Anterior Shoulder Region

The anterior shoulder or pectoral region is formed by

• Pectoralis Major

• Pectoralis Minor

Pectoralis Major has two heads

Pectoralis Major has two heads

• sternocostal head

Pectoralis Major has two heads

• sternocostal head

• clavicular head

Anterior View

Pectoralis Major attaches to the lateral lip of the bicipital groove of the proximal humerus

Pectoralis Major

Is supplied by the

medial and lateral pectoral nerves

Pectoralis Major

Sternocostal head adducts and medially rotates the arm

clavicular head adducts and flexes the arm

Pectoralis Minor attaches to the coracoid process of the scapula

Pectoralis Minor attaches to the coracoid process of the scapula

Anterior view

Pectoralis Minor

Arises from ribs 3,4,5

It protracts the scapula

Pectoralis Minor

Is supplied by the

Medial pectoral nerves

The anterior fibres of

Deltoid muscle

lie at the lateral aspect of the anterior chest wall

Muscles Summary

Anterior Chest WallPectoralis Major

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

Insertion Lateral lip of intertubercular groove of humerus

Action Adducts and internally rotates humerus; moves scapula anteriorly and inferiorly;

Nerve Supply Lateral and medial pectoral nerves (C5, C6, C7, C8, and T1)

Blood Supply pectoral branch of thoracoacromial trunk

Anterior Chest Wall

Pectoralis MinorOrigin 3rd to 5th ribs near their costal

cartilagesInsertion Medial border and superior

surface of coracoid process of scapula

Action Stabilises scapula, pulls it inferiorly and anteriorly against thoracic wall

Nerve Supply Medial pectoral nerves; (C8 and T1)

Blood Supply Pectoral branch of the thoracoacromial trunk

Anterior Chest Wall

Serratus AnteriorOrigin Superolateral surfaces of

upper 8 or 9 ribs at the side of chest

Insertion Medial border of scapulaAction Pulls scapula forward and

upward; abducts and rotates it; stabilises medial border of scapula

Nerve Supply Long thoracic nerve (C5, C6, C7)

Blood Supply Circumflex scapular artery

DeltoidOrigin Lateral third of clavicle,

acromion, and spine of scapulaInsertion Deltoid tuberosity of humerus

Action Anterior part: flexes and internally rotates arm; Middle part: abducts arm; Posterior part: extends and externally rotates arm

Nerve Supply Axillary nerve (C5 and C6)

Blood Supply Deltoid branch of thoracoacromial artery