Rekurrens

Rekurrens is a term used in several European languages, notably in medical anatomy, to denote structures that loop back toward the region from which they originate after diverging from a main trunk. It derives from the Latin recurrens, meaning “running back.” In anatomy, rekurrens is most commonly applied to nerves or vessels that re-enter or ascend to supply a target area after a detour in their course.

The best-known example is the nervus recurrens, or recurrent laryngeal nerve, a branch of the vagus nerve (cranial nerve X). On the left, it descends into the chest and loops under the arch of the aorta before ascending between the trachea and esophagus to the larynx. On the right, it loops under the subclavian artery before ascending similarly. Because of this path, the recurrent laryngeal nerve is at particular risk during thyroid, mediastinal, and thoracic surgeries, and injury can cause hoarseness or vocal cord dysfunction.

Outside the laryngeal nerve, rekurrens is used for other nerves or vessels described as recursive or recurrent in their course, i.e., structures that re-enter or re-approach the region they supply. The term is primarily found in medical and anatomical texts in European languages, with usage varying by language. In clinical contexts, it is important to distinguish rekurrens from the general concept of disease recurrence.