PHYSICAL EXAMINATION

LABORATORY STUDIES

DIAGNOSIS

Cryptorchidism

PATHOPHYSIOLOGY OF KEY SYMPTOMS

Early during fetal development, both male and female genitalia are present (Fig. 86-1). The development of the testes and the male external genitalia is stimulated by the testis-determining factor on the short arm of the Y chromosome. The developing testes secrete testosterone and anti-müllerian hormone. Testosterone stimulates the growth of the male external genitalia, and the anti-müllerian hormone causes a regression of the female reproductive structures.

FIGURE 86–1 Both male and female genitalia are present early in fetal development. The development of the testes in the male genitalia is driven by the testis-determining factor on the short arm of the Y chromosome. Differentiation of the fetal gonad to the testis allows production of testosterone and the anti-müllerian hormone, leading to development of the male phenotype.