Potential sites of compression of tibial nerve branches in foot: A cadaveric and imaging study

Abstract

Hypertrophy of abductor hallucis muscle is one of the reported causes of compression of tibial nerve branches in foot, resulting in tarsal tunnel syndrome. In this study, we dissected the foot (including the sole) of 120 lower limbs in 60 human cadavers (45 males and 15 females), aged between 45 and 70 years to analyze the possible impact of abductor hallucis muscle in compression neuropathy of tibial nerve branches. We identified five areas in foot, where tibial nerve branches could be compressed by abductor hallucis. Our findings regarding three of these areas were substantiated by clinical evidence from ultrasonography of ankle and sole region, conducted in the affected foot of 120 patients (82 males and 38 females), aged between 42 and 75 years, who were referred for evaluation of pain and/or swelling in medial side of ankle joint with or without associated heel and/or sole pain. We also assessed whether estimation of parameters for the muscle size could identify patients at risk of having nerve compression due to abductor hallucis muscle hypertrophy. The interclass correlation coefficient for dorso-planter thickness of abductor hallucis muscle was 0.84 (95% CI, 0.63-0.92) and that of medio-lateral width was 0.78 (95% CI, 0.62-0.88) in the imaging study, suggesting both are reliable parameters of the muscle size. Receiver operating characteristic curve analysis showed, if ultrasonographic estimation of dorso-plantar thickness is >12.8 mm and medio-lateral width > 30.66 mm in patients with symptoms of nerve compression in foot, abductor hallucis muscle hypertrophy associated compression neuropathy may be suspected.

Role of ultrasound in posteromedial tarsal tunnel syndrome: 81 cases

“…11), which was confirmed by comparison with the contralateral foot. This condition is already reported in the literature [17].…”

“…Tarsal tunnel syndrome may be caused by idiopathic conditions or for traumatic reasons (bone diseases, injuries to the ligament, thickening of the flexor retinaculum, hematoma, fibrosis, and iatrogenic damage to the nerves), tendon disorders (tendinopathy and flexor tenosynovitis), supernumerary muscles (accessory soleus muscle, medial fibulocalcaneal muscle, and particularly accessory flexor digitorum muscle [16]) or muscle hypertrophy (abductor hallucis muscle [17] or flexor hallucis muscle of the toes). The syndrome may be caused also by bone disorders (talocrural and subastragalar arthritis and arthropathy with talocalcaneal synovitis and synostosis [10], sustentaculum tali [11], sequelae of fracture, change in static foot posture), expansive lesions (ganglion cysts, particularly epineural ganglions [12], soft tissue tumors including intracanal lipomas and tumors of the nerves), vascular disorders (kinking of the tibial artery, venous aneurysms, and varicose plantar veins particularly in the distal tarsal tunnel, which is commonly reported in the literature) [2,8,13,14].…”

An Anatomical Basis for the Myofascial Trigger Points of the Abductor Hallucis Muscle

“…Several studies have examined the pathway of the medial plantar nerve but only up to the margin of the abductor hallucis muscle [35,36].…”

Arterial Anatomy of the Posterior Tibial Nerve in the Tarsal Tunnel

“…The branching patterns of the nerve have been described, with the most common site of branching in proximity to the leading edge of the abductor hallucis fascia [4][5][6] . The fascia of the abductor hallucis has been considered as a site of compression in the clinical presentation of tarsal tunnel syndrome 7 . Frequently, venous comitantes and multiple branching veins are noted at the leading edge of the abductor hallucis fascia.…”