Anatomical Localization of Motor Points of the Abductor Hallucis Muscle: A Cadaveric Study

OBJECTIVE: To identify the anatomical motor points of the abductor hallucis muscle in cadavers. METHODS: Motor nerve branches to the abductor hallucis muscles were examined in eight Korean cadaver feet. The motor point was defined as the site where the intramuscular nerve penetrates the muscle belly. The reference line connects the metatarsal base of the hallux (H) to the medial tubercle of the calcaneus (C). The x coordinate was the horizontal distance from the motor point to the point where the perpendicular line from the navicular tuberosity crossed the reference line. The y coordinate was the perpendicular distance from the motor point to the navicular tuberosity. RESULTS: Most of the medial plantar nerves to the abductor hallucis muscles divide into multiple branches before entering the muscles. One, two, and three motor branches were observed in 37.5%, 37.5%, and 25% of the feet, respectively. The ratios of the main motor point from the H with respect to the H-C line were: main motor point, 68.79%±5.69%; second motor point, 73.45%±3.25%. The mean x coordinate value from the main motor point was 0.65±0.49 cm. The mean value of the y coordinate was 1.43±0.35 cm. All of the motor points of the abductor hallucis were consistently found inferior and posterior to the navicular tuberosity. CONCLUSION: This study identified accurate locations of anatomical motor points of the abductor hallucis muscle by means of cadaveric dissection, which can be helpful for electrophysiological studies in order to correctly diagnose the various neuropathies associated with tibial nerve components.

Multiple Lower Extremity Mononeuropathies by Segmental Schwannomatosis: A Case Report

Schwannoma is an encapsulated nerve sheath tumor that is distinct from neurofibromatosis. It is defined as the occurrence of multiple schwannomas without any bilateral vestibular schwannomas. A 46-year-old man with multiple schwannomas involving peripheral nerves of the ipsilateral lower extremity presented with neurologic symptoms. Electrodiagnostic studies revealed multiple mononeuropathies involving the left sciatic, common peroneal, tibial, femoral and superior gluteal nerves. Histologic findings confirmed the diagnosis of schwannoma. We reported this rare case of segmental schwannomatosis that presented with neurologic symptoms including motor weakness, which was confirmed as multiple mononeuropathies by electrodiagnostic studies.

Correlation of Foot Posture Index With Plantar Pressure and Radiographic Measurements in Pediatric Flatfoot

OBJECTIVE: To investigate the correlation between the Foot Posture Index (FPI) (including talar head palpation, curvature at the lateral malleoli, inversion/eversion of the calcaneus, talonavicular bulging, congruence of the medical longitudinal arch, and abduction/adduction of the forefoot on the rare foot), plantar pressure distribution, and pediatric flatfoot radiographic findings. METHODS: Nineteen children with flatfoot (age, 9.32+/-2.67 years) were included as the study group. Eight segments of plantar pressure were measured with the GaitView platform pressure pad and the FPI was measured in children. The four angles were measured on foot radiographs. We analyzed the correlation between the FPI, plantar pressure characteristics, and the radiographic angles in children with flatfoot. RESULTS: The ratio of hallux segment pressure and the second through fifth toe segment pressure was correlated with the FPI (r=0.385, p=0.017). The FPI was correlated with the lateral talo-first metatarsal angle (r=0.422, p=0.008) and calcaneal pitch (r=-0.411, p=0.01). CONCLUSION: Our results show a correlation between the FPI and plantar pressure. The FPI and pediatric flatfoot radiography are useful tools to evaluate pediatric flatfoot.