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Pectoralis Major

Last updated on Monday, June 1 2009 by blondarb

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Muscle Name: pectoralis major

AKA:   Musculus pectoralis major


Spinal Nerve Roots:

Brachial Plexus Trunks:
    upper trunk
    middle trunk
    lower trunk

Brachial Plexus Cords:
    medial cord
    lateral cord

Named Nerves:
    medial pectoral nerve  (a.k.a. medial anterior thoracic nerve)
    lateral pectoral nerve  (a.k.a. lateral anterior thoracic nerve)

Proximal Attachment:

     Clavicular head: anterior surface of the medial half of the clavicle.
     Sternocostal head: anterior surface of the sternum, the superior six costal cartilages, and the aponeurosis of the external oblique muscle  

Distal Attachment:   Intertubercular groove of the humerus

Action:  Adducts and medially rotates the humerus.

Needle Insertion:   In the anterior axillary fold. 

Activation for EMG:   Adduct the arm.

Pitfalls:  If the needle is too lateral the biceps will be sampled, too deep the corachobrachialis will be sampled.