Superior Gemellus
Gluteal & Hip · Lower Limb
The superior gemellus is the upper of the two small gemelli muscles of the deep gluteal region, forming part of the short lateral rotator group around the hip. It arises from the ischial spine and passes laterally to blend with the tendon of the obturator internus, through which it inserts on the medial surface of the greater trochanter at the trochanteric fossa. Acting with the obturator internus and its fellow gemellus, it laterally rotates the extended thigh, abducts the flexed thigh, and helps stabilise the hip joint by holding the femoral head in the acetabulum. It is supplied by the nerve to obturator internus (L5, S1, S2).
Origin, Insertion, Action & Nerve
Origin
Ischial spine
Insertion
Medial surface of the greater trochanter via the obturator internus tendon (trochanteric fossa)
Action
Laterally rotates the extended thigh; abducts the flexed thigh; stabilizes the hip
Nerve
Nerve to obturator internus (L5–S2)
Attachments explained
The Superior Gemellus is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Ischial spine
Insertion
Medial surface of the greater trochanter via the obturator internus tendon (trochanteric fossa)
Action & function
When the Superior Gemellus contracts, it produces the following movements: Laterally rotates the extended thigh; abducts the flexed thigh; stabilizes the hip.
As part of the Gluteal & Hip group of the Lower Limb, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Superior Gemellus receives its nerve supply from the Nerve to obturator internus (L5–S2). This nerve carries fibres from spinal segment(s) L5, S2.
Because a muscle can only contract when its nerve is intact, injury to the Nerve to obturator internus or to its spinal roots (L5, S2) can weaken or paralyse the Superior Gemellus, impairing the movements it normally produces (laterally rotates the extended thigh). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Superior Gemellus (the OIANS method)
Picture the two gemelli as a pair of small muscles straddling the tendon of obturator internus, forming a tricipital arrangement that acts as one functional unit. The superior gemellus is defined by its origin from the ischial spine; remembering that landmark, just above the lesser sciatic notch, fixes it above its partner and above the emerging pudendal vessels and nerve.
Fix its nerve by association: because the superior gemellus fuses with obturator internus, it shares that muscle's nerve, the nerve to obturator internus (L5, S1, S2), whereas the inferior gemellus takes the nerve to quadratus femoris. Grouping all the short rotators as lateral rotators of the extended hip and abductors of the flexed hip lets you reason out its actions rather than memorising them.
Frequently asked questions
Where is the Superior Gemellus located?
The Superior Gemellus is a muscle of the Gluteal & Hip group, located in the Lower Limb.
What is the origin of the Superior Gemellus?
Ischial spine
What is the insertion of the Superior Gemellus?
Medial surface of the greater trochanter via the obturator internus tendon (trochanteric fossa)
What movements does the Superior Gemellus produce?
Laterally rotates the extended thigh; abducts the flexed thigh; stabilizes the hip
What nerve supplies the Superior Gemellus?
Nerve to obturator internus (L5–S2)
Is the Superior Gemellus free to study in OIANS?
The Superior Gemellus is always free to browse. Its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory. Quiz and Flashcard practice for the Lower Limb is part of the one-time Lifetime upgrade, though; only the Upper Limb decks are free to test yourself on.
Related muscles
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