Bastian–Bruns sign

Bastian–Bruns Sign

The Bastian–Bruns sign is a clinical neurological sign that is used to differentiate between types of spinal cord lesions. It is named after the German neurologists Adolf Bastian and Ludwig Bruns, who contributed to the understanding of spinal cord pathologies.

Clinical Significance

The Bastian–Bruns sign is particularly useful in distinguishing between complete and incomplete spinal cord injuries. It is observed in cases of complete spinal cord transection, where there is a loss of voluntary motor function and sensation below the level of the lesion.

In the presence of a complete spinal cord injury, the Bastian–Bruns sign is characterized by the absence of the superficial abdominal reflexes below the level of the lesion. This is due to the interruption of the corticospinal tract, which is responsible for voluntary motor control.

Pathophysiology

The corticospinal tract, also known as the pyramidal tract, is a major pathway that carries motor signals from the brain to the spinal cord. In a complete spinal cord injury, this pathway is disrupted, leading to a loss of motor function and reflexes below the level of the injury.

The absence of the superficial abdominal reflexes in the Bastian–Bruns sign is due to the interruption of the descending motor pathways that normally facilitate these reflexes. This sign helps clinicians confirm the diagnosis of a complete spinal cord injury.

Diagnosis

To test for the Bastian–Bruns sign, a clinician will gently stroke the skin of the abdomen with a blunt object, such as the end of a reflex hammer, and observe for the contraction of the abdominal muscles. In a normal response, the muscles contract, causing the umbilicus to move towards the stimulus. In the presence of a complete spinal cord injury, this reflex is absent below the level of the lesion.

History

The sign is named after Adolf Bastian (1826–1905) and Ludwig Bruns (1858–1916), who were pioneers in the field of neurology. Their work laid the foundation for understanding the clinical manifestations of spinal cord injuries and the development of diagnostic techniques.