ORIGIN: Anterior surfaces of the third to fifth ribs near their costal cartilages (variable)
INSERTION: Via a tendon to the medial and superior aspect of the coracoid. process of the scapula. Part or all of the tendon may transverse this process and continue into the coracoacromial ligament.
INNERVATION: Medial pectoral nerve (C7, T1).
BLOOD SUPPLY: Branches from the thoraco-acromial artery.
ACTIONS: Scapula protraction, rotation of the scapula downwards, anterior tilting of scapula, when scapula is fixed it helps the inspiration (by elevation of ribs)
Synergist: Pectoralis major
Primary Actions of the Pectoralis Minor:
1. Protraction of the scapula.
Agonists: Serratus Anterior Antagonists: Trapezius (middle fibers), Rhomboid Major, Rhomboid Minor.
2. Depression of the scapula.
Agonists: Serratus Anterior (lower fibers), Trapezius (lower fibers)
Antagonists: Levator Scapulae, Trapezius (upper fibers)
Secondary Actions of the Pectoralis Minor:
1. Assists with downward rotation of the scapula
Agonists: Levator Scapulae, Serratus Anterior (upper fibers), Rhomboid Major, Rhomboid Minor, Trapezius (middle fibers)
Antagonists: Trapezius (upper and lower fibers), Serratus Anterior (lower fibers),
Stabilizer: Trapezius (middle fibers).
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