Thickness (and leaves) A leaf is as thick as the width of one brick, but a wall is said to be one brick thick if it as wide as the length of a brick. Accordingly, a single-leaf wall is a half brick thickness; a wall with the simplest possible masonry transverse bond is said to be one brick thick, and so on.
Thecal sac is the layer that protects the spinal cord. It is filled with cerebrospinal Fluid and has numerous nerve roots Thecal sac is the layer that protects the spinal cord. It is filled with cerebrospinal Fluid and has numerous nerve roots. Thecal sac is enclosed in the Dura Matter. Dura matter is the outer layer which covers the central nervous system, which includes the brain and spinal cord 1. Thecal sac varies in both genders.
A synovial cyst is a relatively uncommon cause of spinal stenosis in the lumbar spine (lower back). It is a benign condition, and the symptoms and level of pain or discomfort may remain stable for many years.1  See Lumbar Spinal Stenosis: A Definitive Guide.he fluid-filled sac creates pressure inside the spinal canal, which can give a patient all the symptoms of stenosis of the spine. Spinal stenosis is a condition that occurs when degeneration in the facet joints causes pressure on the nerves as they exit the spine (see Figure 1).