L22 - Anatomy of the Spine Flashcards
General structure of the spine?
5 regions,24 individual vertebrae and 5 fused sacrum and 5 coccyx (33 total)
Increase vertebrae size down the spine
Cervical = 7 Thoracic = 12 Lumbar = 5 Sacral = 5 (fused) Coccygeal = 4 (fused)
3 functions of the spine?
– Provides vertical support forthe bodyand weight of head
– Houses and protects thespinal cord
– Helps maintain an uprightbody position
What are the curvatures of the spine?
Cervical = Lordotic (convex anteriorly) Thoracic = Kyphotic (concave anteriorly) Lumbar = Lordotic Sacral = Kyphotic
No lateral curvature normally
2 functions of spine curvatures?
– Gives column some flexibility
– Biomechanical support of weight of the body is better than a straight spine
What are primary curvatures of the spine?
– Only primary curves present in the newborn
– Concave anteriorly (Lordosis)
Two primary curvatures:
• Thoracic
• Sacral
What are secondary curvatures of the spine?
- Appear after birth
- Concave posteriorly (Kyphotic)
- Help shift trunk weight over legs
2 secondary curvature:
- Cervical curve (3-4 months)
- Lumbar curve (1 year)
Describe Kyphosis?
Abnormally excessive kyphotic curvature
> > hunchback (e.g. localized to thoracic spine)
> > Result from osteoporosis or poor posture
Define Lordosis?
- Exaggerated lumbar curvature
- Result from added abdominal weight (obesity)
Define Scoliosis?
- Abnormal lateral curvature (at thoracic spine)
- Inflation of thoracic cage more affected on the side with more severe scoliosis
Describe the typical vertebra?
2 parts:
- Body (thick anterior weight- wearing structure)
- Vertebral arch (posterior with articular structures for muscle attachment)
- Body and vertebral arch encloses Vertebral foramen and Vertebral canal = contain spinal cord, BV and lymph.
Composition of Vertebral arch?
- Pedicles (2) from posterolateral margins of body
- Laminae (2) extending posteromedially from edge of pedicle
What are the typical spinal processes?
7 processes, one single and 3 paired:
- Spinous process (1): Most posterior and largest, project from laminae junction
- Transverse processes (pair) : Lateral projection on both sides of vertebral arch
- Superior articular processes (pair)
- Inferior articular processes (pair)
Describe the connection between 2 vertebrae?
1) Intervertebral disc link vertebra body to body = cartilaginous joint/ symphysis
2) Zygophyseal joints between vertebral arches: articular processes + synovial joint capsules
Describe the connection between superior and inferior articular processes?
both originate at junction between pedicles and laminae
Each with smooth articular facet
Inferior facet articulate with Superior facet of the next vertebra below > Facet joint, synovial
What forms the intervertebral foramina?
Lateral openngs between adjacent vertebrae between 2 pedicles, bordered by superior and inferior articular processes
Provide passage for spinal nerve and BV
Composition and structure of intervertebral discs?
- Fibrocartilage pads between 2 vertebral bodies
- Mucopolysaccharide, strongly hydrophilic
Peripheral = annulus fibrosis Centre = Nucleus pulposus
Structure of annulus fibrosis of IVD?
Concentric layers of fibers
Longitudinal fibers in superficial layers become more oblique
Fibers in alternate layers slant in opposite direction
How does IVD change in width?
On standing: pressure on nucleus pulposus = water escapes = IVD thinner
On lying down: less pressure on nucleus pulposus = water imbibed = IVD thicker = taller
Structure of nucleus pulposus?
Inner gelatinous region
Acts as a ball in a swivel joint under pressure within annulus fibrosis
ROM and function of IVD?
Flexion, extension (saggital and lateral)
Rotation
Gliding
- Acts as shock absorber between vertebral bodies, allow vertebral column to bend