The Lumbar Spine And Associated Disorders

Question 1

Give a brief explanation of the structure of the vertebral column.

Answer 1

Vertebral column extends from the skull to the coccyx.
Quarter of the length derived form the internal vertebral discs.
Three quarters derived from the vertebrae and sacrum.
There are 33 vertebrae; 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 4 coccygeal.

Question 2

What are the functions of the lumbar spine

Answer 2

Support
Protection
Movement
Haemopoeisis

Question 3

why does the size of the vertebral bodies increase down the spine?

Answer 3

due to increased compressional forces as you descend the spine

Question 4

what are primary kyphotic curvatures?

Answer 4

The thoracic and sacral curvatures are primary kyphotic curvatures: primary refers to spinal curvatures develop during the fetal period and the term kyphotic means that they are concave anteriorly.

Question 5

what are secondary lordotic curvatures?

Answer 5

secondary spinal curvatures develop during childhood in association with lifting the head and sitting and the term lordotic means that they are concave posteriorly.

Question 6

what are the vertebral end plates?

Answer 6

the superior and inferior articulations of the vertebral bodies. they are covered in hyaline cartilage and articulate with the intervertebral discs.

Question 7

what elements of the vertebral column carry the load of the body/

Answer 7

2/3rds transmitted through the vertebral bodies

1/3rd transmitted through the posterior elements

Question 8

what is the zygapophaseal joint? what is its function?

Answer 8

the zygapophaseal joint is formed between adjacent superior and inferior articular processes and is a synovial joint, lined with hyaline cartilage. The interlocking design of the facet joints prevents antero-posterior (forward-backward) displacement of the vertebrae.

Question 9

what is the composition of the intervertebral discs?

Answer 9

70% water, 20% collagen and 10% proteoglycans.

Question 10

what is the 2 regions of the intervertebral discs?

Answer 10

nucleus pulposus and annulus fibrosis

Question 11

what is the function of the annulus fibrosis?

Answer 11

The annulus fibrosus is the major ‘shock absorber’ of the spine. It comprises lamellae of annular bands of collagen in varying orientations. The outer lamellae are type 1 collagen and the inner lamellae are fibrocartilaginous

Question 12

why is it important to keep your spine straight whilst lifting heavy objects?

Answer 12

Intervertebral discs are very strong in axial (top to bottom) compression but less strong under tangential loading (load applied ‘at an angle’). therefore can fracture if back is bent

Question 13

where is the anterior longitudinal ligament?

Answer 13

It runs continuously from the anterior tubercle of the atlas (C1 vertebra) to the sacrum and is united with the periosteum of the
vertebral bodies

Question 14

what is the function of the anterior longitudinal ligament?

Answer 14

prevents hyperextension of the vertebral column

Question 15

what is the function of the posterior longitudinal ligament?

Answer 15

It prevents hyperflexion of the vertebral column. Its main relevance clinically is that it reinforces the annulus fibrosus centrally so that intervertebral disc prolapse tends to occur lateral to the posterior longitudinal ligament

Question 16

what are the main ligaments of the spinal cord?

Answer 16

anterior longitudinal
posterior longitudinal
ligamentum flavum
interspinous 
supraspinous

Question 17

why is the posterior arch of the vertebrae prone to pathology as we age?

Answer 17

as we age a greater proportion of our load is borne through the facet joints. this can lead to osteoarthritic changes, arthritis, and sciatica

Question 18

what is the sacral hiatus?

Answer 18

the end of the central spinal canal at the fourth sacral vertebrae.

Question 19

what is the cauda equina?

Answer 19

bundle of spinal nerve roots that comprise the second through fifth lumbar nerves (which exit the vertebral canal in the lumbar region and therefore do not enter the central canal of the sacrum) plus the first through fifth sacral nerves and the coccygeal nerve, all of which arise from the lumbar enlargement and the conus medullaris of the spinal cord

Question 20

what is the filum terminale?

Answer 20

The filum terminale is a continuation of the pia mater from the conus medullaris of the spinal cord to the first segment of the coccyx (fig 2.37). It is approximately 20cm in length and gives longitudinal support to the spinal cord.

Question 21

what is senile kyphosis?

Answer 21

the re-establishment of the continuous primary kyphosis that occurs due to disc atrophy with or without accompanying osteoporotic fractures.

Question 22

what are the weak points of the vertebral column where pathology tends to develop?

Answer 22

C1/2
C7/T1
T12/L1
L5/S1
where the centre of gravity passes through the vertebral column

Question 23

what abnormalities are investigated preferentially using MRI of the spine?

Answer 23

tumours
infections
disc herniations
narrowing of the spinal canal (stenosis)

Question 24

what are isotope bones scans of the spine used for?

Answer 24

isotope bone scans can be used to identify an inflammatory process (such as a spinal tumour or infection) or an occult fracture (small fracture not visible on X- ray) as the cause of back pain. They can also be used to identify sites where a primary tumour has metastasised to bone.