RESUMO
BACKGROUND: Technical advances in magnetic resonance (MR) and ultrasound-based neurography nowadays facilitate the radiological assessment of the lumbosacral plexus. OBJECTIVE: Anatomy and imaging of the lumbosacral plexus and diagnostics of the most common pathologies. MATERIAL AND METHODS: Description of the clinically feasible combination of magnetic resonance imaging (MRI) and ultrasound diagnostics, case-based illustration of imaging techniques and individual advantages of MRI and ultrasound-based diagnostics for various pathologies of the lumbosacral plexus and its peripheral nerves. RESULTS: High-resolution ultrasound-based neurography (HRUS) is particularly valuable for the assessment of superficial structures of the lumbosacral plexus. Depending on the examiner's experience, anatomical variations of the sciatic nerve (e. g. relevant in piriformis syndrome) as well as more subtle variations, for example as seen in neuritis, can be sonographically depicted and assessed. The use of MRI enables the diagnostic evaluation of more deeply located nerve structures, such as the pudendal and the femoral nerves. Modern MRI techniques, such as peripheral nerve tractography allow three-dimensional depiction of the spatial relationship between nerves and local tumors or traumatic alterations. This can be beneficial for further therapy planning. CONCLUSION: The anatomy and pathology of the lumbosacral plexus can be reliably imaged by the meaningful combination of MRI and ultrasound-based high resolution neurography.