Joint Type

  • Gliding (zygapophyseal joints)
  • Cartilaginous (intervertebral joints)

Articular Surfaces

Thoracic
Facets are oriented in coronal plane
Lumbar
Facets are oriented in sagital plane
Sacroiliac
Facets are oriented 45°, discs are oriented in horizontal plane

L-Spine Active Range

Flexion 90°
Extension 30°
Lateral Flexion 30°
Rotation 30°

Sacroiliac Active Range

Flexion 0-10°
Int./External Rotation 0-10°

Main Muscle Actions

Flexion
Iliopsoas, Rectus Abdominis, Internal/External Oblique
Extension
Multifidi, Erector Spinae
Lateral Flexion
Erector Spinae, Semispinalis, Rectus Abdominis, Internal/External Oblique
Rotation
Rotatores, Multifidi, Semispinalis, Erector Spinae, Internal/External Oblique

Resting Postion

T-Spine & L-Spine
Mid way between flexion and extension

Close Packed Position

T-Spine & L-Spine
Full extension

Capsular Restriction

T-Spine & L-Spine
Lateral flexion = rotation, then extension

Normal End Feel

Flexion, Extension, Lateral Flexion & Rotation
Tissue stretch

Abnormal End Feel

Early Myospasm Muscle/Ligament Tear
Late Myospasm Instability
Empty Ligament Rupture
Hard Bone Approximation (Osteophyte)

Coupled Motions

Pure rotation and pure lateral flexion do not occur at any region in the spine

T6-L5 Vertebral Segments
  • Left lateral flexion coupled with left rotation
  • Right lateral flexion coupled with right rotation
  • Opposite to the coupling that occurs in the cervical and upper thoracic spine

  • Lumber motion is also coupled with sacral motion
  • Lumber flexion is coupled with sacral nutation (anterior sacral tilting or “nod”)
  • Lumber extension is coupled with sacral counternutation (posterior sacral tilting or extension)