8.1 The Carnegie stages

Synoptic table of the Carnegie stages 17 - 19

Stage 17

Approx. 41rst day

11 - 14 mm

1 2 3 4 5 6 Umbilical cord with physiologic umbilical hernia Nasal pit Pigmented lens placode External acoustic meatus Auricular hillocks Formation of the interdigital zones

Characteristic signs:External acoustic meatus The circumference of the head increases The trunk lengthens Fusion of the 6 auricular hillocks Atrophy of the embryonic tail Formation of the interdigital zones

Stage 18

Approx. 44th day

13 - 17 mm

1 2 3 4 5 6 Cardiac prominence Nasolacrimal groove External acoustic meatus Hand plate with visible finger radiations Footplate with toe primordium Primordium of the palpebra (eyelid)

Characteristic signs: Toe primordium Nasal primordium The elbow joint forms Gonadal gender can be determined in male embryos

Stage 19

Approx. 46th day

16 - 18 mm

1 2 3 4 5 6 7 8 Liver prominence Primordium of the eyelid Eye External acoustic meatus Shoulder Finger Toes that are forming Straightening of the trunk

Characteristic signs:Lengthening and straightening of the torso Appearance of the external acoustic meatus Genesis of the hip and knee joints Atrophied embryonic tail Rupture of the cloacal membrane Maxilla and mandibula

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