9. Osteology
Typical Vertebrae
Body
• Superior and inferior surfaces of body (plateaus)
• Thickened around the rim, location of epiphyseal plates
• Cartilaginous end-plates
Vertebral Arch
• Pedicles, Laminae
• Transverse Processes
• Spinous Process
• Facets – superior articular and inferior articular
Spinal Foramen
Intervertebral Foramen
17. Arthrology
Intervertebral Discs
Fibrocartilaginous joints
Increase in size from C to L (3mm to 9
mm)
Ratio remains the same
Make up 20-30% of length of column
21. Arthrology
Two Components
Outer rim of fibrocartilage called the
anulus fibrosus (attaches to cartilaginous
end plate)
Connects vertebral bodies in a
fibrocartilaginous joint (no capsule, little
motion)
22. Arthrology
Anulus encloses a central mass called
the nucleus pulposus
About 80-90% water, less with increased
age
Contains a mucopolysaccharide matrix
Changes shape, releases and absorbs
water. Thicker in AM than PM
Neither blood vessels or nerves
penetrate nucleus
23. Arthrology
Structure deforms when pressure is put on
vertebral column as in weight bearing
Acts as a shock absorber
Annulus totally encloses the nucleus and
keeps it under constant pressure
As you get older, the H2O content decreases
and the nucleus becomes more
fibrocartilaginous, therefore less easily
deformable and more easily damaged
24. Arthrology
Nucleus, when under extreme pressure, can
herniate or extrude from the disc in a posterior
or posterior-lateral direction
Usually occurs in cervical or lumbar region
Nucleus can put pressure on spinal nerve
causing refereed symptoms (motor and
sensory)
Can cause pressure on cord itself if true
posterior
27. Arthrology
Facet Joints (Typical)
Superior articular facets of one vertebrae with
inferior facets of vertebrae above
Synovial gliding joints
Surrounded by joint capsule and small
capsular ligaments
The type and amount of motion in any given
part of the spine is dictated by the orientation
of the articular facets as well as the fluidity,
elasticity and thickness of the intervertebral
discs
30. Major Ligaments of the Spine
Anterior Longitudinal Ligament - ALL
Dense band along anterior and lateral surface
of the vertebral bodies from C2 to sacrum
• Superficial - bridge several vertebrae
• Deep – short, run from V to V, blends with fibers of
anulus fibrosus
• Limits extension of V column
From C1 to skull, called Atlanto-Occipital
Membrane
34. Major Ligaments
Posterior Longitudinal Ligament
• Runs along posterior surface of vertebral
bodies (anterior to spinal canal)
• C2 to Sacrum
• Short fibers attach ligament to posterior disc,
reinforce disc posteriorly
Superiorly, continues to occiput, called
Tectorial Membrane
Limits flexion
37. Ligaments
Supraspinous
• Spinous process to spinous process – tip to
tip
• C7 to sacrum
Limits flexion
In cervical region, becomes much thicker
with a greater elastic content
Called Ligamentum Nuchae
43. Ligaments
Ligamentum Flavum
Connects lamina of one to lamina of the
other
Found from axis to sacrum
Limit flexion
Continuation to the skull is called
Posterior Atlanto-Occipital
membrane
47. Special Joints of Spine
Lumbo-Sacral
• L5 and S1 (or sacrum)
• Drastic change from lordotic to kyphotic curve
• Strong “shearing forces”
• The sacral segment is inclined anteriorly and inferiorly
forms an angle with the horizontal called the lumbo-
sacral angle
Angle can be increased significantly with an
increase in lumbar curve
During flexion/extension the greatest mobility
of the spine occurs between L5 and S1
50. L5/S1
Spondylolysis – a developmental
anomaly of the lamina wherin a bony
defect separates the sup. and inf.
Articular processes thus separating the
post. Part of the neural arch from the
ant. Arch and the vertebral body
Usually asymptomatic, very common in
males
55. S-I Joint
Review Hip Bone AKA Innominate AKA
Os Coxae
Ilium, Ischium and Pubis
Fuse at Puberty
Acetabulum
Pelvis = 2 coxal bones the sacrum and
coccyx
60. S-I
Auricular surface of ilium with auricular
surface of sacrum-Little movement
Joint under relatively constant pressure
to rotate anteriorly based on anatomical
design
Upper part of joint is not synovial, is
fibrous held in place by tough
Interrosseous S-I ligaments – helps limit
anterior motion
64. S-I – Synovial Aspect of Joint
Major Ligaments – mostly designed to prevent ant.
motion
Posterior S-I – runs down and medially from ilium to
sacrum
Iliolumbar – L4 and 5 transverse processes to
posterior iliac crest
Anterior S-I – ilium to sacrum
Sacrotuberous – iliac tuberosity and post. Surface
of lower sacrum to ischial tuberosity
Sacrospinous – lateral borders of lower sacrum and
coccyx to attach to the spine of ischium
67. Pubic Symphysis
Anterior connection of pelvis
Fibrocartilaginous joint
Limited motion
Motion increase dramatically during
pregnancy, especially at the time of birth
Similar increase in SI joint mobility at this
time
Superior and Inferior Pubic Ligaments
69. Atlanto-Axial Joint
Atlas and Axis
Pivot
Two convex superior facets of axis with two
concave inferior facets of the atlas
Atlas also posses a facet on the internal
surface of the anterior arch which articulates
with the dens of the axis
Major ligaments from spine support – Ant.
Atlanto-Occipital, Tectorial Membrane,
Post. A-O
73. A-A Joint
Alar – from dens to occiput
Transverse - around dens
Cruciate
• Sup. Longitudinal Band
• Inferior Longitudinal Band
• Transverse
74. Atlanto-Occipital Joint
Two concave superior facets of atlas
articulate with two convex surfaces of
occipital condyles of the skull
Supported by major ligaments
Small saddle joint
Very limited motion – nodding type
motions in all directions.