Usually when we think about ankle problems, we think about sprained ankles or a strained muscle, not something called a retinaculum. Yet these fascial structures play a significant role in a wide variety of chronic ankle problems.
So what is a retinaculum? From one perspective a retinaculum is a band of thick deep fascia that holds the long tendons of your ankle (those that cross the ankle) in place. Retinaculum also acts as a pulley system increasing mechanical advantage.
From the second perspective retinaculum are a major source of neurological receptors involved in balance and proprioception. Essentially retinacula have been hypothesized as key structures in spatial control for foot and ankle movements.
The following section is an overview of specific retinacula and what structures pass underneath them. As you look over the individual sections of the retinaculum also think of these areas as part of one large fascial interconnecting unit.
Retinacula do not exist as they are illustrated
At the second international fascia conference in Amsterdam it became very clear to me that retinacula do not exist as they are illustrated in textbooks. There is a lot of interconnecting fascia that has to be removed before retinaculum look the way they are presented in text books. Research is now showing that these fascial connections (which are removed by dissection) are very important for both force transmission and neurological function.
Front (Anterior) Ankle Retinaculum
Extensor retinaculum (2 parts)
o This structure holds in place tendons from the following muscles; tibialis anterior,extensor digitorum longus, extensor hallucis longus, and peroneus tertius.
o The deep peroneal nerve also passes under the retinaculum.
o The inferor retinaculum is shaped like a Y (once the entire surrounding fascia is removed) and has a lower and upper portion. The Y shape has the function of preventing “Bowstringing” of the tendons during ankle motion.
Pain/Symptom pattern: If there is a restriction in an extensor retinaculum, (front of the ankle) you may experience the following symptoms:
- Localized pain or restriction on the front of ankle when running or walking. It is a very common symptom that I see with runners.
- Tension can also alter the muscle firing patterns in the lower extremity. This can create a host of injuries and result in a substantial decrease in athletic performance
- Outside (Lateral) Ankle RetinaculumSuperior peroneal retinaculum:
Inferior peroneal retinaculum:
- This band of fascia holds the tendons of two muscles the peroneous longus and brevis in place just behind the outer ankle bone (fibular malleolus).
Pain/Symptom pattern: Tension or a restriction in this area will often cause lateral ankle pain, altering both foot and ankle motion. This can easily lead to ongoing injury and a decrease in athletic performance.Note: Peroneal retinacula are often injured during ankle sprains (inversion injury). Anytime there is persistent pain after an ankle sprain, a retinaculum injury should be considered. For more information on ankle sprains read my six part blog on Ankle Sprains (Inversion Sprain).Inside (Medial) Ankle Retinaculum
- This band also holds the tendons of the peroneous longus and brevis muscles in place. This retinaculum is continuous with the inferior extensor retinaculum.
- This band holds the tendons of the following muscles in place: tibialis posterior, flexor digitorum longus, flexor hallicus longus, and the tibial nerve.
Tarsal Tunnel Syndrome (TTS): Tarsal Tunnel Syndrome refers to compression of the posterior tibial nerve in the flexor retinaculum.
- Restrictions of the flexor retinaculum are associated with what is known as Tarsal Tunnel Syndrome. In this syndrome people experience sensation of: Pain, tingling and altered sensation anywhere from the ankle, heel, bottom of the feet, to the toes.
- A person with this syndrome will often experience an electric shock sensation, which travels into the foot, when they tap directly over the retinaculum. This is also known asTinel’s sign.
- Persons with flat feet (fallen arches) are susceptible to TTS. Also any type of enlargement in the Tarsal Tunnel can cause this syndrome which includes swollen tendon, cysts, arthritic bone spur, varicose veins, or even inflammation in the surrounding area.
- If this syndrome is left to progress it can lead to permanent nerve damage.
- Conventional therapy can often be very effective in treating this syndrome (Rest, Ice, and Exercise). Active Release Techniques has developed some specific protocols the release the posterior tibial nerve in the Tarsal Tunnel.
Injury To The Retinaculum
When functioning correctly, tendons glide under these retinacula without hindrance. With injury (trauma, repetitive strain), the retinaculum can become a site of tendon restriction, nerve impingement, and circulatory compression. Injury to the retinaculum will cause mechanical and neurological damage.
From a mechanical perspective, when tension is created between the retinaculum, and the structures that pass under them, a considerable amount of tension occurs. This tension can be a major problem since tension creates friction, which can cause micro-tears in the tissue,inflammation, and eventually adhesion formation. These adhesions inhibit relative motion, alter lower extremity biomechanics, and lead to a host of compensations.
From a neurological perspective, injury causes an alteration in neurological receptors (mechanoreceptors and proprioceptors). This leads to both ankle and foot instability. Instability of the ankle and foot creates abnormal motion patterns, compensations which can lead into numerous injuries throughout the body.
Restrictions of the retinacula can be treated quite effectively with Manual Therapy (Active Release Techniques, Graston Technique, and Massage Therapy) and a series of corrective exercises. Treating with manual therapy involves breaking restrictions between the retinaculum and the tendon. Essentially the practitioner is restoring relative motion between the retinaculum and the tendons (and of course the muscles that the tendons are attached to).
The practitioners should also be focusing their treatment on the fascial lines of stress. Lines of stress in fascia are often created during injury in multiple locations not just at the site of pain. If these areas of fascial stress can be released, then normal fascial tension can be restored.
Restoring overall fascial tension, besides releasing adhesions between retinaculum and the soft tissues that pass under them, can have significant effects in resolving an injury.
Fascial interconnections are not theoretical entities; they are actual physical structures that have been mapped out. Researchers such as Thomas Meyers (Anatomy Trains) and Luigi, Carla, and Antonio Stecco (Fascial Manipulation) have spent decades researching these interconnections. During the second International Conference About Fascia at the University of Amsterdam, I had the privilege of listening to medical experts from around the world confirm this and related fascial research.
In my own clinical experience we have seen excellent results in improving ankle stability by removing adhesions at the retinaculum itself, but even better results when we work on restoring overall fascial tension
Exercise plays a significant role in the rehabilitation of a retinaculum injury. Strengthening and flexibility exercises are needed, but because a significant component of a retinatculum injury involves neurological receptors, balance and proprioception exercises are also essential for full recovery.
The following links are examples of exercises that we often recommend for out patients with injuries to the retinaculum (from Core Performance).