Generality
The scrotum is a fibro-muscular cutaneous sac that originates from the base of the penis, protruding between the man's thighs.
Belonging to the male genital apparatus, the scrotum houses the testicles, allowing the production and storage of spermatozoa to occur at temperatures lower than body temperature. Furthermore, the scrotum offers a certain protection to the testicles and - thanks to the important apocrine secretion - also preserves in man a certain role of sexual attraction.
The scrotum thus contributes to making possible the continuity of the species, allowing male sexual reproduction.
Scrotum anatomy
Also called pocket or scrotal sac, the scrotum belongs to the male genital apparatus, in particular, to the so-called external genitalia.
Located at the base of the penis, to which it is connected, the scrotum appears as a wrinkled-looking skin pocket, inside which the two testicles and the epididymis are easily palpable.
The scrotum is made up of skin reinforced by a subcutaneous and muscular layer called tunica dartos:
- skin lining : thin and elastic, of rough and corrugated appearance, it is divided centrally, along the median longitudinal line, by a fibrous ridge called scrotal septum ; thus two cavities are formed, each of which collects a testicle with its epididymis. Externally, the scrotal septum is recognizable by the presence of a median longitudinal cutaneous ridge called perineal raphe, which continues forward on the lower face of the penis and backwards on the perineum.
The skin of the scrotum is thick, wrinkled and pigmented (it is darker than the skin of the rest of the body); it has an important sebaceous secretion, which has the function of sexual recall and further contributes to the mechanism of thermoregulation.
- dartos: is composed of a dense layer of smooth muscle tissue (involuntary), and is rich in collagen and elastic fibers that allow the anchoring of the scrotum at the base of the penis. The dartos adheres intimately to the deep face of the scrotal skin. Together with dartos there is another muscle, the cremaster .
The muscular component of the scrotum explains its property to relax or contract.
Inside the scrotal sac are contained:
- the testicles or didymas . They are the male gonads, that is the main reproductive organs of the male. They are two in number and have the task of producing millions of spermatozoa, or male reproductive cells; they also produce male sex hormones (testosterone), fundamental in the development of primary and secondary sexual characteristics and in the control of the genital apparatus.
- the epididymis : located behind the posterior margin of each testicle, they play an important role in the processes of maturation, selection and sperm enrichment with the liquid part of the sperm
- a spermatic tract of the cord (or cord) : it is composed of testicular vessels (arterial, venous and lymphatic), testicular nerves and vas deferens . The latter are two small channels that join each testicle, first, to the seminal vesicles and then to the prostate. Through the epididymis and the vas deferens of the two testicles the spermatozoa flow destined to mix with the seminal fluid to constitute the sperm.
- a small amount of liquid that facilitates the flow of the testicles.
Scrotum functions
The placement of the scrotum on the outside of the abdominal cavity is intended to guarantee the testicles the optimum temperature for sperm production. In fact, in humans, gametogenesis occurs at some degree of temperature below normal body temperature.
Testicular temperature control is achieved by the contraction of the muscles present in the scrotum, capable of increasing or decreasing - depending on the needs - the distance of the testicles from the pelvis.
The descent into the scrotum of the testicles - which in fetal life develop in the abdomen, near the kidney - occurs around the seventh month of gestation.
The failure of one or both testicles to descend into the scrotum is called cryptorchidism . This condition is quite common in the newborn, but generally regresses within the first year of age.
Shape of the scrotum
The scrotum has a pedunculate shape, which still tends to vary based on age, outside temperature and sexual arousal.
- when it is hot or in the presence of fever: the scrotum tends to relax to favor the descent of the testicles and the lowering of their temperature;
- when it's cold: the scrotum tends to contract to bring the testicles closer to the pelvis and minimize heat loss;
- when the male is sexually aroused the scrotum tends to contract, rising.
The shape of the scrotum also changes during the course of life:
- in the child it appears globose and consistent; keep in mind that at this age the absorption of corticosteroids through the skin of the scrotum is particularly high compared to other skin regions;
- in the adult it lengthens, becoming ovoid and the skin thickens;
- in the elderly it stretches further assuming a pyriform and flaccid appearance; in addition, the skin of the scrotum tends to increase in thickness.
In men, a difference in the position of the testicles is quite common; in particular, the left tends to be lower than the right, so also the scrotum is lower from the left side . This feature may have been selected during evolution to prevent the testicles from hitting one another.
Diseases of the scrotum
The skin of the scrotum may be involved in many inflammatory processes, of a traumatic nature (due to repeated rubbing, intertrigo), chemical (eg diaper dermatitis) or infectious (for example fungal infections).
The scrotum may also be affected by boils or sebaceous cysts, while scrotal neoplasms are rather rare.
An acute pain in the scrotum (acute scrotum) may be due to a testicular torsion.
The swelling of the scrotum may be due to an increase in the volume of scrotal contents, due to the presence of hydrocele, epididymal cysts, local phlogosis (epididymitis or orchitis), scrotal hernias (viscera escaping into the scrotal pocket), testicular tumors or varicocele.
Varicoceles and testicular tumors are more common in young people. Epididymitis and orchitis are often the result of sexually transmitted diseases.
