What neurological sign is characterized by spontaneous flexion of the hips during attempted passive flexion of the neck?

The phenomenon described in the question, in which there is spontaneous flexion of the hips during passive flexion of the neck, is known as Brudzinski’s sign. This neurological sign is a classic indicator of meningeal irritation, often associated with conditions like meningitis. When the neck is flexed, if irritation of the meninges is present, the reflexive action causes the patient's hips and knees to flex as a protective response.

This sign is particularly useful in a clinical setting as it helps in the early identification of meningitis, allowing for timely management and intervention. Recognizing Brudzinski’s sign is essential for healthcare practitioners, as it can prompt further diagnostic evaluations, such as a lumbar puncture, to confirm the diagnosis of meningitis.

While there are other reflexes and signs mentioned, such as Kernig's sign, which involves the inability to straighten the leg when the hip is flexed, and the Babinski sign, which assesses pathways in the central nervous system, they do not specifically present with hip flexion as a direct response to neck flexion. The Moro reflex, on the other hand, is an infant reflex and not applicable in this context. Therefore, the distinction and relevance of Brudzinski's sign