Anatomy
2 questionsAfter trauma, a person cannot move their eye outward beyond the midpoint. Which nerve is injured?
Which of the following extraocular muscle has the longest tendon?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 491: After trauma, a person cannot move their eye outward beyond the midpoint. Which nerve is injured?
- A. 3rd
- B. 4th
- C. 6th (Correct Answer)
- D. 2nd
Explanation: ***6th*** - The **abducens nerve (CN VI)** innervates the **lateral rectus muscle**, which is responsible for moving the eye **outward (abduction)** [1]. - Injury to the abducens nerve would result in an inability to move the eye laterally, causing an **esotropia** (eye turned inward at rest) [1]. *2nd* - The **optic nerve (CN II)** is responsible for **vision**, not eye movement [2]. - Damage to this nerve would cause **visual field defects** or **blindness** [3]. *3rd* - The **oculomotor nerve (CN III)** controls most extraocular muscles, including the **medial, superior, and inferior rectus** and **inferior oblique muscles**, as well as the **levator palpebrae superioris** and **pupillary constriction** [2]. - Injury to CN III would lead to a **down and out deviation of the eye**, **ptosis**, and a **dilated pupil** [2]. *4th* - The **trochlear nerve (CN IV)** innervates the **superior oblique muscle**, which primarily causes **intorsion** (rotation downward and inward) [1]. - Damage to this nerve results in **vertical diplopia**, especially when looking down and in, and a characteristic **head tilt** to compensate [3].
Question 492: Which of the following extraocular muscle has the longest tendon?
- A. Medial rectus
- B. Superior rectus
- C. Superior oblique (Correct Answer)
- D. Inferior oblique
Explanation: ***Superior oblique*** - The superior oblique muscle has the **longest tendon** and overall length of all extraocular muscles because it passes through the **trochlea**, a cartilaginous pulley. - Its long course allows it to have a complex action, primarily **intorsion, depression, and abduction** of the eye [1]. *Superior rectus* - The superior rectus is one of the **straight muscles** (recti) and is not the longest. - Its primary actions are **elevation, adduction, and intorsion** of the eyeball [1]. *Medial rectus* - The medial rectus is another **straight muscle** and is generally considered the **strongest** but not the longest extraocular muscle. - Its main action is **adduction** (moving the eye inward) [1]. *Inferior oblique* - The inferior oblique is the **shortest** of all the extraocular muscles. - Its primary actions are **extorsion, elevation, and abduction** of the eyeball [1].
Community Medicine
1 questionsWhat is the mean birth weight in India?
NEET-PG 2012 - Community Medicine NEET-PG Practice Questions and MCQs
Question 491: What is the mean birth weight in India?
- A. 2.0 - 2.4 kg
- B. 2.4 - 2.5 kg
- C. 2.5 - 2.9 kg (Correct Answer)
- D. > 3.0 kg
Explanation: ***2.5 - 2.9 kg*** - This range represents the **mean birth weight in India**, which is generally lower than in developed countries due to various factors like maternal nutrition and socio-economic conditions. - A mean birth weight in this range indicates a significant proportion of neonates could be close to the **low birth weight (LBW)** threshold of 2.5 kg. *2.0 - 2.4 kg* - This range is considered **low birth weight (LBW)** and is associated with increased morbidity and mortality; it is not the typical mean birth weight for the general population in India. - While a significant percentage of Indian newborns may fall into this category, it does not represent the average birth weight. *2.4 - 2.5 kg* - This range borders on **low birth weight**; while some average birth weights might fall very close to 2.5 kg, a mean of 2.4 kg would be unusually low for a national average. - A mean in this range suggests that a substantial number of infants would be classified as having **low birth weight**. *> 3.0 kg* - This weight range is typical for newborns in many **developed countries** but is **higher than the observed mean birth weight** in India. - While healthy Indian babies can weigh over 3.0 kg, it is not representative of the average for the entire population.
Dental
1 questionsWhat percentage of oral cancer cases is attributed to tobacco use?
NEET-PG 2012 - Dental NEET-PG Practice Questions and MCQs
Question 491: What percentage of oral cancer cases is attributed to tobacco use?
- A. 60% of cases
- B. 10% of cases
- C. 40% of cases
- D. 70% of cases (Correct Answer)
Explanation: ***90%*** - Nicotine is a significant contributor to **oral cancer**, with studies indicating it is responsible for about **90%** of cases [1]. - Its carcinogenic effects are amplified when combined with other risk factors such as **tobacco** and **alcohol** use [1]. *40%* - This percentage underestimates nicotine's role in oral cancer development, which is much higher. - Key studies suggest that the impact of nicotine alone is much greater than **40%**, highlighting its pivotal role in carcinogenesis. *60%* - This estimate also falls short, as the consensus in oncology is that nicotine significantly contributes even beyond **60%**. - Oral cancer risk is further elevated when nicotine is consumed in conjunction with other **carcinogens** [1], rather than just being limited to a single contribution. *10%* - This figure drastically underrepresents nicotine's involvement, as it is a major causative agent in oral cancer. - The **10%** suggestion implies minimal risk, contradicting clinical evidence that strongly supports a far greater role for nicotine. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 738-739.
Internal Medicine
1 questionsWhat is the most common cause of ophthalmoplegia in adults?
NEET-PG 2012 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 491: What is the most common cause of ophthalmoplegia in adults?
- A. Cranial nerve palsy (Correct Answer)
- B. Myasthenia gravis
- C. Diabetes mellitus
- D. Trauma
Explanation: ***Cranial nerve palsy*** - **Cranial nerve palsies**, particularly those affecting cranial nerves III, IV, or VI, are the most frequent causes of isolated ophthalmoplegia in adults [1]. - They can result from various etiologies like **ischemia**, **compression**, or **inflammation**, directly impairing the nerves responsible for eye movement [1]. *Myasthenia gravis* - While it frequently causes **ocular symptoms** (ptosis and diplopia), it typically presents with **fluctuating weakness** that worsens with sustained effort [1]. - It's a neuromuscular junction disorder, not a primary cranial nerve issue, and often affects other muscle groups beyond the eyes. *Diabetes mellitus* - **Diabetic ophthalmoplegia** is a specific type of cranial nerve palsy (often CN III or VI) caused by microvascular ischemia. - While common in diabetics, it is a *cause* of cranial nerve palsy, not the overarching most common cause of ophthalmoplegia itself. *Trauma* - **Trauma** can certainly cause ophthalmoplegia, often due to direct damage to **extraocular muscles**, **orbital fractures**, or **cranial nerve injury**. - However, in the general adult population, non-traumatic cranial nerve palsies are more frequently encountered as the cause of ophthalmoplegia.
Microbiology
1 questionsInfluenza virus culture is done on ?
NEET-PG 2012 - Microbiology NEET-PG Practice Questions and MCQs
Question 491: Influenza virus culture is done on ?
- A. Chorioallantoic membrane
- B. Allantoic cavity (Correct Answer)
- C. Yolk sac
- D. All of the options
Explanation: ***Allantoic cavity*** - The **allantoic cavity** of embryonated chicken eggs is the standard and most effective site for isolating and propagating **influenza viruses** for vaccine production and research. - This cavity provides an optimal environment for viral replication, particularly yielding high titers of **hemagglutinin**, a key influenza antigen. *Chorioallantoic membrane* - While embryonated eggs are used for virus culture, the **chorioallantoic membrane (CAM)** is primarily used for cultivating viruses that produce **pocks** (visible lesions), such as Vaccinia and Herpes Simplex Virus. - Influenza virus growth on the CAM is less efficient and typically doesn't produce distinct pocks, making it unsuitable for high-yield propagation compared to the allantoic cavity. *Yolk sac* - The **yolk sac** of embryonated eggs is ideal for growing viruses or bacteria that require a **lipid-rich environment** and replicate intracellularly, such as Chlamydia or Rickettsia. - It is not the preferred site for influenza virus isolation or proliferation due to suboptimal conditions for viral replication and lower viral yields. *All of the options* - While all these sites are components of an embryonated chicken egg, each serves as a host for different types of microorganisms or for specific purposes in virology. - For **influenza virus culture**, the **allantoic cavity** is the specifically utilized site for optimal growth and high viral yield.
Obstetrics and Gynecology
1 questionsWhen should breastfeeding be initiated after a normal delivery?
NEET-PG 2012 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 491: When should breastfeeding be initiated after a normal delivery?
- A. 2 hours after delivery
- B. 4 hours after delivery
- C. 6 hours after delivery
- D. Immediately after delivery (Correct Answer)
Explanation: **Correct: Immediately after delivery** - Initiating breastfeeding **within the first hour** of birth (early initiation) is crucial for establishing **successful lactation** and promoting optimal infant health. - This early initiation allows for **skin-to-skin contact**, which helps stabilize the newborn's temperature, heart rate, and breathing, and facilitates **bonding** between mother and baby. - Aligned with **WHO and UNICEF recommendations** for best practice in postpartum care. *Incorrect: 2 hours after delivery* - While earlier is generally better, waiting two hours misses the **optimal window** for initiating feeding and bonding. - The newborn's **alert period** is typically strongest in the first hour post-birth, making it an ideal time for the first latch. *Incorrect: 4 hours after delivery* - Delaying breastfeeding by four hours can make it more challenging for the baby to latch effectively as they may have passed their **initial alert state** and become sleepy. - This delay can also hinder the establishment of the mother's **milk supply**, as stimulation from early feeding is important for prolactin release. *Incorrect: 6 hours after delivery* - Waiting six hours significantly **misses the critical window** for early initiation and can lead to increased difficulties with breastfeeding. - Prolonged delays may necessitate supplementation, potentially interfering with exclusive breastfeeding and establishing a **strong milk supply**.
Ophthalmology
3 questionsWhat is the term for the fusion of the palpebral and bulbar conjunctiva?
What is the most common cause of vitreous hemorrhage in diabetic retinopathy?
Shaffer's sign is seen in ?
NEET-PG 2012 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 491: What is the term for the fusion of the palpebral and bulbar conjunctiva?
- A. Trichiasis (inward growth of eyelashes)
- B. Ectropion (outward turning of eyelid)
- C. Symblepharon (Correct Answer)
- D. Tylosis (thickening of skin on palms and soles)
Explanation: ***Symblepharon*** - **Symblepharon** is the term for the adhesion between the **palpebral conjunctiva** (lining the eyelid) and the **bulbar conjunctiva** (covering the eyeball). - This condition can limit eye movement and cause chronic irritation, often resulting from severe conjunctival inflammation or injury. *Trichiasis (inward growth of eyelashes)* - **Trichiasis** refers to the misdirection of eyelashes such that they rub against the cornea or conjunctiva. - It causes irritation, foreign body sensation, and can lead to corneal abrasion, but it does not involve fusion of conjunctival layers. *Ectropion (outward turning of eyelid)* - **Ectropion** is a condition where the lower eyelid turns outward or sags away from the eyeball. - This exposes the conjunctiva, causing dryness, irritation, and epiphora (excessive tearing), but it is not a fusion of conjunctival tissues. *Tylosis (thickening of skin on palms and soles)* - **Tylosis** is a medical term referring to diffuse **hyperkeratosis** or thickening of the skin, typically observed on the palms and soles. - This condition is completely unrelated to the conjunctiva or eye structures.
Question 492: What is the most common cause of vitreous hemorrhage in diabetic retinopathy?
- A. Non-proliferative diabetic retinopathy
- B. Proliferative diabetic retinopathy (Correct Answer)
- C. Severe non-proliferative diabetic retinopathy
- D. Diabetic macular edema
Explanation: ***Proliferative diabetic retinopathy*** - **Neovascularization** is the hallmark of proliferative diabetic retinopathy (PDR), where new, fragile blood vessels grow on the surface of the retina and optic disc. - These delicate vessels can easily rupture and bleed into the vitreous humor, leading to a **vitreous hemorrhage**. *Non-proliferative diabetic retinopathy* - This stage is characterized by **microaneurysms**, hemorrhages, and cotton wool spots, but typically lacks significant neovascularization. - While it involves retinal vascular damage, the absence of **newly formed, fragile vessels** makes vitreous hemorrhage less common. *Severe non-proliferative diabetic retinopathy* - This stage shows extensive microvascular abnormalities, including numerous hemorrhages and venular beading, but generally **still no new vessel formation**. - Without the presence of **fragile neovascular membranes**, the risk of significant vitreous hemorrhage is lower compared to PDR. *Diabetic macular edema* - This condition involves **fluid leakage** from damaged retinal vessels into the macula, causing vision loss. - While it's a common complication of diabetes, it primarily causes **macular swelling** and does not directly lead to vitreous hemorrhage.
Question 493: Shaffer's sign is seen in ?
- A. Acute angle-closure glaucoma
- B. Diabetic retinopathy
- C. Age-related macular degeneration
- D. Retinal detachment (Correct Answer)
Explanation: ***Retinal detachment*** - **Shaffer's sign** refers to the presence of **pigment cells** (tobacco dust) in the **anterior vitreous**, indicating a retinal break or detachment. - This sign is due to the release of retinal pigment epithelium cells into the vitreous following a tear in the retina. *Acute angle-closure glaucoma* - This condition is characterized by a **sudden increase in intraocular pressure** due to blocked fluid outflow, causing pain, redness, and blurred vision. - It does not involve pigment cells in the vitreous, but rather changes in the **anterior chamber angle**. *Diabetic retinopathy* - This is a microvascular complication of diabetes, leading to damage to the blood vessels in the retina, causing **hemorrhages**, **exudates**, and **neovascularization**. - It does not typically present with free pigment in the vitreous as a primary diagnostic sign. *Age-related macular degeneration* - This condition affects the **macula**, often causing distorted vision and central vision loss, and is characterized by drusen and atrophy. - While it can involve retinal changes, it does not classically present with pigment cells in the vitreous as a diagnostic indicator.