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Anatomy Thorax Thoracic cavity surrounded by thoracic wall contains the thymus, heart, lungs, distal part of trachea, most of esophagus. Skeleton of thoracic wall forms osteocartilaginous thoracic cage. Contains 12 thoracic vertebrae and intervertebral discs, 12 pairs of ribs, and sternum. Thoracic vertebrae have costal facets on bodies for articulation with heads of ribs [joint of head of rib, along with adjacent intervertebral disc] facets on transverse processes for articulation with tubercles of ribs (except inf. 2) [costotransverse joint] superior demifacet art. w/ head of own rib; inferior demifacet art. w/ head of inf. rib Ribs 12 pairs (1-7 = true, 8-10 = false, 11-12 = floating; unattached ant., end b/w muscles) Costochondral joints Head = 2 articular facets + crest Tubercle art. w/ transverse process Shaft costal groove on inf. surface, lodges intercostal vessels and nerves Atypical ribs (1, 2, 10, 11 &12) 1 st has one art. facet, is broadest, shortest, most curved scalene tubercle (anterior scalene m.), groove of subclavian a. (ant.) and vein. (post.) 2 nd has has tuberosity for serratus ant. 10 th has single art. facet 11 th and 12 th have single art. facet, no neck or tubercle Sternum Manubrium (T3-T4) jugular notch, 2 clavicular notches (sternoclavicular joints) manubriosternal joint (symphysis) forms sternal angle [of Louis] Body (T5-T9) costal notches 2-7, xiphisternal joint (synchondrosis); cartilagenous, ossified by age 40. Xiphoid process (T10) ossified by age 40 Ligaments Radiate lig. - head of rib to body of vertebrae sup. and inf. Radiate sternocostal ligaments costal cartilage to sternum Intraartciular lig. - manubrium to body Lateral costotransverse lig. - tubercle to tip of transverse process Superior costotransverse lig. - neck to transverse process superior to it Sternocostal joints (1-7) 1 st cartilagenous (synchondrosis) 2-7 synovial Thoracic cage superior aperture = inlet (bounded by T1, first pair of ribs, sup. border of manubrium) trachea, esophagus, V,A&N. inferior aperture = outlet (bound by T12, costal cartilages ribs 7-12, xiphisternal joint) closed by diaphragm, which allows structures to pass through. Inspiration increase vertical, transverse, anteroposterior diameters, and intrathoracic volume. Anteroposterior diameter - costovertebral joints cause ribs 2-6 to rise like pump handles Pectoralis major and scalene muscles are accessory respiratory muscles. Intercostal nerves = ant. rami of T1-T12 (upper = T1-T6, lower = T7-T12) 11 pairs + 12 th subcostal nn.... View Full Document

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