Which of the following is not a contributing factor in thoracic outlet syndrome?
Ans. A. Tumor arising from the middle lobe of lungTumors arising from the upper lobe of lung contributes to the thoracic outlet syndrome and not the middle lobe tumors.The contributing factors to thoracic outlet syndrome may be classified as dynamic and static.Dynamic cause is a fully abducting arm, which pulls the artery up by 180 degrees, causing compression in the retrovascular space.Static factors:* Increased muscle bulk* Decreased muscle bulk* Cervical rib* Malunion or nonunion of fracture clavicle* Arteriosclerosis* Anomalies of the first thoracic ribTumors arising from the upper lobe of the lung, cervico-thoracic scoliosis, and abnormal variations of the scalene muscles are some of the miscellaneous causes.Thoracic Outlet Syndrome
Tumor arising from the middle lobe of lung
Malunion of fracture clavicle
Cervico-thoracic scoliosis
Anomalies of the first thoracic rib
Miscellaneous