Sinus Tarsi Syndrome
Sinus tarsi syndrome describes damage to the structures that run within a tunnel known as the sinus tarsi. The sinus tarsi is located on the outside (lateral aspect) of the ankle, between the heel bone (calcaneus) and one of the ankle bones called the talus. It contains various nerves, blood vessels, ligaments, and structures that help stabilise the ankle and play an important role in balance and proprioception.
The most common cause is from a lateral ankle sprain that results in injury to the tissues and structures on the outside of the ankle. Injuries can range in severity of mild sprains to ligament tears, and are usually followed by inflammation within the sinus tarsi. This may be a result of a one-off sprain, or after repeated sprains and a degree of ankle instability. Ankle instability can allow more movement at the subtalar joint where the sinus tarsi is located, hence aggravating the injury.
Impingement of the structures within the sinus tarsi is another cause, though less common. This tends to occur with very flat or pronated feet or other biomechanical abnormalities that decrease the space within the sinus tarsi tunnel and place pressure on the structures within the tunnel.
Certain sports can also make you more prone to developing sinus tarsi syndrome due to the positioning of the foot, such as ballet, pitching sports, and any activity that involves sitting with the feet tucked underneath you.
Symptoms typically include:
With ankle sprains, other ankle ligaments and structures may also be damaged. Swelling within the sinus tarsi may also press on nerves, producing neural symptoms such as numbness, tingling and pins and needles.
The first part of treatment is to manage the initial painful symptoms. Following the PRICE (protection, rest, ice, compression, elevation) principles can help settle the pain and swelling, allowing the body to begin to repair the damage to the ligaments and structures.
The next part of treatment will focus on addressing the cause to alleviate excess pressure away from this region and reduce the risk of future re-injury. This may involve:
Because poor or delayed management of sinus tarsi syndrome can lead to ongoing stability problems, it is important to see your podiatrist if you’re worried you may have developed this condition. They will conduct a thorough assessment of your feet and legs and create a management plan to account for your symptoms, severity of the injury and daily activities.