|
spinal tap - saonew
|
10-31-2006, 07:21 AM
Inserting a spinal tap needle in the lumbar region, in the midline, you hear and feel a 'pop' at the needle tip. What structure was perforated to cause the 'pop?'
A. intervertebral disk B.anterior longitudinal ligament C.ligamentum flavum D.dura mater E.arachnoid mater
10-31-2006, 07:46 AM
The correct answer is: Dura mater
Crossing the dura mater would cause a "pop" that might be heard while doing a spinal tap. The dura is the toughest covering over the spinal cord, so it is difficult to penetrate it with a needle. Intervertebral discs and the anterior longitudinal ligament would not be disrupted during the spinal tap. Although you would cross the ligamentum flavum and the arachnoid mater with the needle, penetrating those structures would not lead to the popping noise. The ligamentum flavum is made of elastic fibers and is not tough enough to cause the "pop." The arachnoid mater is a thin and fragile layer that would be easy for a needle to penetrate. |
| « Next Oldest | Next Newest » |
