Relationship between testicular size by ultrasonography and testicular function: measurement of testicular length, width, and depth in patients with infertility.

OBJECTIVES: The relationships between simple testicular sizes, including the testicular length, width, and depth and testicular function were evaluated to determine the usefulness of measuring these simple parameters.
METHODS: The mean of right and left testicular length, width and depth were measured in 408 men with infertility (mean age, 35.9 +/- 5.3 years) using ultrasonography. The ultrasonographic testicular volumes were calculated as the length x width x depth x 0.71. To evaluate the relationship between the testicular size and function, the patients were divided into seven to ten groups according to each testicular size parameter.
RESULTS: The mean testicular volume, length, depth, and width were 13.4 ml, 3.86 cm, 1.80 cm, and 2.59 cm, respectively. These three testicular dimensions significantly correlated with sperm density, total sperm count, total motile sperm count, serum follicle-stimulating hormone and luteinizing hormone equal to ultrasonographic testicular volume. The mean sperm density was in the oligozoospermic range in patients with a mean testicular volume below 10 ml, a mean length below 3.5 cm, a mean depth below 1.75 cm, and a mean width below 2.5 cm. The mean total sperm count was subnormal in patients with a mean testicular volume below 10 ml, a mean length below 3.5 cm, a mean depth below 1.5 cm, and a mean width below 2.25 cm.
CONCLUSIONS: The testicular length, width, and depth measured by ultrasonography significantly correlated with the testicular function as well as the ultrasonographic testicular volume. A simple measurement of the testicular length, width, and depth is useful for evaluating the testicular function.