Lumbar Biomechanics Flashcards
Describe the CP, DoF, CPP of the L/sp.
i) side flexion and rotation limited more than ext
ii) 3 DOF: flex/ext, SF (oblique), rotate (oblique)
iii) extension
Describe the OK of the L/sp.
i) flex: anterior rotation, anterior translation (50-70 deg,L4>L3>L2>L5>L1
ii) ext: posterior rot’n, posterior translation (20-35 deg, L1 and L5 >L2, L4 > L3)
iii) side flex: All w/ ipsi translation, upper w/ contral rot’n, L4/5 variable and L5/S1 ipsi rot’n (10 deg)
iv) rotation: pure rot’n 3 deg then axis becomes impacted z-jt, swings laterally and ipsi facet distracted and contra facet impacted
How to vertebral bodies protect discs from failure from overcompression?
With static compression, the annulus bulges circumferentially and places load through the end plate. Fluid is slowly squeezed out via the veins, in the case of rapid rate loading the small vessel size retards fluid outflow increasing the compressive strength of the vertebral body and protecting the disc.
Describe the arthrokinematics of the L/sp.
i) flex: superior anterior glide SAP
ii) ext: posterior inferior glide of SAP
iii) side flex: ipsi inferior and posterir, contra superior and anterior
Describe the classification and OK of the SI joint.
i) diarthro-amphiarthrosis
ii) trunk flexion: innominate posteriorly rotates, sacrum nutates
ii) trunk extension: innominate posteriorly rotates, sacrum nutates
iii) trunk R side flexion: R innominate anteriorly rotates L innominate posteriorly rotates, sacrum rotates L
iv) trunk R rot’n: R innominate posteriorly roates and L innominate anteriorly roates, sacrum rotates R
v) R hip flex: innominate posteriorly rotates, sacrum remains nutated relative to side
Describe the arthrokinematics of the SIJ.
i) anterior rot’n of innominate: inferior and posterior glide
ii) posterior rot’n: anterior and superior glide
iii) sacral counternutation: glides anterior and superior
iv) sacral nutation: glides posterior and inferior
