LUMBAR SPINE AND PELVIS Flashcards
THE LUMBAR SPINE AS A GIANT BENDY SPINE
- The plasticity of the column lies in its make-up, that is multiple components superimposed on one another and interlinked by ligaments and muscles
- A conical column with curves becomes a spring which has both compressive and tensile strength qualities, leading to great tolerance of ground force reaction forces, gravitational forces, multi vector movements
- It is both a support (trunk), and suspender (lower extremity)
FRYET’S LAW
Side bending rarely happens without rotation
FORM FORCE CLOSURE
Pelvis- shapes fit together and form closure to support
Sacrum and ilium each have one flat surface and one ridged surface which interlock together, promotes stability
Force closure
Contraction of muscles and ligaments hold the bones together and keeps them stable
FORCE COUPLING
Pivot point where it has multiple forces pulling in multiple forces to allow rotation
Pivot point around acetabulum
Key muscles groups- Lip erector spine, QL, hamstrings, hip flexors, poses, abdominal walls
CYLINDERS
Provides same tensile compression strengths as well as flexibility
Copes with multiple vectors of movements
CENTRE OF GRAVITY AND THE LATERAL PLUMB LINE
Cervical spine lies central to the plumb line to support the head
Thoracic spine, it lies posterior to plumb line to make room for internal organs
Lumbar spine, it lies central to plumb line to support all the weight of the trunk
INTERVERTEBRAL DISC - COMPOSITION
The discs separate the vertebra as part of a functional segmental unit acting in concert with the facet joints
The intervertebral disc makes up approx. 20-25% total length of the spinal column
INTERVERTEBRAL DISC - INNERVATION
Usually the disc has no nerve supply, except for the peripheral posterior aspect innervated by the sinuvertebral nerve. Lateral aspect innervated peripherally by branches of anterior and grey rami communicants
The pain sensitive structures are the
- ALL
- PLL
- Vertebral body
- Nerve root
- Cartilage of facet joint
STRUCTURE OF INTERVERTEBRAL DISC
Disc separates vertebra as part of functional segmental unit acting in unison with facet Jts
Disc= 20-25% of spinal column
Usually has no nerve supply, except peripheral post aspects innervated by intervertebral nerve
Lateral aspects innervated peripherally by branches of ant and grey rami communicants
P sensitive structures are vertebral body, nerve root, cartilage of facet Jt ALL and PLL
FUNCTION OF INTERVERTEBRAL DISC
Water is non-compressible fluid, allows for ‘preloading’ to occur
Allows greater water resistance to compressive forces
Layering of annulus allows tolerance of asymmetrical loading, especially torsion
20 alternating orientations of layers of annulus allow for multiple vectors of movement
Annulus and nucleus become functional couple reliant on structural integrity of each other
Becomes mechanism of self-stabilisation
Combination of gel-filled nucleus pulpous and fibrous nature of annulus- varies angle between vertebra to accommodate changes in lordotic and kyphotic curves
PATHOLOGICAL PROCESSES OF THE SPINE
o Degenerative – spondylosis
o Developmental – scoliosis/scheurmans
o Rheumatological – Ankylosing spondylosis
o Traumatic – spondylolisthesis
o Nutritional – osteoporosis
IMPACT SCOLIOSIS HAS ON SPINAL MECHANICS
Spinal shear and compression are inc
Overgrowth of ant aspect of spine and rotation of vertebral bodies
Trunk stability is dec due to muscular difference on concave side of spine compared to convex side
IMPACT SCHEURMANS KYPHOSIS HAS ON SPINAL MECHANICS
Inc thoracic flexion, due to inc kyphosis
Tends to cause flattened Lsp or hyper extend neck, or both
Seen in teenagers
SPONDYLOTIC CHANGES - DEFINITION
Spony- spine
Osis- degeneration
SPONDYLOTIC CHANGES - STRUCTURES INVOLVED
- Vertebrae
- Discs
- Facets
- Capsules
- Muscle
- Ligaments
