Inferior gemellus !
The inferior gemellus is a small deep buttock muscle just below the obturator internus tendon; it turns the thigh outward.
Official name: Inferior gemellus muscle
Opens in the Durgical app, no sign-up needed.
What it is
A small muscle running along the lower edge of the obturator internus tendon, from the sitting bone to the greater trochanter.
What it does
Turns the thigh outward and holds the ball steady in the socket.
Key facts
- Origin
- Upper ischial tuberosity
- Insertion
- Obturator internus tendon, to medial surface of greater trochanter
- Action
- Laterally rotates extended hip; abducts flexed hip; steadies femoral head
- Nerve
- Nerve to quadratus femoris (L5–S1)
- Blood supply
- Medial circumflex femoral artery; inferior gluteal artery
Relations
- Above
- Obturator internus tendon
- Below
- Quadratus femoris
- Superficial
- Sciatic nerve, then the gluteus maximus
- Deep
- Nerve to quadratus femoris and the posterior hip capsule; the deep branch of the medial circumflex femoral artery runs nearby toward the femoral head
How to find it
Not palpable. In the posterior approach it is the slip just below the obturator internus tendon and above the quadratus femoris, coming from the upper ischial tuberosity.
On imaging
Too thin to judge alone; on axial MRI it lies along the lower edge of the obturator internus tendon, just above the quadratus femoris. It is assessed with the short rotators after posterior hip surgery. In ischiofemoral impingement the oedema is usually in the quadratus femoris below it, which is the muscle checked. Radiographs and CT add little.
Common problems
- Uncommonly, a source of deep buttock or pelvic pain when strained or tight.
Clinical notes
- The deep branch of the medial circumflex femoral artery, the main supply of the femoral head, runs deep to the gemelli and the obturator internus tendon, so it is at risk when these tendons are detached in posterior hip surgery
- The sciatic nerve crosses the back of the gemelli and the obturator internus tendon; entrapment at this level is one recognised form of deep gluteal syndrome, often provoked by resisted or passive hip rotation
Anatomical variants
- Its origin and insertion vary; rarely both gemelli are missing
Test yourself
Think of the answer, then tap the question to see it.
Which nerve supplies the inferior gemellus, unlike the superior gemellus?
The nerve to quadratus femoris (L5–S1); the superior gemellus gets the nerve to obturator internus.
Where does the inferior gemellus arise and insert?
From the upper ischial tuberosity into the obturator internus tendon, to the medial surface of the greater trochanter.
Which important artery runs deep to the gemelli and is at risk in posterior hip surgery?
The deep branch of the medial circumflex femoral artery, the main supply of the femoral head.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- musculus gemellus inferior TA2 2607
- Official Spanish (DeCS)
- Músculo gemelo inferior
- English (TA2)
- Inferior gemellus muscle
- Also called
- gemellus inferior muscle · musculus gemellus tuberalis
Related
Sources: Terminologia Anatomica (TA2); Anatomy, Bony Pelvis and Lower Limb, Gemelli Muscles.
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.
