Limb Walking Research Articles

Functional analysis of untreated and reconstructed posterior cruciate ligament injuries.

Twenty patients with old ruptures of the PCL were analyzed. Ten patients were untreated, and ten patients had reconstruction of the PCL with the medial head of the gastrocnemius. The patients' gait was analyzed using high speed photography, footswitches, electromyography, and force plate. Patients were studied while walking, running, and stair-climbing. A Cybex muscle strength evaluation was also performed. Clinically, all patients had moderate to severe posterior instability. Five of the 20 patients also had posterolateral instability. Cybex testing showed quadriceps deficits in both reconstructed and untreated groups when comparing involved and uninvolved limbs. The reconstructed group also had deficits on hamstring Cybex testing. Footswitch data showed only minimal abnormalities. Gait velocity of walking was 91% of normal with a normal cadence. There was no significant difference in the single limb support times between the involved and uninvolved limbs in walking, fast walking, or running. The photometric data showed a tendency for increased knee flexion during the midstance phase of the gait cycle in comparing involved and uninvolved limbs. The knee flexion angles during midstance were similar in the patients with posterior instability when compared to the patients with the additional posterolateral instability. Force plate data showed decreased foot-floor reaction in the untreated group during terminal stance while walking. Similar findings were found in the reconstructed group during running.(ABSTRACT TRUNCATED AT 250 WORDS)

The Antagonism Between Somatic Growth and Ovarian Growth During Different Phases in Intermoult (Stage C4) in Sexually Mature Freshwater Crab,Paratelphusa hydrodromous

Summary In adult males of the freshwater crab Paratelphusa hydrodromous, judging from testicular activity, November-May is the reproductively inactive season and June/July through October the active season. The reproductively active period also represents the mating season of this species. In males over one year old, moulting is an annual event scheduled during June/July and the individual remains in intermoult from July/August to May. This intermoult comprises two phases: (1) the reproductive phase (July/August through October) when the physiological emphasis is more on reproduction and much less on somatic growth (as evidenced by the ability to regenerate autotomized walking limb), (2) the somatic phase (February/March through May) when the emphasis is more on somatic growth and much less on reproduction. Thus there exists an antagonism between reproduction and somatic grown in male P. hydrodromous as already established in the female. Experimental studies suggest that the testicular inactive phase of P...

Neuromuscular properties in serially homologous lobster limbs

AbstractThe lobster Homarus americanus has five pairs of serially homologous thoracic limbs, the most anterior being the paired chelae followed by four pairs of walking limbs (WLs). We have examined the opener and closer muscles of the WLs in terms of their fiber composition, axonal branching pattern, and synaptic properties. The opener muscle is similar in these serially homologous limbs being composed of all slow fibers. The closer muscle, however, differs in fiber composition amongst the limbs. In the small, nonchelate 3rd and 4th WL, it consists of only slow fibers, while in the much larger, chelate 1st and 2nd WL it has 40% fast and 60% slow fibers. In the chelae, which are bilaterally asymmetric, the closer muscle is known to consist of 70% fast and 30% slow fibers in the cutter chela and all slow fibers in the crusher chela. These differences in the closer muscle reflect differences in the function of the thoracic limbs. Differentiation in the serially homologous limbs occurs to a lesser extent in the pattern of axonal branching and excitatory innervation. Thus bifurcation of the motor axons into two primary branches each supplying one‐half of the bipinnate muscle is found in the anterior limbs but tends to disappear in the most posterior limb. Fast axon synapses are more prevalent in the closer muscle of the 1st WL than in the 4th WL. Such differences in distribution between 1st and 4th WLs are also found for the single excitor axon synapses to the opener muscle.

Functional demands on the stance limb in walking.

In normal human locomotion, the lower extremities must maintain the erect posture while at the same time permitting forward progression of the body. Walking involves a complex interplay of gravity, momentum changes, and muscle action. A quantitative analysis of the effects of gravity and momentum changes on the stance limb in normal gait has been performed. These effects, represented by the ground reaction force, impose challenges to the muscles of the lower extremity. The nature of the torques about the hip, knee, and ankle joints has been investigated and correlated with the timing of muscle action throughout the gait cycle. Mechanical events in the earliest part of stance phase have been more clearly described than in previous work. Analysis of the effects of gravity and momentum changes improves our understanding of the mechanics of normal walking, and can aid in the diagnosis and treatment of disabled patients.

Effects of Ethanol and Temperature On A Crab Motor Axon Action Potential: A Possible Mechanism for Peripheral Spike Generation

ABSTRACT In autotomized walking limbs of Pachygrapsus crassipes, microelectrode recordings of evoked action potentials were made in the meropodite from the E2 excitor axon to the bender muscle. The action potential spike was followed by a depolarizing after potential. Increases in temperature resulted in a decline in the amplitude and time course of the spike, and an increase in the amplitude of the after potential. Low levels of ethanol or increased levels of calcium increased the size of the after-potential and decreased the temperature threshold for peripheral spike generation. At high temperatures a single orthodromic E2 axon spike provoked the generation of additional impulses at the periphery, with an inter-spike interval of 2–3·5 ms. The after-potential lasted longer than the refractory period following the spike. The axon membrane, therefore, was depolarized after the refractory period and this resulted in a period of low threshold for spike generation. Increases in temperature shortened the refractory period. We suggest that additional spikes are generated at the periphery where the E2 axon diameter is decreased. The increased membrane resistance at these sites increases the size of the depolarizing after-potential. Therefore, if the depolarization following the refractory period is at or above threshold for firing, additional action potentials will be generated at the periphery.

The peripheral generation of action potentials in excitatory motor neurons of a crab.

The effects of temperature on the firing patterns of the excitatory motor supply to the bender muscle were examined in autotomized walking limbs of the crab Pachygrapsus crassipes. A brief electrical shock applied to the limb nerve evoked an action potential in one or both of the excitor axons and an excitatory junctional potential (ejp) in the bender muscle fibers. However, at high temperatures a single shock to one of the excitor axons (E2) resulted in a short train of nerve spikes and a concomitant burst of ejps. Extracellular recordings made from two sites along the E2 axon demonstrated that the additional action potentials are generated peripherally. Furthermore, myogram recordings from bender muscles in untethered animals indicate that peripheral generation of spikes does take place in intact crabs exposed to high temperatures. The peripheral generation of action potentials exhibited a critical temperature threshold which could be altered by acclimation and by low levels of ethanol in the saline bathing the autotomized limb preparation. This phenomenon may, therefore, be closely associated with membrane fluidity.

The effects of tryptamine on transmitter release at a lobster neuromuscular junction

Electrophysiological techniques were employed to characterize the effects of tryptamine at excitatory and inhibitory neuromuscular junctions of the stretcher muscle in the carpopodite of lobster walking limbs. Tryptamine was found to have a concentration dependent, biphasic effect on excitatory junction potential (EJP) amplitude. At concentrations of 0.01-0.5 mM tryptamine increased the amplitude of evoked EJPs, but at higher concentrations (greater than 0.5 mM) the amplitude was decreased by this amine. The high concentrations also decreased the amplitude of inhibitory junction potentials (IJPs) and reduced the frequency of miniature excitatory junction potentials (MEJPs). When a preparation in which the EJPs had been depressed by tryptamine was washed with the control, artificial sea water solution, the EJPs were increased to an amplitude greater than that of the pre-tryptamine control. Current-voltage relationship studies showed that tryptamine did not affect the effective resistance of the muscle fiber membrane. Tryptamine had no effect on the amplitude of excitatory responses evoked by the iontophoretic application of glutamate. Concentrations of tryptamine ranging to 10.0 mM affected neither the conduction velocity in meropodite or that of giant central nervous system (CNS) axons. We conclude that tryptamine affects synaptic transmission pre-synaptically by influencing the transmitter release process. Mass spectrometric analysis showed tryptamine to be an endogenous substance in the lobster; but the concentrations were low in the tissues analyzed. The highest concentration (approximately 0.3 nmol/g wet tissue) was in the subesophageal ganglion. Tryptamine was not detected in the meropodite nerves or carpopodite muscles.

The locomotion of the low spinal cat. II. Interlimb coordination.

The interaction of the two hindlimbs were investigated by an analysis of the muscular activity and the movements in 14 chronic spinal kittens during treadmill locomotion (i.e. in kittens subjected to a transection of the spinal cord (Th10--12)) one or two weeks after birth). At low speed the limbs were alternating (walk or trot). At higher they were activated more simultaneous, as during gallop. The two limbs could walk at different velocities, as during walking in a circle, when the two belts of the treadmill were driven at different speeds. The duration of the support phases was mainly influenced by the speed of the belt on which the limb was walking. The limbs could still maintain a common rhythm up to a two or three fold speed difference, as the flexion or the first extension phase of the limb walking on the "fast" belt was prolonged and the flexion phase of "slow limb" was shortened. At extreme speed differences the limb on the "fast belt" performed 2, 3 and even 4 steps during one stepcycle of the "slow limb". The placement of the feet was found to maintain the most stable relationship during alternating gaits at different speed differences. It is concluded that all phases of the step cycle are modifiable and that there are several mechanisms coordinating the limbs within the spinal cord.

The incidence of autotomy in an estuarine population of the crabCarcinus maenas

The incidence of autotomy is described for a discrete population ofCarcinus maenasin the Yealm Estuary over a period of one year. During this time the crabs showed seasonal trends in distribution whereby during the summer months they congregated at the top of the estuary. This seasonal migration up and down the estuary corresponded with peak rates in the rate of change in temperature of the bottom water. Recruitment occurred in June, July and August. Overall, there were more female than male crabs although the ratio varied throughout the year. All sizes and sexes of crabs autotomized limbs but although autotomy increased with the size of the crabs it showed no obvious relationship with other population parameters. Significantly more chelipeds than walking limbs were lost. There were more multiple autotomies than would be expected if autotomy was a random event. Autotomy is shown to be a rare event for sexually matureCarcinusbut essential to the survival of immature crabs. The means by which crabs may regulate the incidence of autotomy is discussed.

Intersegmental reflex coordination by a single joint receptor organ (CB) in rock lobster walking legs.

In the decapod Crustacea, Palinurus vulgaris and Fasus lalandii, the reflex influences of one particular proprioceptor organ, the coxo-basal chordotonal organ (CB), on all the muscles operating the proximal and distal joints of the same leg, have been analysed. The distal end of CB was clamped in fine forceps mounted on a servo-controlled stretcher, and CB length changes of 2 mm were applied. Motor unit activity of the different muscles was recorded as electromyograms (EMGs). 1. Two types of proprioceptive reflex evoked by CB length changes have been investigated: (a) resistance reflexes of the two levator and two depressor muscles of the same leg segment, the coxopodite, i.e. 'intrasegmental reflexes', (b) 'intersegmental reflexes' induced in the muscles operating the proximal (T-C) joint of the same leg, and in all eight muscles of the limb segments distat to CB. 2. Both levator muscles respond reflexly to imposed CB stretch (which normally occurs with limb 'depression'), while both depressors respond during CB shortening (or passive "elevation" of the leg). 3. Intersegmentally CB stretch reflexly activates the M-C extensor muscle, and sometimes facilitates the T-C remotor and C-P bender muscles. Shortening of the single CB organ of a leg excites one or two tonic motor units of the T-C promotor and M-C flexor muscles, and also facilitates the remotor, I-M reductor, and the single stretcher-opener excitatory motoneurone. 4. Some of the muscles, particularly the M-C flexor and extensor muscles, are also influenced intersegmentally by the resting length of CB, usually but not invariably in the same direction as for the corresponding dynamic reflexes. The role of the CB chordotonal organ is discussed, with particular consideration of its intersegmental reflex influence on the posture of the entire leg, and on the more complex motor behaviour of locomotion, where it may be specially significant in coordination of the limb in lateral walking. A complex picture of both tonic and dynamic, inra- and intersegmental reflex regulation of the positions and movements of the limb segments, thus emerges.

The incidence of autotomy in Carcinus maenas (L.)

A total of 1023 individuals of the common shore crab, Carcinus maenas (L.), were obtained from the environs of Whitby Harbour and Robin Hood's Bay. The bulk of the sample was taken from the sublittoral zone, but crabs from a sheltered shore were included. Each crab was measured, sexed and examined for the incidence of autotomized and regenerated limbs. There was a positive correlation between the incidence of autotomy and carapace width for crabs in both the sublittoral zone and the exposed intertidal zone. In sublittoral crabs the males suffered a higher incidence of autotomy than did the females and the incidence of cheliped autotomy was higher than for the walking limbs. The discrepancy between the loss of the chelipeds and walking limbs was reflected in a similar disparity between the occurrence of the regenerated chelipeds and walking limbs. Crabs on an exposed shore suffered a higher incidence of autotomy than did those from a sheltered shore. There were more crabs with cumulative limb losses than would be expected which suggests that once a crab enters into a state of autotomy it becomes increasingly vulnerable to the loss of another limb. Only 1 % of the population of sublittoral crabs would be expected to carry the loss of five limbs at once. No crabs were found with six or more limbs missing.

Autotomy inCarcinus maenas: The role of the basi-ischiopodite posterior levator muscles

1. The anatomy of the muscles attaching to the dorsal rim of the basi-ischiopodite and the associated cuticular structures ofCarcinus maenas, Maia squinado andPagurus bernhardus was examined. 2. There are four such muscles in brachyuran walking limbs (Figs. 1A and 5B) each of which has a specific function as outlined in Table 1. There is a further subdivision of muscle function in the cheliped (Fig. 1B). 3. Myograms obtained from the posterior levator muscles (PPLM and RPLM) of the walking limbs reveal that in brachyura the muscles are physiologically distinguishable both during limb levation and autotomy (Fig. 2). 4. The antagonistic action of these muscles upon autotomy enables the anterior levator muscle force to be rapidly switched from a cuticular projection onto the cuticular plug which forms the link across the limb breakage plane (Figs. 4 and 7). 5. The reflex control of autotomy by the cuticular stress detector (CSD1) was analyzed.

Agonistic and antagonistic activity of glutamate analogs on neuromuscular excitation in the walking limbs of lobsters.

Forty-six analogs of L-glutamate were tested for activity on muscle fibers in the walking limbs of lobsters. Effects on the membrane potential, input resistance, and amplitude of neurally evoked EPSPs and IPSPs were studied as well as effects on applied L-glutamate. Seventeen of the compounds studied depolarized the muscle fibers in a manner indicative of an agonistic action on receptors in the neuromuscular excitatory membrane. Six analogs selectively reduced the amplitude of evoked EPSPs, and at least three of these (kainic acid, D-glutamate, and D-aspartate) antagonized the excitatory action of applied L-glutamate. Kainic acid was the most potent of the blockers of neuromuscular excitation, but even it was relatively weak since a concentration of 1 mM was required for an apparent effect. Generally those analogs in the L-configuration which possessed activity, had agonistic actions, whereas those in the D-configuration were usually antagonistic. These observations provide pharmacological evidence for the concept that L-glutamate is the transmitter agent which mediates neuromuscular excitation in the walking limbs of lobsters. In addition, our results are consistent with recent studies which indicate that L-aspartate may also function in this neuromuscular excitatory process.

La 3+ blockade of glutamate action at the lobster neuromuscular junction

1. The effect of L-glutamate, when added to the medium bathing the lobster walking limb preparation, resembles that of an endogenous excitatory neurotransmitter. 2. The action of L-glutamate is blocked by application of 20 mM LaCl 3.6H 2O to the bathing medium. 3. At 3°C, miniature end plate potential frequency increases and remains high during the time period that glutamate blockade is observed. 4. La 3+, by itself, dramatically increases the frequency of miniature end plate potentials and then blocks release of endogenous neurotransmitters after a varying time period.

Levels of free amino acids in excitatory, inhibitory and sensory axons of the walking limbs of the lobster

Using a gas chromatography procedure, the levels of several amino acids were determined in individual excitatory and inhibitory axons, in bundles of sensory fibers, and in muscle tissue from the walking limb of the lobster, Homarus americanus . In addition, the levels of amino acids in the hemolymph were also determined. Of the amino acids assayed in the excitatory and inhibitory axons and in the sensory fibers the level of aspartate was highest whereas in hemolymph and muscle, aspartate had one of the lowest values. The levels of glutamate, glycine and proline were significantly higher in the excitatory axons than in the inhibitory axons. GABA was present in inhibitor axons and in the muscle tissue which these axons innervate and was not detected in the other axons assayed nor in the hemolymph. β-Alanine was present at low levels in hemolymph and in muscle but was not detected in the excitatory nor in the inhibitory axons.

Pre-immersion salinity-choice behaviour in Porcellana platycheles

The ability of the littoral porcelain crab Porcellana platycheles (Pennant) to recognise and avoid low-salinity levels when immersed in media has already been demonstrated in previous experiments. It was thought that the ability to identify and avoid diluted sea water before complete immersion would also be of survival value, since this would prevent exposure of the permeable body surfaces (especially the gills) to the swelling effects of the osmotic uptake of water. The experiments reported here demonstrate that such pre-immersion salinity choice behaviour may be elicited from P. platycheles in the laboratory, and that salinity reception is apparently sited upon the walking limbs. Choice between salinity levels is shown to be based on the osmotic concentration of media rather than on the concentration of a particular ion or group of ions.

Studies of Shelf Operation

The results of 50 shelf operations to 45 patients were followed up. The average of their age was 10 years and 1 month, and the average period of observation was 6 years and 4 months.The method of shelf operation was mostly followed after Jinnaka's method.Functional capacity of the hips and X-ray findings were evaluated in each case. The majority of the cases showed good functional hips without limb or pain in walking. Younger the age at surgery revealed better results. the oldest case who was 48 years old at the time of surgery showed poor functional result.Improvement of CE angle and Acetabular angle were detected, however as far as concerning X-ray findings, generally the result of surgery was poor.As a whole, 80% of the cases showed functional improvement more or less, and 6% showed bad result.

Patterns of Sagittal Rotation of the Upper Limbs in Walking

Patterns of Sagittal Rotation of the Upper Limbs in Walking

A Study on the Movement Pattern of Four Limbs in Walking [1

1. The author using 8mm cinecamera (48 or 64 frames per second) observed the movement sequence of four limbs of many mammals while they were walk-ing on all fours. In the slow motion picture, protraction or retraction of each limb was confirmed and the movement sequence of all four limbs was combined. The walking type of many mammals commonly seen in the zoo was "backward cross type" as shown in Fig. 1, but many monkeys showed completely different walking type, "forward cross type", as shown in Fig. 2. These figures show that each limb moves one after another according to the arrows (cf. IWAMOTO & TOMITA 1966).Some examples of walking monkeys are given in Fig. 3-Fig. 6. Names of monkeys which were observed walking with "forward cross type" are shown in Table 1.The prevalence of "forward cross type" in the primates and the "backward cross type" in other mammals is thought to be worthy of notice.2. Movements of four limbs in walking were expressed as the combination of reciprocal movements of right and left fore limbs and that of right and left hind limbs, as shown in Fig. 11-Fig. 12 or Fig. 13-Fig. 15. (cf. Fig. 7, 8, 9). The body support fashion by the limbs while walking with either of the two types was illustrated in Fig. 16 and Fig. 17, 18 (cf. Fig. 10), and the stability of animal body was discussed. In these figures it is obvious that "forward cross type" is rather unstable compared with "backward cross type ". Monkeys may compen-sate the instability in walking with highly developed postural regulation mechanism.3. In walk, ipsilateral fore limb and the contralateral hind limb have the tend-ency of moving together ; and when these two limbs are in retraction phase, either of the protracting two limbs (other fore limb and the contralateral hind limb) must be placed on the ground earlier not to lose the equilibrium of the body if the center of gravity is situated before or behind the line connected between two supporting feet of the limbs. If the center of gravity is before the line, the protracted fore limb must be placed on the ground first ; thereafter "backward cross type" begins. If the center of gravity is behind that line, the protracted hind limb must be placed on the ground first not to tilt the body backwards, then thereafter "forward cross type" occurs.In many non-primate mammals, the body weight falls more heavily on the fore limbs than on the hind limbs (cf. Fig. 19, also IWAMOTO & TOMITA 1966), but in monkeys the body weight falls more heavily on the hind limbs than on the fore limbs (cf. Fig. 20, also IWAMOTO & TOMITA 1966). The difference of the body weight distribution to fore and hind limbs between monkeys and other mammals may be related to the two walking types.4. The author also made dogs to walk with heavy load on the hip. In most cases the animal walked with "backward cross type ", but a few cases of "for-ward cross type" occurred. The author made some discussion on this result. An example of such "forward cross type" walk is shown in Fig. 22.

A Study on the Movement Pattern of Four Limbs in Walking

A Study on the Movement Pattern of Four Limbs in Walking