Vertebral Column

Part of the axial skeleton Consists of 26 irregular bones 24 vertebrae, sacrum, coccyx Vertebral column divisions –Cervical C1-C7 –Thoracic T1-T12 –Lumbar L1-L5 –Sacrum S1-S5(fused)

Spinal curvatures Cervical and lumbar curves are secondary curves Develop after birth Thoracic and sacral curves are primary curves Appear during fetal development Overall curve of the spine is S shaped

Vertebral Anatomy All vertebrae have a common structural plan Structural features are: –Vertebral body –Vertebral arch –Vertebral foramen –Pedicles –Lamina –Articular processes, superior and inferior –Spinous process

Cervical Vertebrae C1-C7 Smallest vertebrae Small vertebral body Triangular shaped vertebral foramen Small spinous process that is usually notched at the end – bifid process ALL cervical vertebrae have a transverse foramen C1 is called the ATLAS C2 is called the AXIS

C1- ATLAS

C2 - AXIS

C1-C2 Articulation

Thoracic Vertebrae T1-T12 Larger vertebral body Oval vertebral foramen Spinous process projects posterocaudally T1-T8 vertebrae have superior and inferior costal facets for rib articulation T1-T10 have transverse costal facets for articulation of tubercles of the ribs

Lumbar Vertebrae L1-L5 Largest vertebrae Large body No articular facets on the body or transverse processes Triangular vertebral foramen Short, flat spinous process Weight bearing vertebrae

Sacrum Five fused sacral vertebrae Fusion begins after puberty and is complete by years of age Curved dorsal surface Special features –Sacral canal –Median sacral crest –Sacral foramina –Lateral auricular surface to form the sacroiliac joint

Thoracic Cage Consists of the –Thoracic vertebrae –Ribs, 12 pair –Sternum –Ribs 1-7 are true ribs, vertebrosternal –Ribs 8-12 are false ribs, vertebrochondrial, do not attach directly to the sternum –Ribs are called floating ribs, NO connection to sternum

Rib articulation to thoracic vertebrae

Features of a typical rib

Sternum Flat bone that forms the midline of the thoracic wall Three components –Manubrium – articulates with the clavicles and costal cartilages of R1 –Manubrium has the jugular notch on the superior surface –Body of sternum, articulation of ribs 2-7 –Xiphoid process