Section 2 Bones of trunk
Bones of trunk include:
* vertebrae
* ribs
* sternum
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A. Vertebral column
is divides into:
1. Cervical vertebrae 7
2. Thoracic vertebrae 12
3. Lumbar vertebrae 5
These 24 are independent
vertebrae (true vertebrae).
4. Sacral vertebrae 5
→sacrum.
5. Coccygeal vertebrae 4
→coccyx (false vertebrae).
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B. General features of the typical vertebra
It is composed of:
1. a body
2. vertebral arch: two pedicles, one lamina.
3. seven processes:
--- a spinous process
--- two transverse processes
--- two superior articular processes
--- two inferior articular processes
* The body with the arch surrounds a vertebral foramen.
* In the vertebral column, all of the foramina form the
vertebral canal, which lodges the spinal cord et al.
* A notch above or below the pedicle with its neighbour
forms the intervertebral foramen, which transmits
spinal nerve et al.
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C. The main characteristics of
vertebrae in each part
1. Cervical vertebrae
a) * a transverse foramen
b) * spinous processes
are short and bifid.
c) the first one hasn’t body
and spinous process (Atlas).
d) the second has a dens (Axis).
e) the 7th’s spine is the longest and easily felt
out (vertebral prominens).
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2. Thoracic vertebrae
a) there are costal fovea
(superior, inferior
and transverse costal fovea)
b) the spinous process are long and
downward sloping.
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3. Lumbar vertebrae
The spines are strong,
square and horizontal.
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4. Sacrum
a) base of sacrum
(promontory).
b) pelvic surface
(concave, 4 pairs of
anterior sacral foramina).
c) dorsal surface
(convex, 4 pairs of
posterior sacral foramina).
d) lateral part
(auricular surface).
e) Sacral canal(sacral hiatus).
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D. Ribs
1. 12 pairs
a) The upper seven ribs are
referred to as true ribs.
b) The lower five ribs
are false ribs.
c) The eighth, ninth and tenth ribs join
together one by one to form the costal
margins(or costal arch) by means of the
costal cartilages.
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2. Shape of a typical rib
a) a posterior extremity
(costal head,
costal neck,
costal tubercal).
b) shaft of rib
(costal angle, costal groove).
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E. Sternum
1. Subdivision
It is divided into:
a) Manubrium
(jugular notch, clavicular
notch and 1st costal notch.
b) Body
(costal notches).
c) Xiphoid process.
2. General feature
a) Sternal angle:
it marks the position of the second rib.
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