Poor response to injection of botulinum toxin (BoNT) into the flexor digitorum longus (FDL) muscle has been reported especially in patients with claw foot deformity. We previously advocated BoNT injection into the flexor hallucis longus (FHL) muscle in such patients. Here, we determined the functional and anatomical relationships between FHL and FDL.

Toe flexion pattern was observed during electrical stimulation of FHL and FDL muscles in 31 post-stroke patients with claw-foot deformity treated with BoNT. The FHL and FDL tendon arrangement was also studied in five limbs of three cadavers.

Electrical stimulation of the FHL muscle elicited big toe flexion in all 28 cases examined and second toe in 25, but the response was limited to the big toe in 3. FDL muscle stimulation in 29 patients elicited weak big toe flexion in 1 and flexion of four toes (2nd to 5th) in 16 patients. Cadaver studies showed division of the FHL tendon with branches fusing with the FDL tendon in all five limbs examined; none of the tendons was inserted only in the first toe. No branches of the FDL tendon merged with the FHL tendon.

Our results showed coupling of FHL and FDL tendons in most subjects. Movements of the second and third toes are controlled by both the FDL and FHL muscles. The findings highlight the need for BoNT injection in both the FDL and FHL muscles for the treatment of claw-toe deformity.

Abnormalities in neurotransmission via N-methyl-d-aspartic acid receptor (NMDAR) play a role in the pathophysiology of neuropsychiatric disorders. The impact of repetitive transcranial magnetic stimulation (rTMS) on NMDAR-related amino acids remains unknown. We aim to investigate the effects of rTMS on NMDAR-related amino acids in serum of post-stroke patients.

Ninety-five consecutive post-stroke patients with upper limb hemiparesis were recruited. In 27 patients, the Beck Depression Inventory (BDI) score was 10 or higher. Twelve depressed patients underwent rehabilitation in combination with rTMS and 15 non-depressed patients underwent rehabilitation only without rTMS for 14 days. 1 Hz rTMS was applied to the primary motor area in the non-lesional hemisphere. BDI was conducted before and after treatment. Serum glutamine, glutamate, glycine, l-serine, and d-serine levels were measured before and after treatment.

There were no differences between depressed patients and non-depressed patients in clinical characteristics, levels of the five amino acids in serum, and the ratio of amino acids. However, in 27 depressed patients, there was a significant correlation between levels of glutamate in serum and BDI (ρ = 0.428, p = 0.026). BDI decreased significantly in depressed patients after treatment with or without rTMS. d-serine decreased in the rehabilitation with rTMS group, but increased in the rehabilitation without rTMS group. l-serine increased in the rehabilitation with rTMS group, but decreased in the rehabilitation without rTMS group.

The results suggest that rTMS can modulate NMDAR-related amino acids in blood, producing beneficial effects.