Small Leg Research Articles

Neuronal coordination of arm and leg movements during human locomotion.

We aimed to study the neuronal coordination of lower and upper limb muscles. We therefore evaluated the effect of small leg displacements during gait on leg and arm muscle electromyographic (EMG) activity in walking humans. During walking on a split-belt treadmill (velocity 3.5 km/h), short accelerations or decelerations were randomly applied to the right belt during the mid or end stance phase. Alternatively, trains of electrical stimuli were delivered to the right distal tibial nerve. The EMG activity of the tibialis anterior (TA), gastrocnemius medialis (GM), deltoideus (Delt), triceps (Tric) and biceps brachii (Bic) of both sides was analysed. For comparison, impulses were also applied during standing and sitting. The displacements were followed by specific patterns of right leg and bilateral arm muscle EMG responses. Most arm muscle responses appeared with a short latency (65-80 ms) and were larger in Delt and Tric than in Bic. They were strongest when deceleration impulses were released during mid stance, associated with a right compensatory TA response. A similar response pattern in arm muscles was obtained following tibial nerve stimulation. The arm muscle responses were small or absent when stimuli were applied during standing or sitting. The arm muscle responses correlated more closely with the compensatory TA than with the compensatory GM responses. The amplitude of the responses in most arm muscles correlated closely with the background EMG activity of the respective arm muscle. The observations suggest the existence of a task-dependent, flexible neuronal coupling between lower and upper limb muscles. The stronger impact of leg flexors in this interlimb coordination indicates that the neuronal control of leg flexor and extensor muscles is differentially interconnected during locomotion. The results are compatible with the assumption that the proximal arm muscle responses are associated with the swinging of the arms during gait, as a residual function of quadrupedal locomotion.

Nutritional Condition and Muscular Features of Wintering Long-Billed Murrelets in Japan

Abstract We analyzed the nutritional condition and morphological characteristics of wintering Long-billed Murrelets (Brachyramphus perdix) in Japan. These birds were well nourished with an average body mass of 293 g, composed of a mean total body fat of 40.7 g (14%). The fat deposit was equivalent to an average energy reserve of 2.5 days at the estimated energy consumption of 615 kJ day−1 or 2.1 kJ g−1 day−1. Muscle mass consisted mainly of water (73%) and fat-free dry matter (26%), with small amounts of fat. Uropygial glands consisted of 33% fat and 17% fat-free dry matter, with 48% water. Long-billed Murrelets were characterized by large pectoral (26% of fat-free body mass) and small leg muscles (2% of fat-free body mass). We believe that these muscular traits, which contrast with those of alcids breeding at coastal colonies, reflect specific adaptations to inland nesting and long-distance foraging. Condicion Nutricional y Caracteristicas Musculares durante el Periodo de Invernada de Brachyramphus perdi...

The role of lasers in the treatment of leg veins.

New developments in laser technology have enabled improved therapy of small and large leg telangiectasia. While sclerotherapy remains the gold standard of treatment, laser therapy should be considered a first line approach for isolated, superficial, fine-caliber, nonarborizing telangiectasia and postsclerotherapy telangiectatic matting. Laser therapy is an excellent option for patients who are fearful of needles or have demonstrated a poor response to sclerotherapy injections. Recent studies have demonstrated good clearance of leg telangiectasia and reticular veins using a variety of laser systems with deeper penetrating, near-infrared wavelengths and higher fluences in conjunction with various epidermal cooling methods. As with sclerotherapy, optimal results are achieved with lasers when larger feeding vessels are treated first using appropriate modalities.

Baby Walkers Delay Motor and Mental Development

Developmental and Behavioral Pediatrics| January 01 2000 Baby Walkers Delay Motor and Mental Development AAP Grand Rounds (2000) 3 (1): 1–2. https://doi.org/10.1542/gr.3-1-1 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Baby Walkers Delay Motor and Mental Development. AAP Grand Rounds January 2000; 3 (1): 1–2. https://doi.org/10.1542/gr.3-1-1 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search nav search search input Search input auto suggest search filter All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: infant walkers, psychological development, walkers Source: Siegel AC, Burton RV. Effects of baby walkers on motor and mental development in human infants. J Dev Behav Pediatr. 1999;20:355–361. Many parents use baby walkers to provide mobility and exercise for their young, pre-ambulatory infants. Manufacturers now equip most walker devices with a wide opaque plastic tray and relatively small leg openings to decrease the likelihood of tipping accidents or suffocation from the infant’s head being wedged in the seat. This design prevents the infant from seeing his or her moving legs. Developmental studies suggest that visual feedback about body position and limb movement is necessary for the timely acquisition of motor milestones.1,2 Therefore, pre-ambulatory walker experience may be conceptualized in terms of early deprivation reminiscent of that created in a classic series of animal experiments on the critical role of visual feedback in developing motor systems. Siegel and Burton analyzed motor and mental development in 109 infants (of those, 102 were white, 4 were Asian, 1 was African American) with and without walker experience between the ages of 6 and 15 months: 34 were 6 months old, 35 were 9 months old, and 40 were 12 months old at initial testing. Fifty-six infants had experience using walkers (Walkers); 53 infants had no walker experience (No-Walkers). The Walker group was further divided into 2 groups: 34 using “Occluding Walkers” with large opaque trays and small leg openings, and 19 infants who used outdated “See-Feet Walkers” that allowed infants to see their legs, thus permitting a form of visual-motor enrichment. A cross-sectional/short-term longitudinal design was used. The cross-sectional component permitted analyses to determine whether infants were more or less sensitive to walker exposure across different ages. The Bayley scales of infant development were administered to all infants at baseline and after 3 months. Parents were instructed to record the exact dates of sitting, crawling and walking on a motor-milestone checklist. Walker-experienced infants sat (P < .000), crawled (P = .03), and walked (P = .02) later than No-Walker controls, and they scored lower on the Bayley scales of mental and motor development. The group using Occluding Walkers that prevented visual feedback of limb position had lower Bayley scores of mental (P < .003) and motor (P < .000) development than did the See-Feet Walker or No-Walker groups. However, contrary to the visual-motor hypothesis, early exposure to the See-Feet walkers did not facilitate motor development when compared to the No-Walkers. The results also suggested that restriction in a walker may exert its greatest negative influence on mental development in the 6- to 9-month age period. The effect of walker use on mental development is not short-lived, as frequent initial use continued to predict comparatively lower mental scores in some infants for as long as 10 months after initial use (P < .001). Given the adverse consequences of walker use with respect to development and the increased risk of injury posed by them, the authors conclude that the... You do not currently have access to this content.

Successful treatment of spider leg veins with a high-energy, long-pulse, frequency-doubled neodymium:YAG laser (HELP-G)

While sclerotherapy has been the standard treatment for spider leg veins for many years, recent advances have allowed lasers to be considered as a treatment option. To study the efficacy of a frequency-doubled Nd:YAG laser at 532 nm with a 50 ms pulse width and chill tip device in the treatment of spider leg veins. Forty-six patients with spider leg veins with a diameter of less than 1 mm or 1-2 mm were treated with a frequency-doubled Nd:YAG laser at 532 nm with a pulse width of 50 ms (VersaPulse HELP-G laser) while using a water-cooled chill tip device. Of patients with veins less than 1 mm in diameter, 60% had greater than 50% clearing after one treatment and 80% had greater than 50% clearing after two treatments. Of patients with veins 1-2 mm in diameter, 39% achieved greater than 50% clearing after one treatment and 67% had greater than 50% clearing after two sessions. Our results suggest that the frequency-doubled Nd:YAG laser with a pulse width of 50 ms and chill tip device offers an excellent alternative to sclerotherapy in the treatment of small spider leg veins.

Acute systematic and variable postural adaptations induced by an orthopaedic shoe lift in control subjects.

A small leg length inequality, either true or functional, can be implicated in the pathogenesis of numerous spinal disorders. The correction of a leg length inequality with the goal of treating a spinal pathology is often achieved with the use of a shoe lift. Little research has focused on the impact of this correction on the three-dimensional (3D) postural organisation. The goal of this study is to quantify in control subjects the 3D postural changes to the pelvis, trunk, scapular belt and head, induced by a shoe lift. The postural geometry of 20 female subjects (X = 22, sigma = 1.2) was evaluated using a motion analysis system for three randomised conditions: control, and right and left shoe lift. Acute postural adaptations were noted for all subjects, principally manifested through the tilt of the pelvis, asymmetric version of the left and right iliac bones, and a lateral shift of the pelvis and scapular belt. The difference in the version of the right and left iliac bones was positively associated with the pelvic tilt. Postural adaptations were noted to vary between subjects for rotation and postero-anterior shift of the pelvis and scapular belt. No notable differences between conditions were noted in the estimation of kyphosis and lordosis. The observed systematic and variable postural adaptations noted in the presence of a shoe lift reflects the unique constraints of the musculoskeletal system. This suggests that the global impact of a shoe lift on a patient's posture should also be considered during treatment. This study provides a basis for comparison of future research involving pathological populations.

Three-dimensional kinematics and limb kinetic energy of running cockroaches.

We tested the hypothesis that fast-running hexapeds must generate high levels of kinetic energy to cycle their limbs rapidly compared with bipeds and quadrupeds. We used high-speed video analysis to determine the three-dimensional movements of the limbs and bodies of cockroaches (Blaberus discoidalis) running on a motorized treadmill at 21 cm s-1 using an alternating tripod gait. We combined these kinematic data with morphological data to calculate the mechanical energy produced to move the limbs relative to the overall center of mass and the mechanical energy generated to rotate the body (head + thorax + abdomen) about the overall center of mass. The kinetic energy involved in moving the limbs was 8 microJ stride-1 (a power output of 21 mW kg-1, which was only approximately 13% of the external mechanical energy generated to lift and accelerate the overall center of mass at this speed. Pitch, yaw and roll rotational movements of the body were modest (less than +/- 7 degrees), and the mechanical energy required for these rotations was surprisingly small (1.7 microJ stride-1 for pitch, 0.5 microJ stride-1 for yaw and 0.4 microJ stride-1 for roll) as was the power (4.2, 1.2 and 1.1 mW kg-1, respectively). Compared at the same absolute forward speed, the mass-specific kinetic energy generated by the trotting hexaped to swing its limbs was approximately half of that predicted from data on much larger two- and four-legged animals. Compared at an equivalent speed (mid-trotting speed), limb kinetic energy was a smaller fraction of total mechanical energy for cockroaches than for large bipedal runners and hoppers and for quadrupedal trotters. Cockroaches operate at relatively high stride frequencies, but distribute ground reaction forces over a greater number of relatively small legs. The relatively small leg mass and inertia of hexapeds may allow relatively high leg cycling frequencies without exceptionally high internal mechanical energy generation.

LASER TREATMENT OF ACQUIRED VASCULAR LESIONS

Several quasi-continuous wave and pulsed lasers can effectively treat a variety of vascular lesions. The PDL follows the theory of selective photothermolysis, is safe for infants and children, and has a low incidence of side effects. It is successful in treating telangiectasias, spider and cherry angiomas, pyogenic granulomas, venous lakes, and poikiloderma of Civatte, as well as small leg telangiectasias. Quasi-continuous wave lasers such as the APTDL, copper vapor, krypton, and KTP lasers can be used to treat telangiectasias and other vascular lesions as well. Although they carry a higher risk of complications, they may prove more useful in treating larger caliber vessels. Although the PDL often produces superior clinical results than the quasi-continuous wave lasers, some patients may prefer these latter lasers because of the lack of post-operative purpura. Lastly, newer lasers, as well as noncoherent light sources, are being developed for the treatment of leg telangiectasias. Continuing advances in laser technology will enhance results, decrease side effects, improve equipment, and reduce costs, with great benefit to an increasing patient population.

Influence of Irradiation on Development of Caribbean Fruit Fly (Diptera: Tephritidae) Larvae

Larvae of the Caribbean fruit fly, Anastrepha suspensa (Loew), were irradiated at hatching with 0, 5, 10, 20, 50, 75, 100 and 150 Gy doses from a Cesium-137 source and dissected for measurements of the supraesophageal ganglion (brain) and proventriculus (B/Prv) as mature third instars. Cross-sectional area of a plane through the brain and proventriculus, and simple dorsal width measurements of the two organs were evaluated as indicators of radiation exposure. Brain area, brain width, and brain/proventriculus (B/Prv) ratios were significantly different from controls in insects treated with a dose {ge}20 Gy. Detailed dissections of hatching larvae exposed to 50 Gy revealed reductions in brain growth, small and misshapen compound eye and leg imaginal disks, and a ventral nerve cord that was elongated and sinuous. Larvae irradiated on the 1st d of each of the three instars had smaller brains, with the percentage of reduction in brain size being greater the younger the larvae were at the time of exposure. Brain and proventriculus measurements and calculated B/Prv values are indicative of irradiation in Caribbean fruit fly larvae, but the procedure may not be adaptable for routine use by quarantine inspectors. 14 refs., 4 figs., 2 tabs.

New Marine Tardigrades from Hawaiian Beach Sand and Phylogeny of the Family Halechiniscidae

Two new species of marine interstitial arthrotardigrades, both members of a new genus, are described from Anahola Bay, Kauai, Hawaiian Islands. Dipodarctus n. gen. is characterized by long primary clavae situated ventral to short lateral cephalic cirri; small ovoid leg IV papillae with short terminal spines; and unequal toe-length patterns on feet IIII as compared to foot IV. Toes on foot IV are of Tanarctus-type with long medial toes, while feet I-III possess at least 3 equal, short toes. Dipodarctus borrori n. sp. has stubby, 2piece cephalic cirri; an unusual protrusible mouth cone; and outermost toe on feet I-III twice the length of remaining toes on these feet. Dipodarctus anaholiensis n. sp. has long, tapering cephalic cirri; all toes on feet I-III equal; and coarsely punctate cuticle. Dipodarctinae is erected as a new subfamily within the Halechiniscidae to include these animals. Unifying features of the subfamily include ventrally set primary clavae; short sensory papilla on leg IV; feet of legs I-III differing from foot of leg IV. Character-state polarities among the members of the subfamilies of Halechiniscidae are used to construct a cladogram in which two basic groups are distinguished primarily on the basis of toe-length patterns, claw features, and the shape of cephalic appendages. Additional key words: Tardigrada, Heterotardigrada, Arthrotardigrada, Dipodarctinae, Dipodarctus borrori, D. anaholiensis Unique hot spot origins coupled with modern accessibility have made the Hawaiian islands a major focus for studies of island ecology (e.g., a recent series of review articles introduced by Simon, 1987). However, the shallow-water, interstitial marine meiofauna there remains largely undescribed. This is the first published record of marine tardigrades from Hawaii. In fact, the literature provides little information on interstitial tardigrades from the entire Eastern Pacific. Infaunal tardigrades from the west coast of North America have been reported by McGinty (1969) and Pollock (1989). Salvat & Renaud-Mornant (1969) and Renaud-Mornant (1976, 1981) found shallow-water species among the Society Islands. Interstitial tardigrades from the Galapagos Islands have been described by Ax & Schmidt (1973) and especially by McKirdy et al. (1976) and from the coast of El Salvador by Schulz (1953). Finally, deep-water species have been reported by Renaud-Mornant (1981) and by Bussau (1992). Altogether, these reports account for 19 species in 13 genera. The purpose of this study was to provide initial taxonomic groundwork for a limited survey of the intertidal marine tardigrades from 3 islands in the Hawaiian group. During the course of this investigation, 2 new, related tardigrade species were found within a single beach at Anahola Bay, Kauai. They possessed features so unique as to constitute a new genus and to require the erection of a new subfamily. In order to view the new subfamily in perspective, I offer a discussion of possible phylogenetic relationships among halechiniscid subfamilies.

DETECTION OF AIRBORNE SOUND BY A COCKROACH 'VIBRATION DETECTOR': A POSSIBLE MISSING LINK IN INSECT AUDITORY EVOLUTION

Extracellular recordings from nerve 5 in metathoracic legs of Periplaneta americana disclose a sense organ that is extremely responsive to vibration but also detects sound (best response near 1.8 kHz) with a sensitivity similar to some insect auditory organs. The energy required from an auditory signal for a criterion response is similar or even smaller than for an optimal vibratory input. Responses originate in the subgenual organs (SGO) in the proximal tibiae, and cross-modal adaptation indicates that the same cells respond to both vibration and sound. Sound is picked up directly on some internal structure, not via sound-induced substratum vibration. Adaptation at different frequencies discloses no frequency-selectivity in the SGO. The nerve response is a burst of synchronized impulses at a frequency, fR, of approximately 300 Hz, that is practically invariant both with sound intensity and within the burst, suggesting that fR might represent some underlying resonance phenomenon, either of the SGO or of air in the tracheal system. The latter possibility is ruled out by observations made while the tracheae are perfused with He&shy;O2. Similar responses can be recorded from the pro- and mesothoracic legs. Although Periplaneta is thought to be deaf and appears to ignore loud tones presented to the home colony, a more sensitive assay detects small leg movements in response to sound, confirming the presence of a functional auditory sense. The SGO is suspended from an expansion of the leg trachea, which may function to enhance sensitivity to vibration. This linkage preadapts the SGO to detect airborne sound transmitted in the tracheal system, and contact vibration may also stimulate the system in part by deforming the tracheae. It is proposed that auditory organs of crickets evolved from an ancestral SGO that already possessed dual responsiveness by subsequently developing effective vibration-isolating filters.

Spectral exponents of enstrophy cascade in stationary two-dimensional homogeneous turbulence.

Direct numerical simulations with up to ${4096}^{2}$ resolution are performed to address the question of universality of statistical properties of the enstrophy cascade in homogeneous two-dimensional turbulence driven by large-scale Gaussian white-in-time noise. Data with different Reynolds numbers are compared with each other. The energy spectrum is found to be very close to 1/${\mathit{k}}^{3}$. It is shown that the primary contribution to the enstrophy transfer function comes from wave-number triads with one small leg and two long ones, corresponding to wave numbers in the inertial range.

A randomized controlled trial of cultured keratinocyte allografts for chronic venous ulcers

The efficacy of cultured keratinocyte allografts on the healing rate and pain relief of 30 small and medium-sized chronic venous leg ulcers was assessed in a prospective, randomized, placebo-controlled study. Measurements of surface area, ulcer bed appearance and pain severity were made at fortnightly intervals for 6 weeks. There was significant healing of ulcers in both the allografted and control groups (P = 0.001), but there was no significant difference between the two groups (P>0.05). There was also no significant difference between the two treatments in the amount of pain relief obtained. Thus, a single application of cultured keratinocyte allografts to chronic venous ulcers offered no advantage for wound healing or pain relief as compared with placebo. The low efficacy and the expense of cultivating and storing allografts does not allow a single application of cultured allografts to be recommended at present as a routine treatment for venous leg ulcers.

Small vessel leg angiography for distal vessel bypass grafts

Small vessel leg angiography for distal vessel bypass grafts

Small vessel leg angiography for distal vessel bypass grafts

To improve visualization of the small vessels for distal bypass grafting, arteriograms of the lower extremity were obtained in 187 patients by use of active warming of the extremities, selective distal positioning of the catheter for contrast agent injections, and intraarterial administration of tolazoline. With these techniques, satisfactory visualization was obtained for planning of operation, and in only one patient was an intraoperative arteriogram necessary before bypass grafts were placed.

Additional Observations on Abdominal Appendages of Notched Sternite Mutants of Blattella germanica (Dictyoptera: Blattellidae)

The notched sternite (st) mutant of the German cockroach, Blattella germanica (L.), alters development of ventral abdominal segments. Reoccurrence of valvulae on a pregenital segment and of a stylus-bearing appendage that lies laterally to the first valvulae (gonapophyses) in st females is described. Also reported is a replacement of a pleuropodium by a small segmented leg and pleuropodia-like structures on abdominal segments posterior to the first segment in embryos. Evolutionary implications of these structures are considered.

Heat loss and thermoelectric generator design

With the object of evaluating its importance to thermoelectric generator design, heat loss is introduced into the standard thermoelectric generator design theory. The theory for both the constant hot and cold junction temperatures model and the constant heat input model are so modified. The modification is first order and, therefore, is limited to small leg heat-transfer coefficients. Numerical results using representative properties show that significant differences can exist between the optimum geometry and performance of a generator idealized as lossless and those of a generator designed by the modified theory. The largest differences occur with the constant heat input model.

Numerical Simulation Of The North Ricinus Cardium A Reservoir

Abstract The North Ricinus Cardium A Pool is a beach barrier system located on the edge of the disturbed belt, approximately 130, km northwest of Calgary, Alberta. The current operating mode for the pool involves a cycling scheme in the retrograde gas cap with the oil leg on primary depletion. A standard 3D-3 phase black oil model, modified with several specialized subroutines, was used to simulate the cycling scheme in the history match and prediction modes. Pseudo-relative permeability curves were used to describe displacement of rich gas by lean gas in the gas cap, while two sets of relative permeability curves were required to match oil production. The model was subsequently utilized to establish reserves and to optimize natural gas liquid recovery by infill drilling in the gas cap. Introduction The Ricinus Cardium A Pool, discovered in January 1969, is located approximately 130 kilometres northwest of Calgary, FIGURE 1. Location map. (Available in full paper) FIGURE 2. North Ricinus geology.(Available in full paper) Alberta (Fig. 1). The pool initially was considered to be a large retrograde condensate gas cap in association with a relatively small oil leg containing a high shrinkage oil. An application in June 1971(1) to concurrently produce the gas and oil based on good production practice was refused by the ERCB. In July 1972 a scheme to cycle the gas cap was subsequently approved with the provision that the operator show cause after one year of production why a VRR of unity need not be maintained(2). Gas cap cycling commenced in April 1973 and a performance review submitted in July 1974(3) indicated that a VRR of between 0.85 and 1.00 had no appreciable effect on gas cap liquid recoveries and the ERCB did not impose a full voidage replacement ratio at that time. Subsequent step out drilling to the north indicated that the oil leg was much larger than previously estimated; and in May 1979, the ERCB(4) requested a study to determine the effect of VRR on the oil recovery and also an updated estimate of original reservoir volumes. A black oil reservoir simulation study, incorporating special modifications, was initiated in June 1979 to address the ERCB's concerns. The model was subsequently utilized to establish pool reserves and to investigate optimization of natural gas liquid recovery by infill drilling. Geology The Ricinus Cardium Pools occur in the Cardium A Sand of Upper Cretaceous age. The reservoir is a beach barrier system trending 20 km in a northwesterly direction and averaging 3 – 5 km in width at a mean depth of 1325 m ss (Fig. 2). The reservoirs are complex structural traps occurring at the edge of the disturbed belt. The Cardium A Pool consists of a retrograde gas cap condensate overlying a volatile oil pool in a weakly folded synclinal structure that plunges gently to the northwest with the gas oil contact occurring at 1463 m ss. A major under thrust forms a pressure barrier to the Cardium K pool to the southwest with porosity pinchouts forming the reservoir boundaries in other directions (Fig. 2).

Passive leg raising does not produce a significant or sustained autotransfusion effect.

Passive leg raising is widely used to treat hypotension associated with hypovolemia. Presumably gravity causes a central translocation of leg venous blood and an increase in filling pressure, cardiac output, and arterial pressure. Ten healthy volunteers, 25 to 35 years old, had measurements of heart rate, blood pressure, and cardiac output in the supine position after 20 sec and 7 min of 60 degrees passive leg elevation. The protocol was performed 3 and 45 min after the subjects changed from an ambulatory upright to a supine position. Stroke volume and cardiac output increased transiently (8-10%) when the legs were raised after 3 min rest in the supine position. By 7 min of leg elevation, these beneficial effects disappeared. After 45 min supine, leg raising had no effect on stroke volume or cardiac output but increased blood pressure (4 mm Hg) by increasing peripheral resistance (15%). Thus, leg raising, like application of the MAST trousers, fails to produce any sustained increase in cardiac output or stroke volume. Small venous leg volumes and time-dependent changes in the distribution of venous volume and compliance may explain the absence of any sustained 'autotransfusion' effect.

The distal limb motor neurons in the thoracic ganglion of the spiny lobster.

The 16 motor neurons which innervate the muscles in the limb distal to the autotomy plane have been found in the third thoracic ganglion of the southern rock lobster, Jasus novaehollandiae. They were traced from the autotomy plane to the ganglion by stripping them from the small and large leg nerves to the edge of the ganglion where they were filled with cobalt dye. Cell bodies of 11 of these neurons lie in an anterior cluster of somata, and the remainder lie in a ventral rind of somata. The neurites from these somata expand into enlarged central segments, 400 micrometers long and 10-30 micrometers in diameter. These segments run parallel and in apposition to each other as they course through the neuropile a few cell layers beneath the dorsal surface of the ganglion. Near their origin some central segments send branches both medially between fibers of the interganglionic connectives, and anteroventrally into the connective. Distally the segments give rise to side branches which project around the anterior and posterolateral borders of the neuropile. The central segments constrict near the lateral edge of the neuropile, rise to its surface, and form axons. Eight axons, including those which innervate the flexor muscle of the carpus, enter an anterior motor tract which exists the side of the ganglion in a first root, the source of the small leg nerve. The remaining eight axons, which include those that innervate the extensor muscle of the carpus, enter a posterior motor tract which exists the side of the ganglion in a second root, the source of the large leg nerve. All the motor fibers which innervate the muscles of the limb, with the exception of the retractor of the coxa, run in these two tracts within the ganglion. Fibers which innervate the retractor of the coxa and the muscles of the thorax leave the ganglion in a third root at the posterodorsal border of the ganglion. The central segment, as the common structure of confluence of neuropilar branches, is the likely candidate for the integrating region of each neuron.