Research Review: Mapping the Sensory Innervation of the Ankle Joint
By Nicholas Rolnick SPT, MS, CSCS
Edited by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS
Original Citation: Mentzel M, Fleischmann W, Bauer G, and Kinzl L. (1999). Ankle joint denervation. part 1: anatomy - the sensory innervation of the ankle joint. Foot and Ankle Surgery. 5: 15-20. ABSTRACT.
Why is this relevant?: Much of the practical aspect of being a human movement professional is built upon a foundation of functional anatomy knowledge. Ankle pain may affect as much as 15% of middle-aged and older adults (2), which implies that functional anatomy of the ankle is a content area that should be a priority for all human movement professionals. This milestone study used a cadaveric dissection model to map the sensory innervations of the ankle joint (talocrural articulation and talocalcaneonavicular) in an effort to further understand ankle joint sensation (including nociception).
Caption: The talocalcaneonavicular joint is where the head of the talus articulates with the navicular bone, the spring ligament, the sustentaculum tali, and the articular surface of the calcaneus. - www.quizlet.com The talocalcaneonavicular joint is where the head of the talus articulates with the navicular bone, the spring ligament, the sustentaculum tali, and the articular surface of the calcaneus. - www.quizlet.com
Study Summary
| Study Design | Observational Dissectional Cadaveric Study |
| Level of Evidence | Level 4 |
| Subject Demographics | - Age: N/A
- Gender: N/A
- Characteristics:
- Protocol
- 8 cadaver legs (2 from the same individual, the rest from 6 unique individuals) were amputated at the distal thigh and fixed in formalin.
- The dissection was carried out on each leg looking through spectacles with magnifying loupes and underneath a microscope using hand-surgical and microsurgical instruments.
- Sketches and photographs were made of the nerves observed in the dissection, with special emphasis on the ankle and the talocalcaneonavicular joint.
- Inclusion Criteria: N/A
- Exclusion Criteria: N/A
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| Outcome Measures | - The five major nerves that innervate the ankle were investigated - the saphenous, tibial, sural, superficial peroneal, and deep peroneal. The goal was to establish the sensory distribution of the ankle joint and the areas that each nerve innervates.
|
| Results | - Saphenous Nerve (sensory terminal branch of the femoral nerve)
- This nerve follows the course of the long saphenous vein down to the lower leg.
- By the time it reaches the lower leg, it already gives off 1-2 branches which spread out and down the rest of the lower leg.
- One of these branches is named the "medial cutaneous nerve", which extends to the distal section of the lower leg and can have anastomoses (where nerves communicate with each other) with the trunk itself (as was observed in one cadaver leg)
- Between the middle and distal third of the lower leg, the nerve crosses the medial border of the tibia.
- The nerve travels down the medial surface of the tibia terminating at the distal end medial malleolus.
- At this junction, the nerve gives off 4-6 branches which spread out towards the posterior aspect of the tibial periosteum to the medial malleolus where it joins with the anterior side nerve branches in a "finger-like manner."
- In three cadaver legs, there was branching observed of the saphenous nerve in the distal third of the lower leg, traveling with the long saphenous vein in 2-3 distinct branches.
- Each of these terminal branches were involved directly in sensory innervation of the ankle joint, the distal tibial periosteum, the medial malleolus, the medial and ventral ankle capsule, and the medial capsule of the talocalcaneonavicular joint.
- Tibial Nerve (Motor/Sensory Branch off the Sciatic Nerve)
- The tibial nerve travels with the posterior tibial artery and vein in the lower leg.
- In the distal section of the lower leg, the tibial nerve runs posterior to the tendons of the tibialis posterior and flexor digitorum longus muscles and anterior to the the tendon of flexor hallucis longus.
- The nerve continues to travel to the ankle, moving between the superficial and deep layers of the flexor retinacula, where it splits into its terminal branches - the medial and lateral plantar nerves.
- Medial Plantar Nerve
- Variations were found in the terminal branch, with up to 6 branches that extend to the medial ankle joint and the medial and caudal aspects of the talocalcaneonavicular joint.
- Lateral Plantar Nerve
- This branch rarely innervates any aspect of the ankle joint. In one cadaver, a branch from the lateral plantar nerve was observed to innervate the talocalcaneonavicular joint medially and caudally.
- In the distal third of the leg, the medial calcaneal branches were given off, which was generally observed as a trunk with two distinct nerve branches travelling towards the medial section of the heel.
- Nerve branches from the medial calcaneal branches were observed to travel dorsally to both the ankle joint and to the talocalcaneonavicular joint.
- Anastamoses between the tibial and medial calcaneal branches, as well as between the medial calcaneal and lateral calcaneal branches were observed in some individuals as well.
- Approaching the distal third of the leg near the ankle, approximately 2-6 branches were observed leaving the tibial nerve proper and traveled to the posterior periosteum of the tibia and to the ankle joint capsule.
- Sural Nerve (Joining of the Medial And Lateral Sural Nerves from the Tibial and Common Fibular Divisions of the Sciatic Nerve, Respectively)
- Their anastomoses into the sural nerve proper, in some cadavers, did not occur until the distal section of the lower leg towards the foot, traveling with the short saphenous vein.
- In the distal third of the lower leg, 1-3 lateral calcaneal branches diverge from the sural nerve proper and head posteriorly towards the lateral heel.
- These nerves can also emanate from the medial and lateral sural nerves prior to joining together to form the sural nerve, or they may be the terminal branches of the sural nerve itself.
- In the beginning of the distal third of the lower leg towards the level of the ankle joint, 2-5 branches leave the sural nerve proper and travel anteriorly towards the periosteum of the posterior surface of the fibula and the dorsal portion of the ankle joint capsule.
- Proximal to the ankle joint or at the level of the ankle joint, the sural nerve gives off a branch which wraps around the lateral malleolus "in a finger-like" fashion, innervating the fibular periosteum, the talofibular joint capsule, and the lateral aspect of the talocalcaneal joint.
- Up to 6 smaller nerve branches were observed to extend to the lateral malleolus and to the lateral aspect of the foot to innervate the subtalar and talonavicular joints of the talocalcaneonavicular joint.
- One cadaver was observed to have anastomoses with the sural and superficial peroneal nerve in the lateral malleolar region.
- Superficial Peroneal Nerve (Motor/Sensory Branch off the Sciatic Nerve)
- The superficial peroneal nerve sends motor branches to the fibularis longus and brevis and travels along the muscle towards the distal portion of the lower leg.
- In the distal lower leg, 3-8 nerve branches exit the superficial peroneal nerve proper and innervate the lateral malleolus on both the ventral and dorsal aspects as well as (in some cases) anastomoses with the sural nerve.
- Some nerve branches remain anterior, innervating the tibial periosteum, the fibular periosteum, and the ventral distal tibiofibular joint.
- Some nerve branches travel medially and also innervate the distal tibiofibular joint as well as the medial malleolus where anastomoses with the saphenous nerve was observed.
- In the distal lower leg after the first branching occurs, it pierces the fascia and splits into the medial and lateral sensory branches which travel to the dorsal foot subcutaneously.
- It was also observed that three distinct branches could be given off instead of two. These nerves join together and travel in parallel to the original nerves.
- In one cadaver, the lateral branch was observed to extend to the talonavicular and talocalcaneal joints.
- Deep Peroneal Nerve (Motor/Sensory Branch off the Sciatic Nerve)
- After branching off the common fibular nerve, it gives off muscular branches to the anterior compartment (tibialis anterior, extensor digitorum longus, extensor hallucis longus).
- A singular branch arises from one of the muscular branches and travels on the interosseous membrane on the extensor side, innervating the tibial periosteum anteriorly and laterally, the syndesmosis, and the capsule of the distal tibiofibular joint and the cranial aspect of the ankle joint.
- In the lower leg, the deep peroneal nerve travels with the anterior tibial atery and veins between the tibialis anterior and the extensor digitorum longus muscle distally to the level of the ankle joint.
- At the level of the ankle joint, 1-2 nerve branches can diverge from the tibial nerve proper and innervate the anterior capsule of the ankle joint.
- 1-2 main branches are formed from the tibial nerve, where the lateral branches give off a motor innervation to the extensor digitorum brevis and extensor hallucis brevis muscles. The rest of the branches are sensory (up to 10 individual branches) and innervate the anterior and lateral ankle joint capsule along with the talocalcaneonavicular joint.
- In two cadavers, two nerve branches were observed to innervate the lateral aspect of the talar head.
- The medial branches off the tibial nerve (up to 5 main branches) innervate the ventral part of the ankle joint capsule and the talonavicular joint.
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| Conclusions | The terminal branches of the nerves of the lower extremity all have a role in innervating portions of the ankle and talocalcaneonavicular joint, as well as the distal lower leg. |
| Conclusions of the Researchers | N/A |
Caption: Cadaver Dissection, soft tissue removed of the anterior ankle. Mortise, malleoli, head of talus and neck of talus clearly labeled. Cadaver Dissection of Ankle Joint. The current study investigated the sensory innervations of the talocrural joint, which involves the distal tibia and the trochlea of the talus - By Anatomist90 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=25307064
Review & Commentary:
The current study is unique in the level of detail of the description. The authors described the course of each of the 5 major nerves of the lower leg to their termination in or around the ankle joint (talocrural and talocalcaneonavicular joint), as well as a description of branches that exited the main nerve trunk along the way providing innervation to other areas, such as the interosseous membrane or periosteum of the tibia/fibula. Second, the authors provided detailed illustrations of the course of each of the nerves and its subsequent branches, providing clarity to much of their written descriptions, which can be hard to follow due to the use of anatomical direction terms that are sometimes used interchangeably (dorsal, posterior, distal, inferior, etc.). As mentioned, the unique level of detail in this study was a step forward in our knowledge of ankle sensation.
The study had a few weakness that should be mentioned. The investigators did not list demographic information such as gender, age, ethnicity, and body mass. Further, their was no discussion of inclusion or exclusion criteria that should have included information like medical conditions, history of injury to the examined ankle, complaints of pain in the examined ankle, etc. Seven cadavers were used to examine eight legs (two legs were used on one individual); which begs the question, "why not examine both legs on seven cadavers for a total of 14 specimens?". Would 14 specimens have provided enough data to add statistical analysis on the prevalence of certain variations noted between individuals? Although more appropriate for a follow up study, nerve testing on live subjects to confirm observed neural innervations would provide additional data for the creation of an ankle joint sensation "map." Last, the authors did not include a conclusion or summary which may have been helpful in understanding the implications of this study.
Why is this study important?
As far as we know (the Brookbush Institute), the current study provides the most detailed and current information on sensory innervation of the ankle joint (talocrural and talocalcaneonavicular joint).
- Sensory Innervation of Joints (Brookbush Institute summary based on this study and others) :
- Proximal Tibiofibular Joint Capsule: Innervated by branches form the common fibular and popliteal nerves (3).
- Distal Tibiofibular Joint: (No Capsule) Innervated by branches of the sural, deep fibular and tibial nerves.
- Ankle (Tibiotalar) – Innervated by distal branches of all 5 major nerves of the lower leg, including the saphenous (medial ankle and malleolus), tibial (anterior, medial and talocalcaneonavicular), sural (lateral), superficial peroneal (medial and ventral), and deep peroneal nerve (anterior ankle) (1, 4).
- Talocalcaneal – The anterior facets are likely innervated by the deep peroneal nerve, the sural nerves has branches that penetrate the lateral joint line, this joint may also receive innervation from the tibial and medial plantar nerves (1, 5).
How does it affect practice?
Although the information in the article does not imply specific techniques or suggestions for practice, the information may inspire new directions for treatment of ankle pathology, and/or be recalled by the practitioner to help in the formation of a hypothesis specific to a client/patient case.
How does it relate to Brookbush Institute Content?
Ankle joint dysfunction is commonly the root cause/driver of the compensation pattern described in the Brookbush Institute predictive model of lower leg dysfunction (LLD) . The current study suggests that sensation from the ankle joint (including nociception/pain) is the result of transmission from the saphenous, sural, superficial and deep peroneal, and tibial nerves, and further consideration may be necessary for how these nerves may be affected by dysfunction - including entrapment, stretch injury, inflammation, etc.
The Brookbush Institute promotes an integrated approach to rehabilitation, fitness and performance enhancement. Integral to this concept is the consideration of all systems that comprise the human movement system, including articular, muscular, fascial and neural. Although, soft tissue and joint mobilization techniques may improve neurodynamics, the addition of specific neurodynamic techniques are an important adjunct to an integrated approach and will be included in Brookbush Institute content in the future.
The following videos are useful in providing context to the anatomy of the lower leg and ankle, as well as giving introductory steps towards addressing LLD .
Brookbush Institute Videos
Ankle Joint Actions
Gastroc Soleus SA Release
Calf and Fibularis Peroneal SA Static Stretching Technique
Ankle Mobilization
Quick Tibialis Anterior and Tibial Internal Rotator Activation
Tibialis Anterior Activation Taping
Bibliography:
- Mentzel M, Fleischmann W, Bauer G, Kinzl L. Ankle joint denervation. Part 1: Anatomy –the sensory innervation of the ankle joint. Foot and Ankle Surgery Volume 5, Issue 1, pages 15–20, March 1999
- Thomas MJ, Roddy E, Zhang W, et al. (2011). The population prevalence of foot and ankle pain in middle and old age: a systematic review. Pain. 152(12): 2870-2880.
- de Sèze MP1, Rezzouk J, de Sèze M, Uzel M, Lavignolle B, Durandeau A, Casoli V, Midy D. Anterior innervation of the proximal tibiofibular joint. Surg Radiol Anat. 2005 Mar;27(1):30-2. Epub 2004 Nov 19.
- Clendenen SR, Whalen JL. Saphenous nerve innervation of the medial ankle. Local and Regional Anesthesia. 2013;6:13-16. doi:10.2147/LRA.S42603.
- Rab M, Ebmer J, Dellon AL.Innervation of the sinus tarsi and implications for treating anterolateral ankle pain. Ann Plast Surg. 2001 Nov;47(5):500-4.
© 2016 Brent Brookbush
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