The fibula gets short shrift. Overlooked and underrated as a mere “outrigger” of the leg, the fibula is one of the body’s many structures that help balance the exquisitely paradoxical qualities of stability and adaptability (Image 1). As such, fibular mobility plays an important role in normal movement and in recovery from ankle injuries (of which there are an estimated 25,000 per day), yet many hands-on practitioners ignore it.
While modern Latin-derived languages call it the “peroneal bone” (from the Greek word for “pin”), for about 300 years, English texts have used the Latin word fibula, which also signifies the pin of a brooch, buckle, or clasp. It is this clasp-like relationship of the fibula with the tibia, much like the two sides of a safety pin (Image 2), which helps the ankle mortise to hold the foot’s talus bone in a springy but firm grip at the distal tibiofibular joint (Image 3). It is this joint’s combination of resilience and firmness that allows the ankle hinge to be stable enough to support our weight, but to swing freely in plantarflexion and dorsiflexion.
It is the ankle’s strong ligaments that give it the adaptability to spring back (in most cases) when stressed. When forces are too great for the ligaments, they can slightly, partially, or completely tear—known as Grade I, II, or III sprains, respectively. The tibia, fibula, and talus can also fracture in more severe injuries. Ankle injuries of all severities cause damage to the joint capsules, tendons, retinacula, and fascial layers of the lower leg, which are often responsible for much of an injury’s swelling, pain, and discoloration. Injury to these connective-tissue structures is more common than serious ligamentous or bone damage.
While many sources agree that some of the ankle’s connective tissues can recover from many injuries relatively quickly, the conventional view is that if the ligaments themselves are compromised, recovery can take anywhere from 6 weeks to 1 year for moderate to severe sprains, according to the American Academy of Orthopaedic Surgeons, which also advises that “patience and learning to cope with an injury is essential to recovery.”1 Or it may take even longer—one study says that as many as 30 percent of those who injure their ankles still have pain after one year.2 Views vary though, and others claim that by encouraging gentle movement and increased blood flow early in an injury (rather than the conventional application of rest, ice, compression, and elevation), recovery times can be significantly shorter.3
A full discussion of ankle injuries’ many aspects is beyond the scope of this article. Whether damaged ligaments and tissues recover quickly or slowly, once the acute phase has passed, they can be left thickened, adhered, and scarred, leading to less fibular adaptability and continuing ankle limitation, pain, and irritation. It is here that we’ll focus. I’ll describe two techniques (from Advanced-Trainings.com’s Advanced Myofascial Techniques seminar, webinar, and DVD series) that can be helpful in keeping the fibula mobile and in recovering lost fibular adaptability, whether from injury, habitual movement patterns, or activity.
To understand fibula motions, we need to review the shape of the talus, the top bone in the foot. The superior articular surface of the talus, where it lies within the forklike mortise formed by the tibia and fibula, is wider anteriorly than posteriorly. As this wider part of the wedge-shaped talus rolls between the tibia and fibula in dorsiflexion, these two bones spread apart (Image 4). Normally, lateral translation is 3–5 millimeters, limited by the stretch of the interosseous and tibiofibular ligaments, which give this joint its spring. (This is also the mechanism that explains why squeezing the lateral and medial malleoli together on a cadaver reportedly results in foot plantarflexion, which postural tone presumably prevents in living bodies.)4
In addition to lateral translation
and posterior glide, the fibula also rotates slightly with ankle flexion (Image 4).5 This small but significant fibular rotation is considered an essential part of normal ankle function, as it helps the talus remain in close contact with the ankle mortise throughout its dorsiflexion/plantarflexion range. This close but pliable contact is crucial for even load distribution and balanced stability/adaptability in standing and gait.6 Said another way, unimpaired fibula translation and rotation helps protect the ankle bones’ thin layer of articular cartilage from undue stress and degeneration.7
Ideas for freeing the talus by working with the retinacula and interosseous membrane were covered in “Working With Ankle Mobility, Part 2” (Massage & Bodywork, May/June 2011, page 110). Here are two techniques to further your work with these vital structures.
Distal Tibiofibular Joint Technique
At their lower end, the fibula and tibia join at the distal tibiofibular joint (also known as the tibiofibular syndesmosis). This stiff articulation is bound together by tough, pearly ligaments in front (the anterior tibiofibular ligament, Image 4), in back (the posterior tibiofibular ligament, not pictured), and between the bones (the interosseous ligament, Image 4). As discussed earlier, a small amount of springy adaptability here is important for balanced function of the ankle, especially for full dorsiflexion, so this technique is useful whenever ankle dorsiflexion is limited.
Feel for the gap between the distal end of the tibia and fibula with your thumb (Images 5 and 6) or another tool. Once you’ve located this fissure between the bones (it’s often more lateral than you think), bring your client’s ankle into passive dorsiflexion. When the distal end of the fibula is free, this fissure will open or deepen slightly with your passive dorsiflexion as the wedge-shaped talus pushes the fibula laterally. There should be no pain or discomfort; be precise with your touch, but don’t be too sharp or pointed. Wait for the joint to respond by a softening or slight widening.
While you’re here, you can use a similar hand position to assess and release anterior/posterior fibular glide. Feel for evenness of fibular mobility at its distal end by stabilizing the tibia’s medial malleolus with your medial hand and using a thumb pad or other broad tool to push the fibula’s lateral malleolus posteriorly, feeling for quality and amount of gliding motion. Compare this to pulling the malleolus anteriorly. You can also use your thenar eminence or palm to check for superior glide of the fibula, gently pushing upward on the underside of the lateral malleolus. Pressure in this direction, in combination with a bit of posterior glide, often brings relief after an inversion ankle injury, as these injuries frequently displace the fibula anteriorly in relationship to the tibia.8
In working with any of these gliding motions, your grip is firm but comfortable. Feel bone rather than soft tissue, sensing for a small 1–3 millimeter yielding in each direction, comparing anterior with posterior movement. As long as there is no pain, lean into the more-restricted direction and wait for a release.
With any of these techniques, excessive mobility accompanied by joint pain with passive fibular motion may indicate ligamentous damage. In this case, you can be helpful by working very gently, without causing any pain, to encourage subtle mobility and circulation, rather than trying to release bigger mobility restrictions using the deeper pressure more appropriate to scarred tissues or restricted joints. Referral to a rehabilitation specialist may also be indicated.
Fibular Head Technique
The fibula doesn’t have just one end. Although the distal joint takes the brunt of most activities, your work will be more complete if you include the proximal end of the fibula in your work with the ankle. The proximal end of the fibula articulates with the tibia via a synovial joint, which allows a bit of gliding movement in each direction, as well as a small amount of rotation. In addition to being a different kind of joint than the distal syndesmosis, the proximal joint has smoother articular surfaces than the stiffer distal juncture, so is more suited to gliding and translation. Even though the proximal joint is a more mobile structure, in biomechanical testing, it usually moves less than the sturdier distal joint, reflecting the much greater forces at work on the distal end.
With your client’s knee up (to slacken the biceps femoris, which could otherwise immobilize the fibula), begin by finding a comfortable grip on the distal end of the fibula (Images 7 and 8). Check with your client to be sure you’ve avoided the common peroneal nerve where it passes just behind the fibular head (Image 9). In contrast to the firm, subtle movement of the distal end, the synovial joint of the proximal head will have a distinct glide to it, with a clear start and stop to its mobile range. Check for front/back fibular mobility against the tibia. As with the lower end, balance the fibula’s mobility by comparing one direction to the other and waiting for a softening response in the stiffer direction.
Some interesting trivia about the nontrivial fibula:
•There are seven named muscles that pull downward or distally on the fibula (extensor hallucis and digitorum longii; peroneus longus, brevis, and tertius; tibialis posterior; and soleus), but only one (biceps femoris) that pulls proximally, leading some anatomists to speculate that the fibula is more often displaced inferiorly. However, the interosseous membrane of the leg (Image 4) resists this imbalanced downward pull on the fibula through its obliquely angled fibers, which are oriented to stabilize the fibula against the downward pull of the numerous leg muscles.
•The middle part of the fibula is sometimes used for bone graft reconstruction of the mandible. When “harvested,” the fibula’s ends are carefully left in place—the distal end, because of its special role in forming the ankle mortise, and the proximal end because of its close association with the peroneal nerve.
•The fibula does not articulate with the femur, of course, making it functionally related more to the ankle than the knee, at least in humans; in some animals, the fibula does not articulate with their foot bones or their femurs, making their fibulae free at both ends. In horses, the tibia and fibula form a single joined bone.
Working the fibula is part of a bigger picture, of course. For example, you can prepare for the techniques in this article by addressing any restrictions related to tight gastrocnemius or soleus (“Working with Ankle Mobility, Part 1,” Massage & Bodywork, March/April 2011, page 110), which are a logical compliment to the work described here. Ankle pronation/supination, hip/knee/ankle alignment, as well as hip and femur rotation are all aspects to consider and address as part of your overall work with ankle and lower leg issues (“Working with Hip Mobility,” Massage & Bodywork, March/April 2012, page 114).
Notes
1. American Academy of Orthopaedic Surgeons, “Sprains and Strains: What’s the Difference?” accessed June 2013, http://orthoinfo.aaos.org/topic.cfm?topic=A00111.
2. K. L. Margo, “Review: Many Adults Still Have Pain and Subjective Instability at 1 Year After Acute Lateral Ankle Sprain,” Evidence-Based Medicine 13, no. 6 (2008): 187.
3. D. Hartzell and M. Shimmel, Don’t Ice that Ankle Sprain!
(Ohio: Jump Stretch Inc., 2006).
4. I. A. Kapandji, Physiology of the Joints Volume II, 5th ed.
(Philadelphia: Elsevier, 1987), 164.
5. There is some disagreement about the way in which fibular rotation is coupled with ankle movement. Although Kapandji (1987) describes the opposite, most references surveyed for this article agree that the fibula rotates externally when the ankle dorsiflexes. One study [M. Bozkurt et al., “Axial Rotation and Mediolateral Translation of the Fibula During Passive Plantar Flexion,” Foot Ankle International 29, no. 5 (2008): 502–7] showed variations in extension-coupled rotational direction between different individuals. There is also little agreement on the amount of rotation, with cited measurements ranging from 2 degrees [A. Beumer et al., “Kinematics of the Distal Tibiofibular Syndesmosis: Radiostereometry in 11 Normal Ankles,” Acta Orthopaedica Scandinavica 74, no. 3 (2003): 337–43] to 30 degrees (Kapandji, 1987) of malleolus rotation.
6. J. H. Calhoun et al., “A Comprehensive Study of Pressure Distribution in the Ankle Joint with Inversion and Eversion,” Foot & Ankle International 15, no. 3 (1994): 125–33.
7. T. P. Rüedi et al., eds., AO Principles of Fracture Management (Switzerland: AO Foundation Publishing, 2007).
8. B. Vicenzino et al., “Mulligan’s Mobilization-With-Movement, Positional Faults and Pain Relief: Current Concepts from a Critical Review of Literature,” Manual Therapy 12, no. 2 (2007): 98–108.
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