Axial Skeleton: the Vertebral Column and Rib cage

Vertebral Column 26 bones: Vertebrae (24) Sacrum Coccyx (tailbone) Functions: - support head, neck & trunk - protect spinal cord - maintain upright body position

Vertebral Column Consists of three main parts: cervical (C1-C7), thoracic (T1-T12), and lumbar (L1-L5) vertebrae

Vertebral Column The first cervical (C1) vertebrae is called the atlas The second cervical (C2) vertebrae is called the axis Atlas spins around its axis!

Special Features of Vertebrae Transverse Process Body Spinous Process Spinous Process Vertebral Foramen

Distinction between vertebrae Cervical vertebrae are flat, have smaller bodies, and a bifurcated (divides into two branches) spinous process Thoracic vertebrae have thicker bodies and a spinous process that projects inferiorly Lumbar vertebrae have the largest bodies and the shortest, thickest spinous process of all the vertebrae

The Thoracic Cage Function: - Protects heart and lungs Consists of: Ribs Sternum Thoracic vertebrae

Ribs Aka Costa (12 pair) 1st 7 pairs = true ribs Pairs 8-12 = false ribs because they do not attach directly to the sternum Last two pairs (11 and 12) = floating ribs = do not touch sternum Cartilage between ribs and sternum = costal cartilage

Ribs 1- Head of Rib 2- neck of rib 3- tubercle 4- costal cartilage A tubercle is a projection at one end of a bone for the attachment of a muscle or tendon

Ribs True Ribs (1-7) Costal Cartilage Thoracic Vertebrae (T1) Manubrium True Ribs (1-7) Sternum Body Xiphoid Process Costal Cartilage False Ribs (8-12) Floating Ribs (11-12)

Hyoid Bone Attaches tongue, voice-box, and throat Only bone in body not directly attached (articulated) with another bone Can be an indication of strangulation as cause of death. In children the greater horns have not fused to the body yet, so fractures may not always been seen even if strangulation occurs *Fusion of hyoid rarely occurs before the age of 40