Pemberton's sign: Explained nearly 70 years later

Context: Pemberton's sign is used to evaluate venous obstruction in patients with goiters. The sign is positive when bilateral arm elevation causes facial plethora. It has been attributed to a "cork effect" resulting from the thyroid obstructing the thoracic inlet, thereby increasing pressure on the venous system. According to some, the "cork effect" is caused by the thyroid descending into the thoracic inlet during arm elevation. According to others, the obstruction is due to elevation of the thoracic inlet against the thyroid. Objective: We studied a 36-year-old man with a positive Pemberton's sign secondary to a goiter extending to the substernal region. Design and Intervention: Clinical, biochemical, and radiological assessments were done. Magnetic resonance angiography of the neck was performed while the patient's arms were elevated and at his sides. After the imaging studies were completed, the patient underwent thyroidectomy. Results: Magnetic resonance angiography demonstrated that there was no craniocaudal movement of the goiter relative to the thoracic inlet. However, the lateral aspect of the clavicle moved medially and inferiorly, obstructing the right external jugular vein and subclavian vein confluence. Conclusions: In the present case, we demonstrated that when eliciting Pemberton's sign, facial plethora and venous engorgement were due to the clavicles moving and compressing venous vasculature against the enlarged thyroid and not to a "cork effect." Rather, the clavicular motion observed duringarmelevation couldbecomparedto themovementof a "nutcracker" compressing major venous structures within a narrowed thoracic inlet against a relatively fixed and enlarged thyroid.