Vertebral Column

Question 1

The Mobile Segment

Answer 1

Smallest functional unit of the spine

Consists of any two adjacent vertebrae, the intervening intervertebral disc, and all the soft tissues that secure them together

Question 2

Vertebral Column Composed of:

Answer 2

33 vertebrae
23 intervertebral discs (IVDs)
5 regions

All vertebrae have commonalities in structural design but do show regional variations

Question 3

What are the 5 regions of the vertebral column and how many?

Answer 3

Cervical: 7
Thoracic: 12
Lumbar: 5
Sacral: 5 (fused)
Coccygeal: 4 (fused)

Question 4

Vertebral movements are named for ___________ and ____________ of the vertebral body are doing

Answer 4

the cranial vertebrae; the anterior aspect

Question 5

Vertebral arthrology
2 Major Parts

Answer 5

Anterior: Cylindrically shaped vertebral body
Posterior: Irregularly shaped neural arch

Question 6

Vertebral Body

Answer 6

Weightbearing surface
Restrict compression
Its structure dictates its function
Block of tubercular bone covered by a layer of cortical bone

Question 7

Neural Arch

Answer 7

Pedicles
Posterior element

Question 8

Pedicles

Answer 8

Short, stout pillars with thick walls that connect the vertebral body to the posterior elements
Transmit bending forces from posterior elements to vertebral body

Question 9

Posterior elements

Answer 9

Laminae
Pas Interarticularis
Articular Processes: from the articular pillar
-2 Superior facets
-2 Inferior facet
Spinous process
Transverse Processes

Question 10

Laminae

Answer 10

Thin, vertical plate that constitutes the central portion of the arch posterior to the pedicles
Pars interarticularis transfers force from the articular, transverse, and spinous processes to the pedicles

Question 11

Transverse processes

Answer 11

Lateral projections of bone that originate from the laminae
Serve as muscle attachments and provide mechanical lever

Question 12

Spinous process

Answer 12

A posterior projection of bone that originates from the central portion of the laminae
Serves as muscle attachment and provides mechanical lever; may also serve as a bony block to motion

Question 13

Vertebral foramen

Answer 13

Opening bordered by the posterior vertebral body and the neural arch
Combined with all segments, forms a passage and protection for the spinal cord

Question 14

Intervertebral Disc (IVD)
2 Principal Functions

Answer 14

1. To separate two vertebral bodies, thereby increasing available motion
2. To transmit load from one vertebral body to the next

Question 15

Size of the IVD

Answer 15

Amount of motion
Magnitude of the loads

Question 16

Thickness of the IVD varies per region

Answer 16

3mm (cervical)
9mm (lumbar)

Ratio of disc thickness with vertebral body height determines the available motion

Question 17

What region has the greatest ratio, and what does that mean?

Answer 17

Cervical has the greater ratio, which means there is greater intersegmental mobility available.
Lumbar is 2nd
Thoracic has the smallest

Question 18

Common structure: IVD

Answer 18

All are composed of 3 parts:
1. Nucleus pulposus
2. Annulus fibrosus
3. Vertebral endplate

Question 19

Nucleus pulposus

Answer 19

Gelatinous mass found in the center
80% water
Type I and II (more; resist compressive loads) collagen 15%
Proteoglycans 65%

Question 20

Annulus Fibrosus

Answer 20

Fibrous outer ring
60 % water
20% proteoglycans
50% collagen Type I (more; resist tensile forces) and II
Attached to the endplates

Question 21

Vertebral endplate

Answer 21

Cartilaginous layer covering the superior and inferior surfaces of the disc, separating it from the cancellous bone of the vertebral bodies above and below
Proteoglycans, collagen, and water,

Question 22

What type of cartilage does the vertebral endplates consist of?

Answer 22

Both hyaline cartilage and fibrocartilage.
Hyaline cartilage is present closest to the vertebral body and is found mainly in young discs. Fibrocartilage is present closest to the nucleus pulposus

Question 23

Innervation and Nutrition of the IVD

Answer 23

Do not receive blood supply from any major arterial branches.
Endplates receive supplied from metaphyseal arteries
Annulus fibrosus supplied from small branches of the metaphyseal arteries
The rest via diffusion

Question 24

Common Joint Articulations

Answer 24

Interbody Joints: Cartilaginous, symphysis-type

Zygapophyseal (facets) Joints: Synovial, planar joint

Question 25

Interbody joints

Answer 25

The joints between the vertebral bodies; 6 DOF
Available Movements:
Sliding/translation-anterior to posterior, medial to lateral, and as axial rotation (torsion)
Distraction-combination
Compression-combination b
Tilting-anterior to posterior and in lateral directions

Question 26

Zygapophyseal (apophyseal or facet) joints

Answer 26

Orientation of the facets vary based on region
Motion is referred to as sliding/gliding:
Anterior/posterior
Superior/inferior

Question 27

Anterior longitudinal ligament

Answer 27

Limits extension and reinforces anterolateral portion of annulus fibrosus and anterior aspect of intervertebral joints

Question 28

Posterior longitudinal ligament

Answer 28

Limits forward flexion and reinforces posterior portion of the annulus fibrosus

Question 29

Ligamentum flavum

Answer 29

Limits forward flexion, particularly in the lumbar area, where it resists separation of the laminae

Question 30

Interspinous ligament

Answer 30

Resist flexion, end-range extension, posterior shear of superior vertebra on the vertebra below

Question 31

Supraspinous ligament

Answer 31

Limit forward flexion

Question 32

Intertransverse ligament

Answer 32

Limit forward flexion, and contralateral lateral flexion