Sexual size dimorphism and geographic variation in forearm length of Rafinesque’s Big-eared Bat (Corynorhinus rafinesquii) and Southeastern Myotis (Myotis austroriparius)

Sexual size dimorphism is common in many taxa and results from various pressures, including competition, reproductive requirements, functional differences, and sexual recognition. For mammals, males are typically the larger sex; however, for vespertilionid bats, females are more often the larger sex. Forearm length, a feature that influences overall wing and body size and is often sexually dimorphic, is a standard morphological measurement taken from bats. Forearm length was measured in two vesper bat species (Corynorhinus rafinesquii and Myotis austroriparius) that co-occur across much of the southeastern United States. Forearm length was greater in females of both species, and females of both species also exhibited regional variation in forearm length. By having a longer forearm and therefore being larger in size, females may be more maneuverable and better equipped to carry young. While this study did not directly investigate the mechanisms behind regional variation in forearm length, it is possible this is the result of variability in habitat types, resources, or thermodynamic constraints. Knowledge of sexually dimorphic characteristics is important for obtaining a general understanding of a species and its morphology.

Prosthetic liner-socket design for children with long congenital and amputated shoulder

BACKGROUND: Traditional cosmetic prosthetic designs for a long shoulder stump in children have several disadvantages, such as a rigid uncomfortable receiving socket, the need to use a strap fastening, and the non-cosmetic product due to the disproportionate shoulder and forearm length compared with the preserved limb. AIM: This study aimed to design, manufacture, and test a prototype of the shoulder stump liner-socket. MATERIALS AND METHODS: A new liner-socket of a shoulder cosmetic prosthesis has been developed, confirmed by a Russian Federation patent for an invention, which for the first time, in the practice of domestic prosthetics, is made of two types of silicone and has been successfully used in cosmetic prosthetics for 17 children, of whom 10 previously used traditional long stump prosthesis. Satisfaction with new liner-socket prosthesis was analyzed using a psychometric scale compared with a conventional prosthesis. RESULTS: The developed design combines both the inner socket function, which allows the elbow hinge to be attached to it and the liner properties, which ensures a comfortable stay of the stump in the receiving socket due to the properties of silicone and excludes the use of traditional bandages. CONCLUSIONS: The presented medical and technical solution ensures the simplicity and reliability of fastening the cosmetic shoulder stump prosthesis, including on the long shoulder stump, without disturbing the relatively healthy limb proportions, as well as wearing comfort.

"Physical factors affecting the strength of arm wrestling"

Arm-wrestling is known as an easy-to-use, friendly play or competition. Since arm-wrestling is won by involving the opponent's arm and falling down, it is said that the size of the body frame, the grip strength, which is the gross muscle strength of the entire arm, or the effective mechanical activity of the muscle groups is important. However, there has been no research on the factors that are effective in winning arm wrestling. Therefore, we examined the factors necessary to win arm wrestling by examining the arm wrestling rate and forearm length, weight, grip strength, and maximum internal rotation vector value of the shoulder joint by using 16 healthy 20-22 years old as subjects. The relationship was examined statistically by Spearman's correlation coefficient. Then, using a multiple regression analysis, the winning rate of arm wrestling was analyzed as a dependent variable, and items with significant correlation were analyzed as independent variables. As a result, it was found that the winning rate of arm wrestling has a high correlation between forearm length and the maximum internal rotation vector value of the shoulder joint, and the latter is particularly involved.

Morphometric Sex Identification of Nestling and Free-Flying Tasmanian Wedge-Tailed Eagles (Aquila audax fleayi)

ABSTRACT The endangered Tasmanian Wedge-tailed Eagle (Aquila audax fleayi) is the focus of continued research and conservation efforts. A tool for accurate and efficient identification of the sex of individuals would be a valuable aid to research and management. However, plumages are monomorphic between the sexes, making sex identification difficult without molecular analyses. Our aim was to assess whether Tasmanian Wedge-tailed Eagles of different age classes could be sexed accurately using morphological measurements. We took measurements of 25 live late-stage eagle nestlings and 108 carcasses of free-flying birds found opportunistically throughout Tasmania. Sex of all individuals was confirmed via genetic analyses. Free-flying birds were larger than nestlings; thus, we used age-specific statistical tools to distinguish the sexes. For both nestlings and free-flying birds, females were significantly larger than males, but overlap between the sexes prevented accurate sex identification using any single measurement. We used stepwise linear discriminant function analyses to select morphometric measurements necessary for accurate sex identification. Free-flying birds could be sexed with 97.6% accuracy using a combination of measurements of the forearm length, tarsus width (i.e., lateromedial width), and hallux length. Late-stage nestlings (9–10 wk old) could be sexed with 95.4% accuracy using measurements of the hallux width (i.e., lateromedial width), hallux breadth (i.e., anteroposterior width of hallux), and tarsus breadth (i.e., anteroposterior width of the tarsometatarsus at the narrowest point). The discriminate functions we present also allow the identification of sex in cases where morphological sex identification may be in doubt and molecular analyses should be prioritized. These equations provide a valuable research tool for studies of sexual differences in behavior and causes of mortality of this endangered subspecies.

Correlation of hand functionality and grip strengths with anthropometric measurements

BACKGROUND: Using objective anthropometric measurement data and anthropometric ratios, grip strength and hand functionality can be evaluated. OBJECTIVE: The aim of this study was to obtain anthropometric measurements regarding the forearm and hand, to evaluate the hand functionality in addition to hand and finger grip strengths, and to investigate the correlation between these values. METHODS: One-hundred eight-four subjects between 18 and 25 years were included in the study. Forearm and hand anthropometric measurements and ratios were measured. Hand and lateral grip strengths were evaluated. Jebsen Taylor Hand Function Test (JTHFT) was used to assess hand functionality. RESULTS: A statistically weak and consistently negative correlation between the ratios of forearm length to forearm/wrist circumferences and the ratio of hand length to metacarpal head circumference and hand-lateral grip strengths was found. There was a statistically weak and consistently negative correlation between these ratios and the subtests of JTHFT. It was shown that there was a statistically weak–moderate positive correlation between the hand-lateral grip strengths and JTHFT subtests. CONCLUSIONS: In conclusion, when evaluating grip strength and hand functionality, forearm and hand anthropometric measurements and ratios, which could affect the results, should be considered.

3D Scanning of the Forearm for Orthosis and HMI Applications

The rise of rehabilitation robotics has ignited a global investigation into the human machine interface (HMI) between device and user. Previous research on wearable robotics has primarily focused on robotic kinematics and controls but rarely on the actual design of the physical HMI (pHMI). This paper presents a data-driven statistical forearm surface model for designing a forearm orthosis in exoskeleton applications. The forearms of 6 subjects were 3D scanned in a custom-built jig to capture data in extreme pronation and supination poses, creating 3D point clouds of the forearm surface. Resulting data was characterized into a series of ellipses from 20 to 100% of the forearm length. Key ellipse parameters in the model include: normalized major and minor axis length, normalized center point location, tilt angle, and circularity ratio. Single-subject (SS) ellipse parameters were normalized with respect to forearm radiale-stylion (RS) length and circumference and then averaged over the 6 subjects. Averaged parameter profiles were fit with 3rd-order polynomials to create combined-subjects (CS) elliptical models of the forearm. CS models were created in the jig as-is (CS1) and after alignment to ellipse centers at 20 and 100% of the forearm length (CS2). Normalized curve fits of ellipse major and minor axes in model CS2 achieve R2 values ranging from 0.898 to 0.980 indicating a high degree of correlation between cross-sectional size and position along the forearm. Most other parameters showed poor correlation with forearm position (0.005 < R2 < 0.391) with the exception of tilt angle in pronation (0.877) and circularity in supination (0.657). Normalized RMSE of the CS2 ellipse-fit model ranged from 0.21 to 0.64% of forearm circumference and 0.22 to 0.46% of forearm length. The average and peak surface deviation between the scaled CS2 model and individual scans along the forearm varied from 0.56 to 2.86 mm (subject averages) and 3.86 to 7.16 (subject maximums), with the peak deviation occurring between 45 and 50% RS length. The developed equations allow reconstruction of a scalable 3D model that can be sized based on two user measures, RS length and forearm circumference, or based on generic arm measurements taken from existing anthropometric databases.

STATURE PREDICTION OF PUNJAB POPULATION (PAKISTAN) FROM HAND, FOREARM AND FOOT MEASUREMENTS

Anthropometry is a systematic study of body measurements in man. Forensic anthropologist tries best to answer the questions relating to age, origin, height, gender, and race after examination of the body remains. The biological profile of a person such as age, sex, ethnicity, and stature can be determined with the help of anthropometry. Results of the study revealed the normal distribution of data and with tests, statistics are found to be significant at p≤0.05 level of significance for all parameters employed in this study. Males have consistently larger values as compared to the female's forearm length, hand length right/left, hand width right/left, foot length right/ left and foot width right/left. Therefore, it is concluded that there is a significant difference between males' and female's character measurements including hand, forearm, and foot.

Postnatal growth and development of Natalus mexicanus (Chiroptera: Natalidae)

Natalus mexicanus is a bat species distributed from northern México to Central America. It inhabits various types of tropical vegetation, roosting mainly in caves with high relative humidity and temperature, and feeding mostly on arachnids. This study investigated postnatal growth and flight development of populations under natural conditions inhabiting “Los Laguitos” cave, Chiapas, southern México. Forty-four females and 50 males were monitored from birth to 55 days of age; at five-day intervals, we measured body mass, forearm length, cartilaginous epiphyseal gap of the fourth metacarpal-phalangeal joint, and development of four characters. We used statistical analyses and growth models to quantify the changes in morphometric parameters. Neonates are altricial; the ears began to unfold since day one, while the eyes opened at day 25. Greyish hair appeared between 25 to 35 days. Forearm length and body mass increased linearly over 35 days, then the growth rate decreased. The cartilaginous epiphyseal gap increased in size until day 25 and then started to close. The logistic equation yielded the best fit for forearm length (K = 0.07) and body mass (K = 0.10). Sustained flight was first achieved at 35 days of age. N. mexicanus neonates are altricial and relatively small compared with other bats. Eye-opening and fur development took place at a slower rate than in most species of insectivorous bats. In the Chiapas population, eye-opening, fur development, and volancy occurred more slowly relative to the population inhabiting Álamos, Sonora. These differences are probably consequences of local variations. The morphometric postnatal growth pattern of N. mexicanus was like that of other insectivorous bats, i. e., linear growth rate before the onset of flight and slowing down thereafter. As in other studies, the logistic model best fitted the growth pattern of body mass and forearm length, but growth coefficients were lower versus other tropical bats. The cartilaginous epiphyseal gap of the fourth digit closes at an intermediate age relative to other insectivorous bats. Sustained flight was attained when the relative body mass and forearm length of individuals approached adult body dimensions, as in other bat species.

Ultrasonographic Analysis of Optimal Needle Placement for Extensor Indicis

Objective To determine the most optimal needle insertion point of extensor indicis (EI) using ultrasound.Methods A total 80 forearms of 40 healthy volunteers were recruited. We identified midpoint (MP) of EI using ultrasound and set MP as optimal needle insertion point. The location of MP was suggested using distances from landmarks. Distance from MP to medial border of ulna (MP-X) and to lower margin of ulnar head (MP-Y) were measured. Ratios of MP-X to Forearm circumference (X ratio) and MP-Y to forearm length (Y ratio) were calculated. In cross-sectional view, depth of MP (Dmp), defined as middle value of superficial depth (Ds) and deep depth (Dd) was measured and suggested as proper depth of needle insertion.Results Mean MP-X was 1.37±0.14 cm and mean MP-Y was 5.50±0.46 cm. Mean X ratio was 8.10±0.53 and mean Y ratio was 22.15±0.47. Mean Dmp was 7.63±0.96 mm.Conclusion We suggested that novel optimal needle insertion point of the EI. It is about 7.6 mm in depth at about 22% of the forearm length proximal from the lower margin of the ulnar head and about 8.1% of the forearm circumference radial from medial border of ulna.