The perineal nerve is a

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the Electrochemistry, electrochemical nerv ...

of the pelvis. It arises from the

pudendal nerve The pudendal nerve is the main nerve of the perineum. It is a Mixed nerve, mixed (motor and sensory) nerve and also conveys Sympathetic nervous system, sympathetic Autonomic nervous system, autonomic fibers. It carries sensation from the exter ...

in the pudendal canal. It gives superficial branches to the

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

, and a deep branch to

muscles Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

. It supplies the skin and muscles of the

perineum The perineum (: perineums or perinea) in placentalia, placental mammals is the space between the anus and the genitals. The human perineum is between the anus and scrotum in the male or between the anus and vulva in the female. The perineum is ...

. Its latency is tested with

electrodes An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or a gas). In electrochemical cells, electrodes are essential parts that can consist of a variety ...

Structure

The perineal nerve is a branch of the

. It lies below the

internal pudendal artery The internal pudendal artery is one of the three pudendal arteries. It branches off the internal iliac artery, and provides blood to the external genitalia. Structure The internal pudendal artery is the terminal branch of the anterior trunk ...

. It accompanies the perineal artery. It passes through the pudendal canal for around 2 or 3 cm. Whilst still in the canal, it divides into superficial branches and a deep branch. The superficial branches of the perineal nerve become the posterior scrotal nerves in men,Essential Clinical Anatomy. K.L. Moore & A.M. Agur. Lippincott, 2 ed. 2002. Page 263 and the posterior labial nerves in women. The deep branch of the perineal nerve (also known as the "muscular" branch) travels to the muscles of the perineum. Both of these are superficial to the

dorsal nerve of the penis The dorsal nerve of the penis is the deepest of three divisions of the pudendal nerve; it accompanies the internal pudendal artery along the Ischium#Structure, ramus of the ischium; it then runs forward along the margin of the inferior ramus of t ...

or the dorsal nerve of the clitoris.

Function

The perineal nerve supplies the skin and muscles of the

. The superficial branches supply sensation to the perineum, and the

scrotum In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin ''scortum'', meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin ...

in men or the

labia majora In primates, and specifically in humans, the labia majora (: labium majus), also known as the outer lips or outer labia, are two prominent Anatomical terms of location, longitudinal skin folds that extend downward and backward from the mons pubis ...

in women. The deep branch supplies

superficial transverse perineal muscle The transverse perineal muscles (transversus perinei) are the superficial and the deep transverse perineal muscles. Superficial transverse perineal ...

, the

bulbospongiosus muscle The bulbospongiosus muscles (in older texts bulbocavernosus and, for female muscle, constrictor cunni) are a subgroup of the superficial muscles of the perineum. They have a slightly different origin, insertion and function in males and females. ...

, the ischiocavernosus muscle, the

bulb of penis The bulb of penis is the proximal/posterior bulged end of the (unpaired median) corpus spongiosum penis. Together with the two crura (one crus on each side of the bulb), it constitutes the root of the penis. It is covered by the bulbospongiosu ...

levator ani The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis. It is attached to the inner surface of each side of the ...

, and the external anal sphincter.

Clinical significance

The latency of the perineal nerve can be measured with

. It is used to test nerve function.

Additional images

File:Gray837.png, Sacral plexus of the right side. (Perineal nerve visible at center right.)

References

External links

* - "The Female Perineum: The Perineal Nerve" * * * {{Authority control Nerves of the lower limb and lower torso