The<unk>  may pulsate, and although the precise cause of this is not known, it is normal and seems to echo the heartbeat, perhaps via the arterial pulse within the brain vasculature, or in the meninges. This pulsating action is how the soft spot got its name –<unk>  is borrowed from the old French word fontenele, which is a diminutive of fontaine, meaning "spring". It is assumed that the term spring is used because of the analogy of the dent in a rock or earth where a spring arises. Parents may worry that their infant may be more prone to injury at the<unk> s. In fact, although they may colloquially be called "soft-spots", the membrane covering the<unk> s is extremely tough and difficult to penetrate.<unk> s allow the infant brain to be imaged using ultrasonography. Once they are closed, most of the brain is inaccessible to ultrasound imaging, because the bony skull presents an acoustic barrier.
Fontanelle
Hemotympanum
Orbital septum
Lacrimal groove
Optic recess
Craniopharyngeal canal
Ateronon
Rhomboid fossa