Location
The lesser sciatic foramen is located in the posterior part of the pelvis, bordered by several
pelvic bones and ligaments:
Structure
Shape: The foramen is an oval-shaped opening with its long axis directed anteroposteriorly.
Borders: The lesser sciatic notch of the ischium forms its bony boundary, while the sacrotuberous and sacrospinous ligaments create the soft
tissue margins.
[8]
Function
- Neurovascular Passage: The primary function of the lesser sciatic foramen is to serve as a passageway for neurovascular structures. [5]This includes the pudendal nerve and internal pudendal vessels which re-enter the pelvis through this foramen after exiting the greater sciatic foramen.
- Muscular Passage: The tendon of the obturator internus muscle and its associated nerve traverse through the lesser sciatic foramen as they move from the pelvis to the gluteal region.
Clinical significance
The lesser sciatic foramen, though smaller in size, is of significant clinical importance due to the essential structures it harbors.
[2]Central to its relevance is the
pudendal nerve, a primary sensory and motor nerve of the perineum. Compression or irritation of this nerve as it traverses the foramen can result in pudendal neuralgia, characterized by chronic pelvic pain, tingling, or numbness.
[4] Moreover, this foramen allows passage for the internal pudendal vessels, which supply blood to various structures of the
perineum. In surgical procedures involving the perineum or posterior pelvis, inadvertent injury to these vessels can lead to hemorrhage or compromised blood supply.
The foramen also facilitates the movement of the obturator internus muscle, and any anomaly or injury around the foramen can impact the muscle's function, affecting hip movements.
[7] For clinicians, especially gynecologists, urologists, and orthopedic surgeons, understanding the anatomy and potential pathologies related to the lesser sciatic foramen is crucial for accurate diagnosis and effective therapeutic interventions.
[6]