Neural-Dural Transition at the Thoracic and Lumbar Spinal Nerve Roots: A Histological Study of Human Late-Stage Fetuses

Figure 2

Thoracic and upper lumbar nerve roots in a fetus with a crown-rump length (CRL) of 230 mm. This is the same specimen that is shown in Figure 1. (a) displays a posterior view of the cord, including the conus medullaris. (b), which corresponds to a square in (a), shows a sheath (arrows) of the right twelfth thoracic nerve (rt T12). The sheath protrudes from the meningeal layer of the dura (dura) and continues to a sheath (stars) of the dorsal root ganglion (DRG). A radicular artery (RA) is embedded in the 12th nerve root. (c), which is a section that is 0.5 mm anterior to (a) (a circle by interrupted line), exhibits a radicular artery (RA) at the right third lumbar level (rt L3). A sheath of the DRG is cut tangentially (stars). (d), which corresponds to the other square in (a), exhibits RA running outside of the sheath of the right first lumbar nerve (rt L1). Scale bars: 10 mm in (a); 1 mm in (b)–(d).

(a)

(b)

(c)

(d)