Gracilis
Thigh · Lower Limb
The gracilis is a long, thin, strap-like muscle that lies most medially in the thigh and is the only muscle of the medial group to cross both the hip and the knee. It arises from the body and inferior ramus of the pubis and descends to insert on the superomedial surface of the tibia as part of the pes anserinus. It adducts the hip and flexes and medially rotates the knee. It is supplied by the obturator nerve (L2, L3).
Origin, Insertion, Action & Nerve
Origin
Body and inferior ramus of pubis
Insertion
Superomedial surface of tibia (pes anserinus)
Action
Adduction of hip; flexion and medial rotation of knee
Nerve
Obturator nerve (L2, L3)
Attachments explained
The Gracilis 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
Body and inferior ramus of pubis
Insertion
Superomedial surface of tibia (pes anserinus)
Action & function
When the Gracilis contracts, it produces the following movements: Adduction of hip; flexion and medial rotation of knee.
As part of the Thigh 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 Gracilis receives its nerve supply from the Obturator nerve (L2, L3). This nerve carries fibres from spinal segment(s) L2, L3.
Because a muscle can only contract when its nerve is intact, injury to the Obturator nerve or to its spinal roots (L2, L3) can weaken or paralyse the Gracilis, impairing the movements it normally produces (adduction of hip). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Gracilis (the OIANS method)
Study the gracilis as the slender two-joint member of the adductor group, distinguished from the others by reaching past the knee. Its origin on the pubis gives it the adductor action shared with its neighbours, while its insertion on the medial tibia allows it to also flex and medially rotate the knee, which the shorter adductors cannot do.
Group its insertion with sartorius and semitendinosus as the pes anserinus on the superomedial tibia, and keep it with the adductors on the obturator nerve (L2, L3). Its long, superficial, and expendable nature, which makes it a common tendon graft, is a useful memory hook for its strap-like form.
Frequently asked questions
Where is the Gracilis located?
The Gracilis is a muscle of the Thigh group, located in the Lower Limb.
What is the origin of the Gracilis?
Body and inferior ramus of pubis
What is the insertion of the Gracilis?
Superomedial surface of tibia (pes anserinus)
What movements does the Gracilis produce?
Adduction of hip; flexion and medial rotation of knee
What nerve supplies the Gracilis?
Obturator nerve (L2, L3)
Is the Gracilis free to study in OIANS?
The Gracilis 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
Study the Gracilis
Test yourself on Lower Limb muscles with interactive quizzes and flashcards in the free OIANS app.
Quiz yourself → Flashcards Open the OIANS app
Browsing is always free. A one-time Lifetime unlock adds every region's quizzes, flashcards, progress tracking and explore tools.