The size of the left kidney is about 96 x 45mm, which is generally abnormal and relatively small. Normal physiology: the human body has two kidneys, one on the left and one on the right, shaped like a fava bean, with the right kidney positioned lower than the left. The length, width and thickness of the kidneys of Chinese adults are 10.5~11.5cm, 5~7.2cm and 2~3cm respectively. the weight of the kidneys of males is 100~140g, and that of females is slightly lighter. According to the above criteria, the size of the left kidney is about 96×45mm, which is abnormal and relatively small. Pathological conditions: smaller kidney is also known as kidney atrophy, common causes of kidney atrophy are renal vascular stenosis, kidney stones, glomerular disease, etc.; larger kidney may be associated with acute nephritis, renal cysts, diabetic nephropathy, renal tumor disease and so on. It is recommended that the patient should consult the regular hospital in time, and under the guidance of the physician, complete the relevant examinations to clarify the condition and carry out targeted treatment.