Obturator Externus

Authors
Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Figure 1: Hip and Thigh Muscles

Deep muscles of the medial thigh2

Deep muscles of the medial thigh
Figure 2: Muscles of the gluteal and posterior femoral region
Reading list
  • Ch57 piriformis, obturator internus, gemellus, obturator externus, quadratus femoris muscles
  • MMT

Origin

Outer surface of the obturator membrane and its bony boundaries.

Path

From its origin the OE and its tendon wind posteriorly below the hip joint and run superiorly to its insertion on the floor of the trochanteric fossa.

Insertion

Trochanteric fossa of the femur

Innervation

Obturator N. (L3, L4)

Action

  • Hip: adduction and external rotation
  • Pelvic Stabilization: Sagittal plane

According to Brad Jones, the OE is an external rotator when in hip flexion, and acts to slightly flex the hip.

At ~30-40° of internal rotation, the OE’s runs exactly inferior to the center of the joint, and thus stops functioning as an external rotator. When the hip is internally rotated past 40°, the OE generates an external rotation torque.

Overview

“The obturator externus muscle arises from the external side of the obturator membrane and adjacent ilium (see Fig. 12.14). The belly of this muscle is visible from the anterior side of the pelvis after removal of the adductor longus and pectineus muscles (see Fig. 12.26, left side). The muscle attaches posteriorly on the femur at the trochanteric fossa (see Fig. 12.6). (Based on its leverage to produce adduction, location, and innervation, the obturator externus is more anatomically associated with the adductor group of muscles than with the other five short external rotators. The obturator externus is innervated by nerve roots that originate from the lumbar plexus [via the obturator nerve], as are most of the other adductor muscles. The other small external rotators, in contrast, are innervated through the sacral plexus, with nerve roots as low as S2.)”

References

1.
Betts JG, Blaker W. Anatomy and Physiology. 2nd ed. OpenStax; 2022. https://openstax.org/details/books/anatomy-and-physiology-2e/?Book%20details
2.
Gray H. Anatomy of the Human Body. 20th ed. (Lewis WH, ed.). Lea & Febiger; 1918. https://www.bartleby.com/107/
3.
Donnelly JM, Simons DG, eds. Travell, Simons & Simons’ Myofascial Pain and Dysfunction: The Trigger Point Manual. Third edition. Wolters Kluwer Health; 2019.
4.
Weinstock D. NeuroKinetic Therapy: An Innovative Approach to Manual Muscle Testing. North Atlantic Books; 2010.
5.
Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.
6.
Jones B. B Project Foundations. b Project; 2025.
7.
Neumann DA, Kelly ER, Kiefer CL, Martens K, Grosz CM. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 3rd ed. Elsevier; 2017.

Citation

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