Lumbar Osteokinematics/Arthokinematics

L1-L4 sit in what plane?

Sagittal (25-40º)

L5-S1 sit in what plane?

Frontal

Superior Articular facets Orientation

Medial and posterior

Inferior Articular facets orientations

Lateral and anterior

L/S facet bear ______ of load

20%

What position puts the most stress on the facet joints?

Hyper lordosis

What percent of BW goes through S1 end plate?

60%

An angle increase to 55º leads to

80% of BW gong through S1 anteriorly

Open-Packed position

Neural

Closed-packed position

Extension

Capsular pattern

Side-bending , rotation > extension

Normal value for flexion

40-60º

Normal value for extension

15-20º

Normal value for side-bending

20-25º

Normal value for rotation

5-10º

Flexion: Inferior Facets

Upglides

Flexion: Intervetebral foramen

Opens

Flexion: Disc

Pushed posterior

What structures limit flexion?

Ligamentum flavum, PLL, posterior disc, interspinous/supraspinous ligaments

Extension: Inferior facets

Downglide

Extension: Intervertebral foramen

Closes

Extension: Discs

Pushes anterior

What limits extension?

ALL and anterior discs

Side-bending: Inferior facets

Ipsilateral: Downglide/Compresses

Contralateral: Upglides/Gaps

Side-bending:Intervertebral foramen

Ipsilateral: Closes

Contralateral: Opens

What limits side-bending?

Contralateral side ligaments

Rotation: Facets

Ipsilateral: Gaps

Contralateral: Compresses

Rotation: Intervertebral Foramen

Ipsilateral: Closes slightly

Contralateral: Opens slightly

SI joint is what type of joint

Synovial; Syndesmosis

SI joint runs from ________

S1-S3

S1 is wider at the

Dorsal surface

S3 is wider at the

Anterior surface

Nutation

flexion or anterior tilt of sacrum

Counter nutation

Extension or posterior tilt of sacrum

Closed pack position Of SI joint

Full nutation

When does nutation happen?

1st 60º of spinal flexion

Goal of ipsidirectional lumbopelvic rhythm

Displacement of the trunk

Contradirectional lumopelvic rhythm

Displacement of pelvis on fixed femur

During contradirectional lumbopelvic rhythm the lumbar spine __________

decouples motion

Lumbopelvic rhythm: Flexion

Spine flexes, sacral nutation, APT, hip flexion, sacral counternutation at the end of motion

Lumbopelvic rhythm: Flexion Ratio

2:1 Hip to L/S

Lumbopelvic rhythm: Extension

Hips extend, ilium posterior rotating, spine extends, sacrum counternutates, sacrum rests in nutation at the end position

Lumbopelvic rhythm: Rotation

Pelvis rotates to the same side, Ipsilaterally ilium posterior rotation, contralateral ilium anterior rotation, sacrum nutates Ipsilaterally