Inferior Gemellus
Gluteal & Hip · Lower Limb
The inferior gemellus is the lower of the two small gemelli muscles of the deep gluteal region and a member of the short lateral rotator group of the hip. It arises from the ischial tuberosity and runs laterally to join the tendon of the obturator internus, through which it inserts on the medial surface of the greater trochanter at the trochanteric fossa. Working with the obturator internus and the superior gemellus, it laterally rotates the extended thigh, abducts the flexed thigh, and helps stabilise the hip joint. It is supplied by the nerve to quadratus femoris (L4, L5, S1).
Origin, Insertion, Action & Nerve
Origin
Ischial tuberosity
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 quadratus femoris (L4–S1)
Attachments explained
The Inferior 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 tuberosity
Insertion
Medial surface of the greater trochanter via the obturator internus tendon (trochanteric fossa)
Action & function
When the Inferior 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 Inferior Gemellus receives its nerve supply from the Nerve to quadratus femoris (L4–S1). This nerve carries fibres from spinal segment(s) L4, S1.
Because a muscle can only contract when its nerve is intact, injury to the Nerve to quadratus femoris or to its spinal roots (L4, S1) can weaken or paralyse the Inferior 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 Inferior Gemellus (the OIANS method)
Separate the inferior gemellus from its twin by their origins: the inferior arises from the ischial tuberosity, the lower bony prominence you sit on, while the superior arises from the ischial spine above it. Both blend with the obturator internus tendon and act as one, so remembering the two bony landmarks is the cleanest way to tell the pair apart.
Fix its nerve by contrast with the superior gemellus: the inferior gemellus shares the nerve to quadratus femoris (L4, L5, S1), the muscle lying just below it, whereas the superior shares the nerve to obturator internus. Deducing its actions from the short-rotator rule, lateral rotation of the extended hip and abduction of the flexed hip, keeps the whole group consistent in memory.
Frequently asked questions
Where is the Inferior Gemellus located?
The Inferior Gemellus is a muscle of the Gluteal & Hip group, located in the Lower Limb.
What is the origin of the Inferior Gemellus?
Ischial tuberosity
What is the insertion of the Inferior Gemellus?
Medial surface of the greater trochanter via the obturator internus tendon (trochanteric fossa)
What movements does the Inferior Gemellus produce?
Laterally rotates the extended thigh; abducts the flexed thigh; stabilizes the hip
What nerve supplies the Inferior Gemellus?
Nerve to quadratus femoris (L4–S1)
Is the Inferior Gemellus free to study in OIANS?
The Inferior 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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