Orbital Trauma — MCQs

10 questions

Which of the following is NOT a characteristic of a blowout fracture of the orbit?

During a baseball game, the pitcher is hit in the left eye with a hard-hit line drive. He is rushed to the nearest emergency department where CT scan reveals left orbital rim and floor fractures and fluid in the left maxillary sinus. What are physical findings likely to include?

A patient presented with a history of diplopia and restricted eye movements. What is the most likely diagnosis based on the clinical and CT images?

Tear drop sign is seen in?

Best method of detection of a retained glass intraocular foreign body is

In blowout fractures, which of the following is seen?

Orbital blow-out fracture involves:

A man presents 6 hrs after head injury complaining of mild proptosis and scleral hyperemia:

Blow out fracture of orbit commonly involves:-

Q10

An orbital fracture caused by a ping pong ball is:

Orbital Trauma Indian Medical PG Practice Questions and MCQs

Question 1: Which of the following is NOT a characteristic of a blowout fracture of the orbit?

A. Orbital floor and medial wall involvement are common
B. Exophthalmos (Correct Answer)
C. Tear drop sign on CT scan
D. Diplopia due to muscle entrapment

Explanation: ***Exophthalmos*** - A **blowout fracture** typically causes the orbital contents to herniate into adjacent sinuses (maxillary or ethmoid), leading to an **increase in orbital volume**. - This increased orbital volume, combined with swelling and potential hemorrhage, usually results in **enophthalmos** (recession of the eyeball), not exophthalmos (protrusion of the eyeball). *Orbital floor and medial wall involvement are common* - The **orbital floor** (paper-thin bone separating the orbit from the maxillary sinus) and **medial wall** (separating the orbit from the ethmoid sinus) are the weakest structures of the orbit and are most commonly fractured in a blowout injury. - These areas are susceptible to fracture due to the force transmitted to the orbital contents, causing a sudden increase in intraorbital pressure. *Tear drop sign on CT scan* - The **tear drop sign** on a CT scan is a classic finding in orbital blowout fractures, representing the **herniation of orbital fat** or inferior rectus muscle into the maxillary sinus. - This sign indicates the displacement of soft tissue through the fractured orbital floor. *Diplopia due to muscle entrapment* - **Diplopia** (double vision) is a common symptom in blowout fractures, often caused by the **entrapment of extraocular muscles** (most commonly the inferior rectus or medial rectus) within the fracture site. - Muscle entrapment restricts ocular motility, particularly on upward or sideways gaze, leading to double vision.

Question 2: During a baseball game, the pitcher is hit in the left eye with a hard-hit line drive. He is rushed to the nearest emergency department where CT scan reveals left orbital rim and floor fractures and fluid in the left maxillary sinus. What are physical findings likely to include?

A. Exophthalmos
B. Cheek numbness (Correct Answer)
C. Lateral diplopia
D. Epistaxis

Explanation: ***Cheek numbness*** - **Orbital floor fractures** commonly damage the **infraorbital nerve**, which runs through the **infraorbital canal** in the orbital floor. - The infraorbital nerve provides sensation to the **lower eyelid, upper cheek, lateral nose, upper lip, and upper gingiva**. - **Cheek numbness (infraorbital nerve paresthesia) is the MOST COMMON physical finding** in orbital floor fractures, occurring in up to 80% of cases. - This is a classic exam finding and key diagnostic feature. *Epistaxis* - While theoretically possible if there's communication between the orbit and nasal cavity, **epistaxis is NOT a common or characteristic finding** in isolated orbital floor fractures. - Would require significant displacement with direct nasal involvement or fracture extension into the nasal bones. - The fluid in the maxillary sinus on CT represents blood/edema, not necessarily active nasal bleeding. *Exophthalmos* - This term means **protrusion of the eyeball** forward from the orbit. - Orbital floor fractures cause the OPPOSITE finding: **enophthalmos** (recession of the eyeball backward). - This occurs due to herniation of orbital contents (fat, muscles) into the enlarged orbital cavity (maxillary sinus). *Lateral diplopia* - **Lateral diplopia** (horizontal double vision) results from dysfunction of the **medial or lateral rectus muscles** (or their nerves). - Orbital floor fractures characteristically cause **VERTICAL diplopia** due to entrapment or contusion of the **inferior rectus muscle** or **inferior oblique muscle**. - Patients have double vision when looking up or down, not side to side.

Question 3: A patient presented with a history of diplopia and restricted eye movements. What is the most likely diagnosis based on the clinical and CT images?

A. Le Fort fracture
B. Maxillary fracture
C. Zygomatic fracture
D. Blowout fracture (Correct Answer)

Explanation: ***Blowout fracture*** - The CT image shows a **fracture of the orbital floor**, with associated **herniation of orbital contents** (fat and inferior rectus muscle) into the maxillary sinus. - This type of fracture commonly causes **diplopia** (due to muscle entrapment) and **restricted eye movements**. *Le Fort fracture* - Le Fort fractures involve the **midface and maxilla** as a whole, typically causing widespread facial instability. - They are classified into three types (I, II, III), none of which are exclusively characterized by an isolated orbital floor fracture with muscle entrapment. *Maxillary fracture* - While an orbital floor fracture involves the maxilla, a "maxillary fracture" is a broad term and does not specifically describe the characteristic features of **orbital content prolapse** and their resulting symptoms. - Isolated maxillary fractures might not cause diplopia or restricted eye movements unless they directly involve the orbit. *Zygomatic fracture* - A zygomatic fracture (either isolated or as part of a zygomaticomaxillary complex fracture) primarily affects the **cheekbone**. - While it can involve the orbital rim, it typically presents with **facial asymmetry**, **numbness** in the infraorbital nerve distribution, and sometimes **trismus**, rather than isolated muscle entrapment causing diplopia, as seen in the image.

Question 4: Tear drop sign is seen in?

A. Fracture zygomatic arch
B. Fracture maxilla
C. Fracture mandible
D. Blow out fracture (Correct Answer)

Explanation: ***Blow out fracture*** - The **tear drop sign** on imaging (often CT scan) is characteristic of an **orbital blow-out fracture**, indicating herniation of orbital contents (fat, muscle) into the maxillary sinus. - This fracture typically involves the **orbital floor** or medial wall, often caused by a blunt force trauma to the eye. *Fracture zygomatic arch* - A fracture of the zygomatic arch is often associated with a **flattening of the malar prominence** rather than a "tear drop" sign. - It might lead to restricted jaw movement if the arch impinges on the coronoid process. *Fracture maxilla* - Maxillary fractures (e.g., Le Fort fractures) involve the midface bones and cause **facial deformity**, malocclusion, and mobility of the maxilla. - The tear drop sign is not a primary diagnostic feature of maxillary fractures. *Fracture mandible* - Mandibular fractures present with pain, swelling, and **malocclusion** of the teeth. - Imaging would reveal a break in the mandible, not a tear drop sign associated with orbital contents.

Question 5: Best method of detection of a retained glass intraocular foreign body is

A. USG
B. Radiography
C. Tonometry
D. CT scan (Correct Answer)

Explanation: ***CT scan*** - **CT scans** are highly sensitive and specific for detecting **retained glass intraocular foreign bodies** due to their excellent spatial resolution and ability to visualize foreign materials with different densities. - Unlike MRI, CT is safe with metallic foreign bodies and provides precise localization, aiding surgical planning. *Radiography* - While helpful for detecting radio-opaque foreign bodies like metal, **plain X-rays display limited soft tissue contrast** and may struggle to visualize small or less dense objects like glass effectively within the complex orbital structures. - **Glass foreign bodies can be difficult to discern** from surrounding bony structures or soft tissues on conventional radiographs, leading to false negatives. *USG* - **Ultrasound (USG)** is effective for imaging soft tissues and can detect some foreign bodies, but its utility is limited when the object is small, non-reflective, or located deep within the globe, especially behind structures like the lens or iris. - **Acoustic shadowing** and artifact creation can also obscure the foreign body or mimic its presence, reducing diagnostic accuracy for glass. *Tonometry* - **Tonometry measures intraocular pressure** and is primarily used to screen for or monitor glaucoma. - It provides no information about the presence or location of **intraocular foreign bodies**.

Question 6: In blowout fractures, which of the following is seen?

A. Bulbar hemorrhage
B. None of the options
C. Enophthalmos (Correct Answer)
D. Exophthalmos

Explanation: ***Enophthalmos*** - A **blowout fracture** of the orbit typically involves the orbital floor or medial wall from direct trauma to the eye or periorbital region. - The fracture allows orbital contents (fat and muscle) to herniate into the maxillary sinus or ethmoid sinuses, **increasing orbital volume**. - This increased volume causes the eye to recede backward into the orbit, resulting in **enophthalmos** (sunken eye appearance). - **Key clinical features**: enophthalmos, diplopia (due to inferior rectus/medial rectus entrapment), restricted eye movements, infraorbital nerve hypoesthesia. *Exophthalmos* - **Exophthalmos** (proptosis) is forward protrusion of the eye, occurring when orbital volume is **decreased** or orbital contents are **increased** (e.g., thyroid eye disease, orbital tumors, orbital hemorrhage). - This is the **opposite** of enophthalmos and would not occur in a blowout fracture where orbital volume increases. *Bulbar hemorrhage* - **Subconjunctival hemorrhage** may occur as an associated finding from ocular trauma but is not a characteristic or defining feature of blowout fractures. - Many types of blunt ocular trauma can cause conjunctival hemorrhage without orbital fracture. *None of the options* - Incorrect because **enophthalmos** is the classic and characteristic finding of orbital blowout fractures.

Question 7: Orbital blow-out fracture involves:

A. Lateral wall and roof of orbit
B. Medial wall and floor of orbit (Correct Answer)
C. Medial wall and roof of orbit
D. Lateral wall and floor of orbit

Explanation: Medial wall and floor of orbit - An orbital blow-out fracture typically involves the **medial wall** (lamina papyracea of the ethmoid bone) and the **floor** (maxillary bone) of the orbit because these are the weakest bony structures. - The force of impact on the globe is transmitted to the orbital walls, causing them to fracture outwards into the adjacent sinuses. *Lateral wall and roof of orbit* - The **lateral wall** (zygomatic bone) and **roof** (frontal bone) of the orbit are structurally strong and less commonly involved in isolated blow-out fractures. - Fractures in these areas typically result from high-impact trauma and are often associated with other facial bone injuries. *Medial wall and roof of orbit* - While the **medial wall** is frequently involved, the **roof** of the orbit is a thick, sturdy bone and is less susceptible to blow-out forces. - Fractures of the orbital roof usually occur due to direct impact or high-energy trauma to the forehead. *Lateral wall and floor of orbit* - Although the **floor** is commonly fractured, the **lateral wall** is a robust structure and is not typically involved in isolated blow-out fractures. - Combined fractures of the lateral wall and floor would indicate a more extensive orbital impact, often with other mid-facial trauma.

Question 8: A man presents 6 hrs after head injury complaining of mild proptosis and scleral hyperemia:

A. Caroticocavernous fistula
B. Retro-orbital hematoma (Correct Answer)
C. Pneumo-orbit
D. Orbital cellulitis

Explanation: ***Retro-orbital hematoma*** - The sudden onset of **proptosis** and **scleral hyperemia** within hours of a head injury is highly suggestive of bleeding behind the eye. - A **retro-orbital hematoma** causes increased orbital pressure, leading to the forward displacement of the eyeball (proptosis) and conjunctival injection (scleral hyperemia). *Caroticocavernous fistula* - This condition involves an abnormal communication between the carotid artery and the cavernous sinus, typically presenting with a **pulsatile proptosis** and a **bruit** over the eye. - While it can cause proptosis and hyperemia, its onset is usually not as acute as 6 hours post-trauma without being a direct major vessel injury in a recent trauma. *Pneumo-orbit* - A pneumo-orbit involves **air entering the orbit**, often following trauma that fractures an orbital wall communicating with a paranasal sinus. - Symptoms include **periorbital crepitus** and exophthalmos, but scleral hyperemia is not a primary or dominant feature. *Orbital cellulitis* - Orbital cellulitis is an **infection of the orbital tissues**, usually presenting with proptosis, ophthalmoplegia, pain, and fever. - This is an infectious process and would typically take longer than 6 hours to develop to such an extent after an acute trauma without an open wound or obvious contamination.

Question 9: Blow out fracture of orbit commonly involves:-

A. Medial wall is involved first as it is the thinnest
B. Floor is involved first (Correct Answer)
C. Roof is involved first as it bears the maximum impact
D. The patient is not able to look up due to inferior rectus entrapment

Explanation: ***Floor is involved first*** - The **orbital floor** (composed mainly of the maxillary bone and portions of the palatine and zygomatic bones) is the most common site for a **blowout fracture** due to its relative weakness. - Trauma to the globe increases **intraorbital pressure**, causing the weakest part of the orbit, which is commonly the floor, to fracture and displace fragments into the maxillary sinus. *Medial wall is involved first as it is the thinnest* - While the **medial wall** (primarily the lacrimal bone and the lamina papyracea of the ethmoid bone) is indeed the **thinnest** portion of the orbit, it is structurally supported by the ethmoid air cells, making it less prone to fracture from direct globe impact compared to the floor. - Fractures of the medial wall can occur but are less common as the primary site of injury than the orbital floor. *The patient is not able to look up due to inferior rectus entrapment* - While **inferior rectus muscle** entrapment in orbital floor fractures does cause restricted upward gaze, this is a **complication** of the fracture, not what the fracture "commonly involves" anatomically. - The question asks which **anatomical structure** is commonly involved, not the clinical presentation. - Inferior rectus entrapment occurs in blowout fractures but doesn't answer which orbital wall is most commonly fractured. *Roof is involved first as it bears the maximum impact* - The **orbital roof** (formed by the frontal bone) is the strongest part of the orbit and rarely fractures from globe impact alone; it typically requires high-energy trauma to the forehead. - If the roof were involved, it would likely be due to direct impact to the supraorbital region, not from compression of the globe which usually affects the floor or medial wall.

Question 10: An orbital fracture caused by a ping pong ball is:

A. Blow in fracture
B. Orbital fracture
C. Compound fracture
D. Blow out fracture (Correct Answer)

Explanation: ***Blow out fracture*** - A **blow-out fracture** occurs when an object, like a ping pong ball, impacts the orbital rim and compresses the globe, causing a sudden increase in intraorbital pressure. - This pressure then fractures the weakest parts of the orbit, typically the **orbital floor** (into the maxillary sinus) or the **medial wall** (into the ethmoid sinus), while sparing the orbital rim. *Blow in fracture* - A **blow-in fracture** involves a direct impact to the orbital rim, causing the rim bones to be pushed inward. - This type of fracture often results from a **smaller, high-velocity object** directly hitting the bone and forcing the orbital contents inward. *Orbital fracture* - **Orbital fracture** is a general term that encompasses any break in the bones surrounding the eye socket. - While a blow-out fracture is a type of orbital fracture, this option is too broad and does not specifically describe the mechanism of injury by a ping pong ball. *Compound fracture* - A **compound fracture** (also known as an open fracture) is one where the broken bone penetrates the skin, creating an open wound. - This term describes the **integrity of the skin** around the fracture, not the mechanism of the orbital injury.

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