Tendons are bands of tissue at the end of each muscle that attach to the bone. When they become overused or injured, you get inflammation around the tendon, called tendonitis. If left untreated, tendonitis can lead to continued inflammation, chronic pain and dysfunction, and sometimes tearing or partial tearing of the tendons.
Bursas are small, fluid-filled sacs that form cushions between your bones and other body parts like muscles, tendons or skin. When a bursa becomes injured or inflamed, it is called bursitis. Bursitis can cause muscle deterioration and limited movement in your ankles or feet.
Tendonitis and bursitis can cause swelling and inflammation in joints that are injured or overused. As mentioned, overuse, strain and frequent, repetitive motion may cause bursitis and tendonitis. However, in some cases, infection, sudden injury or abnormal foot structure may also be the cause.
The most common types of tendonitis and bursitis in the feet and ankles are:
Achilles tendinitis—affects your Achilles tendon—a fibrous band of tissue that links the muscles in your calf to your heel. When your Achilles tendon becomes swollen, inflamed and irritated, it is called Achilles tendinitis.
Flat feet—happens if the tendons of your feet become loose or worn out due to aging, injuries or illness. Flatfoot is also called posterior tibialis tendon dysfunction or PTTD. It’s one of the most common problems of the ankles and feet.
High arches—these can make you prone to overuse injuries. Because a smaller portion of your foot touches the ground, high arches make poor shock absorbers, which can cause issues like pain and swelling in your feet and ankles.