1. formation of atrioventricular valves complete
2. truncoconal septum growth completed
3. ventricular septation continues
4. skull formation
   1. membranous neurocranium
      1. vault overlying the brain; frontal and parietal bones
      2. intramembranous ossification starts around week 8 but is not complete until after birth
      3. neural crest origin
   2. chondrocranium
      1. base of the skull, floor of the brain case
      2. endochondrial ossification
      3. ethmoid, sphenoid, occipital and temporal bones
      4. neural crest and paraxial mesoderm
   3. viscerocranium
      1. bones of the face and mouth
      2. neural crest and lateral mesoderm
      3. maxilla and mandible by intramembranous
      4. the rest by endochondral ossification
5. 90-degree rotation of stomach completed
6. pontine flexure has now completely folded metencephalon onto myelencephalon
7. bones of middle ear
   1. malleus
      1. derived from Mn process
   2. Incus
      1. derived from Mx process
   3. Stapes
      1. derived from pharyngeal arch 2
8. lingual papillae appear
9. pre-Sertoli cells begin to secrete anti-mullerian hormone that causes regression of mullerian duct in males