W-1 Chest Muscles

Pectoralis Major Purposeful Activity:

Reaching across the body into overhead cabinet; putting on a seat belt

Pectoralis Major Action: Clavicular head

shoulder flexion and horizontal adduction

Pectoralis Major Action: Sternocostal head

shoulder extension from a flexed position

Pectoralis Major Action: Together

shoulder adduction, IR

Pectoralis Major Origin:

• anterior surface of medial half of clavicle

• anterior surface of sternum, superior six costal

cartilages, aponeurosis of external oblique

muscle

Pectoralis Major Insertion

• lateral lip of intertubercular sulcus (groove) of

humerus

Pectoralis Major Innervation:

primarily by the lateral pectoral nerve (C5-C7);

Some innervation of SC fibers by medial pectoral

nerve (C8-T1)

Pectoralis Major Blood Supply:

Thoracoacromial artery

Pectoralis Minor Purposeful Activity:

Walking with crutches, taking a deep breath

Pectoralis Minor Action:

Scapular stabilization, depression, anterior tipping, downward rotation

Pectoralis Minor Origin:

3rd–5th ribs near their costal cartilages

Pectoralis Minor Insertion:

medial surface of coracoid process of scapula

Pectoralis Minor Innervation:

medial pectoral nerve (C8-T1) and sometimes the lateral pectoral nerve (C5-C7)

Pectoralis Minor Blood Supply:

Thoracoacromial artery

Serratus Anterior Purposeful Activity:

Pushing open a heavy door

Serratus Anterior Action:

Scapular protraction, upward rotation, depression, stabilizer

Serratus Anterior Origin:

External surfaces of lateral parts of 1st–8th ribs

Serratus Anterior Insertion:

Anterior surface of entire medial border of scapula

Serratus Anterior Innervation:

Long thoracic nerve (C5-C8)

Serratus Anterior Blood Supply:

Lateral thoracic artery