Muscles of the Pectoralis Region

Question 0

Pectoralis Minor

Answer 0

Origin: 3rd to 5th Ribs near Cartilages
Insertion: Coracoid Process of Scapula
Action: Depresses Scapula, Elevates Ribs of Origin to assist in respiration when the shoulder is fixed
Nerve: Medial Pectoral Nerve

Question 1

Pectoralis Major

Answer 1

Origin: Medial Half of the Clavicle, Sternal and Costal Cartilages 1-6
Insertion: Lateral Lip of Bicipital Groove (Intertubercular Sulcus)
Action: Adducts and Medially Rotates the Arm, Flexes Arm (Clavicular Head), Assists in Respiration when Shoulder is Fixed (Sternocostal Head)
Nerves: Medial and Lateral Pectoral Nerves from the Medial and Lateral Cords of the Brachial Plexus

Question 2

Serratus Anterior

Answer 2

Origin: Upper Eight Ribs
Insertion: Medial (vertebral) Border of Scapula
Action: Rotates Scapula, Draws Scapula Forward around Thoracic Wall (protraction), Holds Scapula Against Thoracic Wall
Nerve: Long Thoracic (also called Nerve to the Serratus Anterior)

Question 3

Subclavius

Answer 3

Origin: 1st Costal Cartilage
Insertion: Inferior Surface of Clavicle
Action: Anchors and Depresses Clavicle During Upper Limb Movement
Nerve: Nerve to Subclavius