Exam 3 Learning Objectives Flashcards
Components of an Intervertebral Disc
- Nucleus pulposus
- Annulus fibrosus
- Vertebral Endplate
Nucleus pulposus
Structure
- Central portion of the disc, except in the L-spine → posterior
- Loose collagen fibril network contained w/in an extensive gelatinous matrix (Primarily type II collagen)
- High proteoglycan content at birth, decreases w/ age and is replaced by collagen
- Degeneration begins after 20 years
- Leads to a loss of disc height causing more load to be placed on the facets
- Imbibing properties of the proteoglycans lead to an increased water content percentage (85% at birth, 65% ~60)
Function
- Imbibition
- Force Transmission
- Stress Equalization
- Movement
- Nutrition
Annulus Fibrosus
Structure
- Made up of ~20 concentric rings
- Fiber pattern in each ring is offset (~60-120 degrees, depending on the source)
- Well innervated, contributes to discogenic pain when it bulges
Function
- Handles compression, shear, and torsional forces
Vertebral Endplate
A 1 mm thick plate of hyaline cartilage that helps attach the disc to the body of the vertebrae from above and below
Alignment of Cervical Facets
- Oblique
- 45 degrees to transverse plane and parallel to the frontal plane
- Allows for all movements (flex, ext, lateral flex, and rotation)
Alignment of Thoracic Facets
- 60 degrees to transverse plane and 20 degrees to frontal plane
- Mostly lateral flexion and rotation w/ limited flexion/extension
Alignment of Lumbar Facets
- 90 degrees to transverse plane and 45 degrees to frontal plane
- Maximal flexion/extension and lots of lateral flexion
- Minimal rotation
Why is ligamentum flavum yellow?
High elastin content
What is the purpose of the ligamentum flavum?
- Allows it to stretch during flexion and “contract” in extension
- Helps to add pre-tension to the disc and stabilize the spine in the posterior segment
Cervical Vertebrae
- 7 vertebrae
- Transverse foramen
- Bifid spinous process
Atlas
Does not have a body or disc
Axis
- Has dens to articulate w/ atlas
- 50% of neck rotation comes from atlantoaxial joint
Thoracic Vertebrae
All 12 have a notch in their transverse processes and a facet on their bodies for rib attachment
Lumbar Vertebrae
- Thicker and bigger to handle compressive loads and strong muscle forces
- Lordotic curve places shear force on the discs at the lower levels
Law of Motion for Cervical Vertebrae
Sidebending and rotation to same side
Law of Motion for Thoracic Vertebrae
Sidebending and rotation to opposite side
Law of Motion for Lumbar Vertebrae
Sidebending and rotation to opposite side except in extreme flexion (same at this point)
Spine Movement- Rotation
- Greatest in cervical and upper thoracic spine
- Limited in lumbar spine until L5-S1
Spine Movement - Flexion
- Greatest in cervical and lumbar spine
- Increases in thoracic spine moving caudally
- Spinal flexion occurs in the lumbar spine for the first 50-60 degrees of movement
Spine Movement- Lateral Flexion
- Greatest in cervical and thoracic spine
- Limited in lumbar spine, especially at L5-S1
Factors that Increase Spinal Pressure Under Load
- Position of the object relative to the COM (further = more pressure)
- Size, shape, weight, density of the object
- Degree of flexion and rotation of the spine
- Rate of loading
Function of Facets
- Facets “open” w/ flexion, “close” w/ extension
- Facets guide movement of the motion segment
- Assist in load-bearing
- Greatest load on facets occurs in hypertextension
- Increased load when fully flexed coupled w/ rotation
4 Steps of Disc Herniation
- Protrusion
- Prolapse
- Extrusion
- Sequestration
Protrusion
- Posterior bulge in the nucleus pulposus
- Does not rupture the innermost laminae
Prolapse
Nuclear bulge ruptures all layers except for outermost laminae
Extrusion
Nucleus pulposus escapes into the extradiscal space
Sequestration
- Complete rupture and leaking of nucleus into space
- Formation of discal fragments from the annulus fibrosus and nucleus pulposus in the extradiscal space
Cauda Equina Syndrome
- Rarely, a disc herniation can be so big that it fills the entire spinal canal
- The subsequent pressure on the spinal cord may cause paralysis of the muscles that control the bowels and bladder, as well as bilateral loss of function in lower extremities
Sacral Torsion and Nutation
- When the lumbar spine flexes, the sacrum posteriorly nutates (extends)
- When the lumbar spine extends, the sacrum anteriorly nutates (flexes)
- Abnormal mechanics in the lumbar spine can negatively affect sacral movement
- Abnormal sacral position directly affects the pelvis and proper pelvic motion
Factors that increases dynamic loads on the spine
- Faster walking speeds = greater load (Greatest at L3-4 found at initial swing)
- Forward flexed posture increases intradiscal pressure while walking
- Limiting arm motion increases load and intradiscal pressure
- Walking is safe overall for back patients, esp at slower speeds
Mechanical Back Pain
- Damage or irritation to ligament, muscle, connective tissue, or bone
- Not directly nerve related
- Can radiate down to about the level of the knee
Possible Causes of Mechanical Back Pain
- Irritated facet capsule
- Arthritic
- Degenerative changes
- Osteophytes on surrounding bone
Referred Pain
- Pain perceived at a location other than the site of the painful stimulus
- Usually used in terms of internal organ referred pain patients
Radiating Pain
Pain along a nerve root
Spoldylolysis
- AKA “Scotty Dog fracture”
- A defect or stress fracture in the pars interarticularis of the vertebral arch
- Younger patients have good potential to return to normal activity w/ proper rest, unloading and proper core cork
- Progression leads to disc and degenerative problems
Spondylolisthesis
- Forward slippage of a lumbar vertebrae on the vertebrae below it
- A secondary effect of spondylolysis due to fracture of the pars interarticularis
- Distance of slipping determines severity of disc, joint, and nueral involvement
- Extension is more painful in this condition
Distribution of Causes for Spodylolisthesis
- 50% → pars fracture
- 20% → congenital (no fracture)
- 30% → older population (degenerative lumbar facets that allow displacement)
What is the “core”?
- Everything between lower chest and pelvis (anterior and posterior)
- Abs, erector spinae, etc
What is scoliosis?
- Lateral curvature of the spine
- Curve is named for the convex side
- Hump forms based on thoracic motion rules
Cobb’s Measurement
X-ray is used to measure the curvature in scoliosis
Anterior Pelvic Tilt
- Tight Back extensors
- Tight Hip flexors
- Weak Hamstrings
- Weak Abdominals
Posterior Pelvic Tilt
- Tight Hamstrings
- Tight Abdominals
- Weak Back extensors
- Weak Hip flexors
SI Joint Problems
Sacroiliac Problem
Iliosacral Problem
Sacroiliac Problem
Sacrum is not positions or moving correctly on the innominate
Iliosacral Problem
The innominate is not moving properly on the sacrum
Standing Flexion Test
- Palpate PSIS on both sides w/ thumbs
- See if one PSIS moves more superiorly than the other when the patient bends over to touch their toes
- Tells if there is a problem with innominate movement and which side
Seated Flexion Test
- Perform same procedure are Standing Flexion Test
- Tells whether or not there is a problem w/ sacral movement (NOT WHICH SIDE)
Long Leg Sitting Test
- Check malleoli length when lying supine
- Have the patient sit up and check length again
- Anteriorly rotated innominate will shorted
- Posteriorly rotated innominate will lengthen
Gillet’s Test
- 1 thumb on PSIS and the other on the sacral spine
- Patient flexes hip 90 degrees and PSIS should drop down
- If PSIS does not drop down test is positive
Landmarks used for palpation of hip/pelvis symmetry for SI Joint
- ASIS
- PSIS
- Iliac crest
- Sacral spine
- Inguinal ligament (pelvic dysfunction)
Possible Innominate Problems
- Up/downslip
- Rotated innominate
- In/outflare
- Pubic Dysfunction
Possible Sacral Problems
- Left on Left/Right on Right Sacral Torsion
- Left on Right/Right on Left Sacral Torsion
Pelvic Neutral
- The position of the pelvis is neither anterior nor posteriorly tilted
- This position should be maintained for core strengthening exercises
- Pelvic neutral should be taught to back pain patients to hold during daily activities and exercise
Why do sit-ups increase discal pressure?
- When doing sit-ups, the hip flexor muscles (esp psoas major) are predominately used
- Since these muscles are being used to support the whole upper body, there is a large moment arm on the lumbar vertebrae
- This moment arm leads to an increase in discal pressure
Types of imaging used for evaluating spinal problems
- X-ray
- MRI
- CAT Scan
- Myelogram
- Discogram
- Bone scan
What is a laminectomy?
- When the major problem appears to be spinal stenosis the spinal canal needs to be made larger
- Usually done by performing a complete laminectomy
- Removing the lamina allows more room for the nerves and enables the surgeon to remove bone spurs around the nerves
- Scar tissue replaces the bone and protects the spinal nerves
Rib Dysfunction
- An acute onset of mechanical pain
- Rib dysfunction is a common cause of thoracic based pain
- Pain is usually localized in the back, but some can radiate pain around the rib toward the sternum
- Can exist w/o “back pain” and be evident in respiratory restrictions
- Subluxations tend to cause nagging pain and tautness of the iliocostalis muscle around the rib angle
Pump Handle
- Major movement in upper 6 ribs
- Inhalation and exhalation
- Ribs elevate, expands rib cage in anterior direction (1-6)
Bucket Handle
- Major movement below rib 6
- Inhalation and exhalation
- Lateral-superior direction (7-10)
Caliper Motion
- Major movement for ribs 11 and 12
- Movement in lateral direction (transverse plane), opening up anteriorly (8-12)
What material helps discs “rehydrate” or increase the water content?
Proteoglycans
What is imbibition?
Taking up and holding fluid
What are the stages involved in the chronic pain cycle?
Pain → Muscle Tension → Reduced Circulation → Muscle Inflammation → Reduced Movement → Pain
Timetable for acute pain
3-4 weeks
Timetable for subacute pain
Up to 12 weeks
Timetable for chronic pain
Longer than 3 months (12 weeks)
Tropism
- Abnormalities that can occur in the shape of the facets
- Somewhat common to find at the L5-S1 level
- Can produce abnormal amounts of facet joint stress and degeneration w/ difficulty in particular movements for that segment
Distribution for Tropism
- Flat (normal) → 57%
- Asymmetric half-moon/half-flat shape → 31%
- Half-moon shape → 12%
