Anatomy
1 questionsA person is not able to extend his metacarpophalangeal joint. Injury to which of the following nerve result in this?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 931: A person is not able to extend his metacarpophalangeal joint. Injury to which of the following nerve result in this?
- A. Posterior Interosseous nerve injury (Correct Answer)
- B. Radial nerve injury
- C. Ulnar nerve injury
- D. Median nerve injury
Explanation: Posterior Interosseous Nerve (PIN) injury - The Posterior Interosseous Nerve is the deep motor branch of the radial nerve that specifically innervates the extensor muscles of the fingers and thumb - These muscles include: Extensor Digitorum, Extensor Indicis, Extensor Digiti Minimi, Extensor Pollicis Longus and Brevis [1] - PIN injury causes inability to extend the MCP joints and interphalangeal joints of the fingers [1] - Wrist extension is preserved because the Extensor Carpi Radialis Longus (ECRL) and often ECRB are innervated by the radial nerve proper before it gives off the PIN [1] - This results in a characteristic finger drop without wrist drop Radial nerve injury - A high radial nerve injury (proximal, above the elbow) would cause both wrist drop AND finger extension loss - However, radial nerve injury at the spiral groove (most common site) typically spares the PIN or affects it less severely - The question asks specifically about isolated inability to extend MCP joints, which is the hallmark of PIN injury, not general radial nerve injury - Radial nerve proper gives branches to triceps, brachioradialis, and ECRL before dividing into PIN and superficial branch Ulnar nerve injury - The ulnar nerve innervates intrinsic hand muscles (interossei, lumbricals to digits 4-5, hypothenar muscles, adductor pollicis) [1] - Ulnar nerve injury causes claw hand deformity with MCP hyperextension (not loss of extension) and IP joint flexion - This is the opposite of what is described in the question Median nerve injury - The median nerve innervates the thenar muscles, lateral two lumbricals, and forearm flexors [1] - Median nerve injury causes ape hand deformity with loss of thumb opposition and flexion - It does not affect MCP joint extension, which is an extensor function
Biochemistry
1 questionsWhich of the following conditions is primarily treated with Vitamin B6?
NEET-PG 2013 - Biochemistry NEET-PG Practice Questions and MCQs
Question 931: Which of the following conditions is primarily treated with Vitamin B6?
- A. Cystathionuria
- B. None of the options
- C. Xanthourenic aciduria
- D. Homocystinuria (Correct Answer)
Explanation: ***Homocystinuria*** - The most common form of **homocystinuria** is caused by **cystathionine β-synthase (CBS) deficiency**, which requires **pyridoxal phosphate (Vitamin B6)** as a cofactor. - Approximately **50% of patients** with CBS deficiency are **B6-responsive**, making **high-dose Vitamin B6 (100-500 mg/day)** a **first-line primary treatment** for these cases. - This is a **clinically significant condition** that requires treatment, manifesting with features like **ectopia lentis, marfanoid habitus, intellectual disability, and thromboembolism**. - B6 supplementation enhances residual CBS enzyme activity and reduces plasma homocysteine levels. *Cystathionuria* - Caused by **cystathionine γ-lyase deficiency**, which also uses **Vitamin B6** as a cofactor. - This is generally a **benign, asymptomatic condition** that does **NOT require treatment**. - While B6 can reduce cystathionine accumulation, it is **not a primary treatment indication** because the condition is clinically insignificant. *Xanthurenic aciduria* - Caused by **kynureninase deficiency** in the **tryptophan metabolism pathway**, which requires **pyridoxal phosphate**. - This is a **rare and usually benign condition** that does not typically require treatment. - Not a primary indication for B6 therapy. *None of the options* - Incorrect, as **Homocystinuria** (CBS deficiency) is a **primary indication** for high-dose Vitamin B6 therapy in B6-responsive patients.
Internal Medicine
1 questionsWhat is the volume of blood loss associated with Class III hemorrhagic shock?
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 931: What is the volume of blood loss associated with Class III hemorrhagic shock?
- A. 750 - 1500 ml
- B. 1500 - 2000 ml (Correct Answer)
- C. > 2000 ml
- D. < 750 ml
Explanation: ***1500 - 2000 ml*** - **Class III hemorrhagic shock** is characterized by a significant loss of blood volume, typically ranging from **30-40%** of total blood volume. - For an average adult, this translates to an estimated **1500-2000 ml** of blood loss, leading to marked physiological compromise. *750 - 1500 ml* - This range of blood loss corresponds to **Class II hemorrhagic shock**, where physiological changes are moderate, but compensatory mechanisms are still largely effective. - Patients in Class II shock typically present with **tachycardia** and a slight decrease in pulse pressure but generally normal blood pressure. *> 2000 ml* - A blood loss exceeding **2000 ml** (or >40% of total blood volume) is indicative of **Class IV hemorrhagic shock**, the most severe category. - This level of blood loss results in pronounced **hypotension**, severe tachycardia, and often requires immediate massive transfusion to prevent irreversible organ damage. *< 750 ml* - This range represents **Class I hemorrhagic shock**, which involves a minimal blood loss of up to 15% of total blood volume. - Patients in Class I shock typically show **minimal to no clinical signs of shock**, as compensatory mechanisms are highly effective in maintaining vital signs.
Orthopaedics
4 questionsWhat is a Hangman's fracture?
Most common cause of kyphotic deformity ?
Saturday night palsy is which type of nerve injury?
Which of the following movements is typically restricted in Perthes disease?
NEET-PG 2013 - Orthopaedics NEET-PG Practice Questions and MCQs
Question 931: What is a Hangman's fracture?
- A. Fracture dislocation of C2 (Correct Answer)
- B. Fracture dislocation of ankle joint
- C. Fracture of odontoid
- D. Subluxation of C5 over C6
Explanation: ***Fracture dislocation of C2*** - A Hangman's fracture classically refers to a **bilateral fracture of the pars interarticularis of the axis (C2)**, often with an associated anterior subluxation of C2 on C3. - This injury is typically caused by **hyperextension-distraction forces**, such as those experienced in judicial hangings or motor vehicle accidents. *Subluxation of C5 over C6* - While cervical subluxations are serious, a **C5-C6 subluxation** does not specifically describe a Hangman's fracture. - This type of injury involves different vertebral levels and typically results from different mechanisms. *Fracture dislocation of ankle joint* - This option refers to an injury in the **lower limb**, completely unrelated to the cervical spine. - A Hangman's fracture is a specific type of **cervical vertebral fracture**. *Fracture of odontoid* - A fracture of the odontoid process involves the **dens (odontoid process)** of C2. - This is a distinct type of C2 fracture from a Hangman's fracture, which involves the **pars interarticularis**.
Question 932: Most common cause of kyphotic deformity ?
- A. Trauma
- B. Osteoporosis (Correct Answer)
- C. Ankylosing spondylitis
- D. Rickets
Explanation: ***Osteoporosis*** - **Osteoporosis** leads to vertebral compression fractures, particularly in the thoracic spine, which causes a gradual collapse of the vertebral bodies and an increase in the kyphotic curve. - This condition is very common, especially in **postmenopausal women** and the elderly, making it the most frequent cause of kyphotic deformity. *Trauma* - While significant **spinal trauma** can lead to kyphotic deformities, it is generally less common than the gradual kyphosis resulting from osteoporosis. - Traumatic kyphosis usually results from severe injuries leading to **vertebral body collapse** or neurological deficits. *Ankylosing spondylitis* - **Ankylosing spondylitis** can cause severe kyphosis, often referred to as a "bamboo spine," due to chronic inflammation and fusion of the vertebrae. - However, it is a less prevalent condition compared to **osteoporosis-related kyphosis**. *Rickets* - **Rickets**, a childhood bone disorder caused by **vitamin D deficiency**, can lead to bone deformities including kyphosis due to softened bones. - While a cause in children, its prevalence is lower than osteoporosis globally as a cause of kyphosis and it primarily affects a different age group.
Question 933: Saturday night palsy is which type of nerve injury?
- A. Neuropraxia (Correct Answer)
- B. Axonotemesis
- C. Complete section
- D. Neurotmesis
Explanation: ***Neuropraxia*** - This is the mildest form of nerve injury, involving a **temporary conduction block** without axonal disruption, often due to **compression** or mild stretching. - **Saturday night palsy**, caused by prolonged compression of the radial nerve, is a classic example, characterized by rapid and complete recovery, typically within days to weeks. *Axonotemesis* - This involves **axon damage** and Wallerian degeneration distal to the injury, but the **endoneurium and connective tissue sheaths remain intact**. - Recovery is slower and often incomplete, as it requires axonal regeneration through the preserved connective tissue tubes, taking months. *Neurotmesis* - This is the most severe type of nerve injury, involving **complete transection of the nerve fiber**, including the axon, myelin, and all connective tissue sheaths. - Recovery is often poor and requires surgical intervention to attempt re-approximation of the nerve ends. *Complete section* - This term is largely synonymous with **neurotmesis**, indicating a full anatomical disruption of the nerve. - It involves the severance of all nerve components, leading to complete loss of function distal to the injury and the poorest prognosis for spontaneous recovery.
Question 934: 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
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.
Pathology
1 questionsWhat are the common causes of vertebra plana?
NEET-PG 2013 - Pathology NEET-PG Practice Questions and MCQs
Question 931: What are the common causes of vertebra plana?
- A. Eosinophilic granuloma
- B. Metastatic disease
- C. Tuberculosis
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - **Vertebra plana** refers to the severe flattening of a vertebral body, often caused by a destructive lesion, and all listed options are known causes. [5] - While **eosinophilic granuloma** is a classic cause, **metastatic disease** and **tuberculosis** can also lead to significant vertebral collapse. [3], [5] *Eosinophilic granuloma* - This is a benign condition, a form of **Langerhans cell histiocytosis**, which commonly affects children and can cause vertebra plana. [1] - It results from proliferative lesions of **Langerhans cells** that infiltrate the bone, leading to its destruction and collapse. [1] *Metastatic disease* - **Malignant tumors** often spread to the spine, causing osteolytic lesions that weaken the vertebral body. [4], [5] - The destruction caused by metastatic deposits can lead to **vertebral collapse** and associated pain. [5] *Tuberculosis* - **Tuberculosis of the spine (Pott's disease)** is an infectious inflammatory condition that can severely damage vertebral bodies. [2], [3] - The granulomatous inflammation and caseous necrosis can erode the bone, leading to **vertebral collapse** and kyphosis. [2] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 630. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1197-1198. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 669-670. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 724-725. [5] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 671-672.
Pediatrics
2 questionsWhat is the standard duration used to define apnea of prematurity?
What is the average weight gain per day for infants from 6 weeks to 12 weeks of age?
NEET-PG 2013 - Pediatrics NEET-PG Practice Questions and MCQs
Question 931: What is the standard duration used to define apnea of prematurity?
- A. Between 10 and 15 sec
- B. 20 sec (Correct Answer)
- C. More than 30 sec
- D. Less than 10 sec
Explanation: ***20 sec*** - Apnea of prematurity is defined as a cessation of breathing lasting **20 seconds or longer**, or a shorter pause in breathing accompanied by **bradycardia** (heart rate <100 bpm), **cyanosis**, or **pallor**. - This duration is crucial for determining the need for intervention and diagnosis in preterm infants. - The definition is standardized by the **American Academy of Pediatrics (AAP)** and is widely accepted in neonatal care. *Between 10 and 15 sec* - While pauses in breathing of this duration can be observed in preterm infants, they are usually considered **central periodic breathing** and not true apnea of prematurity unless accompanied by desaturation or bradycardia. - These shorter pauses are often considered benign, as significant physiological changes like bradycardia or cyanosis are less likely to occur. *More than 30 sec* - While a breathing cessation of more than 30 seconds certainly qualifies as apnea of prematurity, **20 seconds is the established minimum duration** for diagnosis. - Any apnea lasting longer than 20 seconds signifies a more severe event, indicating a greater risk to the infant. *Less than 10 sec* - Pauses in breathing lasting less than 10 seconds are generally considered **normal physiological variations** in both preterm and full-term infants. - These short pauses do not typically lead to significant oxygen desaturation or bradycardia and are not indicative of apnea of prematurity.
Question 932: What is the average weight gain per day for infants from 6 weeks to 12 weeks of age?
- A. 30 g/d (Correct Answer)
- B. 40 g/d
- C. 50 g/d
- D. 60 g/d
Explanation: ***30 g/d*** - From **6 to 12 weeks** of age, infants typically experience a rapid growth phase, with an average daily weight gain of approximately **30 grams** (or about 1 ounce per day). - This rate of gain is crucial for monitoring proper nutrition and overall development during this early stage of infancy. *40 g/d* - A daily weight gain of **40 g/d** is higher than the typical average for infants between 6 and 12 weeks of age. - While individual growth rates can vary, sustained gains at this level might raise questions about overfeeding or unusually rapid growth, although it is not usually a cause for concern. *50 g/d* - A weight gain of **50 g/d** is significantly above the expected average for infants in the 6- to 12-week age range. - Such rapid weight gain, if sustained, could indicate excessive caloric intake or potentially signal underlying metabolic issues that need evaluation. *60 g/d* - A daily weight gain of **60 g/d** is an exceptionally high rate for infants between 6 and 12 weeks, far exceeding the average. - This level of growth would be a strong indicator for further investigation into feeding practices and the infant's health to rule out any potential concerns.