Fig. 1. А - Embryo, crown-rump lengh 8 mm ( from the apex of cervical flexure to the coccygeal one - 10 mm). The cervical flexure is sharply marked. The face is closely adjacent to the heart prominence. In optic primordia a smoll lens surrounded by a narrow pigment border evident. Upper and lower limbs appear as short outgrowth ending in flat spatulas with a rounded everrborder. Б - transverse sections of the embryo 8 mm
1 - spinal cord, 2 - spinal ganglion, 3 - spinal nerve running to the primordium of the upper limb, 4 - trachea, 5 - oesophagus, 6 - lung primordium, 7 - heart , 8 - primituve kidney, 9 -aorta, 10 - notochord
Fig. 2. Differentiation of human mesoderm
1 - notochord, 2 - aorta, 3 - spinal ganglion, 4 - dorsal edge of the somite, 5 - myotome, 6 - dermatome, 7 - migration of mesenchyme cells from sclerotome, 8 - migration of mesenchyme cells from somatopleura, 9 - coelom, 10 - migration of mesenchyme cells from dermatome
По Theiler's (1989)17 стадия развития. 10,5-й день