Applied anatomy of the compression of the proper plantar digital nerves of the medial great toe

Abstract

Objective To identify the routes and branches of the proper plantar digital nerves(PPDN) in the medial of the great toe and its adjoining relationship among the surrounding fascia tissues and organs, which was expected to provide accurate localization of the nerve impingement and possible relevant of anatomical basis for the treatment of nerve entrapment in clinical utility. Methods From December, 2016 to January, 2019, a total of 54 formalin fixed feet were collected. Fifty of them were performed conventional anatomical procedure, the other 4 were prepared with sectional anatomical technique. The seats and branches of the PPDN in the medial of the great toe were observed; The width and thickness of the nerve were measured at the first metatarpophalangeal joint(FMPJ), along with its proximal and distal sides 0.5 cm. The origin and origin of fascia were observed by foot dissection. Masson staining was used to observe the tissue changes of the nerves in the FMPJ. Results The PPDN of the medial great toe run between the flexor pollicis longus tendon and the abductor pollicis tendon at the proximal, issued (4.21±0.12) final branches. And governed the sensation of the medial half of the great toe. The width of the nerve at the FMPJ was (3.50±0.09) mm, which was significantly increased compared with that of the near [(1.58±0.04) mm] and far [(1.56±0.03) mm] from the joint. The difference was statistically significant (P<0.05); The thickness of the nerve in the proximal segment was (0.83±0.04) mm, and that in the distal segment was (0.82±0.03) mm. Compared with that in the FMPJ [(0.67±0.02) mm], the difference was statistically significant (P<0.05). A deep fascia was observed on the superficial surface of the PPDN at medial great toe, which was stretched between the tendon sheath of the flexor pollicis longus tendon and the tendon of the abductor pollicis muscle. Masson staining showed obvious proliferation of nerve outer membrane fibers at the metatarpophalangeal joint, the number of nerve fiber bundles increased, and obvious thickening of nerve fiber bundles and nerve fascia. Conclusion Long-term compression can lead to thickening of the epineurium and perineurium, and the superficial fascia is an important factor of thumb pain and numbness caused by the compression of the PPDN at medial of the great toe. Key words: Proper plantar digital nerves; Great toe; Nerve conformity; Foot; Applied anatomy