Obturator Internus Muscle (OI)

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
Figure 2: Muscles of the gluteal and posterior femoral region
Reading list
  • Pelvic floor muscles
  • Ch57 piriformis, obturator internus, gemellus, obturator externus, quadratus femoris muscles
  • Neuman
  • MMT
Table 1 
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
Cell In[1], line 4
      2 import pandas as pd
      3 from pyprojroot import here
----> 4 from IPython.core.display import display, HTML
      6 # Set the path for the script file
      7 script_file_path = here("scripts/process_oian_table.py")

ImportError: cannot import name 'display' from 'IPython.core.display' (/Users/nathanielyomogida/Documents/GitHub/YK-lab-master/myenv/lib/python3.13/site-packages/IPython/core/display.py)

Origin

The OI originates from the Inner surface of the obturator membrane and its bony boundaries.

Path

From its origin the OI courses through the pelvic cavity posteriorly and exits through the lesser sciatic foramen. At the lesser sciatic foramen the OI tendon bends sharply to continue laterally to run parallel with the piriformis to its insertion on the medial surface of the greater trochanter.

Insertion

Medial surface of the greater trochanter

Innervation

Sacral plexus (L5, S1)

Action

  • External rotation and extension of the hip joint (also active in abduction, depending on the joint’s position)
  • Stabilizes hip joint -DrK

Function

“Ultrasound ­guided EMG analysis of the obturator internus and several other external rotator muscles in 10 human subjects.98 The obturator internus was usually the first muscle to become active during a gradually increasing isometric effort to abduct and externally rotate the hip.”

Palpation

Due to the common insertion of the inferior gemellus, obturator internus, and superior gemellus it is difficult to differentiate between these structures during palpation. Instead, I just palpate and treat these as a group.

Dysfunction

  • Gemelli-obturator internus syndrome

Pain Referral Pattern

According to Myers, there is no pain referral pattern for the obturator internus.

Myers does state that it is clinically correllated with pain in the coccyx and posterior thigh.

Obturator Internus Syndrome

Stretch

Child’s Pose stretch can be used to stretch the Obturator Internus muscle. By cueing the knees to stay straight instead of moving into hip ER, this better stretches the obturator internus.

References

1.
Betts JG, Blaker W. Openstax 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.
Neumann DA, Kelly ER, Kiefer CL, Martens K, Grosz CM. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 3rd ed. Elsevier; 2017.
5.
Weinstock D. NeuroKinetic Therapy: An Innovative Approach to Manual Muscle Testing. North Atlantic Books; 2010.
6.
Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.
7.
Jones B. B Project Foundations. b Project; 2025.
8.
Myers HL, Devine WH, Fossum C, et al. Compendium Edition: Clinical Application of Counterstrain. Compendium ed. Osteopathic Press; 2012.

Citation

For attribution, please cite this work as: