Exam 1 - Pectoralis Major, Pectoralis Minor, Subclavius

Pectoralis Major: Actions

- Entire muscle: Adduction and medial rotation of the humerus, Forced inspiration - Clavicular portion: Flexes humerus and shoulder joint - Sternocostal portion: Extend humerus and shoulder joint

Pectoralis Minor: Actions

1) involved with abduction of the scapula 2) elevates the rib cage and thus involved with forced inspiration

Poland Syndrome

Unilateral condition in which both the pectoralis major/minor muscles are missing. atrophy of the mammary glands and absence of several ribs

Syndactylism

Hand on the affected side is smaller and may show webbing between the digits

Subclavius: Actions

1) Pulls the clavicle medically and thus stabilizes the sternoclavicular joint 2) Serves as protective cushion between a fractured clavicle and underlying blood vessels

Pectoralis Minor: Insertion

Coracoid process/scapula

Pectoralis Major: Origin

- Clavicle - Sternum and upper ribs - External oblique

Subclavius: Origin

First rib

Pectoralis Major: Insertion: Insertion

Lateral aspect of the greater tuberosity

Pectoralis Major: Nerves

Medial (C8-T1) and Lateral (C5-C7) pectoral nerves

Pectoralis Minor: Origin

Ribs 3-5

When the pectoralis major flexes at the clavicular portion, what direction does the humerus move?

Medial

Pectoralis Minor: Nerve

Medial Pectoral nerve (C8-T1)

Subclavius: Nerve supply

Nerve to the subclavius (C5-C6)

Subclavius: Insertion

Subclavian groove/clavicle