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?
A retinaculum is a band of thick deep fascia that holds the long tendons of your ankle (those that cross the ankle) in place.
The retinaculum also acts as a pulley system increasing mechanical advantage.
The retinaculum is 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 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 looks the way they are presented in textbooks. Research is now showing that these fascial connections (which are removed by dissection) are very important for both force transmission and neurological function.
ANTERIOR ANKLE RETINACULUM ANATOMY
Superior extensor retinaculum:
This structure holds in place tendons from the following muscles; tibialis anterior, extensor digitorum longus, extensor hallucis longus, and peroneus tertius.
The deep peroneal nerve also passes under the retinaculum.
Inferior extensor retinaculum:
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 with anterior ankle retinaculum: 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
LATERAL 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.
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.
MEDIAL ANKLE RETINACULUM
Restrictions of the flexor retinaculum are associated with what is known as Tarsal Tunnel Syndrome. In this syndrome, people experience 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 as Tinel’s sign. (1)
Tarsal Tunnel Syndrome (TTS): Tarsal Tunnel Syndrome refers to compression of the posterior tibial nerve in the flexor retinaculum.
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 spurs, varicose veins, or even inflammation in the surrounding area.
If this syndrome is left to progress it can lead to permanent nerve damage.
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, and compensations which can lead to numerous injuries throughout the body.
Restrictions of the retinacula can be treated quite effectively with Manual 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 video below is a demonstration of how we use Motion Specific Release to remove restrictions that could be causing tension in the retinaculum.
4 Point Dorsi Flexion Protocol - Motion Specific Release: Dorsiflexion is the movement at the ankle joint where the toes are brought closer to the shin. The muscles of the shins help your foot to clear the ground during the Swing Phase (concentric contraction) of your stride, and absorb much of the impact shock during running
Exercise plays a significant role in the rehabilitation of a retinaculum injury. A combination of mobility, strengthening and proprioceptive exercises will achieve the best results.
Foundational - Foot Stretching Routine (Follow Along): This foot stretching routine focuses on the long and short flexors and extensors of the foot.
Foot & Ankle Strengthening Routine - Using a Theraband: This foot and ankle strengthening routine works the flexor, extensors, and internal and external foot rotators using a Theraband.
Balance Exercises with the Bosu Ball: Balance Exercises - Here are some great suggestions on how to improve your balance using a Bosu Ball (or wobble board). Balance is essential for both rehabilitation and sports performance.
DR. BRIAN ABELSON DC.
Dr. Abelson believes in running an Evidence-Based Practice (EBP). EBPs strive to adhere to the best research evidence available while combining their clinical expertise with the specific values of each patient.
Dr. Abelson is the developer of Motion Specific Release (MSR) Treatment Systems. His clinical practice in is located in Calgary, Alberta (Kinetic Health). He has recently authored his 10th publication which will be available later this year.
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Tarsal tunnel sydrome-A narrative literature review., McSweeney SC, Cichero M. The Foot 2015;25:244-50. (Level of Evidence 5)