What is a lumbar disc bulge?
The lumbar spine (i.e. lower back) comprises of many bones known as vertebrae, each of which is separated by a disc (figure 1). The disc comprises of many layers of strong connective tissue wrapping around the disc. In the middle of the disc lies a soft jelly-like substance which is capable of changing shape. When this jelly-like substance protrudes from the disc due to a tear in several layers of the connective tissue, this is known as a lumbar disc bulge (figure 1). To understand the mechanism of a lumbar disc bulge, it is useful to liken the disc to a vanilla slice. Imagine a vanilla slice wrapped in five layers of sandwich wrap. The top and bottom layers of pastry represent the vertebra (bones), the custard represents the jelly-like substance of the disc and the sandwich wrap represents the connective tissue around the disc. If you were now to pinch the front of that vanilla slice, you could imagine, the custard would squeeze towards the back of the vanilla slice and may tear two o
