A 42-year-old woman from Delhi presents to the ENT clinic with a painless, firm, solitary nodule in the lower pole of the right lobe of the thyroid gland. On examination, the nodule is mobile with swallowing and moves upward with tongue protrusion. The patient is euthyroid. During surgical planning for thyroidectomy, the surgeon is concerned about injury to a nerve that runs in the tracheoesophageal groove and supplies the intrinsic muscles of the larynx. Which nerve is at greatest risk during mobilization of the lower pole of the thyroid gland?