Vertebral Column and bony
thorax
Vertebral Column and bony thorax
•Formed
from 34-56 bones in the different adult
animals
•Extends
from skull to pelvis
•Transmits
weight of trunk to the lower limbs
•Surrounds
and protects the spinal cord
Vertebral Column
1- Cervical Vertebrae
2- Thoracic Vertebrae
3- Lumbar Vertebrae
4- Sacrum
5- Coccyx (Caudal)
Typical Vertebrae:
Consists of:
1- Body (1)
2- A vertebral arch
- right and left Pedicles and Lamiae
3- Transverse process (7)
4- Spinous process (9)
5- Articular process (5)
Cervical Vertebrae
Seven
cervical vertebrae (C1 – C7) – smallest and
lightest vertebrae
•C 3
– C7 are typical cervical vertebrae
•Body
is small, wider side to side
•Spinous
processes - short and bifid (except C7)
•Vertebral
foramen - large and triangular
•Transverse
foramina
processes- contain transverse
Atlas – C1
•Lacks
•No
a body and spinous process
intervertebral disc between C1 and C2
•Supports
the skull
–Cranial
articular facets receive the occipital
condyles (Atlanto-occipital Joint)
The Axis - C2
-The most prominent feature is
ridge like spinous process
- Cranially the body project peg
like eminence (the dens)
Vertebrae (T1 – T13)
All
articulate with ribs
•Spinous
process- long, sharp, projects caudally
•The
spine of 11th vertebrae is perpendicular
(anticlinal).
•12th
and 13th process project cranially
•Vertebral
•Each
Foramen - circular
side of the body bears demifacets for
articulation with ribs
Lumbar Vertebrae (L1 – L5)
Body–
large, kidney shaped
•Transverse
•Spinous
processes are thin and tapered
processes are short, thick, blunt, and
point caudally
Sacrum (S1 – S3)
•Formed
from 3 fused vertebrae
Coccyx (Caudal):
•Is
the "tailbone"
•Small,
triangular bone
•Formed
•Offers
from 15-20 vertebrae
only slight support to pelvic organs
Intervertebral Discs
•Cushion-like
pads between vertebrae
•Nucleus
pulposus – gives the disc its elasticity
and compressibility
•Annulus
fibrosis – strong outer ring of
fibrocartilage which surrounds the nucleus
pulposus and limits its expansion
Bony Thorax
Forms
the framework of the chest
•Components
•Thoracic
•Ribs
of the bony thorax
vertebrae – dorsally
– laterally
•Sternum
and costal cartilage – ventrally
•Functions
•Protects
thoracic organs
•Supports
shoulder girdle and upper limbs
•Provides
attachment sites for muscles
Sternum
•Composed
form eight unpaired segments, the
sternbrae.
•
Joined by intersternebral cartilages
–Manubrium
–Xiphoid
– 1st sternbra
process – last sternbra
Ribs
•13
pairs, form the sides of the thoracic cage
•All
ribs attach to vertebral column dorsally
•True
ribs - superior nine pairs of ribs which
attach directly to sternum by costal cartilage
•False
ribs – remaining 3 pairs of ribs which
attach indirectly to the sternum
•Float
ribs-rib#13
- Structure
•Shaft
–bulk of the rib
•Head
– dorsally most end
•Neck
– constricted portion of head beyond head
•Tubercle
– articulates with transverse process of
the thoracic vertebrae