Muscle
Obturator internus
Pelvic-wall muscle with a tendon turning toward the hip
High-yield
The lesser sciatic foramen is the key opening on its route. Its nerve is the nerve to obturator internus, a sacral plexus branch, distinct from the obturator nerve supplying obturator externus.
Overview
Obturator internus begins on the inner pelvic wall around the obturator foramen. Its tendon changes direction at the lesser sciatic notch, leaves through the lesser sciatic foramen and travels toward the femur between the gemelli.
Reference facts
- Origin
- Pelvic face of the obturator membrane and adjacent bone around the obturator foramen
- Insertion
- Medial greater trochanter through a tendon joined by the superior and inferior gemelli
- Action
- Externally rotates an extended hip, abducts a flexed hip and contributes to joint stability
- Innervation
- Nerve to obturator internus, usually summarized as L5-S2
- Blood supply
- Branches from the internal pudendal, obturator and gluteal arterial networks
Frequently asked questions
What does the obturator internus do?
The obturator internus externally rotates an extended hip, abducts a flexed hip and contributes to joint stability.
What nerve innervates the obturator internus?
The obturator internus is innervated by the nerve to obturator internus, usually summarized as L5-S2.
Where does the obturator internus attach?
Origin: Pelvic face of the obturator membrane and adjacent bone around the obturator foramen. Insertion: Medial greater trochanter through a tendon joined by the superior and inferior gemelli.
What is the blood supply of the obturator internus?
Branches from the internal pudendal, obturator and gluteal arterial networks.