Human Anatomy - Kotsan I. Y. 2009

Urogenital Apparatus
Genitals - External Male Genitalia
Age-related characteristics of the male genital organs

The Testes in newborns are small, but relative to overall body size, they are larger than in adults. Until Puberty, the Testis grows slowly, after which its development accelerates sharply. At birth, the length of the testis is 10 mm and its mass is 0.2 g. By the age of 14, the length reaches 20–25 mm, and the mass reaches 2 g. At 18–25 years of age, the length of the testis is 30–40 mm, and the mass increases up to 20 g. In mature adulthood (22 years and older), the dimensions of the testis increase very little, and after 60 years they decrease slightly. Throughout all age periods, the right testis is larger and heavier than the left one and is positioned higher.

The Epididymis is relatively large in newborns. Its length is 20 mm and its mass is 0.12 g. During the first 10 years, the epididymis grows slowly, after which its growth accelerates.

The Appendix of the epididymis and the appendix of the testis are relatively large in newborns, grow until 8–10 years of age, and then gradually undergo involution (regression).

The convoluted and straight seminiferous tubules, as well as the tubules of the rete testis, lack a lumen in newborns. The lumen appears only during puberty. In adolescence, the diameter of the seminiferous tubules doubles, and in adult men, it increases threefold compared to the diameter of the seminiferous tubules in newborns.

The Seminal Vesicles are poorly developed in newborns; the length of a vesicle is 1 mm, and its cavity is very small. Until 12–14 years of age, the seminal vesicles grow slowly, and during adolescence (13–16 years), their growth accelerates. As age increases, THE POSITION OF the seminal vesicles also changes. In newborns, they are located high and are covered by the Peritoneum on all sides. By the age of two, the vesicles descend and are located retroperitoneally. The peritoneum adheres only to their apices.

The Prostate Gland in newborns and in children under one year of age has a spherical shape, a soft consistency, is located high, and lacks glandular tissue. Accelerated growth of the gland is observed after 10 years of age. By adolescence, lobes appear, the gland acquires the shape characteristic of an adult, glandular tissue develops, prostatic ducts are formed, and the gland acquires a dense consistency. The mass of the prostate gland in newborns is 0.82 g, at 1–3 years it is 1.5 g, at 8–12 years it is 1.9 g, and at 13–16 years it is 8.8 g.

The Ductus deferens (vas deferens) in newborns is very thin, and the longitudinal muscular layer in its wall is absent (it appears by the age of 5).

The ejaculatory ducts in newborns are short (8–12 mm in length).

The Spermatic Cord and the structures composing it grow slowly until 14–15 years of age, after which their growth accelerates. The thickness of the spermatic cord in newborns is 4–4.5 mm, and in a 15-year-old adolescent, it is approximately 6 mm.

The Penis grows slowly until puberty, after which its growth accelerates. The length of the penis in newborns is 2–2.5 cm, and the prepuce (foreskin) is long, completely covering the glans penis.

The Scrotum in newborns is small in size, and its Skin is wrinkled due to a well-developed dartos tunic. Intensive growth of the scrotum occurs during puberty.