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Lecture DetailsEdit

Colin McHenry; Week 10 MED1022; Anatomy

Lecture ContentEdit

Thorax contains thorax walls and diaphragm, pleural sacs and lungs, pericardial sac and heart, mediastinum. Ribs have a head, neck, tuberosity and facets. Attachments are of variable importance. True ribs are from 1-7 (sternocostal), are primary cartilaginous, don't have much movement (have pump handle movement), false ribs (do not go into the sternum, cartilage merges before then) are from 8-10 and have bucket handle movement. Ribs from 1-10 are fixed, 11 and 12 are floating. Typical ribs are 3-9; have vertical surfaces, joints with two bodies and tuberosity. Age variation leads to immobility, fractures are a result of blunt or sharp trauma, can result in scoliosis. The head of the rib attaches to the facets of the vertebral column, with the tuberosity articulating with the transverse process. The groove of the shaft shelters the neurovascular bundle. NVB goes VAN from top to bottom.

Costal cartilages are hyaline, sternal or chondral, articulates with ribs. 1-7 articulate with sternum, 8-10 with each other to form a costal margin, 11-12 have small cartilage tips and do not articulate. Excavatum is funnel chest, carinatum is pigeon chest.

Manubrium is the upper segment of the sternum, sternal angle of Louis and T4/5 disc, defines the sternal plate. Xiphisternum is a small, dagger like part attached to the diaphragm which articulates with the body at the level of the 7th costal cartilage and T9 body. Joints are costovertebral and costotransverse, bucket handle vs pump handle movement. Chondrochondritis (costochondritis) is inflammation of costal cartilage, degeneration, ankylosing spondylitis can occur. Intercostal spaces have external, internal and innermost intercostal muscles, NVB travel between internal and innermost. Sternal foramen can exist.

Superior aperture separates the thorax from the root of the neck, between T1, first ribs and manubrium. Inferior aperture separates thorax from abdomen, composed of xiphisternum, costal margin and T12, enclosed by teh diaphragm which contains major and minor apertures. Diaphragm has muscular origins peripherally, there is a central tendon at the height of diaphragmatic domes. Nerve supply is phrenic (3, 4, 5), sensory centrally by phrenic nerves, peripheral by T7-12 spinal nerves.

Major apertures are through vena cava at T8, oesophageal at T10, aortic at T12. Diaphragmatic herniae can be congenital or acquired (traumatic).

Internal thoracic artery supplies the anterior intercostals, superior epigastric arteries and musculophrenic arteries. Posterior intercostal arteries arise from the aorta, some may give spinal cord feeder arteries. Internal thoracic veins can be intercostal, recieve tributaries from the breast. Posterior intercostal veins drain into the azygos vein and communicate with vertebral venous system. Lymphatics drain breast to parasternal nodes. Internal thoracic artery is used in coronary artery surgery.

Breast pathology and referred pain is via thoracic spinal nerves, somatic from thoracic wall, visceral from eg MI, neurogenic.

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