Expansion
L1 and L2, afferent by the ilioinguinal nerve and efferent by the genitofemoral
Expansion
- Stimulus - stroking the skin of the upper medial thigh
- Afferent - ilioinguinal nerve (L1)
- Efferent - genital branch of the genitofemoral nerve (L1, L2)
- Response - contraction of cremaster, elevating the ipsilateral testis
The reflex is brisk in children and often diminished in adults, so absence alone is not diagnostic. Loss can indicate:
- Testicular torsion - a well-recognised though imperfect sign
- L1 or L2 spinal cord or root lesion
- Nerve injury after inguinal hernia repair
Cremaster contraction can also raise a testis into the superficial inguinal pouch, giving a retractile testis, an important distinction from a genuinely undescended testis in a child, since retractile testes need no surgery.