Urinary tract calculi are primarily formed from which of the following substances?

Urinary tract calculi, also known as kidney stones, are primarily composed of calcium in various forms, such as calcium oxalate and calcium phosphate. The formation of these stones is often associated with elevated levels of calcium in the urine, which can result from dietary factors, metabolic disorders, or other health conditions.

Calcium stones are the most prevalent type of urinary stones, representing approximately 70-80% of all cases. When calcium combines with oxalate or phosphate, it forms crystals that can grow into larger stones if not excreted. Understanding this is important for identifying risk factors for stone formation and implementing preventive measures in patients.

The other substances listed, such as ammonium, sodium, and potassium, do not represent the primary components of urinary calculi. While they may play roles in other types of stones or urinary composition, they are not the main constituents of the most common urinary tract calculi. Therefore, the acknowledgment that calcium is the primary substance involved in the formation of kidney stones aligns with established medical knowledge on this topic.