Anatomy of the vertebral
column
Objectives
1. Describe the general structure of the vertebra
2. Describe the structure of the atypical cervical
vertebrae
3. Describe the structure of typical cervical
vertebrae
4. Describe the structure of the thoracic vertebra
5. Describe the structure of the lumbar vertebra
6. Describe the structure of the sacrum
7. List the differences between vertebrae in different
regions of the vertebral column
Vertebral Column
• Consists of 31 vertebrae and the
intervening discs
• It appears as straight line
anteroposteriorly, and with
multiple curves laterally
• According to shape and location,
vertebrae can be divided into:
Cervical
Thoracic
Lumbar
Sacral
• Primary vs Secondary curve
• Spine abnormalities
Vertebral Column
• 7 C, 12 T, 5 L, 5 S
(Fused as Sacrum),
4 coccygeal
• Primary Curves
• Secondary Curves
Secondary Curves (Lateral view)
Vertebral Column
• General structure of vertebra :
Body
Pedicle
Lamina
Spine
Transverse process
Vertebral foramen
Vertebral notch
Superior articulating process
Inferior articulating process
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
Vertebral Foramen
Vertebral notch
Intervertebral Foramen
Typical Vertebrae
Ligaments of the Spine
•
•
•
•
•
Anterior longitudinal
Posterior longitudinal
Supraspinous
Interspinous
Ligamentum flavum
Vertebral Relationships
Intervertebal Discs
• Intervertebral Discs
• Fibrocartilaginous
joints
• Increase in size from
C to L (3mm to 9 mm)
• Make up 20-30% of
length of column
Discs
Discs
• Outer rim of fibrocartilage called the anulus
fibrosus (attaches to cartilaginous end plate)
• Connects vertebral bodies in a fibrocartilaginous
joint (no capsule, little motion)
• 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.
• Neither blood vessels or nerves penetrate nucleus
Discs
• 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
• With increased age, the H2O content
decreases and the nucleus becomes more
fibro cartilaginous, therefore less easily
deformable and more easily damaged
Discs
• 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 referred symptoms (motor and
sensory)
• Can cause pressure on cord itself if true
posterior
Cervical Vertebrae
• 1st cervical vertebra(Atlas)
No body
No spine
Anterior arch
Posterior arch
• 2nd cervical vertebra (Axis)
Looks like typical vertebra
It has odontoid process
(Dens)
Typical Cervical Vertebrae
• Typical cervical vertebra:
Characterized by the general structure of vertebra
but each has a bifid spine
• 7th cervical vertebra:
Characterized by
general structure
of vertebra but
it has NO bifid spine
Thoracic Vertebra
Thoracic Vertebra
•
•
•
•
•
Heart-shaped body
Long, thin, vertical spine
Round vertebral foramen
Body/foramen ratio almost 2
Superior articulating facets
facing posteriorly
• Body has impression for rib
articulation( COSTAL facet)
Lumbar Vertebra
Lumbar Vertebra
•
•
•
•
•
Kidney-shaped body
Short, thick, horizontal spine
Triangular vertebral foramen
Body/foramen ratio almost 3-4
No impression for rib articulation
Sacrum and Coccyx
The Sacrum
• Identify the following:
- Anterior sacral foramina
- Transverse lines
- Promontory
- Ala
- Posterior sacral foramina
- Median sacral crest
- Medial (Intermediate)
sacral crest
- Lateral sacral crest
- Sacral hiatus
- Cornu
- Sacral canal
Ligaments of the Spine
•
•
•
•
•
Anterior longitudinal
Posterior longitudinal
Supraspinous
Interspinous
Ligamentum flavum
Ligaments of the Spine
•
•
•
•
Tectorial membrane
Interspinous ligaments
Supraspinous ligament
Ligamentum flavum
Atlanto-Occipital Joint
• Two concave superior facets of atlas articulate with
two convex surfaces of occipital condyles of the
skull
• Supported by major ligaments:
1- Ant. Atlanto-Occipital,
2- Tectorial Membrane,
3- Post. A-O
• Small saddle joint
• Very limited motion
• nodding type motions in all directions.
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 – alar ligament and
cruciate ligament
• Cruciate ligament
Superior longitudinal
Inferior longitudinal
Transverse
C1/C2