Dentosphere : World of Dentistry

 # Superior rectus helps in all of the following movements EXCEPT: A. Upward rotation B. Lateral rotation C. Intorsion D. Medial rotation The correct answer is B. Lateral rotation.  All the rectus muscles are involved in medial rotation of eye except the lateral rectus. Lateral rectus is the only rectus muscle involved in lateral rotation.  CLICK HERE FOR MORE MCQs

 # Which of the following group of muscles is involved in elevation of the eyeball? A. Superior rectus and inferior oblique B. Inferior rectus and Superior oblique C. Superior Oblique and superior rectus D. Inferior oblique and Inferior rectus The correct answer is : A. Superior rectus and inferior oblique Action of Individual Muscles: Levator Palpebrae superioris - Elevation of upper eyelid Superior rectus - Upward rotation, medial rotation and intorsion Inferior rectus- Downward rotation, medial rotation and extorsion Medial rectus- Medial rotation Lateral rectus- Lateral rotation Superior oblique- Downward rotation, lateral rotation and intorsion  Inferior oblique- Upward rotation and extorsion Single movements of eyeball and muscles involved: Upward rotation (Elevation)- Superior rectus and inferior oblique Downward rotation (Depression)- Inferior rectus and Superior oblique Medial rotation (Adduction)- Medial rectus, Superior rectus and Inferior rectus Lateral rotation (A...

 # Nasolacrimal duct is directed: A. Downward, medially, backwards B. Downward, laterally, backwards C. Downward, laterally, forward D. Downward, medially, forward The correct answer is: B. Downward, laterally, backwards Nasolacrimal duct: The groove for nasolacrimal duct is located medially near the orbital margin. It is a membranous passage of 18 mm length. It begins at the lower end of the lacrimal sac, runs downwards, backwards and laterally, and opens into the inferior meatus of the nose. A fold of mucous membrane called the valve of Hasner forms an imperfect valve at the lower end of the duct.  CLICK HERE FOR ALL MCQs

 # Stapedius muscle has its nerve supply from: A. Trigeminal nerve B. Facial nerve C. Glossopharyngeal nerve D. Stato-acoustic nerve The correct answer is: B. Facial nerve Stapedius muscle along with the tensor tympani are muscles of ossicles of middle ear. Stapedius is supplied by facial nerve, whereas tensor tympani is supplied by mandibular nerve. Stapedius and tensor tympani both act simultaneously to damp down the intensity of high pitched sound waves, thus protecting the internal ear. In paralysis of the muscle even normal sounds appear too loud, which is known as "hyperacusis".  CLICK HERE FOR MORE MCQs

 # The lower one-third of pinna is supplied by: A. Auriculotemporal nerve B. Great auricular nerve C. Lesser occipital nerve D. Vagus nerve The correct answer is: B. Great Auricular Nerve. Greater auricular nerve supplies lower one third of both lateral and medial surface of pinna. Auriculotemporal nerve supplies upper 2/3rds of lateral surface of pinna. Lesser occipital supplies upper 2/3rds of medial surface of pinna. Vagus nerve supplies root of the pinna. Facial nerve supplies muscles of pinna.  CLICK HERE TO VIEW MORE MCQs

 # Which of the following areas are regarded as the ‘dangerous area’ of the face? A. Chin and lower lips B. Lower and upper lips C. Upper lip and lower part of the nose D. Upper part of nose and forehead The correct answer is C. Upper lip and lower part of the nose. The dangerous area of the face is drained by the facial vein. Deep connections of the facial vein with cavernous sinus includes: i. A communication between the supraorbital and superior ophthalmic veins.  ii. Another with the pterygoid plexus through the deep facial vein which passes backwards over the buccinator. The pterygoid venous plexus in turn communicate with the cavernous sinus through an emissary vein. The veins of the dangerous area of face are valveless. Movements of the facial muscles and absence of valves in the facial vein might facilitate retrograde flow of blood. This allows retrograde infection, which is carried by facial, angular and nasofrontal veins and superior ophthalmic veins into cavernous s...

 # The branch of facial artery that crosses the submandibular region, runs anteriorly over mylohyoid muscle and divides into two branches, a deep branch and a superficial branch, is: A. Submental artery B. Tonsillar artery C. Superior labial artery D. Retromandibular artery The correct answer is A. Submental artery. Submental artery: The largest cervical branch, it arises as the facial artery emerges out from the submandibular gland, turning forwards on the mylohyoid below the mandible. It supplies the surrounding muscles and anastomoses with a sublingual branch of the  lingual and mylohyoid branch of the inferior alveolar arteries; at the chin it ascends the mandible, dividing into superficial and deep branches, which anastomose with the inferior labial and mental arteries, supplying the chin and lower lip.  CLICK HERE FOR MORE MCQs