower fibers)
The middle part of the trapezius is a stabilizer.
3. Protraction of the scapula
Agonists:
- Pectoralis Minor
Antagonists:
- Trapezius (middle fibers)
- Rhomboid Major
- Rhomboid Minor
4. Depression of the scapula
Agonists:
- Pectoralis Minor
- Trapezius (lower part)
Antagonists:
- Trapezius (upper part)
- Levator Scapulae
5. Stabilizes the medial border of the scapula to the chest wall during movement of the arm at the shoulder.
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Muscle Pain Information: The serratus anterior muscle contributes to pain in the shoulder, arm, hand, and upper back.