Anatomy
1 questionsWhich nerve is not involved in superior orbital fissure syndrome?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 1061: Which nerve is not involved in superior orbital fissure syndrome?
- A. 1st cranial nerve (Correct Answer)
- B. 3rd cranial nerve
- C. 4th cranial nerve
- D. 6th cranial nerve
Explanation: ***1st cranial nerve*** - The **olfactory nerve (CN I)** is responsible for the sense of smell [2] and passes through the **cribriform plate** of the ethmoid bone, not the superior orbital fissure. - Due to its distinct pathway, it is not affected in **superior orbital fissure syndrome**. *3rd cranial nerve* - The **oculomotor nerve (CN III)** passes through the superior orbital fissure and is frequently involved in the syndrome. - Its involvement leads to ophthalmoplegia, ptosis, and a dilated pupil due to paralysis of most extrinsic ocular muscles [1], [3] and the parasympathetic fibers [1]. *4th cranial nerve* - The **trochlear nerve (CN IV)** also travels through the superior orbital fissure. - Damage to this nerve causes **diplopia** and impaired downward and intorsion movements of the eye due to paralysis of the **superior oblique muscle** [3]. *6th cranial nerve* - The **abducens nerve (CN VI)** enters the orbit via the superior orbital fissure. - Injury to the abducens nerve results in **lateral rectus muscle** palsy, leading to esotropia (medial deviation of the eye) and impaired abduction [3].
Ophthalmology
8 questionsIn congenital dacryocystitis, the blockage occurs at?
Dacryocystorhinostomy involves?
Surgery of choice for chronic acquired dacryocystitis
Commotio retinae affects which part of the retina -
Parachute lesions are associated with which of the following conditions?
Which of the following is a specific sign of albinism?
Epithelial xerosis of conjunctiva is caused by?
Which agent is known to cause corneal ulcers that may resemble fungal infections?
NEET-PG 2013 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 1061: In congenital dacryocystitis, the blockage occurs at?
- A. Nasolacrimal duct (Correct Answer)
- B. Punctum
- C. Lacrimal canaliculi
- D. Lacrimal sac
Explanation: ***Nasolacrimal duct*** - **Congenital dacryocystitis** is primarily caused by an obstruction in the **nasolacrimal duct**, specifically at the **valve of Hasner** at its distal end near the inferior meatus. - This blockage prevents the proper drainage of tears into the nasal cavity, leading to tear overflow (epiphora), mucoid discharge, and potential secondary infection. - Present in approximately **5-6% of newborns**, with most cases resolving spontaneously by 12 months of age. *Punctum* - Congenital **punctal agenesis** is rare and not the typical site of obstruction in congenital dacryocystitis. - The puncta are usually patent in this condition. *Lacrimal canaliculi* - Obstruction of the **lacrimal canaliculi** is uncommon in congenital cases. - Canalicular obstruction is more often acquired (trauma, infection, medications). *Lacrimal sac* - The **lacrimal sac** itself is not the site of primary obstruction in congenital dacryocystitis. - The sac may become distended due to downstream obstruction at the nasolacrimal duct.
Question 1062: Dacryocystorhinostomy involves?
- A. Opening the terminal blocked end of the nasolacrimal duct
- B. Complete excision of the lacrimal sac
- C. Insertion of a drainage tube in the lacrimal sac
- D. Connecting the lacrimal sac to the nose by opening the medial wall (Correct Answer)
Explanation: ***Connecting the lacrimal sac to the nose by opening the medial wall*** - A **dacryocystorhinostomy (DCR)** is a surgical procedure to create a new drainage pathway between the **lacrimal sac** and the **nasal cavity**. - This bypasses an obstruction in the **nasolacrimal duct**, allowing tears to drain properly into the nose. *Opening the terminal blocked end of the nasolacrimal duct* - This describes a **dacryocystoplasty** or an attempt to probe the existing duct, which is a less invasive procedure than a DCR and often insufficient for complete obstruction. - While it aims to restore tear flow, it specifically addresses the terminal end rather than creating a new anastomosis. *Complete excision of the lacrimal sac* - This procedure is known as a **dacryocystectomy**, which is typically performed for tumors or chronic infections of the lacrimal sac that cannot be resolved otherwise. - It results in permanent dry eye and does not aim to restore tear drainage but rather to remove the problematic sac. *Insertion of a drainage tube in the lacrimal sac* - This describes **intubation** of the lacrimal drainage system, often using silicone tubes, which is usually a temporary measure to keep the duct patent after a procedure or for partial obstructions. - It is not the definitive surgical creation of a new permanent pathway, as achieved with a DCR.
Question 1063: Surgery of choice for chronic acquired dacryocystitis
- A. Dacryocystorhinostomy (Correct Answer)
- B. Dacryocystectomy
- C. Conjunctivo-cystorhinostomy
- D. None of the options
Explanation: ***Dacryocystorhinostomy*** - This procedure creates a new connection between the **lacrimal sac** and the **nasal cavity**, bypassing the obstructed nasolacrimal duct. - It is the **surgery of choice** for chronic acquired dacryocystitis as it provides a permanent solution for tear drainage. *Dacryocystectomy* - This involves **excision of the lacrimal sac**, which can relieve symptoms of infection but eliminates the sac's function. - It is generally reserved for cases where dacryocystorhinostomy is contraindicated or has failed, and is **not the primary choice** for restoring tear flow. *Conjunctivo-cystorhinostomy* - This procedure creates a bypass from the **conjunctiva** directly to the **nasal cavity**, typically used when the canaliculi are also obstructed. - It is a more complex surgery indicated for **proximal lacrimal system obstruction** (e.g., canalicular block) rather than isolated nasolacrimal duct obstruction. *None of the options* - **Dacryocystorhinostomy** is the well-established and most effective surgical intervention for chronic acquired dacryocystitis. - Therefore, this option is incorrect as there is a suitable surgical choice available.
Question 1064: Commotio retinae affects which part of the retina -
- A. Posterior pole (Correct Answer)
- B. Peripheral retina
- C. Inferior-nasal part
- D. Superior-nasal part
Explanation: ***Posterior pole*** - **Commotio retinae**, also known as Berlin's edema, primarily affects the **posterior pole** of the retina, particularly the macula. - This condition results from **blunt trauma** to the globe, causing disruption of the outer retinal photoreceptors and retinal pigment epithelium, leading to retinal whitening in the area of impact. *Peripheral retina* - While blunt trauma can affect the peripheral retina, commotio retinae specifically refers to the **edematous whitening** that occurs more centrally. - Trauma to the periphery is more commonly associated with **retinal tears or detachments**, rather than the diffuse whitening seen in commotio retinae. *Inferior-nasal part* - This is a specific quadrant of the retina, but commotio retinae is not confined to or preferentially found in the **inferior-nasal part**. - The location of commotio retinae depends on the **point of impact** and the transmission of force, but symptoms are most prominent when the macula at the posterior pole is involved. *Superior-nasal part* - Similar to the inferior-nasal part, the **superior-nasal part** is a specific retinal quadrant. - Commotio retinae is a more generalized finding of retinal edema and whitening due to trauma, not consistently localized to this particular region, though it can occur if that area is directly impacted.
Question 1065: Parachute lesions are associated with which of the following conditions?
- A. Eale's disease (Correct Answer)
- B. Diabetes
- C. Sickle cell anemia
- D. None of the options
Explanation: ***Eale's disease*** - **Eale's disease** is an idiopathic retinal perivasculitis affecting young males, characterized by recurrent vitreous hemorrhages. - In the context of this question (NEET-2013), the term "parachute lesions" refers to the characteristic pattern of hemorrhages seen in Eale's disease. - The disease features retinal periphlebitis, capillary non-perfusion, and neovascularization leading to vitreous hemorrhage. - **Note:** The term "parachute hemorrhages" in broader ophthalmology typically describes preretinal/subhyaloid hemorrhages that settle inferiorly (boat-shaped), more commonly seen in proliferative diabetic retinopathy. *Diabetes* - **Diabetic retinopathy** presents with microaneurysms, dot-blot hemorrhages, hard exudates, cotton-wool spots, and neovascularization. - While proliferative diabetic retinopathy can cause preretinal "parachute-shaped" hemorrhages (boat-shaped hemorrhages that settle inferiorly), this is not the association being tested in this NEET-2013 question. - The specific context of this exam question associates the term with Eale's disease. *Sickle cell anemia* - **Sickle cell retinopathy** features characteristic sea-fan neovascularization in the peripheral retina. - Can cause salmon-patch hemorrhages, black sunburst lesions, and angioid streaks. - While vitreous hemorrhage can occur, "parachute lesions" is not standard terminology for sickle cell retinopathy manifestations. *None of the options* - This option is incorrect because **Eale's disease** is the correct answer according to the NEET-2013 exam key.
Question 1066: Which of the following is a specific sign of albinism?
- A. Iris transillumination (Correct Answer)
- B. Sensitivity to light (photophobia)
- C. Involuntary eye movements (nystagmus)
- D. Decreased visual acuity
Explanation: ***Iris transillumination*** - This is a highly **specific sign** of albinism, resulting from the severe reduction or absence of pigment in the iris. - When light shines through the pupil, it passes through the unpigmented iris, creating a visible red reflex, indicating the lack of pigment that normally blocks the light. *Sensitivity to light (photophobia)* - While common in albinism due to the lack of pigment in the iris and retina allowing more light to enter the eye, **photophobia is not specific** to albinism. - It can be a symptom of various other ocular conditions like uveitis, corneal abrasions, or migraines. *Involuntary eye movements (nystagmus)* - **Nystagmus is frequently associated with albinism** due to foveal hypoplasia and impaired visual development but is **not specific**. - It can also be caused by neurological disorders, inner ear problems, or other ocular conditions. *Decreased visual acuity* - **Reduced vision is a characteristic feature of albinism** resulting from foveal hypoplasia and abnormal optic nerve pathways, but it is **not specific** to the condition. - Numerous eye conditions, such as refractive errors, cataracts, and retinal diseases, can lead to decreased visual acuity.
Question 1067: Epithelial xerosis of conjunctiva is caused by?
- A. Xerophthalmia (Correct Answer)
- B. Infectious conjunctivitis caused by Chlamydia trachomatis
- C. Autoimmune blistering conjunctivitis
- D. Bacterial conjunctivitis due to Corynebacterium diphtheriae
Explanation: ***Xerophthalmia*** - **Xerophthalmia** is a medical condition characterized by **dryness of the eye**, often due to **vitamin A deficiency**. - **Epithelial xerosis of the conjunctiva** is one of the early and hallmark signs of xerophthalmia, representing the drying and thickening of the conjunctival epithelium due to goblet cell loss and squamous metaplasia. *Infectious conjunctivitis caused by Chlamydia trachomatis* - This typically causes **trachoma**, characterized by chronic inflammation, scarring, and eventual blindness. - While it can lead to dryness and scarring in later stages due to **symblepharon** or **entropion**, it does not primarily manifest as epithelial xerosis. *Autoimmune blistering conjunctivitis* - This condition involves **immune-mediated inflammation** leading to subepithelial blistering, scarring, and shrinkage of the conjunctiva. - It results in significant **ocular surface damage** and vision loss but is distinct from the primary epithelial changes seen in xerosis due to vitamin A deficiency. *Bacterial conjunctivitis due to Corynebacterium diphtheriae* - **Diphtheritic conjunctivitis** is a severe form of bacterial conjunctivitis that causes a distinctive **"pseudomembrane"** on the conjunctiva. - It leads to acute inflammation and potentially systemic illness, not primarily epithelial xerosis.
Question 1068: Which agent is known to cause corneal ulcers that may resemble fungal infections?
- A. Nocardia asteroides (Correct Answer)
- B. Mycobacterium
- C. Klebsiella pneumoniae
- D. Chlamydia trachomatis
Explanation: ***Nocardia asteroides*** - This organism can cause **Nocardia keratitis**, which often presents with a **feathery or crystalline appearance** in the cornea, mimicking a fungal infection. - It tends to occur in patients with **contact lens use** or ocular trauma and requires specific antimicrobial treatment different from fungal therapy. *Mycobacterium* - **Atypical mycobacteria** can cause chronic, indolent corneal ulcers, particularly after trauma or surgery. - While they can be challenging to diagnose, their appearance typically differs from the **feathery morphology** associated with fungal or Nocardia infections. *Klebsiella pneumoniae* - **Klebsiella pneumoniae** is a common cause of **bacterial keratitis**, especially in contact lens wearers. - Infections usually manifest as a rapidly progressing infiltrate with significant inflammation and often produce abundant **mucopurulent discharge**, not typically mistaken for fungal infections. *Chlamydia trachomatis* - **Chlamydia trachomatis** is the causative agent of **trachoma**, leading to recurrent conjunctivitis and eventually corneal scarring and blindness in endemic areas. - It does not cause acute corneal ulcers that resemble fungal infections; rather, it results in a chronic inflammatory process with **follicular conjunctivitis** and **pannus formation**.
Surgery
1 questionsAt which anatomical location is the opening created in dacryocystorhinostomy?
NEET-PG 2013 - Surgery NEET-PG Practice Questions and MCQs
Question 1061: At which anatomical location is the opening created in dacryocystorhinostomy?
- A. Middle meatus (Correct Answer)
- B. Superior meatus
- C. Sphenoethmoidal recess
- D. Inferior meatus
Explanation: ***Middle meatus*** - In **dacryocystorhinostomy (DCR)**, the anastomosis is created between the **lacrimal sac** and the nasal cavity at the level of the **middle meatus**. - The lacrimal sac is located **lateral to the middle turbinate**, making this the anatomically appropriate site for creating the surgical opening. - This placement allows direct drainage of tears from the lacrimal sac into the nasal cavity, **bypassing the obstructed nasolacrimal duct**. - The **middle meatus** provides optimal access and physiological tear drainage. *Inferior meatus* - The **nasolacrimal duct** naturally drains into the **inferior meatus** under normal anatomy. - However, DCR is performed to **bypass** an obstructed nasolacrimal duct, so the anastomosis is created more **superiorly** at the lacrimal sac level. - The inferior meatus is **below** the level of the lacrimal sac and would not provide direct access to it. *Superior meatus* - The **superior meatus** is located above the superior turbinate and receives drainage from the **posterior ethmoidal sinuses**. - This location is **too superior** for DCR and does not correspond to the anatomical position of the lacrimal sac. *Sphenoethmoidal recess* - The **sphenoethmoidal recess** is the most superior and posterior area, receiving drainage from the **sphenoid sinus**. - This location is far too **superior and posterior** to be used for lacrimal drainage surgery.