The nerve to obturator internus (also known as the obturator internus nerve) is a mixed (sensory and motor)

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 ...

providing motor innervation to the

obturator internus muscle The internal obturator muscle or obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, and the rim of the pubis. It exits the pelvic cavity through the lesser sciatic foramen. The ...

and gemellus superior muscle, and sensory innervation to the hip joint. It is a branch of the

sacral plexus In human anatomy, the sacral plexus is a nerve plexus which provides motor and sensory nerves for the posterior thigh, most of the lower leg and foot, and part of the pelvis. It is part of the lumbosacral plexus and emerges from the lumbar verteb ...

. It is one of the group of deep gluteal nerves. It exits the pelvis through the

greater sciatic foramen The greater sciatic foramen is an opening (:wikt:foramen, foramen) in the posterior human pelvis. It is formed by the sacrotuberous ligament, sacrotuberous and sacrospinous ligaments. The piriformis muscle passes through the foramen and occupies ...

to innervate the gemellus superior muscle, then re-enters the pelvis to innervate the obturator internus muscle.

Structure

Origin

The nerve to obturator internus is a branch of the lumbosacral plexus. It arises from the

anterior Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

divisions of (the

anterior rami The ventral ramus (: rami) (Latin for 'branch') is the anterior division of a spinal nerve. The ventral rami supply the antero-lateral parts of the trunk and the limbs. They are mainly larger than the dorsal rami. Shortly after a spinal nerve e ...

of) L5- S2.

Course and relations

It emerges inferior to the

piriformis muscle The piriformis muscle () is a flat, pyramidally-shaped muscle in the buttock, gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group. The piriformis muscle has its origin upon the front surface of the sacrum, ...

and exits the pelvis through the

. It travels round the base of the

ischial spine The ischial spine is part of the posterior border of the body of the ischium bone of the pelvis. It is a thin and pointed triangular eminence, more or less elongated in different subjects. Structure The pudendal nerve travels close to the ischia ...

lateral to the internal pudendal artery and nerve, and - while doing so - issues a branch to the gemellus superior, which enters the upper part of the posterior surface of the muscle. It then re-enters the pelvis through the lesser sciatic foramen to innervate the

, piercing the pelvic surface of this muscle.

References

Nerves of the lower limb and lower torso {{neuroanatomy-stub

Structure

Origin

Course and relations

See also

References