Obturator Externus Anatomy: Origin, Insertion, Function & Clinical Relevance
The obturator externus is a small, deep muscle located along the external surface of the pelvis. It is one of the six deep external rotators of the hip, but unlike most of the group, it sits more anteriorly, inferiorly, and medially.
From the outside of the obturator membrane, the muscle travels beneath the femoral neck and wraps toward the posterior femur before inserting into the trochanteric fossa.
This unusual path positions the obturator externus to assist with hip external rotation, femoral head stability, and precise rotational control during demanding movements.
Watch the Obturator Externus Anatomy Breakdown: https://youtu.be/pSnyC7eY6Ag
In this episode of Anatomy Breakdown – Muscle by Muscle, we cover:
Obturator externus origin and insertion
Its position within the deep six hip rotators
Its path beneath the femoral neck
Hip external rotation and adduction
Femoral head stabilization
Innervation and nerve roots
Its potential role in ballet turnout
Its importance during high-level rotational activity
What Is the Obturator Externus?
The obturator externus is one of the deep six external rotators of the hip.
The deep six include:
Piriformis
Superior gemellus
Obturator internus
Inferior gemellus
Obturator externus
Quadratus femoris
The obturator externus is somewhat different from the rest of the group.
Most of the deep six are commonly visualized along the posterior hip beneath the gluteus maximus. The obturator externus begins more anteriorly and inferiorly on the outside of the pelvis.
It then runs laterally and posteriorly beneath the neck of the femur before reaching the back of the proximal femur.
This gives the muscle a unique position underneath the hip joint.
Obturator Externus Origin
The obturator externus originates from the:
External surface of the obturator membrane
External bony margins surrounding the obturator foramen
The obturator foramen is the large opening located in the pelvis below the acetabulum.
Most of this opening is covered by the obturator membrane. The obturator externus arises from the external surface of this membrane and the surrounding pelvic bone.
The word externus refers to the muscle’s position on the outside of the obturator region.
Obturator Externus Insertion
The obturator externus inserts onto the:
Trochanteric fossa of the femur
The trochanteric fossa is a deep depression located on the medial surface of the greater trochanter.
From its origin, the obturator externus travels:
Laterally from the obturator region.
Posteriorly beneath the femoral neck.
Around the inferior portion of the hip joint.
Toward the medial side of the greater trochanter.
Into the trochanteric fossa.
In simple terms:
External obturator membrane to trochanteric fossa
Or:
Anterior-inferior pelvis to posterior proximal femur
Obturator Externus vs. Obturator Internus
The obturator externus and obturator internus both originate around the obturator foramen, but they occupy opposite sides of the obturator membrane.
Obturator Externus
Located on the external surface of the pelvis
Passes beneath the femoral neck
Inserts into the trochanteric fossa
Innervated by the obturator nerve
Obturator Internus
Located primarily inside the pelvis
Exits through the lesser sciatic foramen
Wraps around the ischium
Inserts near the medial greater trochanter
Innervated by the nerve to obturator internus
A simple distinction is:
Obturator internus is on the inside.
Obturator externus is on the outside.
Obturator Externus Function
The primary action of the obturator externus is:
Hip external rotation
When the hip is extended or positioned near neutral, the muscle helps rotate the femur outward.
It may also assist with:
Hip adduction
Femoral head stabilization
Inferior hip-joint support
Rotational control
Control of the femur during flexed positions
Because the muscle passes beneath the femoral neck, it may help support and stabilize the femoral head from below.
Obturator Externus and Hip Stability
The obturator externus is not a major power-producing muscle.
Instead, it acts as a deep stabilizer that helps:
Keep the femoral head centered
Control rotation within the hip
Support the inferior portion of the joint
Improve joint congruency
Guide movement through demanding ranges
Maintain control during rapid or repetitive hip rotation
This role may be especially important during movements involving:
Hip external rotation
Hip abduction
Deep hip flexion
Single-leg stance
Cutting
Pivoting
Kicking
Turnout
End-range rotational control
The obturator externus is therefore more than a muscle that turns the leg outward. It helps maintain clean and controlled movement of the femoral head within the acetabulum.
Obturator Externus Innervation
The obturator externus is innervated by the:
Posterior division of the obturator nerve
The associated nerve roots are:
L3 and L4
This differentiates it from the obturator internus.
Obturator externus receives the obturator nerve.
Obturator internus receives the nerve to obturator internus.
The obturator nerve also supplies several muscles within the medial thigh, including the hip adductors.
The obturator externus sits near the path of this nerve as it exits the pelvis through the obturator canal.
Obturator Externus and the Deep Six
The obturator externus shares the standard deep-six function of hip external rotation.
However, its position makes it anatomically distinct.
While the piriformis, gemelli, obturator internus, and quadratus femoris are commonly viewed from the posterior hip, the obturator externus begins around the front and lower portion of the pelvis.
It then wraps beneath the femoral neck to reach its posterior insertion.
This allows it to support the hip from an inferior position and may give it a specialized role during movements that challenge the femoral head near the limits of hip motion.
Obturator Externus and Ballet Turnout
The obturator externus may be especially relevant during ballet turnout.
Turnout places repeated demands on:
Hip external rotation
Hip abduction
Single-leg control
Pelvic stability
End-range hip positioning
Rotational precision
Research comparing professional ballet dancers with nondancing athletes found that the obturator externus was larger in the dancers.
The difference was approximately 14%.
Interestingly, the obturator internus did not demonstrate the same significant difference between the groups.
This suggests that long-term ballet training may place a particularly high demand on the obturator externus.
Why Might Ballet Load the Obturator Externus?
Ballet dancers repeatedly train positions involving:
Turnout
Single-leg stance
Deep external rotation
Hip abduction
Extreme hip range
Precise femoral control
Rapid transitions between positions
Because the obturator externus passes underneath the femoral neck, it may help stabilize the femoral head from below during these demanding positions.
It can be visualized as a deep sling or hammock beneath the hip joint.
The muscle may not generate large visible movements, but it may help maintain joint control while the hip is loaded at end range.
Obturator Externus in Athletes
The obturator externus may also be important for athletes who repeatedly use rotational hip positions.
This may include:
Ballet dancers
Soccer players
Hockey players
Martial artists
Gymnasts
Figure skaters
Football players
Lifters training deep hip positions
These athletes require more than general hip strength.
They also need:
Rotational precision
Single-leg stability
End-range control
Femoral head stability
Rapid coordination
Control during kicking, cutting, and pivoting
The obturator externus may contribute to these higher-level hip demands.
Obturator Externus and Soccer
Soccer repeatedly challenges the hip through:
Kicking
Cutting
Pivoting
Rapid changes of direction
Single-leg stance
Hip rotation
Hip abduction
High-speed loading
During a kick, one leg must produce rapid movement while the opposite leg stabilizes the body.
The obturator externus may contribute to the deep rotational control needed in both the kicking and stance limbs.
It is not likely to be isolated during movement, but it works with the other deep rotators, gluteal muscles, adductors, and trunk musculature to control the hip.
Obturator Externus and Hockey
Hockey players frequently work in wide, abducted positions.
Skating also involves repeated combinations of:
Hip external rotation
Hip abduction
Hip extension
Single-leg loading
Rotational control
The obturator externus may help support the femoral head while the hip moves through these demanding positions.
This may be particularly relevant for athletes who spend substantial time in low or wide skating postures.
Obturator Externus and Martial Arts
Martial artists require precise hip control during:
Roundhouse kicks
Side kicks
Spinning techniques
Single-leg balance
Rapid rotation
End-range positioning
The obturator externus may contribute to the deep stability required to control these movements.
Large muscles generate force, but the smaller deep rotators help organize the femur within the socket.
Can the Obturator Externus Cause Hip Pain?
The obturator externus can potentially be involved in deep hip or groin-region symptoms, but it is difficult to isolate clinically.
Possible symptoms may include:
Deep hip pain
Groin discomfort
Pain with hip rotation
Pain during kicking
Pain during turnout
Discomfort in deep flexion
Symptoms during high-level rotational activity
These symptoms are not specific to the obturator externus.
Other possible sources include:
Hip joint pathology
Adductor injury
Iliopsoas irritation
Labral pathology
Obturator nerve involvement
Other deep hip rotators
Femoroacetabular impingement
Referred lumbar or pelvic pain
A complete clinical examination is needed before attributing symptoms to one small deep muscle.
Obturator Externus Exercises
The obturator externus is difficult to isolate because it works with several other hip muscles.
Exercises that may train the surrounding system include:
Resisted hip external rotation
Clamshells
Seated hip rotation
Bridges
Lateral band walks
Monster walks
Split squats
Single-leg balance
Controlled step-downs
Rotational lunges
Cutting drills
Kicking progressions
Turnout-control exercises
Later-stage training may focus on:
End-range control
Single-leg stability
Rotational deceleration
Sport-specific kicking
Direction changes
Controlled pivoting
Dynamic hip stability
The goal is generally to strengthen and coordinate the entire hip system rather than isolate the obturator externus perfectly.
Can You Isolate the Obturator Externus?
Complete isolation of the obturator externus is difficult.
Hip external rotation involves several muscles, including:
Piriformis
Superior gemellus
Obturator internus
Inferior gemellus
Quadratus femoris
Gluteus maximus
Posterior gluteus medius fibers
The obturator externus may also assist with hip adduction depending on position.
Instead of attempting to isolate it completely, rehabilitation and training should focus on:
Deep hip strength
Rotational control
Femoral head stability
Single-leg balance
End-range movement control
Functional and sport-specific loading
Clinical Takeaway
The obturator externus is one of the most anatomically unique members of the deep six.
It contributes to:
Hip external rotation
Hip adduction
Femoral head control
Inferior hip-joint stability
Deep rotational coordination
End-range hip control
Single-leg stability
Its location beneath the femoral neck places it in an ideal position to help support the femoral head from below.
Research involving ballet dancers suggests that the muscle may adapt to repeated high-level turnout and rotational demands.
The obturator externus is small, difficult to access, and easy to overlook. However, its position makes it an important deep stabilizer for dancers, athletes, and anyone performing demanding rotational hip movements.
Frequently Asked Questions
What does the obturator externus do?
The obturator externus primarily externally rotates the hip. It may also assist with hip adduction and helps stabilize the femoral head within the acetabulum.
Where is the obturator externus located?
It is located along the external surface of the obturator membrane and surrounding pelvis. It passes beneath the femoral neck before inserting into the trochanteric fossa.
What is the origin of the obturator externus?
It originates from the external surface of the obturator membrane and the surrounding margins of the obturator foramen.
Where does the obturator externus insert?
It inserts into the trochanteric fossa on the medial surface of the greater trochanter.
What nerve innervates the obturator externus?
The obturator externus is innervated by the posterior division of the obturator nerve, primarily from L3 and L4.
Is the obturator externus part of the deep six?
Yes. It is one of the six deep external rotators of the hip.
What is the difference between obturator internus and externus?
The obturator internus begins on the internal surface of the pelvis and exits through the lesser sciatic foramen. The obturator externus begins on the external surface and passes beneath the femoral neck.
Why is the obturator externus important in ballet?
Ballet turnout repeatedly challenges hip external rotation, abduction, single-leg control, and end-range stability. Research has found a larger obturator externus in professional ballet dancers compared with nondancing athletes.
Does the obturator externus stabilize the femoral head?
Yes. Its location beneath the femoral neck may allow it to help stabilize and control the femoral head from below.
Can the obturator externus cause groin pain?
It may contribute to some deep hip or groin symptoms, but these complaints can arise from several different structures and should not automatically be attributed to the obturator externus.
What exercises train the obturator externus?
Exercises involving hip external rotation, single-leg stability, rotational lunges, cutting, kicking, and end-range hip control may train the obturator externus as part of the larger hip system.
Can you isolate the obturator externus?
Complete isolation is difficult because it works closely with the other deep hip rotators and surrounding hip musculature.
Continue Learning Anatomy
Continue exploring the origins, insertions, innervation, actions, and clinical relevance of the deep hip muscles through Anatomy Breakdown – Muscle by Muscle.
Quadratus Femoris Anatomy
Superior and Inferior Gemellus Anatomy
Obturator Internus Anatomy
Piriformis Anatomy
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