General Anatomy of Thorax MCQs

The surface marking of the oblique tissue of the lung will not touch 4th costal cartilage. On either side, the upper and lower lobes of the lung are separated by the oblique fissure. This can be marked by a line that runs anteroinferiorly from the posterior end of the 4th rib (the spinous process of the T3 vertebra), crosses the 5th rib in the midaxillary line, continues inferiorly, crossing either the 6th intercostal space/ 7th rib on the right or the 5th rib/ 5th intercostal space on the left, on both sides at the midclavicular line. The left oblique fissure is located at a higher level and courses more vertically than the right oblique fissure. Reference : Textbook of Gray's Anatomy for students, 3rd Edition, Thorax, Page number - 124

The arrangement of the components of the neurovascular bundle in the intercostal space from below upwards is nerve-artery-vein. The arrangement can be remembered from above downwards with the mnemonic VAN: vein-artery-nerve. Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Thorax, Page number - 162

Ans. B. Rhodopsin Several different rhodopsin gene mutations have been identified in the pedigrees with autosomal dominant retinitis pigmentosa.

Ans.A Cortical cells. CELLS IN CEREBRAL CORTEX: Cortical cells: Majority are pyramidal cells Pyramidal cells - "Sine qua non" for cerebral cortex Axons of pyramidal cells leave the cortex Forms descending tract (e.g. Corticospinal, Corticobulbar etc).

Answer- B. Hypospadias Circumcision is not done in patients with hypospadias as the prepuce can later be used in surgical repair. Circucision is mostly done for cultural reasons. The medical indications for circumcision are: Phimosis & Paraphimosis Recurrent balanoposthitis (i.e. inflammation of the foreskin) Recurrent urinary tract infection

Ans. D: Decrease in O2 affinity of hemoglobin when the pH of blood falls The decrease in O2 affinity of hemoglobin when the pH of blood falls is called the Bohr effect and is closely related to the fact that deoxygenated hemoglobin (deoxyhemoglobin) binds H+ more actively than does oxyhemoglobin. The pH of blood falls as its CO, content increases, so that when the PCO2 rises, the curve shifts to the right and the P5„ rises.

The 8th rib is the false rib because it does not articulate with the sternum anteriorly. First 7 ribs are true ribs as they are attached anteriorly to the sternum by costal cartilages. Ribs 8-10 are false ribs as they join the superjacent costal cartilage. Ribs 11 and 12 are floating ribs as they float freely without costal attachment. Reference : Textbook of Gray's Anatomy for students, 3rd Edition, Thorax, Page number - 124

Ans. is 'a' i.e., Ileocolic Ileo-ileo-colic (-12) Ileoileal (-5%) Colocolic (-2%) Multiple (1%) Retrograde The most common type of intussusception is ileocolic (also known as ileocecal) (90%).