Transcript Skull and Vertebral Column

Skull and Vertebral
Column
Locked in each human skull is
a little world all its own
– Robert Tusker
Skull
• Skull is not a single bone; 22 bones
make skull.
• Baby’s skull not fused until 18 months!
• Cranium vault made of 8 bones
• Skeletal structure of head composed of
facial and cranial bones (14 + 8)
• The occipital bone at the base of the
skull forms a complex joint with the first
vertebra of the neck, known as the atlas,
permitting rotation and bending of the
head
Baby’s Skull
Skull : Function
Skull protects sense organs
Forms the mechanical framework
Attachments for muscle
Protect and support entry points of
both, digestive and respiratory system
• The only movable facial bone ?
• Hyoid important in forensic sciences
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History of Skull!
• Earlier skulls of human ancestors
have been shown to have markedly
smaller cranial capacities, as well as
more powerful jaws, than do the Homo
sapiens species which exist today
• Phrenologists thought they could
determine a person’s personality by
the bumps on their head.
• Vikings used the skulls of their
enemies as drinking vessels.
Skull sizes
Vertebral Column
• 33 different bones
• Intervertebral disc between them to
absorb shock
• 4 curves: cervical, thoracic, lumbar,
and pelvic
• Protects the spinal cord
Cervical and Dorsal Spine
• Cervical bones - smallest. 7 bones.
First two are names as Atlas and axis.
• Atlas supports the weight of skull and
axis acts as a pivot allowing atlas to
function
• Thoracic – 12 vertebrae. Start out
smaller, increase in size until similar
to lumbar. Articulates with ribs.
Lower Back Spine
• Lumbar – 5 vertebrae. Receives most
stress, so very large. Commonly referred
to as low back
• Sacrum – 5 fused into one. Connects two
coxal bones. Articulates with L5, coccyx
at bottom, and coxals on each side
• Coccyx – Tail bone. 4 (3-5) fused into
one. Offers a small amount of support
for pelvic region.
• 31 pairs of spinal nerves
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