Pectoral Region Anatomy: Fascia and Muscles

• The lecture discusses the anatomy of the pectoral region, focusing on fascia and muscles.
• The pectoral region is located at the front of the upper part of the chest.
• The contents of the pectoral region include skin, superficial fascia, and deep fascia and muscles.

Superficial Fascia

• Superficial fascia encloses the mammary glands and cutaneous vessels and nerves.

Deep Fascia

• Deep fascia layers include the pectoral fascia and clavipectoral fascia.
• Pectoral fascia is a thin layer of connective tissue covering the pectoralis major muscle.
• Clavipectoral fascia is a thick connective tissue sheet connecting the clavicle to the floor of the axilla.
• The clavipectoral fascia encloses the subclavius and pectoralis minor muscles.
• Clavipectoral fascia covers the gap between the subclavius and pectoralis minor muscles.
• A thickened upper border forms the costo-coracoid ligament (from the first rib to the coracoid process).
• Structures that pierce the clavipectoral fascia include the cephalic vein, thoraco-acromial artery, lateral pectoral nerve, and lymphatics.

Muscles of the Pectoral Region

• The muscles include the pectoralis major, pectoralis minor, and subclavius.

Pectoralis Major

• A large, superficial muscle in the pectoral region.
• The clavicular head originates from the anterior surface of the medial half of the clavicle.
• The sternocostal head originates from the anterior surface of the sternum and the upper seven costal cartilages.
• Insertion is on the lateral lip of the bicipital groove (intertubercular sulcus) of the humerus.
• Nerve supply is from the lateral and medial pectoral nerves.
• When both heads act together, they flex, adduct, and medially rotate the arm at the shoulder joint.

Pectoralis Minor

• A small, triangular muscle that lies deep to the pectoralis major.
• Originates from anterior surfaces and superior borders of ribs 3 to 5.
• Inserts onto the coracoid process of the scapula (medial border and upper surface).
• Nerve supply is from the medial pectoral nerve.
• Action includes protraction and depression of the scapula.

Subclavius

• A small muscle lying deep to the pectoralis major muscle.
• Originates from the first rib at the junction between the rib and its costal cartilage.
• Inserts onto the subclavius groove.
• Nerve supply is from the nerve to subclavius.
• Action stabilizes the sternoclavicular joint and depresses the clavicle.