Sagittal section of lumbar area of spinal column showing pertinent anatomy. Needle is removed leaving catheter in place between L3 and L4 vertebrae.

Transverse, or horizontal (axial), MRI of the thorax at the level of the lower heart and T9. The image to the right indicates the level of each transverse MRI.

Sagittal section of lumbar area of spinal column showing pertinent anatomy. Left: needle inserted into epidural space between L3 and L4 vertebrae. Right: Needle is removed leaving catheter in place.

Cross-section of thorax at L3-L4 disc showing relevant lumbar anatomy; two spinal needles illustrate the medial and lateral approaches into the subarachnoid space where the cerebrospinal fluid is located.

Transverse, or horizontal (axial), MRI of the thorax at the level of the right brachiocephalic artery bifurcation and T3. The image to the right indicates the level of each transverse MRI.

Cross-sections of the brain, midbrain, pons, medulla, cervical spinal cord and thoracic spinal cord showing the efferent corticospinal tract leading to a skeletal muscle.

Cross-section of spinal cord at L4 vertebral level.