Lower Limb Practice Questions

Q: Physiological unlocking is caused by -

Popliteus. ***Popliteus*** - The **popliteus muscle** is responsible for the **physiological unlocking** mechanism of the knee joint at the beginning of flexion from a fully extended position. - It **internally rotates the tibia** on the femur (or externally rotates the femur on the tibia) to disengage the femoral condyles from their locked position, allowing flexion to initiate. *Sartorius* - The **sartorius muscle** is a strong flexor, abductor, and external rotator of the hip, and a flexor and internal rotator of the knee joint. - It does not primarily contribute to the unlocking mechanism of the knee. *Rectus femoris* - The **rectus femoris** is one of the quadriceps muscles and is a powerful extensor of the knee. - It plays no role in initiating knee flexion by unlocking the joint. *Semimembranosus* - The **semimembranosus** is part of the hamstring group, primarily involved in knee flexion and hip extension. - While it contributes to knee flexion, it does not perform the specific rotational movement required for unlocking the knee.

Q: Which structure is closely associated with the fibular collateral ligament?

Biceps femoris. ***Biceps femoris*** - The **biceps femoris tendon** passes superficial and lateral to the fibular collateral ligament before inserting onto the head of the fibula. - These two structures run parallel to each other and are anatomically closely related at the lateral aspect of the knee joint. - The **intimate relationship** between the biceps femoris tendon and the fibular collateral ligament makes them key anatomical landmarks for understanding lateral knee anatomy. *Peroneus longus* - The **peroneus longus** muscle is located in the lateral compartment of the leg and its tendon courses around the lateral malleolus, but it does not have a direct anatomical association with the fibular collateral ligament at the knee joint. - Its primary role is in **eversion and plantarflexion of the foot**, not direct knee joint stabilization. *Semimembranosus* - The **semimembranosus** muscle is a hamstring muscle located in the posterior compartment of the thigh, inserting predominantly on the medial tibial condyle. - It strengthens the medial aspect of the knee joint and has no direct anatomical relationship with the lateral fibular collateral ligament. *Adductor magnus* - The **adductor magnus** is a large muscle of the medial compartment of the thigh, involved in adduction of the hip. - It inserts on the femur and its tendinous attachments are far removed from the lateral knee structures like the fibular collateral ligament.

Q: Foot drop is caused due to injury to which nerve?

Common Peroneal Nerve. Common peroneal nerve - Injury to the common peroneal nerve (also known as the common fibular nerve) leads to weakness or paralysis of the muscles responsible for dorsiflexion and eversion of the foot. - This results in a condition called foot drop, where the foot cannot be lifted at the ankle, causing a characteristic high-stepping or steppage gait. Obturator Nerve - The obturator nerve primarily innervates the adductor muscles of the thigh, which are responsible for pulling the legs together. - Injury to this nerve would cause difficulty with leg adduction and sensation over the medial thigh, not foot drop. Tibial Nerve - The tibial nerve innervates the muscles of the posterior compartment of the leg, responsible for plantarflexion and inversion of the foot. - Damage to the tibial nerve would result in an inability to stand on tiptoes or reduced sensation in the sole of the foot, not foot drop. Femoral Nerve - The femoral nerve innervates the quadriceps femoris muscle, essential for knee extension, and also provides sensation to the anterior thigh and medial leg. - Injury to this nerve would primarily lead to weakness in knee extension and difficulty climbing stairs, not foot drop.

Q: Housemaid's knee is inflammation of:

Prepatellar bursa. ***Prepatellar bursa*** - **Housemaid's knee** refers to **prepatellar bursitis**, an inflammation of the bursa located anterior to the patella. - This condition is often caused by **prolonged kneeling**, leading to frictional irritation and inflammation of the prepatellar bursa. *Anserine bursa* - Inflammation of the anserine bursa is known as **pes anserine bursitis**, typically causing pain on the medial aspect of the knee below the joint line. - It is not commonly referred to as "housemaid's knee" and is associated with conditions like **osteoarthritis** or overuse in runners. *Infrapatellar bursa* - Inflammation of the infrapatellar bursa is known as **clergyman's knee**, causing pain below the patella, either superficial or deep. - It is typically caused by repetitive kneeling or direct trauma to the area just below the kneecap. - Note: **Jumper's knee** refers to patellar tendinitis, not bursitis. *Suprapatellar bursa* - The suprapatellar bursa is located superior to the patella, communicating with the knee joint. - Inflammation of this bursa is less common in isolation and usually associated with **effusion within the knee joint itself**.

Q: Which of the following muscles do NOT work for inversion of foot?

Peroneus longus. ***Peroneus longus*** - The **peroneus longus** (also known as the fibularis longus) is a primary **evertor** of the foot and also contributes to plantarflexion. - Its insertion on the **medial cuneiform** and base of the first metatarsal provides a pull that turns the sole of the foot outwards, opposing inversion. *Tibialis posterior* - The **tibialis posterior** is a primary and powerful **inverter** of the foot, inserting on multiple tarsal bones and metatarsals. - It also aids in **plantarflexion** and helps maintain the medial longitudinal arch of the foot. *Tibialis anterior* - The **tibialis anterior** is a strong **inverter** of the foot, inserting on the medial cuneiform and base of the first metatarsal. - It works synergistically with the tibialis posterior for inversion and is also a primary **dorsiflexor** of the ankle. *Extensor hallucis longus* - The **extensor hallucis longus** contributes to **inversion** of the foot, though its primary action is to **extend the great toe**. - Its partial line of pull contributes to turning the sole of the foot inward during its action.

Q: Which ligament prevents hyperextension of the knee joint?

Anterior cruciate. ***Anterior cruciate*** - The **anterior cruciate ligament (ACL)** is the **primary restraint against hyperextension** of the knee joint - It prevents **anterior translation of the tibia** relative to the femur and tightens during terminal extension to limit hyperextension - The ACL is crucial for maintaining knee stability during activities that involve sudden stops or changes in direction *Posterior cruciate* - The **posterior cruciate ligament (PCL)** prevents **posterior translation of the tibia** relative to the femur - It is the primary restraint during **knee flexion** and prevents excessive flexion, NOT hyperextension - The PCL is stronger than the ACL and is less commonly injured *Lateral collateral* - The **lateral collateral ligament (LCL)** is located on the outer side of the knee and primarily resists **varus stress** (forces that would create a bow-legged deformity) - It does not play a significant role in preventing hyperextension *Medial collateral* - The **medial collateral ligament (MCL)** is located on the inner side of the knee and primarily resists **valgus stress** (forces that would create a knock-kneed deformity) - It does not play a significant role in preventing hyperextension

Q: Which spinal nerve roots contribute to the formation of the sciatic nerve?

L4-S3. ***L4-S3*** - The **sciatic nerve** is the largest nerve in the body, formed from the confluence of nerve roots from the **lumbar (L4, L5)** and **sacral (S1, S2, S3)** plexuses. - These nerve roots combine to form the sciatic nerve, which then travels down the posterior thigh. *L1-L3* - These nerve roots primarily contribute to the formation of the **femoral nerve** (L2-L4) and obturator nerve (L2-L4), which innervate the anterior and medial compartments of the thigh, respectively. - They do not directly contribute to the formation of the sciatic nerve. *L2-L4* - Nerve roots from **L2, L3, and L4** primarily form the **femoral nerve** and the **obturator nerve**. - While L4 is a component of the sciatic nerve, L2 and L3 are not. *S1-S4* - While **S1, S2, and S3** contribute to the sciatic nerve, the inclusion of S4 is incorrect for its primary formation. - The S4 nerve root has other significant roles, including contributions to the **pudendal nerve**.

Q: A 60-year-old female presents with weakness in dorsiflexion of the foot and sensory loss in the web space between the first and second toes. Which nerve is likely to be involved?

Deep peroneal nerve. ***Deep peroneal nerve*** - This nerve innervates **anterior compartment muscles** responsible for **dorsiflexion** of the foot. - It also provides sensory innervation to the **web space between the first and second toes**, matching the patient's symptoms. *Sural nerve* - The sural nerve provides **sensory innervation** to the lateral aspect of the foot and ankle and has no motor function related to foot dorsiflexion. - Damage to this nerve typically presents as numbness or paresthesia along the **lateral calf and foot**. *Superficial peroneal nerve* - This nerve primarily innervates the **lateral compartment muscles**, responsible for **eversion of the foot**. - Its sensory distribution includes the dorsum of the foot, but **excludes the first web space**. *Tibial nerve* - The tibial nerve innervates the **posterior compartment muscles** of the leg, controlling **plantarflexion** and toe flexion. - Sensory loss associated with tibial nerve injury typically affects the **sole of the foot**.

Q: During a physical examination, a 60-year-old man is found to have a pulsatile mass in his left popliteal fossa. Which artery is most likely involved?

Popliteal artery. Popliteal artery - The **popliteal artery** is located in the **popliteal fossa**, the anatomical space behind the knee [1], [2]. A pulsatile mass in this location is a classic presentation of a **popliteal artery aneurysm** [2]. - **Popliteal artery aneurysms** are the most common peripheral aneurysms and are frequently associated with **abdominal aortic aneurysms** [1]. *Femoral artery* - The **femoral artery** is located in the **groin region** and passes down the thigh, not in the popliteal fossa [1]. - A pulsatile mass involving the femoral artery would be found in the **thigh** or **groin**, not behind the knee. *Tibial artery* - The **tibial arteries** (anterior and posterior) are located in the **lower leg** below the knee, supplying the foot [3]. - While they are palpable, a pulsatile mass in the popliteal fossa would not typically be attributed to these vessels, as they are distal to this region. *Peroneal artery* - The **peroneal artery** is also located in the **lower leg**, deep within the posterior compartment [1]. - Similar to the tibial arteries, an aneurysm of the peroneal artery would present in the lower leg and not in the popliteal fossa.

Q: What anatomical considerations should an orthopedic surgeon take into account to minimize the risk of damaging the sciatic nerve during hip replacement surgery?

Avoid deep dissection near the piriformis muscle. ***Avoid deep dissection near the piriformis muscle*** - The **sciatic nerve** typically exits the pelvis below the **piriformis muscle**, making this a crucial area to protect during deep dissection. - Excessive retraction or direct injury to the nerve in this region can lead to **postoperative sciatica** or neurological deficits. *Identify and protect the nerve as it courses anterior to the piriformis* - The sciatic nerve almost always courses **posterior** (or inferior) to the piriformis muscle, not anterior. - An anomalous high division of the nerve or an atypical course through the piriformis can occur but a normally positioned nerve is posterior. *Maintain dissection superficial to the gluteus maximus* - The gluteus maximus is the most superficial muscle in the gluteal region, and while a superficial approach minimizes nerve damage, it would not provide adequate access for **hip replacement surgery**. - Hip replacement requires deeper dissection to access the **acetabulum** and **femoral head**. *Understand the nerve's path in relation to the acetabulum for surgical planning.* - While it is generally important to understand the overall anatomy, focusing solely on the relationship with the **acetabulum** overlooks the most common site of injury, which is usually in the vicinity of the **piriformis** and **posterior capsule**. - The nerve's relationship to the acetabulum becomes more critical with specific approaches (e.g., direct anterior) or implant placement, but the **piriformis region** is a more universal concern.

Question 1

Physiological unlocking is caused by -

Accepted Answer

Popliteus

Answer

Sartorius

Answer

Rectus femoris

Answer

Semimembranosus

Question 2

Which structure is closely associated with the fibular collateral ligament?

Accepted Answer

Biceps femoris

Answer

Peroneus longus

Answer

Semimembranosus

Answer

Adductor magnus

Question 3

Foot drop is caused due to injury to which nerve?

Accepted Answer

Common Peroneal Nerve

Answer

Obturator Nerve

Answer

Tibial Nerve

Answer

Femoral Nerve

Question 4

Housemaid's knee is inflammation of:

Accepted Answer

Prepatellar bursa

Answer

Anserine bursa

Answer

Infrapatellar bursa

Answer

Suprapatellar bursa

Question 5

Which of the following muscles do NOT work for inversion of foot?

Accepted Answer

Peroneus longus

Answer

Tibialis posterior

Answer

Tibialis anterior

Answer

Extensor hallucis longus

Question 6

Which ligament prevents hyperextension of the knee joint?

Accepted Answer

Anterior cruciate

Answer

Lateral collateral

Answer

Posterior cruciate

Answer

Medial collateral

Question 7

Which spinal nerve roots contribute to the formation of the sciatic nerve?

Accepted Answer

L4-S3

Answer

L1-L3

Answer

L2-L4

Answer

S1-S4

Question 8

A 60-year-old female presents with weakness in dorsiflexion of the foot and sensory loss in the web space between the first and second toes. Which nerve is likely to be involved?

Accepted Answer

Deep peroneal nerve

Answer

Sural nerve

Answer

Superficial peroneal nerve

Answer

Tibial nerve

Question 9

During a physical examination, a 60-year-old man is found to have a pulsatile mass in his left popliteal fossa. Which artery is most likely involved?

Accepted Answer

Popliteal artery

Answer

Femoral artery

Answer

Tibial artery

Answer

Peroneal artery

Question 10

What anatomical considerations should an orthopedic surgeon take into account to minimize the risk of damaging the sciatic nerve during hip replacement surgery?

Accepted Answer

Avoid deep dissection near the piriformis muscle

Answer

Identify and protect the nerve as it courses anterior to the piriformis

Answer

Maintain dissection superficial to the gluteus maximus

Answer

Understand the nerve's path in relation to the acetabulum for surgical planning.

Lower Limb — MCQs

Lower Limb — MCQs

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