Quadratus femoris !
The quadratus femoris is a square muscle deep behind the hip, the lowest of the short rotators; it turns the thigh outward.
Official name: Quadratus femoris muscle
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What it is
A flat, square muscle behind the hip, from the sitting bone to the back of the femur.
What it does
Turns the thigh outward and steadies the hip.
Key facts
- Origin
- Lateral border of ischial tuberosity
- Insertion
- Quadrate tubercle on intertrochanteric crest
- Action
- Laterally rotates hip; steadies femoral head
- Nerve
- Nerve to quadratus femoris (L5–S1) (some texts: L4–S1)
- Blood supply
- Medial circumflex femoral artery; inferior gluteal artery
Relations
- Above
- Inferior gemellus
- Below
- Upper border of the adductor magnus (adductor minimus)
- Superficial
- Sciatic nerve, then the gluteus maximus
- Deep
- Obturator externus tendon, the lesser trochanter and the deep branch of the medial circumflex femoral artery
How to find it
Not palpable. On axial MRI at the level of the lesser trochanter it is the flat muscle crossing from the outer edge of the ischial tuberosity to the back of the femur, behind the obturator externus.
Examination
- Long-stride walking test: buttock pain when walking with long strides that eases with short strides suggests ischiofemoral impingement
- Ischiofemoral impingement test: pain on passive hip extension with the thigh adducted, relieved when the same extension is done in abduction, points to the same narrowing
On imaging
MRI in ischiofemoral impingement: a narrowed gap between the ischium and the lesser trochanter, with oedema and later fatty change in the quadratus femoris.
Common problems
- Ischiofemoral impingement: the muscle is pinched between the sitting bone and the femur, causing deep buttock pain.
Clinical notes
- Lying right under the sciatic nerve, it is a landmark for the subgluteal sciatic nerve block on ultrasound, where the nerve sits between the gluteus maximus and this muscle
- Ischiofemoral impingement: a narrow gap between the ischial tuberosity and the lesser trochanter pinches the muscle, and MRI shows oedema or fatty change inside it
Test yourself
Think of the answer, then tap the question to see it.
Which nerve runs directly on the back of the quadratus femoris?
The sciatic nerve, on its way into the thigh; on ultrasound it sits between the gluteus maximus and this muscle (subgluteal block).
Which condition pinches the quadratus femoris between the ischium and the lesser trochanter?
Ischiofemoral impingement, with oedema and later fatty change of the muscle on MRI.
Why does dividing the quadratus femoris endanger the femoral head?
The deep branch of the medial circumflex femoral artery passes just deep to its upper border.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- musculus quadratus femoris TA2 2608
- Official Spanish (DeCS)
- Músculo cuadrado femoral
- English (TA2)
- Quadratus femoris muscle
Related
- Inferior gemellus
- Sciatic nerve
- Obturator externus
- Nerves to the hip rotators
- Gluteal arteries
- Circumflex femoral arteries
- Femur
- Hip bone
Sources: Terminologia Anatomica (TA2); Anatomy, Bony Pelvis and Lower Limb, Hip; Anatomy, Bony Pelvis and Lower Limb: Posterior Thigh.
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Representative model, for educational purposes only.
