In order to discuss the evaluation method of human upper limb movements, the patterns of movement coordination during healthy people prehension have been researched. Eight subjects were asked to perform different reaching-grasping and drinking water from the cup tasks with different indices of difficulty, and the arm movement trajectories and the main muscles group electromyography (EMG) data were collected. To explore the prehension control mechanism, a comparison has been made between the solution of the theoretic calculation and the experimental data. The results show that the topological invariance was observed in the trajectories of different task performance, and the linear relationships between joints covariation were exhibited. Moreover, the different muscles were controlled and combined into units of synergistic muscular group necessary to reach and grasp the goal.
Adult ; Electromyography ; Hand ; physiology ; Hand Strength ; physiology ; Humans ; Male ; Models, Biological ; Range of Motion, Articular ; physiology ; Upper Extremity ; physiology

This study was done to evaluate differences in pressure pain threshold, grip strength, manual dexterity and touch pressure threshold in the dominant and non-dominant hands of right- and left-handed subjects, and to compare findings within and between these groups. Thirty-nine right-handed and twenty-one left-handed subjects participated in the study. Pressure pain threshold was assessed using a dolorimeter, grip strength was assessed with a hand-grip dynamometer, manual dexterity was evaluated using the VALPAR Component Work Sample-4 system, and touch pressure threshold was determined using Semmes Weinstein monofilaments. Results for the dominant and non-dominant hands were compared within and between the groups. In the right-handed subjects, the dominant hand was significantly faster with the VALPAR Component Work Sample-4, showed significantly greater grip strength, and had a significantly higher pressure pain threshold than the non-dominant hand. The corresponding results for the two hands were similar in the left-handed subjects. The study revealed asymmetrical manual performance in grip strength, manual dexterity and pressure pain threshold in right-handed subjects, but no such asymme-tries in left-handed subjects.
Adult ; Female ; Hand/innervation/*physiology ; Hand Strength/*physiology ; Humans ; Laterality/*physiology ; Male ; Motor Skills/*physiology ; Pain Threshold/*physiology ; Physical Stimulation ; Touch/*physiology

Bipedalism (using only two legs for walking) and having the capability to use tools have long been considered characteristic features that differentiate human beings from animals. Being able to walk upright freed up human hands, allowing us to reach, grasp, carry food, make and use tools, which greatly increased the survivability of our ancestors. Hand actions not only involve muscles and joints to execute actions but also require computations in the brain to analyze the visual environment and select the appropriate action, as well as formulate the action before execution and correct it in real-time during execution. Here, we review the behavioral and brain imaging research of human hand actions from a perspective of cognitive neuroscience. The review includes the research contents and methods of visually-guided action, existing theories, current debates, new evidence of existing theories, and the applications of action research in robotics and artificial intelligence.
Brain ; diagnostic imaging ; physiology ; Hand ; Humans ; Neuroimaging ; Psychomotor Performance

OBJECTIVES: To investigate the link between cigarette smoking and muscle strength in Japanese men. METHODS: We used data on 4249 Japanese men, aged 43.3+/-13.9 years, in this cross-sectional investigation study. Grip strength and leg strength were measured as indicators of overall muscle strength. Meanwhile, subjects' cigarette smoking habits were recorded by trained medical staff. The effect of cigarette smoking on muscle strength was evaluated. RESULTS: A total of 1618 men (38.1%) were smokers and 1481 men (34.9%) exercised regularly. Significant differences in muscle strength were noted between men with and without a Brinkman index of 400 or greater, after adjusting for age. After adjusting for age, height, body weight and exercise habits, associations between the Brinkman index and leg strength and the ratio of leg strength to body weight were attenuated. CONCLUSIONS: Cigarette smoking might be negatively associated with muscle strength, especially grip strength in Japanese men.
Adult ; Body Weight ; Exercise ; Hand Strength/physiology ; Humans ; Japan ; Male ; Middle Aged ; Muscle Strength/*physiology ; *Smoking

Objective: To investigate the present situation of pelvic floor muscle strength, and to analyze the factors affecting pelvic floor muscle strength. Methods: The data of patients who were admitted into the general outpatient department of gynecology, Peking University People's Hospital from October 2021 to April 2022 were collected, and the patients who met the exclusion criteria were included in this cross sectional study. The patient's age, height, weight, education level, defecation way and defecation time, birth history, maximum newborn birth weight, occupational physical activity, sedentary time, menopause, family history and disease history were recorded by questionnaire. Morphological indexes such as waist circumference, abdomen circumference and hip circumference were measured with tape measure. Handgrip strength level was measured with grip strength instrument. After performing routine gynecological examinations, the pelvic floor muscle strength was evaluated by palpation with modified Oxford grading scale (MOS). MOS grade>3 was taken as normal group and ≤3 as decreased group. Binary logistic regression was used to investigate the related factors of deceased pelvic floor muscle strength. Results: A total of 929 patients were included in the study, and the average MOS grade was 2.8±1.2. By univariate analysis, birth history, menopausal time, defecation time, handgrip strength level, waist circumference and abdominal circumference were related to the decrease of pelvic floor muscle strength (all P<0.05). By binary logistic regression analysis, the level of handgrip strength (OR=0.913, 95%CI: 0.883-0.945; P<0.001) was correlated with normal pelvic floor muscle strength; waist circumference (OR=1.025, 95%CI: 1.005-1.046; P=0.016), birth history (OR=2.224, 95%CI: 1.570-3.149; P<0.001), sedentary time> 8 hours (OR=2.073, 95%CI: 1.198-3.587; P=0.009) were associated with the decrease of pelvic floor muscle strength. Conclusions: The level of handgrip strength is related to the normal pelvic floor muscle strength of females, while the waist circumference, birth history and sedentary time>8 hours are related to the decrease of pelvic floor muscle strength of females. In order to prevent the decrease of pelvic floor muscle strength, it is necessary to carry out relevant health education, enhance exercise, improve the overall strength level, reduce daily sedentary time, maintain symmetry, and carry out comprehensive overall intervention to improve pelvic floor muscle function.
Adult ; Female ; Humans ; Cross-Sectional Studies ; Gynecology ; Hand Strength ; Muscle Contraction/physiology* ; Muscle Strength/physiology* ; Outpatients ; Pelvic Floor/physiology*

This study was designed to establish norms of hand function, and to identify developmental characteristics of hand function among the Korean children. 712 elementary school children participated in measurement of grip strength, three kinds of pinch strength, and dexterity. The hand strength of the Korean children appeared to be weaker than that of western children. The grip strength of boys was significantly stronger than that of girls in all ages for both hands. The order of magnitude of three kinds of pinch strength was, in descending order, lateral pinch, palmar pinch and tip pinch for both boys and girls. There was no significant difference of hand function according to the type of hand dominance in boys. However, girls with left hand dominance showed weakness of bilateral grip, right tip pinch, and bilateral lateral pinch strength compared with girls with right hand dominance. In conclusion, this study provided normative data of hand functions including dexterity, and enabled us to identify some developmental characteristics of hand functions for the Korean elementary school children.
Age Factors ; Child ; Comparative Study ; Female ; Hand/*physiology ; *Hand Strength ; Human ; Korea ; Laterality ; Male ; Motor Skills ; Schools ; Sex Factors ; Students

INTRODUCTIONThe superficial and deep palmar arterial arches are the main sources of blood supply to all structures in the human hand, and variations in these arterial arches are quite common. Although several studies have reported diameters and variations of these arches, to the authors' knowledge, no study has correlated such changes to handedness in adults. It is likely that dominance may play a role in arterial variations, such as those seen in the diameter or number of arteries formed in the palmar arches, much like in other areas of the human body. This cadaver study was conducted to determine any such association.

METHODS42 formalin-fixed hands were dissected to expose the superficial and deep palmar arches. These arches were then thoroughly examined for any variations between the dominant and non-dominant hands. All cadavers were noted to be right-handed as per hospital records.

RESULTS19 complete superficial arterial arches (right hand 14; left hand 5) were found in the 42 hands dissected.

CONCLUSIONMost complete superficial palmar arches were found in the dominant hand of the cadavers studied, and therefore, handedness may have a role to play in determining palmar arterial arch variations in humans. Due to dominance or handedness, some arteries may likely persist into adulthood while others may become obliterated, thus leading to variations. Dissection of foetal hands may help to shed more light on the persistence or obliteration of various arteries after birth. Knowledge of such variations may prove helpful for surgeons during hand surgeries.

Cadaver ; Functional Laterality ; Hand ; anatomy & histology ; physiology ; Hand Deformities ; Humans ; Radial Artery ; anatomy & histology ; Ulnar Artery ; anatomy & histology

The control of prosthetic hand is always a focus in prosthesis research. For solving current problems of controlling signals of skin surface electrical signals, we applied force myography (FMG) signals in prosthetic control of this system. The control system based on FMG signals were designed, containing signal acquisition and pre-processing, prosthetic control, motor driving and so on. Two-freedom artificial hand with proportional control was proposed through acquiring two-channel FMG signals from the amputee stump. The proportional control of prosthetic hand was achieved according to the average of FMG amplitude. The results showed that the control system had a great potential to control artificial hand and to realize speed adjustment effectively. Besides, the Virtual instrument software LabVIEW is adopted to establish the FMG signal collection and calibration of experiment system.
Algorithms ; Artificial Limbs ; Electromyography ; instrumentation ; methods ; Hand ; physiology ; Humans ; Movement ; physiology ; Myography ; Pattern Recognition, Automated ; methods ; Prosthesis Design

OBJECTIVETo assess nutritional status and define gender- and age-specific handgrip strength (HGS) cut-point values for malnutrition or nutritional risk in elderly inpatients.

METHODSA cross-sectional study of 1,343 elderly inpatients was conducted in the Chinese PLA General Hospital. Nutrition Risk Screening (NRS 2002) and Subjective Global Assessment (SGA) were administered. Anthropometric measurements and blood biochemical indicators were obtained using standard techniques. The gender- and age-specific receiver operating characteristic (ROC) curves were constructed to evaluate the HGS for nutritional status by SGA and NRS 2002. Sensitivity, specificity, and areas under the curves (AUCs) were calculated.

RESULTSAccording to NRS 2002 and SGA, 63.81% of elderly inpatients were at nutritional risk and 28.22% were malnourished. Patients with higher HGS had an independently decreased risk of malnutrition and nutritional risk. The AUCs varied between 0.670 and 0.761. According to NRS 2002, the optimal HGS cut-points were 27.5 kg (65-74 years) and 21.0 kg (75-90 years) for men and 17.0 kg (65-74 years) and 14.6 kg (75-90 years) for women. According to SGA, the optimal HGS cut-points were 24.9 kg (65-74 years) and 20.8 kg (75-90 years) for men and 15.2 kg (65-74 years) and 13.5 kg (75-90 years) for women.

CONCLUSIONElderly inpatients had increased incidence of malnutrition or nutritional risk. HGS cut-points can be used for assessing nutritional status in elderly inpatients at hospital admission in China.

Aged ; Aged, 80 and over ; Asian Continental Ancestry Group ; Female ; Hand Strength ; physiology ; Humans ; Inpatients ; Male ; Nutritional Status ; physiology

Many species have been drastically affected by rapid urbanization. Harris's hawks from their natural habitat of open spaces and a supply of rodents, lizards and other small prey have been forced to change their natural environment adapting to living in open spaces in sub- and peri-urban areas. Specific areas include playgrounds, parks and school courtyards. The migration of this predatory species into these areas poses a risk to individuals, and especially the children are often attacked by claws, talons and beaks intentionally or as collateral damage while attacking rodent prey. In addition, the diverse micro-organisms harbored in the beaks and talons can result in wound infections, presenting a challenge to clinical management. Here we would like to present a case of an 80-year-old man with cellulitis of both hands after sustaining minor injuries from the talons of a Harris's hawk and review the management options. We would also like to draw attention to the matter that, even though previously a rarity, more cases of injuries caused by birds of prey may be seen in hospital settings.
Aged, 80 and over ; Animals ; Behavior, Animal ; Cellulitis ; etiology ; Hand Injuries ; etiology ; Hawks ; physiology ; Humans