WEEK 3

STAGE 11;
23 - 26 Days;
2.5 - 4.5 mm;; Somite Number 13 - 20; rostral neuropore closes; Carnegie Stage 11; Features: rostral neuropore closing, forebrain, neural tube in region of developing spinal cord, somites, caudal neuropore, connecting stalk, amnion

WEEK 4

STAGE 12;
26 - 30 Days;
3 - 5 mm;; Somite Number 21 - 29; caudal neuropore closes; Features: day 26, 27 somites, forebrain, site of lens placode, site of otic placode , stomodeum, 1st pharyngeal arch, 2nd pharyngeal arch, 3rdpharyngeal arch, heart prominence, somite

WEEK 5

STAGE 13;
28 - 32 Days; (week 5);
4 - 6 mm;; Somite Number 30; leg buds, lens placode, pharyngeal arches; Features: site of midbrain, lens placode, site of nasal placode, 1,2,3 pharyngeal arches, L. ventricular prominence of heart, L. atrial prominence of heart, umbilical cord, lower limb bud, mesonephric prominence, upper limb bud;

STAGE 14;
31 - 35 Days;
5 - 7 mm;; lens pit, optic cup; Day 32 Features: midbrain, nasal placode, lens pit, 1,2,3 pharyngeal arches, fourth ventricle of brain, 1st pharyngeal groove, heart prominence, cervical sinus, upper limb bud, mesonephric ridge, lower limb bud, umbilical cord

STAGE 15;
35 - 38 Days;
7 - 9 mm;; lens vesicle, nasal pit, hand plate

WEEK 6

STAGE 16;
37 - 42 Days; (week 6);
8 - 11 mm; nasal pits moved ventrally, auricular hillocks, foot plate; (day 40); Features: eye showing retinal pigment, nasolacrimal groove, nasal pit, fourth ventricle of brain, umbilical cord, 1st and 2nd pharyngeal arches, cervical sinus, heart, developing arm with hand plate, foot plate

STAGE 17;
42 - 44 Days;
11 - 14 mm;; finger rays; day 42); Features: pigmented eye, nasal pit, nasolacrimal groove, external acoustic meatus, auricular hillock, heart, digital rays, liver pronminance, thigh, ankle, foot plate, umbilical cord

WEEK 7

STAGE 18;
44 - 48 Days; (WEEK 7);
13 - 17 mm;; ossification commences

STAGE 19;
48 - 51 Days;
16 - 18 mm;; straightening of trunk; day 48) Features: eyelid, eye, external acoustic meatus, auricle of external ear, digital ray, wrist, liver prominence

STAGE 20;
51 - 53 Days; (week 8);
18 - 22 mm;
upper limbs longer and bent at elbow day 51); Features: scalp vascular plexus, eylid, eye, nose, external acoustic meatus, auricle of external ear, arm, elbow, wrist, liver prominence, digital rays

STAGE 21;
53 - 54 Days;
22 - 24 mm;
hands and feet turned inward; day 52); Features: scalp vascular plexus, eylid, eye, nose, auricle of external ear, arm, elbow, wrist, knee, notch between digital rays, umbilical cord;

WEEK 8

STAGE 22;
54 - 56 Days;
23 - 28 mm;; eyelids, external ears

STAGE 23;
56 - 60 Days;
27 - 31 mm;; rounded head, body and limbs; Features: scalp vascular plexus, eylid, eye, nose, auricle of external ear, mouth, sholder, arm, elbow, wrist, toes separated, sole of foot, umbilical cord