Biomechanics Flashcards
Location: Where the following can be palpated
- Spinous Process
- Transverse Process
- Facets Joints
- Vertebral bodies
- C/T/L-Spine
- C/T-Spine
- C/T/L-Spine
- C-Spine
Term: Area bridging the superior and inferior articular processes
Pars Interarticularis
Functions: Pars Interarticularis
Important for load transfer
2 Types of Joints in the Spine
- Facet Joints (posterior column)
- Intervertebral (anterior column)
Term: a disc, 2 vertebral bodies, 2 facet joints, and surrounding soft tissue
Motion segment
Term: The gliding movement of one vertebra across the surface of the other
Translation
Spinal Ligament:
- Entire length of spine anterior to vertebral bodies
- Prevenets hyperextension
- Innervated with sensory nerves
Anterior Longitudinal Ligament
Attachment: Anterior Longitudinal Ligament
Attached more to vertebral bodies than discs
Bulging Disc: Less common and less painful
Anterior Disc Bulge
Spinal Ligament:
- Runs the entire length of the spine
- Fans out across discs
- Prevents posterior disc protrusion
Posterior Longitudinal Ligament
Attachment: Posterior Longitudinal Ligament
Attached primarily to discs, not bodies
Spinal Ligament:
- Covers posterior neural arch and 2 lamina
- Yellow in appearance (due to being 80% elastin)
- Protects spinal cord
- Limits flexion
Ligamentum Flavum
Attachment: Ligamentum Flavum
Attaches to anterior facet joint
Describe the effect of degenerative changes in ligamentum flavum
Degenerative changes lead to decreased elasticity which allows to ligament to buckle and compress the spinal cord roots
Spinal Ligament:
- Segmental ligament
- Gives segmental stability
Intraspinous ligament
Spinal Ligament:
- Thick and cord like
- Has transverse fibers that attach segmentally
- At greatest risk for injury
Supraspinous Ligament
Spinal Ligament:
- Primary ligament of the lumbopelvic region
- Innervated
- Potential source of pain
Iliolumbar Ligament
Attachment: Iliolumbar Ligament
From L4 transverse processes/vertebrae to ilium
Joint Type: Facet Joint
Synovial Joint (Thus can experience arthritic changes and cause pain)
Facet Joint Orientation
- C-spine
- T-spine
- L-spine
- L5-S1
- 45 from horizontal
- coronal or 90 from horizontal
- sagittal
- coronal
List the planes in amount of rotation allowed (from most to least)
Horizontal > Coronal > Sagittal
Thoracic Facet Joint Orientation in the Coronal Plane
- Upper
- Middle
- Lower
- 60
- 90
- 0
Motions Allowed:
- C-spine
- T-spine
- L-spine
- Some rotation and translation
- Allows rotation; prevents AP translation
- Allow AP translation; prevents rotation
Spinal Segments: Accounts for 50% of rotation in C-spine
C1-C2
Structure: Defines movement in the spine
Top vertebrae
Structure: Defines rotation in the spine
Anterior vertebral body (spinous process does opposite)
Describe the Segmental Motion during Spine Flexion
Facets glide superiorly and anteriorly
Anterior sagittal rotation and translation occurs
Foramen and facets are opened
Describe the Mechanics of Flexion
Abs are used to initiate flexion
Beyond 40 degrees Gravity takes over
The abs no longer need to contract as the passive structures (ligaments, capsules, fascia) support flexion
NO eccentric contraction of extensors
Describe the Segmental Motion during Extension
Facets glide posterior and inferior
Posterior sagital rotation and minimal translation occurs
Facets close and foramen narrow
Describe the Mechanics of Extension
Back extensors initiate and maintain extension
Abdominals work eccentrically and aid extensors
Describe the effect of lordosis on the facet joints
Makes them WB joints
Limiters to Rotation:
1st
2nd
3rd
1st = contralateral facet closing
2nd = ipsilateral facet overstretching the capsule
3rd = disc
Describe the Facet Movement with SB
Ipsilateral facet glides inferiorly (extends)
Contralateral facet glides superiorly (flexes)
Neutral Spine Coupling: C-spine
SB and rotation coupled in SAME direction
Neutral Spine Coupling: T-Spine
Above T9: SB and rotation coupled in SAME direction
Below T9: SB and rotation coupled in OPPOSITE direction
Neutral Spine Coupling: L-Spine
SB and rotation coupled in the OPPOSITE direction
Flexed/Extended Spine Coupling: L-Spine
SB and rotation coupled in the SAME direction