Anatomy of the Thoracic Wall Lecture PDF

http://t3.gstatic.com/images?q=tbn:tfx74m7TG1-6kM:http://www.star.uclan.ac.uk/malta2009/uni_logo.jpg Anatomy of the Thoracic Wall The Thoracic wall Boundaries of the thoracic wall: 1. 12 vertebrae 2. 12 pai...

http://t3.gstatic.com/images?q=tbn:tfx74m7TG1-6kM:http://www.star.uclan.ac.uk/malta2009/uni_logo.jpg Anatomy of the Thoracic Wall The Thoracic wall Boundaries of the thoracic wall: 1. 12 vertebrae 2. 12 pairs of ribs with their costal cartilages 3. Sternum 4. Roofed by suprapleural membrane over lung apices 5. Floored by the highly convex diaphragm  A Typical rib A typical rib has the following characteristics: 1. Head – with two articular facets 2. Neck 3. Tubercle – with articulation for transverse process and the lateral costotransverse ligament 4. Angle – point just lateral to the tubercle where the shaft bends forward 5. Shaft with characteristic shape 6. Costal groove – sharp lower border of shaft, lodges the neurovascular bundle  The First Rib - Atypical Shortest, Flattest, Broadest, Most Curved It has upper and lower surfaces, with outer and inner borders One articular facet on head only Groove for subclavian artery and vein separated by the scalene tubercle for attachment of scalene anterior muscle Very little movement during respiration Joins manubrium sternii by a primary cartilaginous joint  The Sternum Composed of uppermost manubrium, intermediate body and the xiphoid process Like the ribs: made up of cancellous bone containing hematopoietic tissue Manubrium markings: - Jugular notch - Concavity for sterno-clavicular joints (synovial) -First costal cartilages at the lateral border -Sternohyoid and Sternothyroid attachments posterior  The Sternum Body of the sternum has articular facets all along its lateral border for 2nd to 7th costal cartilages. These are all synovial joints Pertoralis major arises from the anterior surface of the sternal body The xiphisternum projects downwards for attachment of the linea alba. It usually ossifies in middle age. CostoSternal Joints The upper seven costal cartilages articulate with the sternum at the sternocostal joints (true ribs) The next 3 articulate with each other (interchondral joints) and the eighth articulates with the seventh The last two costal cartilages are free (floating ribs – their costal cartilages do not attach to sternum)  The Diaphragm A dome shaped fibro muscular sheet, separating the thorax from abdominall cavities Main function is inspiration Inverted J Shaped in profile, with long limbs posteriorly [at the crura] and short limb anteriorly [at the xiphisternum] Seen anteriorly, it has two domes, with the right higher than the left Origins of the Diaphragm 1. The Right and Left Crura 2. Median Arcuate Ligament 3. Medial Arcuate Ligament 4. Lateral Arcuate Ligament 5. Inner surface of lower 6 ribs and costal cartilages 6. Posterior surface of xiphisternum  body (1) superior and inferior demifacets (2,3) pedicle (4) superior and inferior articular processes (5, 6) transverse process (with an articular process) (7,10) lamina (8) spinous process (9) superior and inferior notches (13,12) vertebral canal(14) not a bone but an integral part of the vertebral column is the intervertebral disk (11)