Just when you thought we knew everything there was to know about our bodies, scientists say they have discovered a ‘new’ muscle layer in the lower human jaw which plays an essential role in chewing. Health24 reports that the newly discovered, deep muscle layer is found in the masseter muscle, which raises the lower jaw, and that to find it the scientists had to dissect 12 formaldehyde-fixed human cadaver heads. They also analysed CT scans of 16 fresh cadavers, looked at MRI data from a living 40-year-old female, and examined histological sections of one formaldehyde-preserved head. The team noted that additional knowledge of the architecture of the masseter muscle may help doctors in managing patients with temporomandibular disorders or help doctors better perform surgery in patients in that region of the jaw.