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66 m a s s a g e & b o d y wo r k m a rc h /a p r i l 2 0 24 Compressing, shearing, and tractioning soft tissues like skin, adipose, and muscle are a big part of our massage sessions, but other parts of our anatomy can benefit from therapeutic touch as well, including the sinewy, bony areas like the wrists and ankles. Keeping these areas healthy may have further-reaching effects than previously thought. Though lacking in squishability, they contain the retinacula, which are well-known anatomical structures with some lesser- known jobs emerging in research. Known for supporting healthy tendon movement, the retinacula have recently been discovered to also aid in proprioception through tensional neurofeedback. FINDING YOUR RETINACULA Before we jump into our discussion, let's start by finding some of your ankle and wrist retinacula. Wrist Circle the fingers of one hand around the opposite wrist, directly at the base of the hand. This encircling bracelet mimics the two retinacula of the wrist. On the palmar side, the f lexor retinaculum creates the roof of the carpal tunnel. On the dorsal side, the extensor retinaculum covers the tendons from the radius to the ulna. Ankle Wrapping your hand around the front of your ankle, wiggle your toes and move through dorsif lexion and plantar f lexion. Note the many tendons passing through this area. The superior and inferior extensor retinacula span over these tendons. Critical Thinking | Anatomy for Touch Extensor retinaculum of the right hand. Beneath the skin and subcutaneous tissue, we see the deep fascia that fully envelopes the muscles and tendons of the forearm (top of the image). This somewhat translucent tissue, called antebrachial fascia, becomes more reinforced by collagen fibers near the wrist, creating the retinacula, a structural specialization of deep fascia (middle of the image). Increased levels of hyaluronan and dense concentrations of sensory nerves within the retinacula provide a gliding surface for the tendons and proprioceptive feedback from the movement of the wrist and hand (bottom of the image). Image courtesy of AnatomySCAPES.com. Retinacula: Finding Our Footing By Rachelle Clauson and Nicole Trombley 1 KEY POINT • Recent research indicates that massage therapists can help with ankle and wrist injuries by focusing on retinacula. NOT AS SEPARATE AS WE THOUGHT Flip through your anatomy books and you will find retinacula drawn as white bands that wrap around the wrists and ankles, hugging the tendons like bracelets and sandal straps. Also found in other joint regions like the knee and elbow, retinacula are typically drawn as separate and distinct structures. It's important to remember, however, the strappy, white bands in our books are always the creation of the anatomist's scalpel and the artist's pen, and they have been cut and drawn the same way for a long time. Recently, fascia researchers headed to the dissection lab to look at retinacula with fresh eyes. Upon careful examination, the retinacula did not appear as they are drawn in the books. Instead of distinct structures, they saw thickening within the continuous, deep fascia layer that envelops the entire limb. 1 Further study revealed retinacula contain extremely high concentrations of hyaluronan, the gel-like, watery substance that allows tissues to glide. 2 We see these same deep fascia and retinacula continuities when we dissect them in our AnatomySCAPES labs and workshops. At the lower leg near the ankles and forearm near the wrists, we first carefully ref lect the skin and adipose