Anatomy of the vertebral column. Objectives 1.Describe the general structure of the vertebra...
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Transcript of Anatomy of the vertebral column. Objectives 1.Describe the general structure of the vertebra...
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 ForamenVertebral notchIntervertebral 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