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.

Prolonged Motor Weakness With Syringomyelia in Japanese Encephalitis: A Case Study

Japanese encephalitis (JE) shows characteristic brain lesions, including bilateral thalamus, midbrain, internal capsule, basal ganglia, and occasionally involves an anterior horn cell. We encountered a case of a 44-year-old man who initially presented with encephalitis, which was finally diagnosed as Japanese encephalomyelitis with syringomyelia. The patient showed severe motor weakness followed by delayed recovery of functional motor activities. Cervical magnetic resonance imaging showed syrinx formation at the C5 level suggesting myelitis, and abnormal electromyographic findings were noted. Clinicians should consider the possibility that the spinal cord may be involved; an example would be syringomyelia due to myelitis in a case of JE presenting with severe and prolonged motor weakness.

Effect of Botulinum Toxin A on Trismus after Pons Infarction: A case report

We report a 77-year-old woman with bilateral pons infarction who presented with severe trismus, which was responsive to botulinum toxin-A injection. She was unable to open her mouth and showed anterior displacement of her temporo-mandibular (TM) joint on MRI findings. She was fed via nasogastric tube because of mouth opening limitation. There was no improvement of her mouth opening after range of motion exercise. She underwent closed reduction of the TM joints under general anesthesia but there was no significant improvement. Electromyography studies revealed continuous muscle activities on masseter and temporalis muscles during mouth opening. Botulinum toxin-A (Botox(R)) was injected into both the masseter and left temporalis muscles under ultrasonographic guidance. There was some improvement in mouth opening at post-injection 5 days. The inter-incisal distance improved gradually, and she could start oral feeding after 18 days. She could maintain an inter-incisal distance of 1.8 cm with favorable response during post-injection 4 months.

Saphenous Mononeuropathy after Repetitive Compression on the Knee in a Ballerina: A Case Report

Saphenous mononeuropathy is an uncommon neuropathy in clinical condition, which may incur from various surgical procedures, direct trauma, or entrapment, and most frequently involves at the adductor canal, or Hunter's canal. A 17-year old female, who was majoring in ballet, visited our rehabilitation clinic for numbness in the medial aspect of the left lower leg for the previous 9 months, without weakness. The electrodiagnostic study revealed only a delayed small potential in the left saphenous nerve. MRI examination showed soft tissue swelling in the medial side of the left knee. Accordingly, we diagnosed the patient with saphenous mononeuropathy around the knee, without lumbar plexopathy or femoral neuropathy. We report a case of saphenous mononeuropathy which developed after repetitive compression on the medial side of the knee without any other iatrogenic injury, and include a review of the relevant literature.