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Although cryptorchidism nearly always refers to congenital absence or maldescent, a testis observed in the scrotum in early infancy can occasionally "reascend" (move back up) into the inguinal canal. A testis that can readily move or be moved between the scrotum and canal is referred to as retractile.
Aphallia or absence of the penis is a very rare variation with an estimated incidence of 1 in 10,000,000 births. [ 9 ] It is a rare condition, with only approximately 60 cases reported as of 1989, [ 10 ] and 75 cases as of 2005. [ 11 ]
The gene for sexual differentiation in humans, called the testis determining factor (TDF), [21] [non-primary source needed] is located on the short arm of the Y chromosome. [ 22 ] [ 23 ] The presence or absence of the Y chromosome determines whether the embryo will have testes or ovaries.
Such a testis has an increased risk of malignancy. One testicle may disappear during development (the so-called vanishing testis) due to some intrauterine insult. This is thought to be most likely vascular, such as testicular torsion. One testicle may have been surgically removed through orchiectomy. One testicle may be injured.
In the presence of a functional SRY gene, the bipotential gonads develop into testes. Gonads are histologically distinguishable by 6–8 weeks of gestation. Subsequent development of one set and degeneration of the other depends on the presence or absence of two testicular hormones: testosterone and anti-Müllerian hormone (AMH).
As the scrotum and labia majora form in males and females respectively, the gubernaculum aids in the descent of the gonads (both testes and ovaries). [3] The testes descend to a greater degree than the ovaries and ultimately pass through the inguinal canal into the scrotum. [3] The mechanism of this movement is still debated. [3]
Azoospermia is the medical condition of a man whose semen contains no sperm. [1] It is associated with male infertility, but many forms are amenable to medical treatment.In humans, azoospermia affects about 1% of the male population [2] and may be seen in up to 20% of male infertility situations in Canada.
This assessment looks out for testicular degeneration, testicular anomalies, and carry out a detailed study of the deep genital tract and glands using a high endorectal probe frequency. This examination makes it possible to visualize the vas deferens over their pelvic path and therefore to diagnose possible agenesis (absence of cells within ...