Anterior Foot Research Articles

Visual-vestibular influences on locomotor adjustments for stepping over an obstacle

Combined visual and vestibular influences on locomotor control, particularly in changing environments, are little understood. We studied such influences on body orientation and foot trajectory control during level walking and obstacle avoidance. Six young adults walked on the level and over an obstacle while vision was present or occluded as well as while vestibular information was intact or perturbed using galvanic vestibular stimulation (GVS). The occlusion of vision caused a slowing of gait during obstacle avoidance as well as increased clearance of the leading limb over the obstruction. GVS caused lateral deviations in head and trunk roll angles as well as in foot and trunk displacements, but these lateral deviations were the same during both level walking and obstacle avoidance. In addition, GVS had no effect at all on sagittal plane factors such as speed, foot proximity to the obstacle and vertical clearance over the obstacle. Overall, there is a complex visual control of bilateral obstacle avoidance, but the lack of differences in GVS effects between level and obstructed walking shows that vestibular information is not upregulated for obstacle avoidance. In addition, the robust indifference of anterior foot placement and body displacement to significant lateral deviations from GVS suggests an orthogonally based sensori-locomotor control.

Serotonin-Immunoreactive CPT Interneurons inHermissenda: Identification of Sensory Input and Motor Projections

Serotonin immunoreactive (5-HT-IR) neurons identified as cerebropleural ganglion triplets (CPTs) in Hermissenda may be homologues of 5-HT-IR neurons identified in other opisthobranch molluscs. In studies of isolated nervous systems and semi-intact preparations we used a combination of immunohistochemical techniques and fluorescent labeling with Lucifer yellow to identify 5-HT-IR CPT neurons after investigating sensory inputs and motor neuron projections. Here we show that identified 5-HT-IR CPT interneurons receive sensory input from mechanoreceptors and photoreceptors. In semi-intact preparations with intact pedal nerves P1 and P2, cutaneous stimulation of the middle or tail regions of the foot with calibrated von Frey hairs elicited spikes recorded from identified CPT interneurons. Illumination of the eyes evoked a small complex excitatory postsynaptic potential (EPSP) and resulted in a modest increase in the spike discharge of CPT interneurons. Immunostaining of Lucifer yellow-labeled neurons revealed that CPT interneurons projected an axonal process to the contralateral pedal ganglion. Depolarization of CPT interneurons with extrinsic current evoked EPSPs and spikes recorded from identified VP2 pedal neurons, motor neurons previously shown to elicit movement of the anterior foot. Extrinsic current stimulation of CPT interneurons in semi-intact preparations evoked movement of the anterior foot but did not facilitate ciliary activity or evoke PSPs recorded in identified VP1 ciliary motor neurons. Our results show that CPT neurons are polysensory interneurons that contribute to reflexive foot contractions in Hermissenda.

SAPHO Syndrome with a Tumour-like Bony Proliferative Lesion in Distal Femur. ACase Report

SAPHO syndrome is a group of bone and joint abnormalities associated with skin lesions. A 29-year-old male presented with severe acne on his trunk and anterior chest wall, right knee and foot pain. Radiographs and magnetic resonance images showed hyperostosis in the sternocostoclavicular region, sclerosis of one-third of the right distal 5th metatarsal bone and bony outgrowth from the medial condyle of the right femur. The histological findings of the biopsy specimen were consistent with those of old osteomyelitis. All fungal and microbacterial cultures were negative. Pain and swelling of the right knee and foot repeated remission and aggravation. There were no radiological changes of the above-mentioned lesions noted within 4-years follow-up.

SIR 2005 Film Panel Case: Peripheral Embolization From Cardiac Myxoma

A 39-year-old man presented with the acute onset of a cold, painful, and numb left leg. Physical examination in the emergency room demonstrated a palpable left femoral pulse and absent left popliteal, dorsalis pedis, and posterior tibial artery pulses. The left foot and lower leg were pale and cool to touch, and the patient exhibited diminished sensation over the anterior foot and decreased mobility at the ankle joint. Vascular examination of the right lower extremity was entirely normal. Past medical history was remarkable only for recreational drug use consisting mainly of cocaine.

Foot thickness and swelling after hallux valgus correction with the Reverdin-Isham procedure: a 4-month follow-up study

The objective of this study was to assess the time course of inflammation of the anterior part of the foot in patients undergoing surgical correction of hallux valgus. The study population consisted of 85 patients (146 feet) who underwent a Reverdin-Isham operation by minimal incision surgery. A comparison of preoperative findings with measures taken at 6 and 16 weeks showed 8.94 and 8.34 cm for width of the anterior foot; 22.92, 22.52 and 21.87 cm for the circumference of the anterior foot; 3.79, 3.81, and 3.64 cm for thickness of the first metatarsal head; 8.34, 8.96, and 8.38 cm for the circumference of the first finger; and 2.12, 2.36, and 2.06 cm for thickness of the first finger. The five parameters showed an association with the angles of the first axis of the foot, greater preoperative hallux valgus as well as proximal and distal metatarsal articular angles, greater swelling of the anterior part of the foot postoperatively. The greater the postoperative decrease of the intermetatarsal angle, the higher the reduction of postoperative swelling.

Statocyst hair cell activation of identified interneurons and foot contraction motor neurons in Hermissenda.

Pavlovian conditioning of Hermissenda produces both light-elicited inhibition of normal positive phototactic behavior and conditioned stimulus (CS)-elicited foot-shortening. Rotation, the unconditioned stimulus (US) elicits foot-shortening and reduced forward ciliary locomotion. The neural circuit supporting ciliary locomotion and its modulation by light is known in some detail. However, the neural circuits responsible for rotation-elicited foot-shortening and reduced forward ciliary locomotion are not known. Here we describe components of the neural circuit in Hermissenda that produce anterior foot contraction and ciliary activation mediated by statocyst hair cells. We have characterized in semi-intact preparations newly identified pedal ventral contraction motor neurons (VCMNs) and interneurons (I(b)). Type I(b) interneurons receive polysynaptic input from statocyst hair cells and project directly to VCMNs and cilia-activating motor neurons. Depolarization of VCMNs with extrinsic current in normal artificial seawater (ASW) and high-divalent cation ASW, and under conditions where central synaptic transmission was suppressed with 5 mM Ni(2+) ASW, elicited a contraction of the ipsilateral anterior foot measured from videotape recordings. Mechanical displacement of the statocyst or depolarization of identified statocyst hair cells with extrinsic current elicited spikes and complex excitatory postsynaptic potentials (EPSPs) in type I(b) interneurons and complex EPSPs and spikes recorded in VCMNs. Type I(b) interneurons are electrically coupled and project to VCMNs and VP1 cilia-activating motor neurons located in the contralateral pedal ganglia. The results indicate that statocyst hair-cell-mediated anterior foot contraction and graviceptive ciliary locomotion involve different interneuronal circuit components from the circuit previously identified as supporting light modulated ciliary locomotion.

Interneuronal projections to identified cilia-activating pedal neurons in Hermissenda.

Neural networks have been shown to support the generation of more than one behavioral motor act. In the nudibranch mollusk Hermissenda, Pavlovian conditioning results in light, the conditioned stimulus (CS), evoking both inhibition of locomotion and foot contraction. The synaptic organization of the eyes and optic ganglion is well documented; however, the characterization of the neural network mediating visually modulated behaviors is incomplete. We have now characterized synaptic connections between identified photoreceptors and a newly identified interneuron (II(b)), identified synaptic projections from type I and type II interneurons to an inhibitory interneuron (III(i)) and to two newly identified pedal neurons, VP1 and VP2. Here we show that VP1 activates ciliary movement on the anterior foot and VP2 innervates the anterior foot and ventral tentacle. Stimulation of the photoreceptors with light produced two effects on the activity of VP1 and VP2. First, light inhibits type I(i) and II(i) interneurons and disinhibits VP1 and VP2. Depolarization of type II(e) interneurons also disinhibits VP1 and VP2. Second, the light-elicited depolarization and increased tonic activity of VP1 and VP2 is produced by excitatory synaptic input from ipsilateral and contralateral type II(b) interneurons. Pedal neurons VP1 and VP2 receive similar synaptic input from type I, II, and III(i) interneurons; this is in agreement with previous research showing that the visual pathway influences both ciliary locomotion and foot movement. The organization of the visual system in Hermissenda provides for the expression of cellular and synaptic plasticity supporting learning without altering the networks ability to carry out the requirements for normal visual processing.

Hydrobia ulvae (Gastropoda: Prosobranchia): a new model for regeneration studies.

Within 2 weeks of decapitation, Hydrobia ulvae was able to regenerate new head structures including buccal ganglia. It was also capable of regenerating propodial ganglia after anterior foot amputation. The functional regeneration of the buccal ganglia was demonstrated by behavioural observations and by electrophysiological experiments. The presence of the oesophagus was shown to be important for regeneration of the buccal complex. H. ulvae provides a new model for regeneration studies, so details of the topographic anatomy and biology of this species are described. To standardize experimental animals in future studies, the effects of age, sex and trematode infestation on the regeneration capacity of H. ulvae have been evaluated. The high capacity for regeneration together with the possibility of using electrophysiological techniques makes H. ulvae a favourable model in which to study neurogenesis in adult animals.

Biomechanical analysis of effects of foot placement with varying chair height on the motion of standing up

Individual experience reveals that posterior foot placement enables one to stand up easily from a chair. However, the way in which foot placement affects this motion has not been investigated in detail. This study was performed to examine the effects of foot placement in the initial stage of the dynamics of standing up from a chair. Subjects wearing light-emitting diode markers and surface electrodes stood up from a chair over force plates, and ground reaction force, joint angle, and muscle activity were measured. The motions required to stand up from chairs 30, 40, or 50cm in height were analyzed with anterior, vertical, and posterior foot placement. With anterior foot placement, the forward-acceleration components of the ground reaction force were recorded with simultaneous and long-sustained activity of the muscles in order to shift the center of gravity of the body forward even more after lift-off. Our findings indicate that the distance between the center of gravity and the point of application of ground reaction force at lift-off are critical factors in the standing-up motion, and that chairs should be of adequate height as well as having sufficient space under the seat to permit the backward movement of the lower legs.

足部外傷後皮膚欠損に対する内側足底筋膜皮弁の使用経験

We report two cases treated with medial plantar fasiocutaneous flap for the reconstruction of the foot and ankle following trauma.(Case 1) A 45-year-old woman: Skin defects of the medial ankle were found. We performed reconstruction using medial plantar fasiocutaneous island flap.(Case 2) A 36-year-old man: Skin defects of the anterior foot were found. We performed reconstruction using medial plantar fasiocutaneous free flap.Reconstruction of the skin and subcutaneous soft tissue defects of the foot is often difficult. Medial plantar fasiocutaneous flap is useful for the coverage of the foot and medial ankle.

O-5-68 - Early decompressive craniectomy after severe head injury: Follow-up and outcome

In this study the effects of connective lesions on the control of pedal locomotion in Aplysia californica were examined. Normal goal directed locomotion consists of a behavioral sequence. The foot is detached, extended, and the anterior edge reattached. A series of waves are generated in the resulting arch which pull the animal forward. Escape locomotion is similar except that the foot extension is exaggerated; the entire body contracts off the substrate and the tail is released following anterior foot attachment. When the cerebropedal and cerebropleural connectives were bilaterally sectioned, locomotion was abolished. Bilateral sectioning of the cerebropedal connectives alone also eliminated the first phases of normal locomotion, although limited pedal waves were still generated. Bilateral sectioning of the cerebropleural connectives only eliminated escape locomotion. Cutting the pleuropedal connectives greatly reduced the rate of normal locomotion and also abolished escape locomotion. Unilateral section of the cerebropedal and cerebropleural connectives resulted in reduced motor activity on the lesioned side, with diagonally running pedal waves (lesioned side trailing) in the foot. Sectioning the pedal commissure caused the motor activity of each hemifoot to become desynchronized. When the pedal ganglia were isolated by cutting both the cerebropedal and pleuropedal connectives limited pedal waves were still generated, although the initial phases of the locomotor sequence were absent. These results suggest that the different parts of the locomotor control system are localized in separate ganglia. The motor pattern generators reside in each pedal ganglion with coordination maintained by the pedal commissure. The results are consistent with the hypothesis that the commands for initiating locomotion originate in the cerebral ganglion and descend to the pedal ganglia via the cerebropedal connectives. The pleural ganglia apparently serve both to modulate the rate of locomotion and as a relay for input to the cerebral ganglion.

Common Musculoskeletal Injuries in Women

The causes of women's sports injuries are currently a topic of vigorous speculation in sports medicine. Research has yet to clearly link gender to any injury etiology. Meanwhile, physicians are analyzing gender differences to find ways that women can better condition themselves for sports, avoid injuries, and recover quickly from the injuries that do occur. An analysis of the most common problems active women face (anterior cruciate ligament, patellofemoral, shoulder, and foot injuries) suggests effective strategies for diagnosis, treatment, rehabilitation, and prevention.

Neandertal pedal proximal phalanges: diaphyseal loading patterns

Abstract Neandertal proximal pedal phalanges have been described as short relative to foot length with relatively wide diaphyses, the latter purportedly to resist elevated levels of mediolateral loading during locomotion. Analysis of proximal pedal phalanges from samples of Neandertals, early modern humans, and recent small-scale and industrial society humans demonstrates that the Neandertals have moderately shorter proximal pedal phalanges with the middle (digits 2–4) phalanges having significantly wider diaphyses relative to the recent humans. The early modern humans have relatively abbreviated phalanges, similar to the Neandertals, and occupy an intermediate position with respect to relative phalangeal shaft breadth. These data suggest: (1) a higher frequency and/or level of mediolateral loading of the anterior foot among Upper Pleistocene humans related to contrasting behavioral patterns, and (2) a generally higher level of robusticity of the anterior foot with the elevated dorsoplantar stress on the phalanges being resisted more by extensor and flexor tendon tension and the mediolateral and torsional stresses being resisted by increased diaphyseal breadth. This study, in conjunction with other lower-limb morphological comparisons between Neandertals, early modern humans and recent humans, suggests gradual decreases in locomotor anatomy robusticity (and hence locomotor activity levels) through the later Upper Pleistocene and Holocene with a possible change in lower-limb loading patterns with the emergence of early modern humans.

Body postural muscles active during food arousal in Aplysia are modulated by diverse neurons that receive monosynaptic excitation from the neuron C-PR

1. We previously found that identified neuron C-PR may mediate the appetitive feeding posture of Aplysia by actions on appropriate motor neurons and perhaps on modulatory neurons innervating the foot and neck. In the present experiments, we attempted to further investigate this hypothesis by characterizing the modulatory neurons that are excited by CP-R. 2. We identified three types of modulatory neurons all of which are excited, at least in part, by monosynaptic excitatory connections from C-PR. 3. The cell bodies of these neurons are located in the posterior region of the pedal ganglion. 4. The neurons send axons to muscles, but rather than producing contractions, they enhance, depress, or alter the relaxation rate of contractions produced by motor neurons. Each of these types of modulatory neurons produces a highly specific effect in terms of the region of the body affected and the nature of the modulation. 5. The primary effect of P1R-E neurons was to enhance longitudinal contractions of the anterior foot. 6. P1R-D neurons depressed longitudinal and transverse contractions of the anterior foot. 7. P8R neurons enhanced longitudinal and transverse contractions of the neck. 8. The results obtained from extracellular recordings of muscle junction potentials suggest that the firing of the modulatory neurons may enhance or depress muscle contractions, at least in part, by increasing or decreasing the size of the excitatory input the motor neurons produce on the appropriate muscles. These changes in excitatory drive to the muscle are likely to underlie, at least in part, the alterations in contraction size produced by the modulatory neurons, but changes in relaxation rate are likely related to other actions of the modulatory neurons. 9. We have evidence for at least nine neurons that modulate the foot or neck and are excited by C-PR, and it is very likely that there are more, perhaps considerably more, of these types of neurons. In fact, it appears as if a significant proportion of the efferent output to the muscles that mediate the appetitive phase of feeding consists of modulatory output rather than conventional motor neuron output that produces discreet contractions.

Effects of cerebral neuron C-PR on body postural muscles associated with a food-induced arousal state in Aplysia

1. Firing of cerebral neuron, C-PR, produced complex bilateral movements of various regions of the body of the marine mollusc Aplysia californica. The movements were similar to those seen when the animal assumes the head-up feeding posture during food-induced arousal. Muscles of the neck largely contracted in transverse and longitudinal directions, and large transverse movements were also induced in the middle part of the foot. On the other hand, firing of C-PR appeared to relax the anterior part of the foot in transverse and longitudinal directions. 2. We identified pedal-ganglion motor neurons that innervate various regions of the animal, and explored the synaptic connections of C-PR with these neurons. Firing of C-PR produced synaptic potentials bilaterally in most of the identified motor neurons. 3. Motor neurons for the neck were largely excited by C-PR firing. C-PR firing also excited the motor neurons that produce transverse movements of the middle part of the foot. On the other hand, C-PR inhibited the spontaneous spike activity of the motor neurons for the anterior part of the foot. 4. One neck motor neuron was found to receive a monosynaptic excitatory postsynaptic potential (EPSP) from C-PR, but the postsynaptic potentials (PSPs) induced by C-PR in the other identified motor neurons were mediated polysynaptically. 5. We also found that the C-PR can modulate movements evoked by firing of the motor neurons for the ipsilateral neck and anterior foot. C-PR enhanced both transverse and longitudinal contractions of the neck. 6. For the anterior foot region, C-PR had different modulatory effects on the longitudinal and the transverse contractions. C-PR largely enhanced or initially depressed and then enhanced longitudinal contractions, whereas C-PR depressed transverse contractions. 7. The overall results support the hypothesis that C-PR is involved in controlling the head-up posture when the animal is aroused by food.

Chemically mediated escape behavior in the marsh periwinkle Littoraria irrorata Say

Marsh periwinkles Littoraria irrorata Say substantially reduce their exposure to predatory crown conchs Melongena corona Gmelin by ascending intertidal plants during high tide, when conchs actively hunt. Studies were conducted to determine if the periwinkle's responses to predator contact were comparable to those of gastropods lacking an equivalent strategy of predator avoidance. Marsh periwinkles exhibit an escape response to contact with crown conchs. consisting of a 64% increase in average speed of locomotion, and a 68% increase in average rate of cephalic tentacle contacts with the substratum. Crown conch mucus alone is sufficient to elicit a full-strength response. The cephalic tentacles, anterior foot, and posterior foot of marsh periwinkles appear equally sensitive to this predator's mucus, but periwinkles do not move in any particular direction relative to the site of stimulation. Mucus of nonprcdators (ragged sea hares, scallops) did not elicit a significant escape response in marsh periwinkles. Contact with mucus from each of five predatory neogastropods did elicit a significant response, but contact with the natural predator ( M. corona) elicited a significantly stronger response than the others. The marsh periwinkle's escape response and chemo-discrimination ability is similar to that reported for some other gastropods.

Neural control of Aplysia feeding posture by the food-arousal neuron C-PR.

Food stimili elicit a characteristic "feeding posture", in which the animal lifts the head and relaxes the anterior part of the foot. A pair of cerebral neuron, C-PR, may function as an important element that evokes a food-arousal state. The C-PR may also mediate the feeding posture by exciting or inhibiting many types of body postural motor neurons. In addition, it has longlasting modulatory effects on the movements of the neck and the anterior foot, which were produced by the motor neurons. These effects may be caused by modulatory neurons receiving monosynaptic excitatory inputs from the C-PR.

Arterial lesions of the foot vessels in diabetic and non-diabetic patients undergoing lower limb revascularisation

This study was undertaken to compare the atherosclerotic involvement of the foot arteries in diabetic and non-diabetic patients with leg ischaemia. Ninety-four non-diabetic and 57 diabetic patients were investigated with intraoperative postreconstruction serial angiography during femoro-popliteal and femoro-distal bypass surgery. The foot vessels were evaluated with regard to the anterior and posterior foot arches which were classified as intact, deficient or occluded. Integrity of the pedal circulation was defined as patency of both the anterior and posterior foot arches. Severe involvement of the foot arches was rarely seen in limbs with 3- or 2-lower leg vessel run-off to the foot. The posterior foot arch was more often spared than the anterior foot arch, especially in the non-diabetic group (P less than 0.001). The integrity of the pedal circulation was similar in diabetic and non-diabetic patients (intact in about 20%). Patients with claudication showed a significantly lower occlusion rate of leg and foot arteries than patients with rest pain or gangrene. The results of this study showed that the foot vessels were similarly affected in diabetics and non-diabetics undergoing lower limb revascularization. The same aggressive diagnostic and therapeutic approach should be applied for limb salvage in both groups.

Trippa molesta, a new dorid nudibranch (Gastropoda: Opisthobranchia) from New Zealand

Abstract Trippa molesta n. sp. is described and illustrated. It is compared only with the two seemingly closest species, Trippa osseosa (Kelaart) and T. spongiosa (Kelaart). The new species is distinguishable from the early descriptions of T. osseosa and from T. spongiosa in having an even median ridge (i.e., there is no pre-branchial protuberance), opaque white on the tubercles of the centre of the mantle, and in being firm but neither cartilaginous nor gelatinous. Only colour distinguishes the new species from the Hawaiian specimens of T. osseosa (only the externals were described for the latter). The form of the inner radular teeth and penis separate the new species from the Madagascan specimens of T. osseosa (as Atagema osseosa). A new name for the New Zealand specimen seems further justified in that it has anterior foot lobes and oral glands, two of the main features of the genus Trippa, features not mentioned in the descriptions of the Hawaiian and Madagascan specimens. The Hawaiian and Madagascan specimens may have to be renamed.

Efficiency of pedal forces during ergometer cycling.

The aim of this study was to record the forces applied to the pedal during ergometer cycling and to calculate the effectiveness of these force vectors. Six healthy subjects rode a weight-braked bicycle ergometer at different work loads, pedaling rates, saddle heights, and pedal foot positions. The left lower limb and crank motions were recorded by a cinefilm camera and pedal reaction forces by a Kistler force measuring transducer mounted on the left pedal. The force effectiveness was computed as a ratio between the force tangential to instantaneous direction of pedal movement and the resultant force. The mean force efficiency ratio significantly increased by an increase of the ergometer work load or use of the anterior foot position instead of the posterior. It was not significantly changed due to alterations of the pedaling rate or saddle height.