Turn-buckle cast is used for ?
Percentage of adrenaline with lignocaine for local infiltration is?
Which of the following is not commonly used for local infiltration anesthesia?
Buon's line is seen in: Al 07; Rajasthan 11; NEET 13; JIPMER 13
Kennedy phenomenon is seen in:
Vertebral compression fracture with intact posterior cortex (hinge fracture pattern) is most commonly seen in:
NEET-PG 2013 - Dental NEET-PG Practice Questions and MCQs
Question 11: Turn-buckle cast is used for ?
- A. Fracture of the humerus
- B. Management of spinal deformities (Correct Answer)
- C. Fracture of the femur
- D. Cervical spine immobilization
Explanation: ***Management of spinal deformities*** - A **turn-buckle cast** is specifically designed to apply gradual, corrective forces for **spinal deformities** like scoliosis or kyphosis. - It allows for incremental adjustments to the cast to achieve progressive stretching and correction of the spinal curve. *Fracture of the humerus* - **Humerus fractures** are typically managed with hanging arm casts, coaptation splints, or surgical fixation, depending on the fracture type and location. - A turn-buckle cast is not suitable for immobilizing or reducing a **humeral fracture**. *Fracture of the femur* - **Femur fractures** in adults usually require surgical intervention, such as intramedullary nailing, due to the high biomechanical stress on the bone. - For conservative management in children, traction or spica casts might be used, but not a **turn-buckle cast**. *Cervical spine immobilization* - **Cervical spine immobilization** is typically achieved using rigid cervical collars, halo vests, or specialized orthoses designed to restrict head and neck movement. - A turn-buckle cast is too bulky and not anatomically suitable for effective **cervical spine stabilization**.
Question 12: Percentage of adrenaline with lignocaine for local infiltration is?
- A. 1:1000
- B. 1:10000
- C. 1:50000 (Correct Answer)
- D. 1:200000
Explanation: ***1:50000*** - This concentration of **adrenaline (epinephrine)** is commonly used with **lignocaine (lidocaine)** for local infiltration to prolong the anesthetic effect and reduce bleeding. - At this concentration, adrenaline acts as a **vasoconstrictor**, decreasing systemic absorption of lignocaine and allowing a higher dose locally. *1:1000* - This concentration of adrenaline is typically used for the treatment of **anaphylaxis** and is considered too high for local infiltration with lignocaine. - Using such a high concentration locally can lead to severe **vasoconstriction**, tissue ischemia, and systemic side effects like **tachycardia** and **hypertension**. *1:10000* - This concentration is too strong for routine local infiltration and is usually reserved for **cardiac arrest** protocols or severe anaphylaxis when administered intravenously. - It would carry a significant risk of **tissue damage** and systemic effects if used for local infiltration. *1:200000* - While sometimes used, **1:50000** is generally the more common and effective concentration for achieving **hemostasis** and prolonging anesthesia during local infiltration. - A 1:200000 concentration provides a lesser degree of **vasoconstriction**, potentially leading to less prolonged local anesthetic effect and reduced bleeding control compared to 1:50000.
Question 13: Which of the following is not commonly used for local infiltration anesthesia?
- A. Lidocaine
- B. Ropivacaine
- C. Dibucaine (Correct Answer)
- D. Bupivacaine
Explanation: ***Dibucaine*** - **Dibucaine** is a local anesthetic with a long duration of action but is rarely used for local infiltration due to its **high toxicity**. - Its narrow therapeutic index makes it less safe for common use compared to other available local anesthetics. *Lidocaine* - **Lidocaine** is one of the most widely used local anesthetics for **local infiltration** due to its rapid onset and intermediate duration of action. - It is effective for a variety of minor surgical procedures and dental interventions. *Ropivacaine* - **Ropivacaine** is an amide-type local anesthetic commonly used for **local infiltration** and regional anesthesia due to its good safety profile and differential block. - It produces less motor block and has a lower potential for cardiotoxicity compared to bupivacaine. *Bupivacaine* - **Bupivacaine** is frequently used for **local infiltration** and regional anesthesia, especially when a longer duration of action is desired. - It is known for its prolonged sensory block but has a higher risk of **cardiac toxicity** compared to lidocaine.
Question 14: Buon's line is seen in: Al 07; Rajasthan 11; NEET 13; JIPMER 13
- A. Phosphorus poisoning
- B. Zinc poisoning
- C. Lead poisoning (Correct Answer)
- D. Arsenic poisoning
Explanation: ***Lead poisoning*** - **Buon's line**, also known as a **gingival lead line** or **Burton's line**, is a blue-black line visible on the gums at the junction of the teeth, characteristic of chronic lead poisoning. - This line is formed by the reaction of circulating lead with sulfur ions released by bacterial action in the mouth, forming **lead sulfide** deposits. *Phosphorus poisoning* - **Phosphorus poisoning** can cause widespread organ damage, including gastrointestinal symptoms, liver and kidney failure, and cardiovascular collapse. - It does not typically present with a characteristic gingival line like Buon's line. *Zinc poisoning* - **Zinc poisoning** is relatively rare and can lead to symptoms like nausea, vomiting, abdominal pain, and copper deficiency. - It is not associated with the formation of Buon's line in the gums. *Arsenic poisoning* - **Arsenic poisoning**, particularly chronic exposure, can manifest with skin lesions, neuropathies, and gastrointestinal issues. - A characteristic skin manifestation is **Mee's lines** (transverse white bands on the fingernails), but not Buon's line.
Question 15: Kennedy phenomenon is seen in:
- A. Burns
- B. Gunshot injury (Correct Answer)
- C. Contusion
- D. Road traffic accident
Explanation: ***Gunshot injury*** - The **Kennedy phenomenon** describes the pattern of injury observed when a **bullet passes through a body part**, leaving an **exit wound larger than the entrance wound**. - This occurs because the bullet creates a **temporary cavity** that collapses, and the tissue at the exit point is stretched beyond its elastic limit, resulting in a larger defect. *Burns* - Burns are injuries caused by heat, chemicals, electricity, or radiation, resulting in **tissue destruction** and often characterized by **blistering, charring, and loss of skin integrity**. - While burns can cause tissue damage, the mechanism of injury and the resulting wound characteristics are distinctly different from the **ballistic trauma** described by the Kennedy phenomenon. *Contusion* - A **contusion**, or bruise, is a type of injury caused by **blunt force trauma** that damages small blood vessels under the skin, leading to discoloration without breaking the skin surface. - This injury mechanism involves **crushing of tissues** and local hemorrhage, which is fundamentally different from the passage of a projectile through tissues. *Road traffic accident* - A road traffic accident can result in a wide range of injuries, including **blunt force trauma**, **lacerations**, **fractures**, and **internal organ damage**. - While significant tissue damage can occur, the specific pattern of an **entry and a larger exit wound** resulting from a penetrating projectile is not a defining characteristic of RTA injuries.
Question 16: Vertebral compression fracture with intact posterior cortex (hinge fracture pattern) is most commonly seen in:
- A. Basilar skull fracture (Correct Answer)
- B. Wrist
- C. Mandible
- D. C1 vertebra fracture
Explanation: ***Basilar skull fracture*** - A vertebral compression fracture with an intact posterior cortex (hinge fracture pattern) describes a specific type of injury seen in the **vertebrae**. While the question implicitly refers to the spine, among the given options, **basilar skull fracture** is the most commonly associated with such a fracture pattern in the context of high-energy trauma affecting the spine and skull base. - This pattern implies that the posterior elements of the vertebra remain intact, acting as a hinge, preventing neurological compromise despite significant anterior compression. *Wrist* - Fractures of the wrist, such as **Colles'** or **Smith's fractures**, are typically seen in falls onto an outstretched hand and do not involve a vertebral compression or hinge fracture pattern. - Wrist fractures involve the distal radius and ulna, not the vertebral column. *Mandible* - **Mandibular fractures** are common facial bone fractures usually resulting from direct trauma to the jaw. - They involve the jawbone and do not present with a vertebral compression or hinge fracture pattern. *C1 vertebra fracture* - A C1 (atlas) vertebra fracture, such as a **Jefferson fracture**, is a burst fracture of the ring of C1. - While it's a vertebral fracture, it typically involves fractures through the anterior and/or posterior arches of C1, distinguishing it from the described simple compression (hinge) pattern seen in a typical vertebral body.