UKMLA PLAB AMC USMLE Prometric MCQ

Correct Answer: E

Explanation:
Loose-jointedness is often striking in patients with the Marfan syndrome. Flat feet (pes planus), hyperextensibility at the knees (genu recurvatum), elbows, and fingers, congenital dislocation of the hips, and recurrent dislocation of the patellae are manifestations of laxity of ligaments and joint capsules. A relatively narrow palm of the hand, long thumb, and longitudinal laxity of the hand are the bases for the Steinberg thumb sign: the thumb apposed across the palm extends well beyond the ulnar margin of the hand. Depression of the sternum (pectus excavatum), protrusion, or an asymmetric combination often results. The vertebral column is frequently deformed. The normal thoracic kyphos is often reduced, resulting in a 'straight back' or an outright thoracic lordosis. Scoliosis may involve multiple segments and may progress rapidly, particularly during the adolescent growth spurt. Most patients with the Marfan syndrome have myopia and about one-half have subluxation of the lenses (ectopia lentis). The ascending aorta bears the main stress of ventricular ejection, leading to progressive dilatation beginning in the sinuses of Valsalva. Aortic regurgitation and dissection are the main causes of death.