Lumbar spine

Question 1

Significance of curves on overall mechanics

Answer 1

• 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), suspends (LEXX’s).

Question 2

Levers

Answer 2

Lumbar lordosis, anteriorly rotated pelvis, increased lumbar lordosis, so trunk forward in plumb line. Puts a functional leverage through the posterior chain in order to make sure we don’t keep leaning forward to the point we fall.

Question 3

Impact of Scoliosis can have on spinal mechanics.

Answer 3

Lateral deviation, left or right.
Idiopathic – Growth spurts, paraspinal musculature doesn’t grow equally on both sides. Body brings in a rotation in order to keep head level. Fryet’s law key. Stetch marks on spine indicate huge growth spurts. Functional scoliosis will even out during T/L flexion. Side bending of the neck one of the first movements to go.

Question 4

Impact of Scheurman’s can have on spinal mechanics.

Answer 4

A/P deviation, increased Tsp flexion/kyphosis which leads to a hyper-extended neck or a flattened Lsp.

Question 5

Structure and function of intervertebral disk

Answer 5

Built like onions, each layer fibres run Criss-cross to each other. Creates huge stability and mobility in vectors of movement.

• The discs separate the vertebra as part of a functional segmental unit acting in concert with the facet joints.
• The intervertebral disc makes up approximately 20-25% total length of spinal column. Explains why you lose height with age.
• Nucleus pulposus 77% water which is a noncompressible fluid so it can withstand a huge degree of compressive forces.
• Annulus fibroses 70% water but higher levels of collagen which is important for flexibility and structural rigidity.
• Usually, the disc has no nerve supply, except for the peripheral posterior aspect innervated by sinuvertebral nerve. Lateral aspect innervated peripherally by branches of ant and grey rami communicants.
• The pain sensitive structures are the ALL, PLL, vertebral body, nerve root and cartilage of facet joint. Disc only causes the mechanical problem.

Question 6

LBP that’s worse when sitting

Answer 6

indicates more of a disc problem, legs dissipate the amount of compressive force from the head and torso, spreading the load. So when sitting all of this force is on the lumbar discs, especially L5/S1.

Question 7

Spondylotic changes – Sequence of events – big question to know

Answer 7

Definition: Spondy – Spine, Osis – degeneration
* Structures involved: Vertebrae, discs, facets, capsules, muscle and ligaments.
* Initial phase : degeneration of disc leading to reduced disc height.
* This leads to approximation of facets ad ligamentous laxity.
* Resulting in acute episodes of pain and muscle spasm.
* Middle stage: segment instability due to, ligamentous laxity, now unguarded movement. Chronic muscle fatigue, hypoxia and microtrauma due increased stabilising effort from muscles. Resulting in constant low-grade ache.
* Late stage: Osteophyte formation around facets and vertebral bodies leads to more episodes of acute pain along with constant acute from overuse of paraspinal musculature.