Gait Analysis and Biomechanics — MCQs
Trendelenburg's sign is positive in injury to which structure?
The kinetic energy of the body is least in one of the following phases of the walking cycle
High stepping gait is due to
Foot drop occurs due to the involvement of:
According to Miller, mobility within a range of 0.5-1.5 mm with lateral movement is classified as which grade?
Lurching Gait is due to paralysis of which of the following?
Trendelenberg test is negative in
In walking, gravity tends to tilt pelvis and trunk to the unsupported side, the major factor in preventing this unwanted movement is?
Which metatarsal is known for its significant mobility in the foot?
A 55-year-old man is admitted to the hospital for an iliofemoral bypass. The operation is performed successfully and the blood flow between the iliac and femoral arteries is restored. During rehabilitation, which of the following arteries should be palpated to monitor good circulation of the lower limb?
Gait Analysis and Biomechanics Indian Medical PG Practice Questions and MCQs
Question 1: Trendelenburg's sign is positive in injury to which structure?
- A. Gluteus maximus
- B. Gluteus medius (Correct Answer)
- C. Quadriceps femoris
- D. Quadratus lumborum
Explanation: ***Gluteus medius*** - A positive **Trendelenburg's sign** indicates weakness or paralysis of the **gluteus medius** muscle, or problem with its innervation or hip joint. - This muscle is crucial for **abduction** and **stabilization** of the pelvis during gait; its dysfunction causes the unsupported side of the pelvis to drop. *Gluteus maximus* - The **gluteus maximus** is primarily involved in **hip extension** and external rotation, not hip abduction or pelvic stability during single-leg stance. - Weakness in this muscle would manifest more as difficulty with climbing stairs or rising from a seated position. *Quadriceps femoris* - The **quadriceps femoris** muscles are responsible for **knee extension**, essential for walking and standing. - Injury to these muscles would primarily affect the ability to **straighten the leg** and bear weight on it, not cause pelvic drop. *Quadratus lumborum* - The **quadratus lumborum** is a deep abdominal muscle involved in **lateral flexion of the trunk** and stabilization of the lumbar spine. - Dysfunction of this muscle would lead to **trunk instability** or pain, but not the specific pelvic drop seen in Trendelenburg's sign.
Question 2: The kinetic energy of the body is least in one of the following phases of the walking cycle
- A. Double support
- B. Mid-stance (Correct Answer)
- C. Toe-off
- D. Heel strike
Explanation: ***Mid-stance*** - During **mid-stance**, the body's center of gravity is at its **highest point**, and the vertical velocity is near zero as the body transitions from upward to downward motion, contributing to **reduced kinetic energy**. - At this phase, forward velocity is relatively constant but the body is at the apex of its vertical trajectory, representing a point of **minimal total kinetic energy** in the sagittal plane. - The body transitions from deceleration to acceleration, with the limb providing stable support as weight passes over the stance foot. *Double support* - In **double support**, both feet are on the ground during the weight transfer phase, and the body's center of gravity is at a lower position compared to mid-stance. - While some energy is dissipated during weight transfer, this phase involves active muscular work and forward momentum maintenance, with kinetic energy being variable. - This represents a transition phase between single support periods, with complex energy exchanges occurring. *Toe-off* - At **toe-off**, the propulsive phase of gait, the body is generating forward momentum with peak forward velocity, meaning there is **significant kinetic energy** as the foot pushes off the ground. - The body's center of gravity is moving upwards and forwards, indicating a higher kinetic energy state. - Ankle plantarflexors are actively propelling the body forward, maximizing kinetic energy output. *Heel strike* - **Heel strike** is a moment of initial contact where the body's forward velocity is still considerable, possessing **significant kinetic energy**. - The limb is preparing to absorb impact forces while the body's center of mass continues moving forward, representing high kinetic energy just before the deceleration phase. - This marks the beginning of the stance phase with substantial horizontal velocity maintained from the swing phase.
Question 3: High stepping gait is due to
- A. Gluteus maximum paralysis
- B. CDH
- C. Quadriceps paralysis
- D. Foot drop (Correct Answer)
Explanation: ***Foot drop*** - **Foot drop** causes the patient to lift the leg higher during walking to prevent the toes from dragging on the ground, resulting in a **high stepping gait**. - This condition is often due to weakness or paralysis of the **dorsiflexor muscles** of the foot, typically from **peroneal nerve injury** or **L4/L5 radiculopathy**. *Gluteus maximum paralysis* - **Gluteus maximus paralysis** causes difficulty with hip extension and is often compensated by a **backward lurch** of the trunk during gait. - It results in a **Trendelenburg gait** (if the gluteus medius is also affected) or instability during standing, but not typically a high stepping gait. *CDH* - **Congenital hip dysplasia (CDH)** involves abnormal development of the hip joint. - It usually leads to a **waddling gait** due to instability and pain, or limb length discrepancy, not a high stepping gait. *Quadriceps paralysis* - **Quadriceps paralysis** results in weakness or inability to extend the knee. - Patients typically compensate by hyperextending the knee or leaning forward over the affected leg during gait, which is not a high stepping gait.
Question 4: Foot drop occurs due to the involvement of:
- A. Obturator nerve
- B. Sciatic nerve
- C. Direct injury to the dorsiflexors
- D. Common peroneal nerve palsy (Correct Answer)
Explanation: ***Common peroneal nerve palsy*** - The **common peroneal nerve** (also known as the common fibular nerve) innervates the muscles responsible for **dorsiflexion** and eversion of the foot (tibialis anterior, extensor hallucis longus, extensor digitorum longus, peroneus longus and brevis). - Damage to this nerve leads to weakness or paralysis of these muscles, resulting in **foot drop**, which is the most common neurological cause. - The nerve is vulnerable at the **neck of the fibula** where it is superficial and can be compressed or injured. *Sciatic nerve* - The **sciatic nerve** divides into the tibial and common peroneal nerves. - Proximal sciatic nerve injury can cause foot drop, but it would also cause additional deficits including hamstring weakness, loss of ankle plantarflexion, and sensory loss over a wider distribution. - Isolated foot drop typically indicates **common peroneal nerve** injury, not sciatic nerve injury. *Direct injury to the dorsiflexors* - Direct trauma to the **dorsiflexor muscles** (tibialis anterior, extensor hallucis longus, extensor digitorum longus) can mechanically impair dorsiflexion. - However, the term "foot drop" typically refers to **neurological causes** rather than direct muscle injury, making common peroneal nerve palsy the more specific answer. *Obturator nerve* - The **obturator nerve** innervates the **adductor muscles of the thigh** (adductor longus, adductor brevis, adductor magnus, gracilis). - It does not innervate any muscles responsible for dorsiflexion of the foot and therefore **cannot cause foot drop**.
Question 5: According to Miller, mobility within a range of 0.5-1.5 mm with lateral movement is classified as which grade?
- A. Grade 2 (Correct Answer)
- B. Grade 0
- C. Grade 1
- D. Grade 3
Explanation: ***Grade 2*** - **Grade 2 mobility** is defined by tooth movement in the range of **0.5-1.5 mm** in any direction, corresponding to the given clinical scenario. - This level of mobility often indicates **moderate loss of periodontal support** or **trauma from occlusion.** *Grade 0* - **Grade 0 mobility** indicates **normal physiological tooth movement**, which is imperceptible or less than 0.2 mm. - This grade signifies a **healthy periodontium** with adequate bone support. *Grade 1* - **Grade 1 mobility** involves tooth movement of **up to 0.5 mm** in a buccolingual direction, which is less than the 0.5-1.5 mm range specified. - It usually suggests **initial periodontal tissue destruction** or slight occlusal trauma. *Grade 3* - **Grade 3 mobility** is characterized by tooth movement **greater than 1.5 mm** in any direction, or the tooth is **depressible** in its socket. - This grade indicates **severe loss of periodontal support** and a poor prognosis for the tooth.
Question 6: Lurching Gait is due to paralysis of which of the following?
- A. Gluteus medius (Correct Answer)
- B. Adductor magnus
- C. Hamstrings
- D. Quadriceps femoris
Explanation: ***Gluteus medius*** * Paralysis of the **gluteus medius** leads to a **Trendelenburg gait** or **lurching gait**, where the pelvis drops on the unsupported side during walking. * This muscle is crucial for **stabilizing the pelvis** during the single-limb support phase of gait. *Adductor Magnus* * Paralysis of the adductor magnus would primarily affect **thigh adduction** and extension, not directly causing a lurching gait. * Problems with this muscle might impact the ability to bring the legs together or stabilize the leg during certain movements. *Hamstrings* * The hamstrings are responsible for **knee flexion** and **hip extension**. * Paralysis would result in difficulty bending the knee and limited hip extension, potentially leading to a stiff-knee gait, but not typically a lurching gait. *Quadriceps femoris* * The quadriceps femoris is essential for **knee extension** and is critical for activities like standing, walking, and climbing stairs. * Paralysis would cause the knee to buckle, leading to a **knee-hyperflexion gait** or difficulty with weight-bearing on that leg.
Question 7: Trendelenberg test is negative in
- A. Polio myelitis
- B. Inferior Gluteal nerve
- C. Normal hip function (Correct Answer)
- D. Superior Gluteal nerve
Explanation: ***Normal hip function*** - A **negative Trendelenburg test** indicates that the hip abductor muscles (primarily the **gluteus medius and minimus**) are functioning correctly and can maintain pelvic stability when standing on one leg. - This suggests the absence of **weakness** or **dysfunction** in the hip abductors or their innervation. *Polio myelitis* - **Poliomyelitis** can cause **paralysis** and **weakness** of various muscles, including the hip abductors, leading to a **positive Trendelenburg test**. - The disease damages **motor neurons** in the spinal cord, impairing muscle function. *Inferior Gluteal nerve* - The **inferior gluteal nerve** primarily innervates the **gluteus maximus**, which is responsible for hip extension, not hip abduction. - Weakness due to inferior gluteal nerve damage would manifest as difficulty with activities like **climbing stairs** or **rising from a chair**, but typically would not cause a positive Trendelenburg test. *Superior Gluteal nerve* - The **superior gluteal nerve** innervates the **gluteus medius and minimus**, which are the primary hip abductors. - Damage to this nerve or weakness of these muscles would result in a **positive Trendelenburg test**, where the contralateral pelvis drops when standing on the affected leg.
Question 8: In walking, gravity tends to tilt pelvis and trunk to the unsupported side, the major factor in preventing this unwanted movement is?
- A. Adductor muscles
- B. Quadriceps
- C. Gluteus medius and minimus (Correct Answer)
- D. Gluteus maximus
Explanation: ***Gluteus medius and minimus*** - The **gluteus medius** and **gluteus minimus** are essential **abductors** of the hip, primarily responsible for stabilizing the pelvis during the **single-limb support phase of gait**. - When one leg is lifted during walking, these muscles on the **stance leg side** contract to prevent the pelvis from tilting downwards on the unsupported swing leg side. *Adductor muscles* - **Adductor muscles** (adductor longus, brevis, magnus, pectineus, gracilis) primarily function to bring the thigh toward the midline of the body. - While they play a role in gait stability, their main action is not to prevent the lateral pelvic tilt described. *Quadriceps* - The quadriceps femoris group (rectus femoris, vastus lateralis, medialis, intermedius) are powerful **extensors of the knee**. - They are crucial for weight acceptance and propulsion during walking but do not directly prevent lateral pelvic tilt [1]. *Gluteus maximus* - The **gluteus maximus** is the largest and most powerful muscle of the hip, primarily responsible for **hip extension** and **external rotation**. - It is crucial for activities like climbing stairs or running, but its main role in normal walking is not to prevent lateral pelvic tilt; that function is more specific to the gluteus medius and minimus.
Question 9: Which metatarsal is known for its significant mobility in the foot?
- A. 3rd metatarsal
- B. 4th metatarsal
- C. 1st metatarsal (Correct Answer)
- D. 2nd metatarsal
Explanation: ***1st metatarsal*** - The **first metatarsal** is highly mobile, articulated with the **medial cuneiform** by a saddle-shaped joint, allowing for significant motion critical for foot adaptation during gait. - Its mobility is crucial for **pronation and supination** of the foot, impacting load distribution and stability, especially during toe-off. *2nd metatarsal* - The **second metatarsal** is the **least mobile** of the metatarsals, deeply recessed and articulated with the three cuneiforms, forming a key part of the **Lisfranc joint complex**. - Its relative rigidity contributes to the **stability** of the midfoot and acts as a central pillar, providing a stable base for the other metatarsals. *3rd metatarsal* - The **third metatarsal** has **limited mobility**, articulating primarily with the **lateral cuneiform**. - While it has some translational and rotational movement, it is significantly less mobile than the first metatarsal and plays a role in the stability of the central ray of the foot. *4th metatarsal* - The **fourth metatarsal** exhibits **moderate mobility**, greater than the second and third but less than the first. - It articulates with the **cuboid** and **lateral cuneiform**, providing flexibility important for adapting the forefoot to uneven surfaces.
Question 10: A 55-year-old man is admitted to the hospital for an iliofemoral bypass. The operation is performed successfully and the blood flow between the iliac and femoral arteries is restored. During rehabilitation, which of the following arteries should be palpated to monitor good circulation of the lower limb?
- A. Anterior tibial artery
- B. Deep fibular (peroneal) artery
- C. Deep plantar artery
- D. Dorsalis pedis artery (Correct Answer)
Explanation: The **Dorsalis pedis artery** is the correct answer because it is the most distal clinically palpable artery in the lower limb. In vascular surgeries like an iliofemoral bypass, the primary goal is to restore perfusion to the entire extremity. Palpating the most distal pulse ensures that the arterial pressure is sufficient to overcome the resistance of the entire vascular tree [1]. * **Dorsalis pedis artery (Correct):** It is the direct continuation of the anterior tibial artery, passing deep to the extensor retinaculum and lying superficial between the tendons of Extensor Hallucis Longus (EHL) and Extensor Digitorum Longus (EDL). Its superficial location over the tarsal bones makes it the gold standard for bedside monitoring of peripheral circulation [1]. **Analysis of Incorrect Options:** * **Anterior tibial artery (A):** While it supplies the leg, it lies deep within the anterior compartment muscles for most of its course, making it difficult to palpate reliably compared to its distal continuation (the dorsalis pedis). * **Deep fibular (peroneal) artery (B):** This is a branch of the posterior tibial artery (via the peroneal trunk). It runs deep in the posterior/lateral compartment and is not palpable. * **Deep plantar artery (C):** This is a terminal branch of the dorsalis pedis that dives deep into the sole of the foot to complete the plantar arch; it is not accessible for surface palpation. **NEET-PG High-Yield Pearls:** * **Surface Anatomy:** The dorsalis pedis pulse is felt on the dorsum of the foot, lateral to the tendon of the **Extensor Hallucis Longus**. * **Clinical Correlation:** Absence of this pulse may indicate Peripheral Arterial Disease (PAD) or Buerger’s disease [1]. However, note that in ~10% of the healthy population, the dorsalis pedis artery is congenitally absent or displaced. * **The "Five P’s" of Acute Ischemia:** Pain, Pallor, Pulselessness, Paresthesia, and Paralysis. Monitoring the distal pulse is the first step in assessing "Pulselessness."
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