Ultrasound observation of the sciatic nerve and its branches at the popliteal fossa: always visible, never seen.

BACKGROUND

In studying patients with sciatic nerve (SN) varices the author found that the sciatic nerve and its major divisions, the tibial and peroneal nerves, could be readily identified on ultrasound imaging of the popliteal fossa. The sciatic nerve lies in the space between the popliteal vein and the small saphenous vein.

OBJECTIVES

To confirm that the sciatic nerve can be identified on ultrasonography in patients with venous disease as well as in normal subjects.

METHOD: Thirty unselected patients (60 limbs) attending for outpatient consultations were investigated by duplex ultrasound examination of the popliteal fossa. In 10 subjects varicose veins were present, in 20 no varices were visible on clinical examination.

RESULTS

The sciatic nerve and its branches where visible and easily recognised in all cases. The sciatic nerve and the small saphenous vein lay in close proximity in cases with of small saphenous vein incompetence.

CONCLUSIONS

Ultrasound identification of the sciatic nerve in the popliteal fossa allows assessment of its relationship with the adjacent veins. This technique may be useful in identifying the location of the nerve prior to surgical intervention for varices in the popliteal fossa as well as for endo-luminal occlusion procedures given the close proximity of the vein to the nerve. Sciatic nerve varices, tumours, extrinsic dislocation and nerve lesions may also be detected.