Tarsal Tunnel Syndrome/Posterior Tibial Nerve Entrapment

Ovid: 5-Minute Sports Medicine Consult, The

Tarsal Tunnel Syndrome/Posterior Tibial Nerve Entrapment
Stephen Simons
Bradley Sandella
  • A peripheral compression neuropathy that results in foot pain and paresthesias along the medial and plantar aspects of the foot and toes secondary to posterior tibial nerve entrapment in the tarsal tunnel (1)[C]
  • Synonym(s): Posterior tibial nerve entrapment
Unknown; rare compared with other peripheral mononeuropathies (upper extremity) (2)[C]
Risk Factors
  • Space-occupying lesions (eg, ganglion or lipoma)
  • Local trauma
  • Scar tissue
  • Abnormal foot/ankle mechanics (eg, excessive pronation)
  • Hindfoot deformities (eg, heel valgus or varus)
  • Repetitive activity
  • Weight gain
  • Lower extremity edema
  • Previous foot or ankle surgery
  • Accessory muscles (eg, accessory soleus)
  • Hypertrophic flexor retinaculum
  • Osteophytes/bone spurs
  • Varicose veins
  • Fat pad dysfunctions
  • Systemic diseases (eg, diabetes)
  • Tarsal tunnel is a fixed anatomic space bordered by the calcaneus and talus superiorly, inferiorly, and laterally and by the flexor retinaculum medially. The flexor retinaculum (or laciniate ligament) runs obliquely from posterior to anterior and forms the roof of the tunnel.
  • Structures passing through the tunnel include the tibialis posterior, flexor digitorum longus, and flexor hallucis longus tendons, as well as the posterior tibial artery, veins, and tibial nerve.
  • Tibial nerve branches at various locations through the tunnel, forming the medial and lateral plantar nerves, along with the medial calcaneal nerve. The medial and lateral plantar nerves then enter their own tunnels.
  • The medial plantar nerve runs deep to the abductor hallucis and flexor hallucis longus muscles.
  • The lateral plantar nerve passes directly through the abductor hallucis muscle.
  • Medial calcaneal nerve pierces through the flexor retinaculum to the medial side of the heel, providing sensory innervation to the posterior and medial heel.
  • Tarsal tunnel can be viewed as an upper tunnel or a lower tunnel, which are different clinical entities based on nerve branching locations.
  • Tarsal tunnel syndrome presents with a nonspecific, highly variable clinical picture.
  • History of trauma or repetitive activity (eg, running)
  • Numbness, tingling, and burning to the medial aspect and sole of the foot; can include calf symptoms and radiation to the toes
  • Foot cramping
  • Prolonged standing or walking often exacerbates the symptoms.
  • Habit of removing shoes to obtain relief
  • Patients lack morning pain and often lack heel pain.
  • Nocturnal pain may awaken the patient, especially after excessive activity.
  • Rest and lower extremity elevation are often helpful in relieving the symptoms.
Physical Exam
  • Numbness/tingling that progresses to a burning sensation at the plantar aspect of the foot; intermittent initially; can become constant
  • Plantar foot pain accentuated by walking and foot dorsiflexion
  • Nocturnal pain often relieved with walking
  • Pain worse at the end of the day
  • Occasional fusiform swelling over the nerve course
  • Motor weakness or loss as late finding: Poor prognostic indicator
  • Muscle fasciculations
  • Tenderness distal or proximal to area of entrapment (Valleix sign)
  • Inspect for biomechanical abnormalities such as excessive heel varus or valgus positioning.
  • Observe for swelling.
  • Observe for toe contractures, which can occur late.
  • Palpate for soft tissue thickening or lesions.
  • Light touch–induced paresthesias
  • Diminished 2-point discrimination often occurs early.
  • Diminished pinprick sensation to plantar foot
  • Intrinsic muscle weakness, although possibly present, is difficult to assess.
  • Atrophy of abductor hallucis or abductor digiti minimi as a late finding
  • Percussion sign (Tinel sign)
  • Cuff sign: Pain with pneumatic pressure device around leg
  • Dorsiflexion-eversion test: Pain elicitated when placing the foot in maximum dorsiflexion and eversion and then maximally dorsiflexing the metatarsophalangeal joints and holding this position for 5–10 s (sensitivity of 97%, specificity of 100%) (3)[A]
Diagnostic Tests & Interpretation
  • Plain x-ray and CT scan to rule out displaced fractures, accessory ossicles, coalition, and bony exostoses
  • Electrodiagnostic studies, if positive, may be helpful but frequently are insensitive and negative.
  • Electromyography (EMG) to evaluate for motor latencies
  • Nerve conduction studies (NCSs) evaluating for sensory action potentials may increase sensitivity (1)[C].
  • Diagnostic US (using a high-frequency machine and 10–15 MHz linear array transducer) can be used to evaluate for tendinopathies and space-occupying lesions (1)[C].
  • MRI is test of choice to evaluate tunnel contents. Bony and soft tissue structures can be viewed (eg, ganglion cysts, accessory or hypertrophied muscles, bone spurring).
  • Pressure-specified sensory device (PSSD) is a computer-assisted device for quantitative sensory testing of peripheral nerves that may allow for earlier recognition of syndrome (1)[C].
Differential Diagnosis
  • Plantar fasciitis
  • Calcaneal bursitis
  • Tendinitis/tenosynovitis [flexor hallucis longus (FHL), posterior tibialis tendon (PTT), flexor digitorum longus (FDL)]
  • S-1 radiculopathy
  • Peripheral vascular disease, including popliteal artery entrapment
  • Peripheral neuropathy
  • Systemic disease (eg, Reiter disease, rheumatoid arthritis, gout) (4)[C]
  • Bony abnormalities (eg, degenerative changes, previous fractures)


Ongoing Care
Follow-Up Recommendations
Surgical referral should be considered for patients recalcitrant to a high-quality nonoperative treatment program.
1. Franson J, Baravarian B. Tarsal tunnel syndrome: a compression neuropathy involving four distinct tunnels. Clin Podiatr Med Surg. 2006;23:597–609.
2. Kinoshita M, Okuda R, Yasuda T, et al. Tarsal tunnel syndrome in athletes. Am J Sports Med. 2006.
3. Dellon AL. The four medial ankle tunnels: a critical review of perceptions of tarsal tunnel syndrome and neuropathy. Neurosurg Clin N Am. 2008;19:629–648.
4. Diers DJ. Medial calcaneal nerve entrapment as a cause for chronic heel pain. Physiother Theory Pract. 2008;24:291–298.
5. Mullick T, Dellon AL. Results of decompression of four medial ankle tunnel in the treatment of tarsal tunnels syndrome. J Reconstr Microsurg. 2008.
Additional Reading
Bailie DS, Kelikian AS. Tarsal tunnel syndrome: diagnosis, surgical technique, and functional outcome. Foot Ankle Int. 1998;19:65–72.
Lau JT, Daniels TR. Tarsal tunnel syndrome: a review of the literature. Foot Ankle Int. 1999;20:201–209.
355.5 Tarsal tunnel syndrome

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