Muscle tone. Definition. noun. (1) The muscle in a steady partially contracted state caused by the successive flow of nerve impulses. (2) The amount of tension or resistance to movement in a muscle. Supplement. Muscle tone or tonus helps in maintaining body posture.
Hydronephrosis is the distention of the pelvis and calyces of one or both kidneys, resulting in thinning of the renal tubules because of obstructed urinary flow. When the obstruction is a stone or kink in one of the ureters, only one kidney is damaged.
Hydronephrosis is defined as distention of the renal calyces and pelvis with urine as a result of obstruction of the outflow of urine distal to the renal pelvis. Analogously, hydroureter is defined as a dilation of the ureter. The presence of hydronephrosis or hydroureter can be physiologic or pathologic. It may be acute or chronic, unilateral or bilateral. It can be secondary to obstruction of the urinary tract, but it can also be present even without obstruction.