Disc

Question 1

Functions

Answer 1

1 - bind together vertebral bodies
2 - permit movement within the segment
3 - transmit loads

Question 2

Paris’ 5 zones

Answer 2

1 - neurovascular capsule (most outer annulus with nerve & blood supply) 
2 - fibrous outer annulus 
3 - inner less fibrous annulus 
4 - nucleus pulposus 
5 - cartilaginous end plate

Question 3

Innervation

Answer 3

Recurrent nerve, sinuvertebral nerve, branches from gray communicans

Question 4

Annulus Fibrosis

Answer 4

10-12 layers of the disc
Outer layers organized with type I collagen
Inner layers organized with type II collagen
Function:
- containment of the nucleus
- stabilization from alternating layers and binding to cartilaginous end plates via sharpey’s fibers
- permission of movement
- minimal shock absorption
- herringbone orientation of fibers vulnerable to twisting b/c only half fibers resist at a time

Question 5

Nucleus pulposus

Answer 5

remnant of the embryological notochord 
80% water at birth 
Decreasing to 70% by 60 y/o 
Function: 
- imbibition 
- nutrition 
- transmission of force 
- equalization of stress - will transmit force in equal directions due to the water property of the disc 
- movement - acts as a "ball bearing"