Obturator Internus

The Obturator Internus is a muscle of the gluteal region.

Anatomical Attachments:

• Origin: Arises from the greater sciatic notch and the inner surface of the obturator foramen as well as the obturator membrane.
• Insertion: Attaches to the greater trochanter of the femur.

Action: Rotates the thigh laterally, abducts and extends the thigh when it is flexed.

Synergist: Lateral rotators of the thigh.

Nerve Supply: Muscular branches of the sacral plexus nerve (L5, S1).

Vascular supply: Internal pudendal and superior gluteal arteries.

Vascular entrapment: According to Travell and Simons, while unsupported by study, the pudendal nerve and the internal pudendal vessels could become entrapped as they pass through the obturator foramen and should be a consideration if an individual is experiencing dysesthesia or perineal pain.

• Primary: The pain refers to the anococcygeal region and the vagina, with a spillover to the posterior thigh.
• Satellite or associated triggers: Gluteus maximus, Gemelli, Obturator externus, Quadratus femoris, and Piriformis.

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Trigger Point Signs and Symptoms: A feeling of fullness in the rectum with some pain referring down the back of the ipsilateral thigh, possible electrical, twinging, or lancinating intervaginal pain.

Trigger Point Activating and Perpetuating Factors: Muscle strain, persistent emotional stress, direct trauma, or post surgical adhesions to the pelvic region.

Differential Diagnosis: (Segmental, Subluxation, Somatic dysfunction) L5 S1 S2 S3 S4 or S5 radiculopathy, Sciatica, Coccygodynia (coccygeal nerve compression), Coccygeal spasm, Coccygeal fracture, Levator syndrome, Tension myalgia of pelvic floor, Pregnancy, Spontaneous Abortion (Miscarriage), Proctalgia fugax, Hemorrhoids, Polyps, Anal fissure, Colorectal cancer, Crohn’s Disease, Diverticular disease, Fecal impaction or Constipation, Proctitis, Prostatitis, Prostate cancer, Vaginismus, Cervical cancer, Vaginal or Intervaginal trauma, Systemic infections or inflammation, Nutritional inadequacy, Metabolic imbalance, Toxicity, Side effects of medication.

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