The lateral rotator group is a group of six small muscles of the hip which all externally (laterally) rotate the femur in the hip joint.
The deep six lateral rotators are a group of muscles under the gluteus maximus.
They are a fan of tissues on the back side of the hip joint.
Attaches inside the sacrum and the top of the greater trochanter on the femur. Its tension holds the sacrum forward.
Lies directly on top of the sciatic nerve. (For some people the nerve is above the Piriformis).
If this muscle is too tight it can cause sciatica (piriformis syndrome). Other causes of sciatica include compression of the nerves as they exit the vertebrae of the spine.
Helps maintain the position of the sacrum relative to the pelvis.
Allows external rotation of the hip
Allows abduction of the hip.
Other muscles (e.g. adductors, internal rotators) need to be flexible to allow the movements to happen.
When the hip is flexed, the orientation of these muscles change and they require external rotation to stretch.
Pigeon pose (Kapotasana) is a good pose for stretching these muscle groups. It helps increase the amount of external rotation at the hip joint when the leg is in a flexed position.
This muscle group can impact the hips. Read more about the Hip Joint in a separate article.
You can also read separate articles on other muscles around the hip joint:
The Deep Six Lateral Rotators (this article is one of the topics in the series)