Asymmetric hamstring reflexes indicative of L5 radicular lesions

Area of Science:

• Neurology
• Neuroscience
• Clinical Electrophysiology

Background:

• The L5 spinal nerve root innervates muscles crucial for lower limb function.
• A reliable reflex solely from L5-innervated muscles is not well-established.
• Hamstring muscles receive primary innervation from L5 and S1 nerve roots.

Purpose of the Study:

• To establish a diagnostic method for L5 root lesions.
• To describe a novel technique for eliciting the medial hamstring reflex.
• To correlate asymmetric hamstring reflexes with confirmed L5 root lesions.

Main Methods:

• Percussion of the conjoint tendon of semitendinosus and biceps femoris at the ischial tuberosity to elicit the medial hamstring reflex.
• Assessment of reflex symmetry in the presence of symmetrical gastrocsoleus reflexes.
• Confirmation of L5 root lesions using electromyography, myelography, and operative findings.

Main Results:

• Asymmetry in hamstring reflexes, with symmetrical gastrocsoleus reflexes, was indicative of an L5 root lesion.
• The described percussion method successfully elicited the medial hamstring reflex.
• Seven patients with asymmetric hamstring reflexes were confirmed to have L5 root lesions.

Conclusions:

• The medial hamstring reflex, elicited by conjoint tendon percussion, can serve as a valuable indicator of L5 root lesions.
• This reflex asymmetry provides a clinical sign for diagnosing L5 nerve root compromise.
• The findings support the utility of this reflex in neurological examinations for lower back pain and sciatica.