Testicular disease

Testicle
Diagram of inner structures of testicles.
Diagram of the external features and surrounding structures of the testicles of an adult male
Details
Artery	Testicular artery
Vein	Testicular vein, Pampiniform plexus
Nerve	Spermatic plexus
Lymph	Lumbar lymph nodes
Identifiers
Latin	testis
Dorlands /Elsevier	Testicle
TA	A09.3.01.001
FMA	7210
Anatomical terminology []

The testicle or testis is the male reproductive gland in all animals, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testosterone. Testosterone release is controlled by the anterior pituitary luteinizing hormone; whereas sperm production is controlled both by the anterior pituitary follicle-stimulating hormone and gonadal testosterone.

Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall. Scrotal asymmetry is not unusual: one testicle extends further down into the scrotum than the other due to differences in the anatomy of the vascululature.

The volume of the testicle can be estimated by palpating it and comparing it to ellipsoids of known sizes. Another method is to use calipers (an orchidometer) or a ruler either on the person or on an ultrasound image to obtain the three measurements of the x, y, and z axes (length, depth and width). These measurements can then be used to calculate the volume, using the formula for the volume of an ellipsoid: 4/3 π × (length/2) × (width/2) × (depth/2).

The dimensions of the average adult testicle are up to 2 inches long, 0.8 inches in breadth, and 1.2 inches in height (5 x 2 x 3 cm). The Tanner scale for the maturity of male genitals assigns a maturity stage to the calculated volume ranging from stage I, a volume of less than 1.5 ml; to stage V, a volume greater than 20 ml. Normal volume is 15 to 25 ml; the average is 18 cm³ per testis (range 12 cm³ to 30 cm³.

There is some evidence to suggest that average human testicle size and weight has been progressively diminishing in recent years among younger cohorts in Western industrialized nations. This may be associated with a decline in sperm counts. The recent changes suggest involvement of environmental or lifestyle factor(s) such as increasing exposure to endocrine disruptors.