The head is more erect and semicircular canals start to form in the inner ear which will enable a sense of balance and body position. Thorax Septum primum fuses with septum intermedium in the heart. Pelvis The gonads form. In about a week, the sex of the embryo will be recognizable in the form of testes or ovaries. Limbs Knee and ankles locations indicated by indentations.
Legs are now at their proper location, proportional to the embryo.
The critical period for the lower limbs is about to end. Toes are almost completely notched and toenails begin to appear. Joints grow more distinct. The trunk elongates and straightens and the bone cartilage begins to form a more solid structure. Muscles develop and get stronger.