A 76-year-old woman trips at home and has a displaced intracapsular fracture of the neck of the right femur. The orthopaedic surgeon advises hemiarthroplasty rather than fixing the fracture with screws, explaining that the femoral head may otherwise die. Which artery's branches, torn by the fracture, carry most of the blood to the femoral head?

Medial circumflex femoral artery

Lateral circumflex femoral artery

Hip, knee and ankle joint anatomy

8 NEET-PG practice questions on Hip, knee and ankle joint anatomy, part of Anatomy. The first 8 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Medium
A 55-year-old obese woman has had pain behind the medial malleolus for months. Now her right medial arch has flattened, the heel has drifted into valgus, and she cannot rise on the toes of that foot alone. Failure of which tendon has led to this deformity?
1. ATibialis posterior
2. BFlexor hallucis longus
3. CPeroneus longus
4. DTibialis anterior
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Answer: A · Tibialis posterior
Tibialis posterior passes behind the medial malleolus and inserts mainly on the navicular tuberosity, supporting the medial longitudinal arch together with the spring (plantar calcaneonavicular) ligament, which holds up the head of the talus. When the tendon degenerates, the talar head sinks, the arch collapses and the heel goes into valgus: adult acquired flatfoot. Inability to do a single-leg heel raise is a key sign. Early stages are treated with orthoses and physiotherapy.
- B: Flexor hallucis longus helps the medial arch but its failure does not cause this deformity.
- C: Peroneus longus passes behind the lateral malleolus and supports the lateral and transverse arches.
- D: Tibialis anterior dorsiflexes the foot and passes in front of the ankle, not behind the malleolus.
Question 2 · Medium
A 19-year-old college student rolls her foot inwards while stepping off a footpath. She has swelling and tenderness just in front of and below the lateral malleolus, and the anterior drawer test of the ankle is positive. Which ligament is most likely torn?
1. ADeltoid ligament
2. BAnterior talofibular ligament
3. CCalcaneofibular ligament
4. DPosterior talofibular ligament
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Answer: B · Anterior talofibular ligament
Inversion with plantar flexion is the commonest mechanism of ankle sprain, and the anterior talofibular ligament is the first and most often torn. It runs from the front of the lateral malleolus to the neck of the talus and prevents the talus from sliding forward, so a positive anterior drawer test points to it. The calcaneofibular ligament tears next in more severe sprains. Most sprains settle with rest, ice, compression, elevation and early rehabilitation.
- A: The deltoid ligament is on the medial side and is injured by eversion.
- C: The calcaneofibular ligament is torn only in more severe sprains, after the ATFL.
- D: The posterior talofibular ligament is the strongest and is rarely torn.
Question 3 · Hard
A physiotherapist explains knee mechanics to a 45-year-old man recovering from knee surgery, who stands for long hours as a security guard. She makes four statements: 1. When the foot is on the ground, the femur rotates medially on the tibia in the last stage of extension. 2. Popliteus unlocks the knee by rotating the femur laterally. 3. In the locked position the main ligaments of the knee are taut. 4. Once locked, the quadriceps must contract continuously to keep the knee extended while standing. Which statements are correct?
1. AStatements 2, 3 and 4 only
2. BStatements 1 and 2 only
3. CStatements 1, 2, 3 and 4
4. DStatements 1, 2 and 3 only
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Answer: D · Statements 1, 2 and 3 only
Statements 1, 2 and 3 are correct. In weight bearing, the larger medial femoral condyle completes its rolling last, so the femur rotates medially on the fixed tibia at the end of extension; the joint is then in its close-packed, locked position, with the collateral and cruciate ligaments taut. Popliteus begins flexion by rotating the femur laterally to unlock it. Statement 4 is false: the locked knee is stable with little muscle activity, which is what lets a person stand for long periods without tiring the quadriceps.
- A: Includes the false idea that quadriceps must work continuously, and omits statement 1.
- B: Leaves out the tight ligaments that make the locked knee stable.
- C: Includes the false idea that standing on a locked knee needs continuous quadriceps action.
Question 4 · Easy
A 30-year-old man stands with the knee fully extended and locked. When he begins to bend the knee, a muscle first rotates the femur laterally on the fixed tibia to unlock the joint. Which muscle is this?
1. APopliteus
2. BBiceps femoris
3. CSartorius
4. DGastrocnemius
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Answer: A · Popliteus
Popliteus unlocks the extended knee. With the foot fixed on the ground, it rotates the femur laterally on the tibia, undoing the medial rotation that locked the joint at the end of extension, so flexion can begin. Popliteus arises within the capsule from the lateral femoral condyle and is attached to the lateral meniscus, which it pulls back during flexion. It is supplied by the tibial nerve.
- B: Biceps femoris flexes the knee and rotates the leg laterally but does not unlock the joint.
- C: Sartorius flexes the hip and knee but is not the unlocking muscle.
- D: Gastrocnemius is a plantar flexor that also flexes the knee once unlocked.
Question 5 · Hard
A 76-year-old woman trips at home and has a displaced intracapsular fracture of the neck of the right femur. The orthopaedic surgeon advises hemiarthroplasty rather than fixing the fracture with screws, explaining that the femoral head may otherwise die. Which artery's branches, torn by the fracture, carry most of the blood to the femoral head?
1. ALateral circumflex femoral artery
2. BArtery of the ligamentum teres
3. CInferior gluteal artery
4. DMedial circumflex femoral artery
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Answer: D · Medial circumflex femoral artery
The femoral head in adults gets most of its blood from retinacular arteries that run up along the neck under the synovial reflection, mainly from the medial circumflex femoral artery. A displaced intracapsular fracture tears these vessels, so the head may undergo avascular necrosis and the fracture may not unite. In the elderly the head is therefore usually replaced (hemiarthroplasty), which also allows early walking. The artery of the ligamentum teres, from the obturator artery, supplies only a small area near the fovea in adults.
- A: The lateral circumflex femoral artery contributes much less to the head than the medial.
- B: The artery of the ligamentum teres supplies only a small area near the fovea in adults.
- C: The inferior gluteal artery contributes only a little to the anastomosis round the hip.
Question 6 · Medium
A 20-year-old college footballer is hit on the outer side of his right knee while his foot is planted on the ground. Examination shows medial joint line tenderness, laxity on valgus stress and a positive anterior drawer test. Which combination of injuries is this, as classically described?
1. AACL, lateral collateral ligament and lateral meniscus
2. BPCL, medial collateral ligament and medial meniscus
3. CPCL, lateral collateral ligament and lateral meniscus
4. DACL, medial collateral ligament and medial meniscus
Answer and explanation in LearnFree account
Question 7 · Medium
A 22-year-old kabaddi player twisted his flexed, weight-bearing knee during a raid. Since then the knee has repeatedly 'locked', so that he cannot straighten it fully until he wiggles it, and he has medial joint line tenderness. Why is this structure injured more often than its lateral counterpart?
1. AIt is smaller and more circular than the lateral one
2. BIt is attached to the popliteus tendon
3. CIt has no attachment to the joint capsule
4. DIt is attached to the tibial collateral ligament and moves less
Answer and explanation in LearnFree account
Question 8 · Easy
A 23-year-old footballer twisted his knee while landing and heard a pop, followed by rapid swelling. With the knee flexed at 20-30 degrees, the tibia moves forward excessively on the femur, with no firm end point. Which ligament is torn?
1. APosterior cruciate ligament
2. BLateral collateral ligament
3. CAnterior cruciate ligament
4. DMedial collateral ligament
Answer and explanation in LearnFree account

Hip, knee and ankle joint anatomy

A 55-year-old obese woman has had pain behind the medial malleolus for months. Now her right medial arch has flattened, the heel has drifted into valgus, and she cannot rise on the toes of that foot alone. Failure of which tendon has led to this deformity?

A 19-year-old college student rolls her foot inwards while stepping off a footpath. She has swelling and tenderness just in front of and below the lateral malleolus, and the anterior drawer test of the ankle is positive. Which ligament is most likely torn?

A 30-year-old man stands with the knee fully extended and locked. When he begins to bend the knee, a muscle first rotates the femur laterally on the fixed tibia to unlock the joint. Which muscle is this?

A 20-year-old college footballer is hit on the outer side of his right knee while his foot is planted on the ground. Examination shows medial joint line tenderness, laxity on valgus stress and a positive anterior drawer test. Which combination of injuries is this, as classically described?

A 22-year-old kabaddi player twisted his flexed, weight-bearing knee during a raid. Since then the knee has repeatedly 'locked', so that he cannot straighten it fully until he wiggles it, and he has medial joint line tenderness. Why is this structure injured more often than its lateral counterpart?

A 23-year-old footballer twisted his knee while landing and heard a pop, followed by rapid swelling. With the knee flexed at 20-30 degrees, the tibia moves forward excessively on the femur, with no firm end point. Which ligament is torn?