Thoracic Muscles Anatomy PDF

# Thoracic muscles ## Thoracic Muscles - An illustration showing the muscles of the chest (thorax) ## Diaphragm - This is a dome-shaped muscle that separates the chest cavity from the abdomen. - It plays a key role in breathing by contracting and relaxing. - It's made up of two domes (right and l...

# Thoracic muscles ## Thoracic Muscles - An illustration showing the muscles of the chest (thorax) ## Diaphragm - This is a dome-shaped muscle that separates the chest cavity from the abdomen. - It plays a key role in breathing by contracting and relaxing. - It's made up of two domes (right and left) that join together. ### Structures passing through the Diaphragm: - Right dome - Central tendon - Left dome - Esophageal hiatus - Aortic hiatus ## Major structures passing between the abdomen and thorax. - Inferior vena cava - Esophagus - Caval opening (vertebral level TVIII) - Aorta - Central tendon of diaphragm - Aortic hiatus (vertebral level TXII) - Esophageal hiatus (vertebral level TX) - LI ## Attachment of the Diaphragm - Vertebral attachment - Sternal attachment - Caval hiatus - Oesophageal hiatus - Aortic hiatus ## The Phrenic Nerves - Right phrenic nerve - Pericardium - Left phrenic nerve ## Muscles and fascia of the pectoral region - **Pectoralis major** - *Origin:* Medial half of clavicle and anterior surface of sternum, first seven costal cartilages, aponeurosis of external oblique - *Insertion:* Lateral lip of intertubercular sulcus of humerus - *Innervation:* Medial and lateral pectoral nerves - *Function:* Adduction, medial rotation, and flexion of the humerus at the shoulder joint - **Subclavius** - *Origin:* Rib I at junction between rib and costal cartilage - *Insertion:* Groove on inferior surface of middle third of clavicle - *Innervation:* Nerve to subclavius - *Function:* Pulls clavicle medially to stabilize sternoclavicular joint; depresses tip of shoulder - **Pectoralis minor** - *Origin:* Anterior surfaces of the third, fourth, and fifth ribs, and deep fascia overlying the related intercostal spaces - *Insertion:* Coracoid process of scapula - *Innervation:* Medial pectoral nerves - *Function:* Depresses tip of shoulder; protracts scapula ## Intercostal Muscles - **External intercostal muscles** - **Internal intercostal muscles** - **Innermost intercostal muscles** - Intercostal nerve - Intercostal artery - Intercostal vein - Collateral branches ## Anatomy of an Intercostal Space - **Posterior ramus of spinal nerve** - **Posterior intercostal artery and vein** - Lateral branches of intercostal nerve and vessels - Intercostal nerve - Costal groove - Collateral branches of intercostal nerve and vessels - Anterior intercostal artery and vein - **Inner area of rib** - Intercostal vein - Intercostal artery - Intercostal nerve - **Outer area of rib** - Lung - Pleural activity - Visceral pleura - Parietal pleura - Collateral branches - Endothoracic fascia - Interna and vei - Ante bran inter - Anter branc interc ## Subcostal muscles and Transversus thoracis muscle - **Subcostal muscles** (A) - **Transversus thoracis muscles** (B) ## Movement of the Thoracic wall during breathing - **Pump handle movement**: Superior and anterior movement of sternum. - **Bucket handle movement**: Elevation of lateral shaft of rib.