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Table 1 Characteristics and Findings for Stages of Genital Development Clinically. Testicular Volumes by (W-ss)3 × 0.88a

From: A medical calculator to determine testicular volumes matching ultrasound values from the width of the testis obtained in the scrotum with a centimeter ruler

Genital stage Age range (years) Testis width in scrotum (cm) Testicular volume Observed (ml) Length of penis (cm) Mean ± SD - Observed range
1 Up to 13.25 > 1.0 to < 1.3 < 1.27 Early childhood 4.8 ± 0.64 - Observed 3.5 to 6.0
2 10 to 15 > 1.5 to 2.1 > 2.1 to 6.5 Early childhood 5.3 ± 0.75 - Observed 4.0 to 6.5
3 11.4 to 15 > 1.9 to 2.2 4.6 to 7.4 Growth of penis 7.4 ± 0.49 - Observed 7.0 to 8.0
4 11.6 to 17 > 2.1 to 2.6 6 to 12.3 Development of glans 8.6 ± 1.29 - Observed 6.5 to 12.0 cm
5 13 to 17.5 > 2.5 to 3.1 10.7 to 21.4 9.5 ± 0.99 - Observed 7.5 to 11.0
Adult >  16 > 2.5 to 3.1 10.6 to 21.2 9.7 ± 1.01 - Observed 8.0 to 11.0
  1. aTesticular values obtained by (W-ss)3 × 0.88, equivalent to ultrasound values calculated by W x H x L × 0.71. For testicular values calculated by W x H x L × 0.52, divide Values reported by 1.365 (0.71/0.52 = 1.365). The width of the testis was measured. The stage of genital development (testes, scrotum and penis only) as defined by Tanner, and range of years were identified. Testicular volumes were calculated. Penile length was measured. Pubic and other hair observed was recorded, but not included in determining stages 1 to 5 of genital development. [Most helpful findings are bolded]