The neuromuscular junction is the site of the signal exchange. The steps of this process in vertebrates occur as follows:(`) The action potential reaches the axon terminal. (2) Voltage-dependent calcium gates open, allowing calcium to enter the axon terminal.he neuromuscular junction is the site of the signal exchange. The steps of this process in vertebrates occur as follows:(`) The action potential reaches the axon terminal. (2) Voltage-dependent calcium gates open, allowing calcium to enter the axon terminal.
Find out more about the common causes, symptoms, diagnosis and treatment options for pain on outside of foot in the ankle sprain section. 3) Cuboid Syndrome Cuboid Syndrome is a less common cause of lateral foot pain (i.e. outer side of foot pain) but it frequently goes undiagnosed which can lead to symptoms being present for long periods. It is caused by one of the small foot bones, the cuboid, being partially dislocated out of position following an injury like an ankle sprain or from repetitive strain on the foot.
1 Buccal exostosis â this type is painless. 2  Retrocalcaneal exostosis â this is a painful bump and you may also have tenderness, swelling, or redness along the bony prominence on the back side of your heel. 3  The pain usually becomes worse when wearing shoes that rub the back of your heel or with any type of activity.n exostosis can be caused by many different things ranging from genetics to environmental stress. 1  Environmental stress â one example of this is if the bone grows into your ear canal and becomes known as surferâs ear.