Orthopedic Biomechanics Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Orthopedic Biomechanics. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Orthopedic Biomechanics Indian Medical PG Question 1: Which of the following is not a ball and socket type of joint?
- A. Incudostapedeal joint
- B. Talocalcaneonavicular joint
- C. Calcaneocuboid joint (Correct Answer)
- D. Shoulder joint
Orthopedic Biomechanics Explanation: ***Calcaneocuboid joint***
- The calcaneocuboid joint is a **saddle joint** (or modified plane joint), which allows for movement primarily in gliding motions, but not the multi-axial movement characteristic of a ball-and-socket joint.
- Its structure, specifically the **reciprocally saddle-shaped articular surfaces** of the calcaneus and cuboid bones, limits its range of motion to primarily inversion and eversion during foot movements.
*Talocalcaneonavicular joint*
- This joint functions as a **modified ball-and-socket joint**, allowing for complex movements like pronation and supination of the foot.
- It involves the head of the talus acting as the 'ball' articulating with the navicular anteriorly and the sustentaculum tali of the calcaneus posteriorly, forming a socket.
- This unique configuration allows for multi-axial movement essential for foot adaptation to terrain.
*Incudostapedial joint*
- This is a **synovial saddle-type joint** (not a ball-and-socket joint) found in the middle ear, connecting the lenticular process of the incus and the head of the stapes.
- It allows for limited rocking motion to efficiently transmit sound vibrations through the ossicular chain.
- The joint permits only small amplitude movements necessary for auditory function, not the multi-axial freedom of a ball-and-socket joint.
*Shoulder joint*
- The shoulder joint, also known as the **glenohumeral joint**, is a classic example of a **ball-and-socket joint**, offering the widest range of motion in the human body.
- The **head of the humerus** (ball) articulates with the **glenoid fossa** of the scapula (socket), allowing for flexion, extension, abduction, adduction, rotation, and circumduction.
Orthopedic Biomechanics Indian Medical PG Question 2: Wolff's law is:-
- A. Epiphyseal centre which appears first unites last with diaphysis
- B. None of above.
- C. Osteogenesis is directly proportional to stress and strain. (Correct Answer)
- D. Epiphyseal centre which appears first unites first with diaphysis.
Orthopedic Biomechanics Explanation: ***Osteogenesis is directly proportional to stress and strain.***
- **Wolff's Law** states that **bone adapts to the loads** under which it is placed. This means bone will remodel and strengthen in response to increased mechanical stress and strain.
- Increased weight-bearing exercise or physical activity leads to **increased bone density** and strength, while lack of stress (e.g., bed rest, immobility) results in bone resorption and weakening.
*Epiphyseal centre which appears first unites last with diaphysis*
- This statement describes **Ritter's law**, which pertains to the sequence of epiphyseal fusion rather than bone's response to mechanical stress.
- Ritter's law is a concept in anatomy related to the order of **epiphyseal plate ossification** and closure.
*None of above.*
- This is incorrect because one of the provided options accurately defines Wolff's Law.
- The third option precisely articulates the principle behind **bone remodeling** in response to mechanical forces.
*Epiphyseal centre which appears first unites first with diaphysis.*
- This statement is generally not a recognized law in bone development and is inconsistent with the principles of epiphyseal fusion, often contradicting Ritter's law.
- The timing of epiphyseal fusion is complex and influenced by various factors, but not simply an "appears first, unites first" rule.
Orthopedic Biomechanics Indian Medical PG Question 3: Buttressing bone formation is the periodontal tissue response to an increase in occlusal forces seen in
- A. Stage I injury
- B. Stage II repair (Correct Answer)
- C. Stage III repair
- D. None of the options
Orthopedic Biomechanics Explanation: **_Stage II repair_**
- In response to increased occlusal forces, buttressing bone formation is a reparative mechanism where the **alveolar bone thickens** to better withstand these forces.
- This adaptive change is characteristic of the **Stage II repair phase**, aiming to reinforce the supportive structures around the tooth.
*Stage I injury*
- This stage typically involves the **initial damage** to the periodontal tissues, such as widening of the periodontal ligament space or increased vascularity.
- **Buttressing bone formation** is a reparative, not an initial injury, response.
*Stage III repair*
- Stage III repair is usually associated with more **severe or chronic injury**, often involving a more pronounced remodeling or even degenerative changes if the forces are persistent and overwhelming.
- While repair continues, buttressing bone formation is most characteristic of the **active phase of adaptation** in Stage II.
*None of the options*
- Buttressing bone formation is a well-documented biological response to increased occlusal forces and is particularly relevant in the context of **periodontal adaptation and repair**.
- Therefore, one of the provided stages is the correct answer.
Orthopedic Biomechanics Indian Medical PG Question 4: Antalgic hip gait is related to which of the following?
- A. Painful hip gait (Correct Answer)
- B. Trendelenberg gait
- C. Waddling gait
- D. Short leg gait
Orthopedic Biomechanics Explanation: ***Painful hip gait***
- An **antalgic gait** is a deviation from a normal gait pattern caused by pain, most commonly experienced in the hip or knee.
- The individual attempts to **minimize the time spent bearing weight** on the painful limb, resulting in a shortened stance phase on the affected side.
*Waddling gait*
- This gait is characterized by a **broad base** and a **swaying motion** from side to side, often due to weakness in the hip abductor muscles.
- While sometimes seen in hip pathologies, it's not synonymous with an antalgic gait, which is specifically pain-driven.
*Trendelenberg gait*
- This gait occurs due to weakness of the **hip abductor muscles** (gluteus medius and minimus) on the stance leg, causing the pelvis to drop on the swing leg side.
- It's a compensatory mechanism for muscle weakness, not directly caused by pain.
*Short leg gait*
- This gait arises from a **discrepancy in leg length**, leading to compensatory mechanisms like hip hiking or circumduction to clear the shorter limb during swing phase.
- While it can lead to secondary pain, the primary cause is a structural difference, not acute pain influencing the weight-bearing phase.
Orthopedic Biomechanics Indian Medical PG Question 5: Which of the following movements is typically restricted in Perthes disease?
- A. Abduction & internal rotation (Correct Answer)
- B. Abduction & external rotation
- C. Adduction & internal rotation
- D. Adduction & external rotation
Orthopedic Biomechanics Explanation: ***Abduction & internal rotation***
- **Perthes disease** affects the femoral head, leading to pain and stiffness that most commonly restricts **abduction** and **internal rotation** of the hip.
- This restriction is an early and consistent clinical finding, often accompanied by a ** Trendelenburg gait** due to gluteal muscle weakness or pain avoidance.
*Abduction & external rotation*
- While abduction can be restricted, a primary restriction in **external rotation** is less typical in early Perthes disease.
- Reduced external rotation is more characteristic of conditions like **slipped capital femoral epiphysis (SCFE)**, especially in older children.
*Adduction & internal rotation*
- **Adduction** is generally preserved or even increased in Perthes disease as the hip seeks a position of comfort due to pain, making it an unlikely primary restriction.
- While internal rotation is restricted, the combination with adduction restriction is not the classical presentation.
*Adduction & external rotation*
- Neither **adduction** nor **external rotation** are typically the primary hip movements restricted in Perthes disease.
- Restriction in adduction is rare, and external rotation is often compensatory or less affected than internal rotation.
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