The development of the main sensory nucleus of the trigeminal nerve in human embryos.

The trigeminal nucleus was investigated on serial sections of 74 human embryos of developmental stages 13 to 23 (28 to 56 days). The main nucleus was identified in embryos of stage 13 in the alar lamina. With advancement of the development the nucleus enlarges anteriorly and posteriorly, and is always located dorsally and laterally to the motor trigeminal nucleus. It is continuous with the nucleus of the spinal tract of V anteriorly, and with the spinal trigeminal nucleus posteriorly.