The lesser sciatic foramen is an opening (
) between the
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 lowe ...
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 o ...
and the
ischial tuberosity and the
sacrospinous ligament 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 ischia ...
.
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 ...
* Superior: the
spine of the ischium and
sacrospinous ligament
* Posterior: 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 lowe ...
Alternatively, the foramen can be defined by the boundaries of the
lesser sciatic notch and the two ligaments.
Function
The following pass through the foramen:
* the tendon of the
Obturator internus
*
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
See also
*
Greater sciatic foramen
References
External links
* - "The Female Perineum: Osteology"
{{Authority control
Bones of the pelvis