1. Hyoid bone
U-shaped bone located just above the larynx and below the mandible
Suspended from the styloid processes of the temporal bone
Only bone in the body that articulates with no other bones

2. Vertebral column Forms the flexible longitudinal axis of the skeleton
Consists of 24 vertebrae plus the sacrum and coccyx
Segments of the vertebral column:
Cervical vertebrae, 7
Thoracic vertebrae, 12
Lumbar vertebrae, 5
Sacrum—in adult, results from fusion of five separate vertebrae
Coccyx—in adult, results from fusion of four or five separate vertebrae

4. Vertebral column Characteristics of the vertebrae
All vertebrae, except the first, have a flat, rounded body anteriorly and centrally, a spinous process posteriorly, and two transverse processes laterally
All but the sacrum and coccyx have vertebral foramen
Second cervical vertebra has upward projection, the dens, to allow rotation of the head
Seventh cervical vertebra has long, blunt spinous process
Each thoracic vertebra has articular facets for the ribs

5. Vertebral column
Vertebral column as a whole articulates with the head, ribs, and iliac bones
Individual vertebrae articulate with each other in joints between their bodies and between their articular processes

6. Sternum
Dagger-shaped bone in the middle of the anterior chest wall made up of three parts:
Manubrium—the upper, handle part
Body—the middle, blade part
Xiphoid process—the blunt cartilaginous lower tip, which ossifies during adult life

7. Sternum Manubrium articulates with the clavicle and first rib
Next nine ribs join the body of the sternum, either directly or indirectly, by means of the costal cartilage

8. Ribs
Twelve pairs of ribs, with the vertebral column and sternum, form the thorax
Each rib articulates with the body and transverse process of its corresponding thoracic vertebra
Ribs 2 through 9 articulate with the body of the vertebra above

9. Ribs
From its vertebral attachment, each rib curves outward, then forward and downward
Rib attachment to the sternum:
Ribs 1 through 8 join a costal cartilage that attaches it to the sternum
Costal cartilage of ribs 8 through 10 joins the cartilage of the rib above to be indirectly attached to the sternum
Ribs 11 and 12 are floating ribs, because they do not attach even indirectly to the sternum