Thorax

• What is the thorax?

  Region between the neck and abdomen
• What forms the thoracic cage?

  Vertebral column, ribs, sternum
• What are the components of the thoracic cage?

  • Vertebral column (posterior)
  • Ribs and intercostal spaces (lateral)
  • Sternum and costal cartilages (anterior)
• How many major spaces is the thoracic cavity divided into?

  Three major spaces
• What are the major spaces of the thoracic cavity?

  1. Mediastinum
  2. Pulmonary cavities
• What covers the thoracic wall?

  Skin and muscles attaching shoulder girdle
• What lines the thoracic wall?

  Parietal pleura
• What forms the thoracic wall?

  • Thoracic vertebrae (posterior)
  • Sternum and costal cartilages (anterior)
  • Ribs and intercostal spaces (lateral)
  • Suprapleural membrane (superior)
  • Diaphragm (inferior)
• What are true ribs?

  1st-7th ribs attaching directly to sternum
• What are false ribs?

  8th-10th ribs with indirect sternum connection
• What are floating ribs?

  11th-12th ribs with rudimentary cartilages
• What are the thoracic apertures?

  Superior and inferior openings
• What is the superior opening of the thorax also known as?

  Thoracic outlet
• What closes the superior opening of the thorax?

  Suprapleural membrane
• What are the boundaries of the superior opening of the thorax?

  • Posterior: 1st thoracic vertebra
  • Lateral: medial borders of 1st rib & costal cartilage
  • Anterior: superior border of manubrium
• What does the inferior opening of the thorax communicate with?

  Communicates with the abdomen
• What closes the inferior opening of the thorax?

  Diaphragm
• What are the boundaries of the inferior opening of the thorax?

  • Posterior: 12th thoracic vertebra
  • Lateral: costal margin
  • Anterior: xiphisternal joint
• What is the diaphragm?

  Thin, dome-shaped muscular and tendinous septum
• What does the diaphragm separate?

  Chest cavity from abdominal cavity
• What are the main openings of the diaphragm?

  1. Aortic
  2. Esophageal
  3. Caval
• What are the parts of the diaphragm's origin?

  1. Sternal
  2. Costal
  3. Vertebral
• What is the diaphragm's insertion?

  Central tendon
• What is the action of the diaphragm?

  Pulls down its central tendon to descend
• What innervates the diaphragm?

  Right and left phrenic nerves
• What are intercostal spaces?

  Spaces between ribs
• What are the joints of the thorax?

  1. Manubriosternal
  2. Xiphisternal
  3. Costochondral
  4. Chondrosternal
  5. Interchondral
  6. Costovertebral
  7. Costotransverse
• What type of joints are manubriosternal and xiphisternal joints?

  • Manubriosternal: symphysis
  • Xiphisternal: synchondrosis
• What type of joint is the costovertebral joint?

  • Synovial plane joint
• What type of joint is the costotransverse joint?

  • Synovial plane joint
• What types of joints are costochondral, interchondral, and chondrosternal joints?

  • Costochondral: synchondrosis
  • Chondrosternal: synchondrosis (1st); synovial plane (2nd-7th)
  • Interchondral: synovial plane (ribs 6-7; 7-8; 8-9); fibrous (ribs 9-10)
• What are the movements of the thoracic wall?

  1. Increase vertical dimension
  2. Increase anteroposterior dimension (pump-handle motion)
  3. Increase transverse dimension (bucket-handle motion)
• What is bucket-handle motion?

  • Elevation and outward turning of lateral ribs
• What is caliper motion?

  • Lower ribs flare outward increasing subcostal angle
• What muscles attach to the thoracic cage?

  1. Thoracoappendicular muscles
  2. Anterolateral abdominal muscles
  3. Back and neck muscles
  4. Muscles of the thoracic wall
• What are the thoracoappendicular muscles?

  1. Pectoralis major
  2. Pectoralis minor
  3. Subclavius
  4. Serratus anterior
  5. Latissimus dorsi
• What are the anterolateral abdominal muscles?

  1. Rectus abdominis
  2. External oblique
  3. Internal oblique
  4. Transversus abdominis
• What are the back and neck muscles?

  1. Erector spinae

  • Spinalis
  • Longissimus
  • Iliocostalis
• What are the muscles of the thorax?

  1. Diaphragm (inspiratory)
  2. External intercostal (inspiratory)
  3. Internal intercostal (expiratory)
  4. Innermost intercostal
  5. Serratus posterior superior (inspiratory)
  6. Serratus posterior inferior (expiratory)
  7. Levatores costarum (inspiratory)
• What is the insertion of the diaphragm?

  Central tendon