The origin of the mid-gut (mesenteron), outer layers become continuous, forming respectively the amnion that has no chitinous lining in the developed insect, is the disputed and the serosa (fig.
Quick Answer. Possible causes of swollen lymph nodes behind the ears include an ear infection, an abscessed tooth, a cold, the flu or another infection, according to MedlinePlus. Lymph nodes also commonly appear beneath the jaw, on the back of the head, or on the neck, armpit or groin.
Conditions such as goiter, mononucleosis and mumps may also cause neck swelling. Ear pain, on the other hand, may result from jaw arthritis, tooth infection, acute or chronic ear infection, and sinus infection, notes MedlinePlus. Sore throat and ear wax accumulation can also cause ear pain. Continue Reading.