Ulnar polydactyly

A retrospective review of 148 patients with ulnar polydactyly was conducted to analyze the types, patterns of involvement, associated anomalies, treatments, and outcomes of this malformation. The hands only were involved in 123 patients, both hands and feet in 20 patients, and five patients had mixed radial and ulnar polydactyly. Ulnar polydactyly was more prevalent among males. Among African Americans, the condition was often bilateral. When unilateral, ulnar polydactyly occurred more often on the left side. The racial distribution was 103 African Americans (70 percent), 37 Caucasians (25 percent), four Native Americans, three Latin Americans, and one Asian. Five types were encountered: type I cutaneous nubbin, type II pedunculated digit, type III articulating digit with fifth metacarpal, type IV fully developed digit with sixth metacarpal, and type V polysyndactyly. The distribution of types in order of frequency was type II, III, V, I, and IV. Types I and II ulnar polydactyly combined were more prevalent (82 percent) than types III, IV, and V (18 percent). Types I and II were more common among African Americans. Types III, IV, and V ulnar polydactyly occurred more frequently among Caucasians, but these were slightly less prevalent than types I and II in this racial group. Five patients were syndromic; four were Caucasians, and one Asian. Most cases of ulnar polydactyly of the hand were treated by ligation (71 percent) in the nursery, whereas polydactyly of the foot was more often referred to a specialist to be treated by surgical ablation (92 percent). Treatment complications occurred more frequently in the hands than in the feet. The complication rate after ligation of ulnar polydactyly of the hand was 23.5 percent. The two main complications were tender or unacceptable nubbins and infections.     

The extensor assembly in two species of opossum,Philander opossum and Didelphis marsupialis

In considering primate and hominoid phylogeny, the fundamental position assigned to opossums is explained partially by the characteristic morphology of their hands and feet. One of the main functional features of the human hand is the ability to make a stabilized arch of the finger. Because the extensor assembly plays a key role in establishing an arched finger, the extensor systems of the digits of both the hands and feet were studied in two species of opossum, Philander opossum and Didelphis marsupialis. In the foot, two extensor tendons join in each toe to form one tendinous plate, which inserts onto the base of the second phalanx. Lumbricals join this plate along the tibial side, and interosseus insertions are found, although a true interosseus wing is lacking. At the proximal interphalangeal level, a terminal tendon takes its origin from this tendinous plate. This terminal tendon is oval in cross-section and contains elastic structures. Oblique bands arise from this terminal tendon and run proximally along the proximal interphalangeal joint inserting onto the base of the first phalanx. There are elastic structures in the flexor tendon on the dorsal side near its site of insertion. In the hand, the main extensor tendons are arranged differently and the interossei contribute substantially to the extensor assembly. Otherwise, the extensor assembly of the hands and feet are quite similar. The function of the so-called paratendinous intravaginal flexors is discussed as are evolutionary aspects of the extensor assembly.     

Spatial compatibility and position of the effectors

Mean reaction times obtained with crossed hands (right had on the left and left hand on the right) are slower than reaction times obtained with uncrossed hands (right hand on the right and left hand on the left). These results have been explained as a compatibility effect between the responding hand and its spatial position. The goal of the present experiment was to establish whether the position of the hand is encoded by the subjects relative to their body (absolute position) or relative to the other hand (relative position). The subjects performed a discrimination task on two visual stimuli. Stimuli and hands were either on the same side of the body (both on the left or both on the right) or had different absolute position. In all conditions the subjects responded with crossed and uncrossed hands. The results support the hypothesis that relative position is encoded.     

Involuntary human hand movements due to FM radio waves in a moving van

Finland TRACT Involuntary movements of hands in a moving van on a public road were studied to clarify the possible role of frequency modulated radio waves on driving. The signals were measured in a direct 2 km test segment of an international road during repeated drives to both directions. Test subjects (n=4) had an ability to sense radio frequency field intensity variations of the environment. They were sitting in a minivan with arm movement detectors in their hands. A potentiometer was used to register the hand movements to a computer which simultaneously collected data on the amplitude of the RF signal of the local FM tower 30 km distance at a frequency of about 100 MHz. Involuntary hand movements of the test subjects correlated with electromagnetic field, i.e. FM radio wave intensity measured. They reacted also on the place of a geomagnetic anomaly crossing the road, which was found on the basis of these recordings and confirmed by the public geological maps of the area.In conclusion, RF irradiation seems to affect the human hand reflexes of sensitive persons in a moving van along a normal public road which may have significance in traffic safety.     

Anatomical variations of the extensor tendons to the fingers over the dorsum of the hand: a study of 50 hands and a review of the literature

The extensor tendons to the fingers were studied in dissections of 50 fresh cadaveric hands, and the divisions of the tendons, as well as the communications (juncturae), were analyzed. The pattern of distribution most frequently observed was as follows. The extensor digitorum communis provided one tendon to the index finger, one to the middle finger, two to the ring finger, and none to the little finger. The extensor indicis exhibited one tendon, whereas the extensor digiti minimi exhibited two tendons. The extensor indicis tendon was always observed to lack a junctura tendinum. The extensor indicis was absent in both hands of one cadaver. A tendon slip from the extensor digiti minimi to the ring finger was observed in one hand. All surgeons must bear in mind the existence of these variations when performing common tendon transfers.     

The practice effect and its difference of the pursuit rotor test with the dominant and non-dominant hands

The purpose of this study was to examine the practice effect and what difference it makes in the pursuit rotor test for the dominant and non-dominant hands in 30 right-handed Japanese male adults aged 18 to 23 years (Age 20.8+/-1.4 yrs). The subjects performed the pursuit rotor test for 1 min in 20 trials with a 1-min interval alternately using the dominant and non-dominant hands. After continuing for 10 trials, a 5-min rest was taken. The measurement order was randomly assigned. Contact time of a steel pen and a target was measured in units of 1/10 sec. The measurements showed a constant increasing tendency at every trial until the 6th trial in both hands. Significant linear regressions were identified, but the increase-rate of the dominant hand was significantly larger. Individual differences showed a decreasing tendency at every trial in the dominant hand, but in the non-dominant hand it increased until the 4th trial then decreased. The relationships between measurements of the 1st and 10th trials in both hands and both hands in the 1st or 10th trial were not high. The performance of the pursuit rotor test improves at every trial in both hands, but the improvement rate decreases after the 7th trial. The improvement rate of the dominant hand is high. The change in individual differences differs in both hands and the relationship between the measurements is not high. It can be judged that the practice effect of the pursuit rotor test differs in the dominant and non-dominant hands.     

A physiological basis for control of a prosthetic hand

Recent surveys from upper limb amputees indicate the sentiment that prosthetic hands do not function in a life-like manner and are not intuitively controlled. Thus, two methods of control for a prosthetic hand are presented. A proportional derivative (PD) force controller is compared to a novel biomimetic application of sliding mode control. The biomimetic sliding mode (BSM) controller was designed to map human muscle signals into prosthesis motor command signals in a physiologically expected manner.The BSM and PD controllers were evaluated analytically and subjectively by one amputee and nine nonamputee test subjects. The posture of the hands of the nonamputee test subjects were measured with a CyberGlove and used to determine if the position of the prosthesis (when driven by both controllers) was highly correlated to the posture of the human hands. Force tracking experiments were also performed by all test subjects with both controllers to evaluate the ability to control the applied force. Finally, a dual object lifting task was performed by all test subjects to determine if the mapping of electromyogram (EMG) signals with the BSM controller resulted in physiologically expected motions. A nonparametric Mann–Whitney U-test was performed on the subjective evaluations to determine the statistical significance of the evaluations.The BSM controller was shown to replicate the posture of the human hand much more accurately than the PD force controller. The BSM controller also enabled better average force tracking results and higher success rates with the dual object lifting experiment while the same task was nearly impossible to perform with the PD controller. Finally, the BSM controller was subjectively rated to be more similar to control in comparison to the human hand with respect to position and force.     

Extensor carpi radialis longus muscle and the evolution of the first intermetacarpal ligament

The morphology and function of tendinous connections between the bases of the first and second metacarpal bone was studied in dissected specimens. The sample comprises 28 hands from eight species of cercopithecidae and pongidae and 23 human hands. Four types were identified: (1) No intermetacarpal connections were present. (2) The extensor carpi radialis longus tendon was divided at the carpus and the side branch inserted on the ulnar side of the base of the first metacarpal bone. (3) Part of the fibers of the extensor carpi radialis longus bypassed the insertion on the second metacarpal bone and continued to the base of the first metacarpal bone. A few proper intermetacarpal fibers were included. (4) An extracapsular, intermetacarpal ligament was present. Its fibers were mainly separated from the extensor carpi radialis longus. Type 1 is a general mammalian form. Type 2 is common in higher, non-human primates. Type 3 was found in 2 of the 23 human hands and otherwise among the anthropoid apes only. Type 4 is apomorph in man. Individual variations exist though. Type 3 and especially type 4 could check ab- and adductions and guide a circumduction in the first carpometacarpal joint.     

Extremity heat loss in water in humans and macaques

Human hands and feet lose about the same amount of heat per unit time in cold water. This is somewhat strange since they are grossly different in size (volume). When corrected for size, the human hand loses far more heat per unit volume than the foot. This study attempted to see if macaques showed comparable hand-foot differences by repeating the human test situation as closely as possible on 20 macaques. The monkeys lose less total heat in cold water because their hands and feet are so much smaller, but on a volume basis they exceeded human heat losses. Even more important, the macaque hand and foot show very similar heat losses when the size difference is removed. The human hand and the macaque hand and foot are reasonably close in heat loss per unit volume; the human foot appears unique. Another sample of human subjects in which both extremity volumes and surface areas were measured showed closer heat loss correspondence between hands and feet on the basis of surface area, but the human foot still was lower. Pedal heat loss in man is apparently conditioned by a combination of the foot's special morphology and vascularity.     

Serological diagnostics of imported malaria in Czechoslovakia

Two serologic techniques for malaria detection were compared in this study; the indirect fluorescent antibody (IFA) test used in 214 persons (38 Czechoslovak citizens returning from visits to tropical countries and 176 foreign visitors arriving to Czechoslovakia from areas endemic for malaria) and the indirect hemagglutination (IHA) test employed in 125 persons (29 Czechoslovak citizens and 96 foreigners). Comparisons revealed poor correlation between the IFA test and IHA test data. Of the two tests the IFA test appeared to be distinctly more reliable, more sensitive and more specific, the IHA test turned out to yield both false positive and false negative results. The antigen from Plasmodium gallinaceum gave lower IFA titres than P. falciparum antigen, but reacted with antibodies to all species of human plasmodia, and gave reliable test results. Positive serologic responses were appreciably more frequent in foreigners (46.0%) than Czechoslovak citizens (23.7%). The maximum percent positivity for malarial antibody was among individuals from tropical countries of Africa (74.6%), seropositivity in people from malaria endemic areas in Asia and Latin America was far less frequent (28.4% and 44.4%, respectively).     

Characteristics and lateral dominance of hand grip and elbow flexion powers in young male adults

This study aimed to clarify the characteristics and the lateral dominance of hand grip power and elbow flexion power. The subjects were 15 healthy young males (mean age 22.1+/-0.7 yr, mean height 171.3+/-3.4 cm, mean mass 64.5+/-4.1 kg). All subjects were right-handed. Peak power was measured by both hands with 6 different loads of 20%-70% of maximum voluntary contraction. The maximum voluntary contraction of hand grip movement and elbow flexion movement was significantly larger in the dominant hand. Peak power of the dominant hand was larger in all loads in hand grip movement and in loads of 20% and 30% of maximum voluntary contraction in elbow flexion movement. In short, lateral dominance was confirmed. Peak power was significantly larger in hand grip movement than in elbow flexion movement in both hands. Peak velocity decreased with increasing loads in both movements, but peak power increased until about 50% of maximum voluntary contraction and then decreased. The peak power ratio of the dominant hand to the nondominant hand was significantly larger in hand grip movement than in elbow flexion movement in all loads and the peak power ratio in elbow flexion movement was more marked in light loads. In conclusion, both powers showed lateral dominance. Lateral dominance is more marked in hand grip power.     

New conditions and intraspecific variation of some muscles of hands and feet of Dendropsophus labialis (Peters, 1863) (Anura,Hylidae)

Systematics of frogs have been based on osteological and molecular characters; however, the morphology of the muscles of hands and feet has proven to be an important complement to these studies, but it has not been sufficiently studied. This study presents undescribed conditions based on the origin, insertion or arrangement of 18 muscles of hands and feet of Dendropsophus labialis, and intraspecific variation. Muscles of four specimens (two males and two females) were examined to observe both sides of each specimen determining new conditions, and comparing them with documented species of Dendropsophus. Four intraspecific variant categories were established: Minor, unique, explosive and mimicking. Mainly mimicking, explosive and unique variations were found. Our results show the need to expand intraspecific studies in more species of Dendropsophus and to assess its value in the phylogeny of the genus. The family Hylidae may be identifiable based upon the combination of character states of some of these muscles: the m. flexor indicis superficialis proprius and the group of tendines superficialis digitorum of hands and foot, the m. extensor brevis superficialis Digiti III of the hand, the m. extensor brevis superficialis Digiti IV in hands and the mm. extensores breves profundi Digiti III in hands.     

Reaction time in bimanual simultaneous motions

Electromyographically determined reaction times (EMG-RTs) of the finger flexor and extensor of both forearms were measured for four different motions: inward (task 1), flexion of both wrists; outward (task 2), extension of both wrists; to the left (task 3), extension of the left wrist and flexion of the right; and to the right (task 4), flexion of the left and extension of the right. The EMG-RTs were shorter and synchronization errors in terms of left to right differences of EMG-RTs were smaller in tasks 1 and 2 than in tasks 3 and 4. Comparing the flexors and the extensors, the extent of prolongation of EMG-RTs in tasks 3 and 4 differed significantly on the left side, being larger in the flexor than in the extensor, but there was no difference in the extent of prolongation between the flexor and the extensor on the right. It was suggested that the timing of initiation of movements in simultaneous motions was primarily determined by the pattern of muscle coupling in both limbs, and not by the direction of movements. The steadiness of motor function and of the right hand in right-handed subjects was also discussed in regard to hand preference.     

Increasing hand efficiency at cold temperatures by training hand vasodilation with a classical conditioning-biofeedback overlap design

The prolonged exposure of hands to cold environments leads to substantial cold pain and severe deterioration of manual dexterity, finger dexterity, hand strength, and tactile sensitivity. This study taught volunteers to warm their hands at –14 degrees Celsius and measured the hand efficiency effects. The subjects were six male and female nonsmoking volunteers. All research was conducted in a cold chamber during the warm summer months to eliminate seasonal factors. A combined multiple-baseline/ABA single-subject design with multiple replications was used. Each subject's hand performance was obtained for both hands in warm and in cold conditions. One hand was trained and both hands were retested in the cold. The second hand was trained and both hands were retested in the cold. Finally, the subject inhibited warming while in the cold (treatment removal) and both hands were tested again. The treatment itself used biofeedback instrumentation to extend and enlarge previously classically conditioned vasodilative episodes. The procedure was found to be effective for bringing about temperature changes in the cold. Large treatment effects were found on all hand efficiency measures. The results suggest wide implications for the workplace, for theory, and for future research.This research was supported by a grant from the Occupational Health and Safety division of the Alberta Department of Labor and by a Doctoral Fellowship from the Social Sciences and Humanities Research Council of Canada.     

Hand preference and tool use in wild chimpanzees

The hand preference of chimpanzees in their natural habitat was studied at Bossou, Republic of Guinea, West Africa. The quantitative difference in left/right hand use was small in food picking and carrying. In contrast, the chimpanzees employed either the right or left hand in nutcracking behavior using a pair of stones. All adults and many adolescents and juveniles utilized one hand exclusively for holding a hammer stone. Left hand preference was more prevalent among adults. However, when adolescents and juveniles were included, there was no significant bias in the ratio of left/right handers. Nut-cracking behavior requires long-term learning of the fine manipulation of stones and nuts by both hands. Each hand has a separate role, and the hands work together in nut cracking. The differential and complementary use of both hands may be a prime factor promoting exclusive hand preference in chimpanzees comparable to that of humans.     

Muscle activation characteristics associated with differences in physiological tremor amplitude between the dominant and non-dominant hand

The aim of this study was to assess differences in physiological tremor amplitude of the hand between the dominant and non-dominant side of right-handed individuals. Mechanical loading of the hand and frequency analysis were used in an attempt to identify the physiological mechanisms involved in observed differences. Seventeen healthy right-handed adults participated in a single session where physiological tremor of the outstretched left and right hands was recorded under different loading conditions (0 g up to 5614 g). Physiological tremor amplitude was quantified through accelerometry and electromyographic (EMG) signals of wrist extensor and flexor muscles were also recorded. The main findings were: ～30% greater amplitude of fluctuations in acceleration for the non-dominant compared with the dominant hand, no difference in the frequency content of acceleration or demodulated EMG signals between dominant and non-dominant sides across all loads, and condition-dependent associations between the amplitude of fluctuations in acceleration and EMG amplitude and frequency content. These associations suggest a potential role of central modulation of neural activity to explain dominance-related differences in physiological tremor amplitude of the hand.     

Cardiovascular and sympatho-adrenal responses to static handgrip performed with one and two hands

12 healthy men aged 21-25 years performed, in the sitting position, a sustained handgrip at 25% of their maximum voluntary contraction, first with each hand separately and then with both hands simultaneously. Heart rate (HR), systolic blood pressure (SBP), stroke volume (determined reographically) and plasma catecholamine concentration were measured during each handgrip test. The HR and SBP increased consistently during each handgrip test while stroke volume decreased by approximately 20% of the initial value. Cardiac output did not change significantly. There were no significant differences in the magnitude and dynamics of the cardiovascular responses between the tests with one and with both hands. Plasma noradrenaline and adrenaline levels showed similar elevations in response to handgrip performed with the right hand and with both hands, while during the exercise performed with the left hand the increase in the plasma catecholamine concentration was less pronounced. It was concluded that: (1) during sustained handgrip, performed in the sitting position by young healthy subjects, the stroke volume markedly decreases and cardiac output does not change significantly in spite of the increased HR; (2) the cardiovascular and sympatho-adrenal responses to static handgrip do not depend on the mass of contracting muscle when the same relative tension is developed.     

Laterality patterns in infants with external birth defects.

The lateral distribution of external birth defects has not been reported in a comprehensive way, and patterns in this distribution have not been examined. This study presents the lateral distribution of 6,390 unilateral defects from among 102 defect categories in data collected by the Metropolitan Atlanta Congenital Defects Program. Among all defects, 49% (95% CI 48-51%) were right-sided. Among males and females, 51% (95% CI 50-53%) and 47% (95% CI 46-49%) of the defects, respectively, were right-sided. Of the 102 defect types, 57 had an excess of defects on the right side of the body; 39 had an excess of defects on the left side; and 6 were equally distributed. The excess on the right side was statistically significant for inguinal hernia, incarcerated inguinal hernia, microtia, preauricular sinus, talipes calcaneovalgus, and lambdoidal craniosynostosis. For the left side, the excess was statistically significant for preauricular tags, cleft lip, fused lip and cleft gum, cleft lip with cleft palate, congenital hip dysplasia, unstable hip, absent forearm or hand, anomaly of the knee, and skin tags. The percentage of right-sided defects among case subjects with unilateral defects was correlated with the percentage of males among all case subjects (r = 0.24, P < 0.05). Among male case subjects with unilateral defects, the correlation coefficient was 0.31 (P < 0. 01), and among females with unilateral defects, it was 0.11 (P > 0. 10). Differences in the lateral distribution of specific birth defects may be due to subtle differences in morphogenesis on the left and right sides of the embryo brought about by establishment of left-right asymmetry prior to organogenesis. The fact that more defect categories were right-sided than left-sided may be related to the observation that mitochondrial maturation in rat embryos is delayed on the right side. The right side, therefore, may be more susceptible than the left to defects caused by prenatal hypoxia. The significant correlation between the percentage right-sided and percentage male may then also be related to the observation that male sex hormones lower the mitochondrial respiration rate in rats and increase rat sensitivity to chemical hypoxia. Investigators should consider reporting the laterality of specific defects in both laboratory and epidemiological studies of birth defects. Right- and left-sided defects should perhaps be considered separately in etiologic studies of birth defects. Teratology 60:265-271, 1999. Published 1999 Wiley-Liss, Inc.     

Studies on the tendinous compartments of the extensor muscles on the back of the human hand and their tendon sheaths. I

In 47 dissected right and left hands of adults of both sexes, kept in a moist condition, significant practical-clinical investigations of the transitional zone between forearm and hand were undertaken. In particular it was sought to determine the characteristic sizes of the extensor retinaculum, the osteofibrous tunnels, the insertion tendons of the hand and finger extensor muscles, and their tendon sheaths. Together with the palmar carpal ligament, the 2 to 3 cm wide extensor retinaculum annularly surrounds the whole circumference of the carpus. It extends obliquely from radial-proximal to ulnar-distal and conducts the extensor tendons over the carpal articulations. According to recent studies, it is divided into a superficial and a deep fibrous layer. From the undermost surface, vertical and oblique septa run to the plane of the forearm and carpal bones. They separate the fibrous portion of the 6 tendinous compartments of the dorsum manus. In 8.5% of cases, an accessory and completely independent tunnel of the extensor pollicis brevis muscle exists in the material investigated, and in 2.2% of cases, there is an additional tunnel for the extensor carpi radialis muscle. Hence, one occasionally finds 8 separate osteofibrous gliding compartments for the extensor muscles in the dorsal hand region. The longest tunnel belongs, as a rule, to the extensor digiti minimi muscle, whilst the widest pertains to the extensor digitorum muscle. Within the tunnel and also proximal and distal to it, the extensor tendons are surrounded by synovial sheaths. Because of its wide encroachment on the dorsum of the hand, the insertion tendon of the extensor digiti minimi muscle possesses the longest tendon sheath, measuring 68.8 mm. The next longest sheath, that of the extensor pollicis longus muscle, which measures 56.2 mm, begins further proximal to the gap of the radiocarpal articulation. In 12.8% of cases, there are divided sheaths of the abductor pollicis longus and of the extensor pollicis brevis muscle. The tendon sheath of both extensor carpi radiales muscles is frequently divided into 2 compartments which, in 2/3 of cases, communicate. The compartment of the extensor carpi radialis brevis muscle, in 91.5% of cases, shares a window-like opening with the roof of the synovial vagina of the extensor pollicis longus muscle. The tendon sheath of the long extensor muscles of the fingers originates 5 mm proximal to the forearm border of the extensor retinaculum and has a communal recess. The IVth tendon sheath opens distally and splays out in a glove-like manner to some distal recesses.(ABSTRACT TRUNCATED AT 400 WORDS)