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THE TRUNK and SPINAL COLUMN
Chapter 12
Bones of the Spinal Column
33 bones, 24 are flexible
A. Cervical - 7B. Thoracic - 12C. Lumbar - 5D. Sacrum - 5 (false
vertebrae - fused together)E. Coccyx - 4 (false
vertebrae - fused together) LINK Click on
picture
Landmarks of the Vertebrae
General Landmarks
1. Spinous process
3. Transverse process - tubercle of rib articulates
5. Body
6. Vertebral foramen
General Landmarks Vertebral notch
Superior Inferior
General Landmarks
Intervertebral foramen
Cervical Vertebrae
Cervical Vertebrae
First 7 vertebrae Identified as C1 – C7 C1 = Atlas C2 = Axis
Atlas (C1)
• Large vertebral foramen
• Transverse ligament
Anterior
Posterior
Axial (C2)
Odontoid process or Dens
Thoracic (T1-T12)
Thoracic (T1-T12)
Lumbar (L1-L5)
Lumbar (L1-L5)
Note the differences:1. Transverse process2. Spinous process3. Body
Note the differences:1. Transverse process2. Spinous process3. Body
Sacrum
Intervertebral Disks
Intervertebral Disks
Actions of the Spinal Column
Flexion Extension Lateral Flexion Rotation
Same sideOpposite side
Flexion
1. Free in all three regions
2. Cervical and thoracic curves may be reduced to straight lines
3. Lumbar curve may be reversed in flexible subjects
Cervical flexion
Lumbar flexion
Extension
1. Free in all three regions
2. Cervical and thorasic curves may be reduced to straight lines
3. Lumbar curve may be reversed in flexible subjects
Cervical extension
Lumbar extension
Lateral flexion
1. Free in cervical and lumbar regions
2. Limited in thorasic region by rib attachments
3. Accompanied by torsion
Cervical lateral flexion
Lumbar lateral flexion
Rotation
1. Freest at top, least free at bottom
2. Accompanied by slight lateral flexion
Cervical rotation
Lumbar rotation
Joints of the Spinal Column
Atlantooccipital joint
Articulation between the head and neck i. Atlas (C1) ii. Occipital bone
Acts as a hinge joint; flexion and extension
No rotation at this joint
Atlantoaxial
Articulation between C1 and C2
a. pivot joint - rotation is here
b. the dens or ondontoid process fits into the inner, anterior portion of the vertebral foramen
with the help of the transverse ligament.
Arthordial or gliding-type joints
Composed of the synovial joint between superior and inferior articulating surfaces
Cartilaginous or synarthrodial joints
Intervertebral disks i. nucleus pulposus - gel ii. annulus fibrosus - covering
Shape and thickness varies with location
Make up approximately 25% of the column length
Allow limited motion in all three planes
Defects of the Spine
Kyphosis - hunchback
Increase anterior concavity ( or curvature) of the thoracic curve
Lordosis - swayback
Increase posterior concavity of the lumbar region. it causes
shortened back extensors
it causes lengthened abdominal
Scoliois Lateral curvatures or sideward
deviations of the spine. Decreases the ability of the
spin to support the body Distorts the body cavity and
that crowds the organs Puts pressure on the nerves Causes:
Imbalance of the deep back muscles and ligaments
Scoliois
Treatment Body cast Electrical stimulation
of deep muscles Harrington Rod
implant - ratchett effect
Sternum
Ribs
12 pairs 7 pair are ‘true’ ribs 5 pair are ‘false’ ribs
3 pair attach indirectly to the sternum 2 pair are ‘floating ribs’ that don’t attach to
the sternum
Ribs