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.
Sudden onset pain on the outer side of the foot can be from a fracture of the 5th Metatarsal and injuries to this bone are a common sports injury. Causes of pain on the outside of the foot are listed here: 1  Midtarsal Joint Sprain A mid tarsal joint sprain is an injury to the ligaments holding the mid tarsal joint together causing pain in the outside middle of the foot. 2  Peroneus Brevis Tendon Injury The Peroneus Brevis tendon inserts into the 5th matatarsal bone on the outside of the foot.
8. Foot Arthritis â Often causes a deep achy pain sensation on top of the foot just in front of the ankle. Caused by a wearing away of the cartilage between the joints on the side and top of the foot. Self-Treatment of Pain on the Outside of the Feet. First, for the best solutions to the specific problems listed above use the links to those pages.