The volume of the testis can be determined on imaging studies assuming an ellipsoid shape.
Parameters:
(1) length of the testis in cm
(2) width in cm
(3) height in cm
equation of Lambert for testicular volume in mL =
= 0.71 * (length in cm) * (width in cm) * (height in cm)
Interpretation:
• The size of the normal testis is affected by race and other factors.
• According to Sunderman and Boerner the dimensions of the normal adult testis are 4-5 x 2.5-3.5 x 2.0-2.7. These dimensions correspond to a volume of 14.2 to 33.5 mL.
• According to Ulijaszek et al, the 10th percentile for adult Europeans is 16 mL and the 90th percentile is 25 mL. (Americans must be more manly).
• In obstructive azoospermia the testis is normal or slightly small in size, while in nonobstructive azoospermia it is often much smaller than normal.
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