Wednesday, February 16, 2011

Bones of Trunk

Axial Bones

Composition :

vertebrae(24)
sacrum (1)
coccyx(1)
sternum(1)
ribs(24)




Cervical vertebra :

a.the body: small

b. transverse foramen

c. spinous processes :

short and bifid (except 1,7 cervical vertebrae)

d. vertebral foramen : triangular and relatively large


Atlas:

the first cervical vertebra.
It looks like an irregular ring .

anterior arch ⑴
posterior arch ⑵
lateral mass
dental fovea ⑶
groove for vertebral artery⑷


Body and spinous process absent, consists of anterior and posterior arches, and two lateral masses.





Axis:

the second cervical vertebra.
dontoid process .


Vertebra prominens:

the seventh cervical vertebra.
long and nonbifid
apinous process.




Thoracic vertebrae:

superior costal foveae ⑴
inferior costal foveae ⑵
transverse costal fovea ⑶
The spinous processes are long, thin and posterodownward sloping.







Lumbar vertebrae :

large, thick bodies

The spinous processes are heavy, rectangular and strong, with posterior directions

The vertebral foramen is triangular, but larger than that in the thoracic region.



Sacrum and Coccyx :

sacral promontory ⑴
anterior sacral foramina ⑵
posterior sacral foramina ⑶
sacral canal ⑷
superior articular processes⑸
sacral hiatus ⑹
transverse lines ⑺

The coccyx is composed of 4-5 fused coccygeal vertebrae after the age of 30 years. ⑻


Sternum :

True ribs : the upper 7 ribs, reach to the sternum anteriorly. (1-7)

False ribs: the lower 5 ribs, fail to reach the sternum. (8-12)
Costal arch ------the 8-10th ribs join the costal cartilage immediately
above to form the costal arch.
Floating ribs------the cartilage of the last two ribs are free.



General features of costal bone :


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