What's with the small testicles?

Normal adult male testicles are generally oblong, about 3×3×4 cm in size. The left and right testicles can vary in size, but the difference is not particularly large. Touch the testicles often has a slight sour feeling, if the testicles are small, less than the reference value above, it is considered testicular dysplasia or testicular atrophy. Testicular atrophy is caused by testicular atrophy after trauma, testicular atrophy after spermatic vascular surgery, testicular atrophy after mumps virus infection and other diseases.