Thoracic Muscles Flashcards
What is the origin of the Pectoralis Major?
Sternum, Clavicle, Costal Margins.
What is the insertion of the Pectoralis Major?
Intertubular groove of the humerus
What are the actions of the Pectoralis Major?
Flexion, adduction, and medial rotation of humerus.
What innervates the Pectoralis Major?
Medial pectoral nerve (C8-T1) and lateral pectoral nerve (C5-C7).
What is the origin of the Pectoralis Minor?
Ribs 3-5
What is the insertion of the Pectoralis Minor?
Coracoid process of the scapula.
What are the actions the Pectoralis Minor?
Stabilizes scapula against posterior thoracic wall.
What innervates the Pectoralis Minor?
Medial pectoral nerve (C8-T1).
What is the origin of the Serratus Anterior?
Ribs 1-8
What is the insertion of the Serratus Anterior?
Medial margin of the scapula.
What are the actions of the Serratus Anterior?
Scapular abduction and stabilizer of the scapula against the thoracic wall.
What innervates the Serratus Anterior?
Long thoracic nerve
What is the origin of the Subclavius?
Medially at Rib 1
What is the insertion of the Subclavius?
Laterally at subclavian groove
What are the actions of the Subclavius?
Pulls clavicle inferiorly and anteriorly, stabilizes sternoclavicular joint, and depress tip of shoulder.
What innervates the Subclavius?
Subclavius nerve
What are the superficial thoracic muscles?
Pectoralis Major, and Minor, Serratus Anterior, and Subclavius
What are the deep thoracic muscles?
External, Internal, and Innermost Intercostals
What is the origin of the external intercostals?
Inferior border of superior rib
What is the insertion of the external intercostals?
Superior border of the inferior rib
What are the actions of the external intercostals?
Elevates ribs to expand chest capacity during inhalation.
What is the origin of the internal intercostals?
Superior border of inferior rib
What is the insertion of the internal intercostals?
Inferior border of superior rib
What are the actions of the internal intercostals?
Depress the ribs to decrease chest capacity during expiration.
What are the actions of the innermost intercostals?
Function of the muscles is expiration because these muscles depress the ribs caudally.
What is the innervation of the deep thoracic muscles?
Intercostal nerves
