The lesser sciatic foramen is an opening (

foramen In anatomy and osteology, a foramen (;Entry "foramen"
in

pelvis The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...

and the back of the thigh. The foramen is formed by the

sacrotuberous ligament The sacrotuberous ligament (great or posterior sacrosciatic ligament) is situated at the lower and back part of the pelvis. It is flat, and triangular in form; narrower in the middle than at the ends. Structure It runs from the sacrum (the lower ...

which runs between the

sacrum The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part ...

and the

ischial tuberosity The ischial tuberosity (or tuberosity of the ischium, tuber ischiadicum), also known colloquially as the sit bones or sitz bones, or as a pair the sitting bones, is a large swelling posteriorly on the superior ramus of the ischium. It marks th ...

and the

sacrospinous ligament The sacrospinous ligament (small or anterior sacrosciatic ligament) is a thin, triangular ligament in the human pelvis. The base of the ligament is attached to the outer edge of the sacrum and coccyx, and the tip of the ligament attaches to the s ...

which runs between the sacrum and 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 isch ...

Structure

The lesser sciatic foramen has the following boundaries: * Anterior: the

tuberosity of the ischium The ischial tuberosity (or tuberosity of the ischium, tuber ischiadicum), also known colloquially as the sit bones or sitz bones, or as a pair the sitting bones, is a large swelling posteriorly on the superior ramus of the ischium. It marks th ...

* Superior: the

spine of the ischium 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 isch ...

and

* Posterior: the

Alternatively, the foramen can be defined by the boundaries of the

lesser sciatic notch Below the ischial spine is a small notch, the lesser sciatic notch; it is smooth, coated in the recent state with cartilage, the surface of which presents two or three ridges corresponding to the subdivisions of the tendon of the Obturator internus ...

and the two ligaments.

Function

The following pass through the foramen: * the tendon of the

Obturator internus 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 i ...

internal pudendal vessels 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 of ...

pudendal nerve The pudendal nerve is the main nerve of the perineum. It carries sensation from the external genitalia of both sexes and the skin around the anus and perineum, as well as the motor supply to various pelvic muscles, including the male or fem ...

* nerve to the obturator internus

References

External links

* - "The Female Perineum: Osteology" {{Authority control Bones of the pelvis

Structure

Function

See also

References

External links