Development of the oculomotor nucleus in staged human embryos during the sixth week

Investigations were made on serial sections of human embryos at developmental stages 16 and 17 (37-41 days). The oculomotor nucleus in embryos at these stages is located at the cephalic flexure of the neural tube. It consists of paired lateral nucleus which is formed by well defined group of large neurons in the basal plate of the midbrain. Within the lateral nucleus two groups of cells (medial and lateral) can he distinguished. Posteriorly these groups unite and form a single nucleus.