In its classic definition, by FranÃ§ois-Louis Ganshof (1944), feudalism describes a set of reciprocal legal and military obligations among the warrior nobility revolving around the three key concepts of lords, vassals and fiefs.
The exact cause of intracardiac echogenic foci remains unclear; however, they appear to be caused by small deposits of calcium in the papillary muscle of the fetal heart.
Description of Neurogenic Claudication and Spinal Stenosis. 1  Most common cause of irritation or pinch is narrowing of the spinal canal. 2  Narrowing of spinal canal is also known as spinal stenosis. Spinal stenosis is a condition caused by narrowing of the lumbar spinal canal.