SKELETON OF THE SPINE AND THE THORAX Pages 37- 42 and 54 - 57 Skeleton of the spine Vertebral Column . forms the basic structure of the trunk . consists of 33-34 vertebrae and intervertebral discs . 7 cervical, 12 thoracic, 5 lumbar = true vertebrae . sacrum and coccyx fused = false vertebrae Vertebra . all vertebrae have certain features in common (vertebral body, vertebral arch and seven processes) and regional differences . vertebral body . vetrebral arch pedicle lamina spinous process transverse process articular processes . vertebral foramen . vetrebral notch Cervical vertebrae . transverse foramen (foramen transversarium) in the transverse process . transverse processes of cervical vertebrae end laterally in two projection for attachment of cervical muscles anterior tubercle and posterior tubercle . bifid spinous process . C6 - tuberculum caroticum . C7 - vertebra prominens Atlas C1 . a ring-shaped bone . has neither a boby nor a spinous process . lateral masses . anterior and posterior arches . anterior and posterior tubercles . superior and inferior articular surfaces . articular facet for dens Axis C2 . serves as the pivot about which the rotation of the head occurs . odontoid process = dens . anterior articular facet Thoracic vertebrae . spinous process is long and running posteroinferiorly . superior costal facet . inferior costal facet . transverse process has an articulating facet for the tubercle of a rib = costal facet . the body is heart-shaped Lumbar vertebrae . massive bodies . accessory process - on the posterior surface of the base of each transverse process . mammilary process - on the posterior surface of the superior articular process . costal process Sacrum solid triangular bone . base . wings (alae) . apex . dorsal surface median crest intermediate crest lateral crest posterior sacral foramina superior art. processes . pelvic surface anterior sacral foramina transverse lines . pars lateralis auricular surface sacral tuberosity . sacral promontory . alae sacrales . sacral canal . sacral horns . sacral hiatus Coccyx . a triangular mass of bone . is the remnant of a human tail . now support the position of the anus and when we sit down and lean back . coccygeal horns . apex of coccyx Skeleton of the thorax Thorax . thoracic cage is formed by ribs and costal cartilages, supported by vertical sternum and thoracic vertebrae . enclosed the thoracic cavity Sternum . flat, elongated bone that forms the middle of the anterior part of the thoracic cage . manubrium and body of the sternum lie in slighly different planes superior and inferior to their junction → sternal angle (the level of the 2nd ribs) . manubrium jugular notch clavicular notchs costal notch . body costal notchs . xiphoid process Ribs . curved, flat bones that form most of the thoracic cage . true ribs (1st-7th) - attach directly to the sternum through their own costal cartilages . false ribs (8th-10th) - their cartilages are connected to the cartilage of the rib above them; their connection with the sternum is indirect . floating ribs (11th and 12th) - the rudimentary cartilages of these ribs do not connect even indirectly with the sternum; they end in the posterior abdominal musculature . body costal groove angle of the rib costal crest . head articular facet . neck costal tubercle articular facet of costal tubercle . the 1st rib grooves for subclavian artery and vein tubercle for the scalene anterior muscle tubercle for the scalene medii muscle . the 2nd rib tubercle for the scalene posterior muscle.