Lecture 37 - L-Spine

Question 1

5 characteristics of the L-spine

Answer 1

1. 5 vertebrae
2. No foramina transversaria
3. No facet for rib articulation
4. Pedicles pass almost directly posterior
5. Large broad (superior to inferior) spinous process

Question 2

3 characteristics of a typical lumbar vertebrae

Answer 2

1. Kidney shaped
2. Shell of cortical bone surrounding a cancellous core
3. Cancellous core formed of horizontal and vertical trabecula

Question 3

Vertebral body is made of [blank] and its function

Answer 3

Made of trabeculae which is important for compressive strength and resilience (load is sustained by combination of vertical pressure and transverse tension in trabecular

Question 4

What are 2 ways the vertebral body provides support for loads through trabeculae

Answer 4

1. Provides vertical load-bearing support to the vertebral endplates
2. Horizontal trabeculae “ties” increase the stiffness of the vertical load bearing beams
   (SUMMED UP: designed to resist vertical and horizontal forces)

Question 5

What are the 2 facets that define a zygapophyseal joint

Answer 5

1. Inferior articular facet
2. Superior articular facet

Question 6

2 characteristics of the inferior articular facet of zygapophyseal joint

Answer 6

1. Biplanar
2. Convex facing anterior and lateral

Question 7

4 characteristics of the superior articular facet of the zygapophyseal joint

Answer 7

1. Large concave facet facing posterior and medially
2. Guide rails for sagittal and frontal plane movement
3. Restrain axial rotation and excessive translation
4. Protect discs from torsional and shearing strains

Question 8

Zygapophyseal Joint Frontal Orientation function (2)

Answer 8

1. Prevents anterior translation
2. Favors axial rotation

Question 9

Zygapophyseal Joint sagittal orientation function (2)

Answer 9

1. Prevents axial rotation
2. Favors anterior translation

Question 10

Zygapophyseal Joint Biplanar orientation function

Answer 10

Limits both anterior translation and axial rotation protecting the discs from both rotation and shearing forces

Question 11

T or F: The sagittal section of vertebral body demonstrates nearly horizontal orientation

Answer 11

F, vertical orientation

Question 12

What happens to the joint as we move down the lumbar spine

Answer 12

The angle increases resulting in joints breaking down at L4/L5 due to harsh angle

Question 13

Joint capsule 4 function (lumbar spine)

Answer 13

1. Increases stability and allows ROM
2. Space filler
3. Increases surface area of contact when articular facets are impacted and transmit some load
4. Protect articular surfaces as they are exposed to extreme flexion and extension

Question 14

What is the intervertebral disc composed of (3)

Answer 14

1. Nucleus pulposus
2. Annulus fibrosis
3. Vertebral End-Plate

Question 15

What 2 structures surround the nucleus pulposis

Answer 15

1. Annulus fibrosis
2. Vertebral endplate

Question 16

Summary slide of intervertebral disc for lumbar spine

Answer 16

Question 17

3 characteristics of nucleus pulposus

Answer 17

1. Semi-fluid gel
2. 70-90% water
3. Proteoglycans form 65% of dry weight

Question 18

2 characteristics of annulus fibrosis (lamellar arrangement)

Answer 18

1. Lamellae arranged in 10-20 concentric circumferential layers
2. Thicker towards center of disc anteriorly and laterally

Question 19

3 structural characteristics of the vertebral endplate

Answer 19

1. 0.6-1 mm thick hyaline cartilage
2. Covers all of nucleus but only center portion of annulus
3. Firmly attached to the disc, but only loosely to the vertebral body

Question 20

Function of vertebral endplate

Answer 20

Necessary for nutrient supply to the nucleus pulposus and annular fibrosis that maintains a delicate homeostatic balance

Question 21

What happens to lesion at vertebral endplate

Answer 21

Denaturation of the nuclear material

Question 22

What are the 2 terms to use for disc herniation

Answer 22

1. Disc protrusion
2. Disc herniation

Question 23

What happens at a disc protrusion

Answer 23

Annular fibers are intact and it can either be a localized (lateral) or diffuse (posterior) annular bulge

Question 24

What 3 things can happens at a disc herniation

Answer 24

1. Prolapsed: Nucleus migrated through inner layers but is still contained
2. Extruded: Nucleus has broken through the outermost layer
3. Sequestered: Nucleus has broken from the disk and is in the spinal or intervertebral canal

Question 25

What are the 3 functions of the lumbar spine

Answer 25

1. To bear and transmit loads from torso to pelvis in erect posture or during dynamic movements (eg. forward bending) 2. Provide significant part of the movement required for bending and reaching 3. Provide stability in load-bearing

Question 26

What are 5 characteristics of lumbar spine ROM

Answer 26

Question 27

3 characteristics of lumbar spine loading

Answer 27

1. Discs provide 85% of axial loading 2. Facets provide 15% load 3. Increased loading of facets in flexion and extension

Question 28

Lumbar pressures that are commonly used in exercises and postures

Answer 28

1. Standing = 100% 2. Bilateral SLR (150%) 3. Sit-ups (210%) 4. Prone extension (130%)

Question 29

Difference between lumbar and cervical rootlet sin travelling toward intervertebral foramen

Answer 29

Cervical: Vertical course towards IVF Lumbar: Increasing obliquity towards IVF and travels downward in lateral recess

Question 30

What 4 structures of the l-spine does the dorsal ramus innervate

Answer 30

1. Zygapophyseal joint 2. Multifidus 3. Long erectors 4. Skin overlying midline of back

Question 31

What are the 3 blood supplies of the spinal cord

Answer 31

1. Anterior spinal artery 2. 2 paired posterior spinal arteries 3. Artery of Adamkiewicz (T9-T10 feeder)

Question 32

What is the blood supply of the nerve root

Answer 32

1. Distal nerve root supplied by radicular branch of lumbar arteries 2. Proximal nerve supplied by proximal radicular branches derived from anterior and posterior chord supply

Question 33

What are the 3 functions of the multifidus muscle

Answer 33

1) Unilaterally: Bends spine to same side and rotates opposite 2) Bilaterally: Extends spine 3) Primary stabilizer for back along with oblique and transverse abdominal muscles

Question 34

What are the 2 ligaments of the lumbar spine

Answer 34

1. Anterior longitudinal ligament 2. Posterior longitudinal ligament

Question 35

Compare and contrast the posterior and anterior longitudinal ligament of cervical and lumbar spine

Answer 35

Anterior: Same Posterior: In both the ligament attaches to the disc and is loos over the vertebral bodies. In l-spine the ligament is dentate shape (wide where it attaches to disc and narrow behind vertebral body) and in c-spine the ligament is ribbon shape (equal width)

Question 36

T or F: Low back pain is leading cause of disability in the world

Answer 36

T (85% of population)

Question 37

What is the projections of healing from lower back pain

Answer 37

1. 70-80% of pop. improve in 3 month period 2. 50-80% will have one recurrent episode 3. 20-30% can become persistent and disabling

Question 38

What are 4 characteristics of low back pain

Answer 38

1. Most common injury seen by PT's 2. Episodic in nature (occasional flare ups) 3. Many capable for improvement and full recovery 4. Pain can results from physical, lifestyle psychological and neurophysiological factors

Question 39

3 characteristics of the pars interarticularis

Answer 39

1. Part of laminae of superior and inferior articular process at junction of vertical laminae and horizontal pedicle 2. Subject to bending forces 3. Some individuals it is not thick and is susceptible to fatigue or stress fractures (spondylolesthesis)

Question 40

What are the 3 biomechanical components for flexion of the lumbar spine

Answer 40

1) Anterior sagittal rotation (8-13 degrees) 2) Anterior translation (103 mm) 3) Facet joints glide superiorly and anterior during flexion

Question 41

What are the 4 biomechanical components for extension of the lumbar spine

Answer 41

1. Posterior sagittal rotation 2. Posterior translation 1.1-1.7mm 3. Limited when inferior articular processes are forced against lamina of the vertebrae below 4. Facet joints glide inferior and posterior

Question 42

What are the biomechanical components for rotation at the lumbar spine

Answer 42

1. Twist of spine accompanied with lateral flexion 2. After 3 degrees of rotation, the axis shifts to the facet joints 3. Contralateral facet compressed 4. Ipsilateral facet gapped 5. Disc is strained by torsion and lateral shear 6. Rotation resisted by disc (35%) and posterior elements (65%)