Bones Of Truck

Axial Bones (Ⅰ)

Bones of Trunk Composition vertebrae （ 24 ） sacrum （ 1 ） coccyx （ 1 ） sternum （ 1 ） ribs （ 24 ）

1. Vertebrae ： cervical vertebrae - 7 thoracic verterbrae - 12 lumbar vertebrae - 5 sacral vertebrae - 1 (5) coccygeal vertebrae -1 (4 or 5 )

General features of vertebra One vertebral body, one vertebral arch, seven processes. 

vertebral arch ⑵

⑵

lamina

⑹

⑸

⑷

pedicle 

⑴

⑷

⑴ ⑺

vertebral body ⑴

⑸

⑶ ⑶

⑵

processes a single spinous process ⑶ paired transverse processes⑷ pairs superior⑸ and inferior⑹ articular processes



vertebral foramen⑺ → vertebral canal



intervertebral foramen

intervertebral foramen

The characteristics of vertebrae in each region (1) 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

A. Atlas: the first cervical vertebra. It looks like an irregular ring .

⑶ ⑴

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

⑷ ⑵

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

B. Axis: the second cervical vertebra. dontoid process .

C. Vertebra prominens: the seventh cervical vertebra. long and nonbifid apinous process.

Cervical vertebra

(2) Thoracic vertebrae



superior costal foveae ⑴



inferior costal foveae ⑵



transverse costal fovea ⑶



The spinous processes are

⑴

long, thin and posterodownward sloping.

⑶ ⑵

(3) 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 ．

Lumbar vertebrae

(4) Sacrum

⑴

•sacral promontory ⑴ •anterior sacral foramina ⑵

⑺

⑵

•posterior sacral foramina ⑶ •sacral canal ⑷ •superior articular processes⑸ •sacral hiatus ⑹ •transverse lines ⑺

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

⑻

⑸

⑷

⑶ ⑹ ⑻

2.Sternum •

position: lies in the midline of the anterior wall of thoracic cage (thorax)

jugular notch

manubrium

(2) parts

body of sternum

Manubrium

xiphoid process

Sternal Angle

(3) sternal angle

Body of sternum

It is an useful landmark, for indicating the level of the second costal cartilage then the ribs and the intercostal space can be determined.

xiphoid process

3.Ribs

Composition

Costal bone Costal cartilage

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

Costal neck

Costal head Costal angle Shaft of rib Costal groove

Costal tubercle

First rib ： short, sharply curved and flattered superior and inferior surfaces; inner and outer borders.

anterior scalene tubercle