Part 1 Final Review Flashcards
Based on moment arm length alone, which connective tissue most effectively limits flexion torque within the thoracolumbar region?
Supraspinous ligaments are located farthest posterior to the medial-lateral axis of rotation through the body of each vertebra. This position maximizes the tissue’s moment arm for resisting a flexion torque.
Describe the arthrokinematics at the apophyseal joints between L2 and L3 during full axial rotation to the right.
The left inferior articular facet of L2 approximates (or compresses) against the left superior articular facet of L3, and the right inferior articular facet of L2 gaps (separates) from the right superior articular facet of L3.
Persons with a history of a posterior herniated disc are usually advised against lifting a large load held in front the body, especially with a flexed lumbar spine. How would you justify this advice?
Lifting a large load held in front of the body can generate large muscular-based compression forces across the lumbar intervertebral discs. Lifting with a flexed lumbar spine converts the large compression force to a large disc pressure. Lumbar flexion tends to direct the flow of the nucleus pulposus in a posterior direction. If degenerative clefts exist in the annulus, the nucleus may flow posteriorly in the direction of the sensitive neural elements.
Assume the subject depicted in Fig. 9-10C has increased lumbar lordosis caused primarily by tightened (shortened) hip flexor muscles. Describe the possible negative kinesiologic or biomechanical consequences that may result within the lumbar and lumbosacral regions.
Significantly increased lumbar lordosis may be associated with the following negative kinesiologic consequences:
1. Increased stress on fully extended lumbar apophyseal joints
2. Increased sacrohorizontal angle and resultant increased anterior shear forces at the L5–S1 junction
3. Reduced size of the intervertebral foramina and possible compression of the exiting lumbar spinal nerve roots
With the visual aid of Fig III-1 (in Appendix III, Part A), explain why a severe posterior herniated disc between the bodies of L4 and L5 can compress the L4 spinal nerve root, but possibly L5 and all sacral nerve roots as well.
The spinal cord ends approximately at the L1 vertebral level. The spinal nerve roots that flow caudally from the end of the spinal cord form the cauda equina, which occupies the vertebral canal of most of the lumbar and sacral vertebrae. Disc material that protrudes posteriorly into the vertebral canal adjacent to L4 and L5, for example, could potentially impinge on all remaining fibers within the cauda equina, which includes all sacral nerve roots.
Describe the mechanical role of the annulus fibrosis in distributing compression forces across the interbody joint.
Increasing the intervertebral joint compression increases hydrostatic pressure within the nucleus pulposus. The increased nuclear pressure pushes radially (outward), as it is resisted and partially absorbed by tension in the stretched annulus fibrosis. The combined nuclear pressure and taut annular rings help support and evenly distribute intervertebral compression. Tears or weakness within the annulus fibrosis reduce the effectiveness of this load absorption system.
Facet orientation:
____-_______ apophyseal joints much closer to ______ plane
Provides ___/____ stability to lumbosacral junction
L5- S1
frontal
A/P
Describe how an overshortened (contracted) iliacus muscle can cause an increased lumbar lordosis while a person is standing. What effect could this posture have on the stress at the lumbosacral junction?
While in a standing position, a contracted iliacus muscle rotates the ilium (pelvis) anteriorly toward the femur. Assuming the trunk is maintained upright, this movement is typically described as an excessive anterior tilt of the pelvis. The lumbar spine is forced to rotate into extension, which increases its lordosis. Excessive lumbar lordosis is likely associated with an increased sacrohorizontal angle and an increased anterior shear force at the L5–S1 junction.
_______ _______ : The amount of intervertebral movement that occurs with the least passive resistance from the surrounding tissues (minimal stiffness zone)
neutral zone
Neutral zone: is increased with _______ or _______ or surrounding tissues
______ or ________ instability can acuse further injury (legs/facets/discs/neural)
weakness; injury
marked; chronic
________ _________ anterior, primary weight-bearing component
vertebral body
_______ _______ : transverse/spinous processes, laminae, articular processes
posterior elements
_________ : bridge that connects body-posterior elements; thick and strong, transfers muscles forces applied to posterior elements for dispersion across body/disc
pedicles
It is thought that the _______ ________ is a better measurement of instability than spine ROM
neutral zone
If the neutral zone grows larger as disc _______ or _________ injury occurs, there is more laxity or instability in the spine to control and more demands are placed on the _______ ________
degeneration
ligamentous
stabilizing systems
_______ stability can also be viewed from a segmental level as well as ______ spine level. When the neutral zone is larger than usual, there is more ______, ________, and ______ of the vertebrae and the spinal segments become ________
Core stability
whole
slide, glide, rotation
unstable
The neutral zone has been found to increase with _______ and _________ and decrease with ______ ______
injury; degeneration
muscle force
With injury (DDD) the _______ motion pattern changes and influences the motion of the whole spine, potentially causing ______ and _______
vertebral
pain
hypermobility
Marked or chronic spinal instability
Believed to cause further injury to _____ _______
Injury to ______ (apophyseal joints), ______ and possibly _____ structures
Can result in loss of pain-free ______ ROM
local ligaments
facets; discs; neural
spinal
The ___________ ________ consists of the bony structures, ligaments, joint capsules, discs, and passive portion of the musculotendinous units This system is thought to send feedback to the neural subsystem about joint positions and challenges to stability at the passive level
passive system
The _______ _______ is composed of the muscles and tendons and is the subject of the core exercises later.
active system
The _______ _______ receives and transmits information from and to the other two systems to manage spinal stability. Neuromuscular control can be compromised in patients with LBP and must be considered in a core stabilization program
neural subsystem
Typically intervertebral joints- 3 functional components:
________/__________ ________
(mechanical levers that increase mechanical leverage of muscles and ligaments)
_________ __________ (guiding intervertebral motion)
_________ ( _____________) _____ (absorb and distribute load, >est adhesion between vertebrae, houses axes of rotation, is a spacer, provides passage for nerves)
transverse/spinous processes
apophyseal joints
interbody; intervertebral joint
__________
Normally compressive forces produce _______ _______ in disc and evenly distribute _____- protecting intervertebral and aophyseal joints
Changes precede _______
Degeneration
hydrostatic pressure
load
OA
Least to most
Supine (LEAST- 1)
Side-Lying (2)
Standing (5)
Standing bent over (8)
Sitting in Chair (4)
Sitting hunched over (6)
Sitting reclined (3)
Standing bent over with box (10)
Standing with box between knees (9)
Standing straight up with box (7)
____ degrees of thoracic flexion
______ degrees of lumbar flexion
= 85 degrees total
35
50
_____ degrees of thoracic extension
______ degrees of lumbar extension
= 35 degrees total
20
15
Rotation ____-_____ degrees
_______ plane
25; 35
horizontal
Lateral flexion to each side ___-____ degrees (ribs prohibit more)
Lateral flexion similar to ___-____
25; 30
C2; C7
What is this?
T1 weighted MR image
anterior spondyliolosthesis of L5 on S1
A normal kinematic strategy used to flex the trunk from a standing position, incorportating a near simultaneous ____ degrees of a flexion of the lumbar spine and _______ degrees of hip (______ on _______ ) flexion
45
60
pelvic; femoral
Lateral flexion of lumbar spine
_____ degrees each side
Slight ______ in disc
20
deformation
