Lateral Head Of Gastrocnemius Muscle Research Articles

正常歩行中の下肢筋活動様式に関する筋電図学的研究

Objectives of this paper were to elucidate essential electrical discharge patterns of lower limb muscles and their variabilities during a normal gait cycle.Subjects employed in the experiments were 217 healthy adults of both sexes, ranging in age from 18 to 22 years, and they had no disorder in the lower limb or the central nervous system in their medical history. Electromyograms (EMGs) were recorded from the Tibialis anterior (Ta), the Gastrocnemius lateral head (Gl), the Vastus medialis (Vm), the Gluteus maximus (Gm), the Rectus femoris (Rf), the Medial Hastrings (MH), and the Biceps femoris (Bf) by conventional method using surface electrodes. Angular changes of the ankle, knee and hip joints and time signals at the heel and the toe contacts with the ground were simultaneously recorded with the EMGs.The essential EMG pattern s of the lower limb muscles during a normal gait cycle were conclusively summarized: 1) The ankle joint muscles; i) The marked discharge of the Ta was observed in the period from the end of the swing phase to the early part of the stance phase, and in the period from the end of the stance phase to the early part of the swing phase. ii) The Gl showed the main discharge in the latter half of the stance phase, and showed almost complete electrical silence in the former half of the swing phase.2) The knee and hip joint muscles; i) The discharge of the Vm started at the latter half of the swing phase and increased abruptly just before or after the heel contact. The marked discharge of the Vm lasted into the first double leg support period. ii) The discharge of the Gm started at the latter half of the swing phase and increased just before or after the heel contact. The Gm showed the continuous discharge during the former half of the stance phase. iii) The main discharge of th Rf was similar to that of the Vm, and the Rf did not show distinguished activity in the former half of the swing phase. iv) The MH and the Bf showed the marked discharges from the the latter half of the swing phase to just before or after the heel contact, but little or no discharge in the former half of the swing phase.In addition to the essential EMG pattern s, the variations in the EMG patterns which were found to be within ranges of the normal activities were as follows: 1) The ankle joint muscles ; i) The distinguished discharge of the Ta at about the mid-swing phase appeared in about 85% of the subjects. ii) The discharge variation of the G1 was hardly observed during the gait cycle.2) The knee and hip joint muscles; i) The discharge of the Vm was seen around the mid-stance phase and in the second double leg support period in about 20% of the subjects. ii)The discharge variations of the Gm were similar to those of the Vm. iii) The discharge of the Rf appeared around the mid-stance phase in less than 20% of the subjects and at the end of the stance phase in about 80%. iv) In about 60% of the subjects the marked discharges of the MH and the Bf in the latter half of the swing phase decreased or disappeared abruptly around the heel contact; however, in the other 40%, the discharges continued until the midstance phase. The discharges of the MH and the Bf at the end of the stance phase were observed in less than 20% of the subjects.The marked discharges of the MH and the Bf decreased or disappeared abruptly at the moment when the Rf abruptly increased its electrical activity around the heel contact, and the spike sessation lasted until the moment when the Rf decreased its activity. It was suggested that the spike inhibition in the MH and the Bf might be due to an antagonistic inhibition caused by facilitation of the Rf.

Peroneal Nerve Palsy caused by Compression of the Fabella A case report

Because the peroneal nerve is present just beneath the skin especially near the lateral aspect of the knee joint, it is very susceptible to injury.Authors presented a case of peroneal nerve palsy maybe caused by compression of the fabella and reviewed the literatures reported untill last year.Case report:53 years old engeneer admitted in February 1975 with a diagnosis of lumbar disc lesion. He had complained of pain and numbness on the lateral aspect of the right leg and the dorsum of the foot. Since the symptomes increased from the full extension of his knee, he was forced to keep his knee flexed at 15-20 degrees.On the physical examination, (1) hypesthesia on the lateral aspect of the right leg and the dorsum of the foot, (2) weakness of extensor hallucis longus muscle, and (3) Tinel's sign over the peroneal nerve at the level of the lateral head of gastrocnemius were demonstrated. Plne X-p., laboratory data, lumbar myelogram and electromyogram were almost normal. On February 25, 1974, surgical exploration of the peroneal nerve was performed. It was compressed and stretched by the osseous mass (fabella) through the gastrocnemius in the full extension of the knee, but by the flexion its tension was decreased. The shape and size of removed fabella was normal and its articular surface was yellow and fibrillated.On next day of operation no pain was noted. Muscle weakness and hypesthesia disappeared within 3 weeks and 8 weeks after the operation.Untill last year 10 cases in Japan and only one case in U. S. A. had be reported. These cases reviewed with the authors case.

THE PHYLOGENY OF THE CRURAL AND PEDAL FLEXOR MUSCULATURE

A study has been made of the long cruro‐pedal flexor muscles in a number of species of Australian marsupials, which exhibit foot specializations closely paralleling those seen among the Eutheria. The phylogeny of this muscle group within the Metatheria is clearly apparent and elucidates the probable history of parallel eutherian specializations. It is suggested that M. flexor perforatus is, in its most primitive form, a crural muscle which has descended to the foot in a number of mammalian species, often becoming incorporated with the plantar aponeurosis as a fibrous or fleshy deep stratum. M. soleus has been derived by a splitting off of part of the substance of the lateral head of gastrocnemius. The large M. flexor fibularis was, apparently, the primary deep flexor of all the digits, and the smaller M. flexor tibialis waa probably at first partly attached to the plantar aponeurosis and medial cuneiform bone and partly to the M. flexor fibularis tendon. Loss of the latter attachment has produced the common marsupial arrangement, and loss of the former has produced the typical eutherian condition with fusion of the flexor tibialis and flexor fibularis tendons in the sole. A variable shredding of this common tendon has produced the different primate arrangements.