When looking at the lower limb from the posterior view, there are two regions that stand out immediately: the gluteal region and the posterior thigh.
Let’s start with what’s arguably the most popular one of the two and which has been featured in countless pop songs - the gluteal region.
The gluteal region is situated posterior to the pelvis and inferior to the iliac crest.
Laterally it overlies the greater trochanter, and anteriorly, it extends up to the anterior superior iliac spine.
It also extends from the iliac crest superiorly to the gluteal fold inferiorly.
The gluteal fold is the crease formed by the inferior aspect of the buttocks and the posterior upper thigh.
Medially, the region extends to the mid-dorsal line and is called the intergluteal cleft, which is the groove that separates the buttocks from each other.
Actually, before we move on, let’s review some important landmarks to help you understand this region’s anatomy better.
First, the posterior sacroiliac ligament is the posterior continuation of the fibrous capsule of the synovial part of the sacroiliac joint, and continues inferiorly with the sacrotuberous ligament.
The sacrotuberous ligament goes from the posterior surface of the ilium and the lateral surfaces of the sacrum to the ischial tuberosity.
A similar ligament, called the sacrospinous ligament, passes from the lateral surface of the sacrum and the coccyx to the ischial spine.
These two ligaments convert the greater and lesser sciatic notches into greater and lesser sciatic foramina.
Simply put, the greater and lesser sciatic foramina are passageways, or “doors” for structures leaving the pelvis and entering the gluteal region and vice versa.
The structures passing through the greater sciatic foramen include the piriformis muscle and the structures that leave the pelvis above it, mostly represented by the superior gluteal vessels and nerve and the structures that leave the pelvis below it - the sciatic nerve, pudendal nerve and internal pudendal vessels, inferior gluteal nerve and vessels, posterior femoral cutaneous nerve and the nerves to obturator internus and quadratus femoris.