Palmar flexion creases in schizophrenia

Palmar flexion creases have been studied in schizophrenics with a family history of schizophrenia or other psychiatric disorders and without such a background, and compared to a control population. Palmar flexion creases have been analyzed according to the method suggested byBali & Chaube (1971). When compared to controls, differences in the DRBC and TRBC frequencies are significant in the subgroup with no family history, supporting the existence of biological heterogeneity in schizophrenia, and of congenital factors when there is no known genetic background.     

On the variability of “flexion creases” in the distal plantar areas of newborns

The plantae of 83 male and 95 female healthy, full-term Caucasian newborns from Austria (gestational age 235–301 days) were photographed and the flexion creases in the distal part were examined. Analysis of the creases was done under four different aspects, the main evaluation based on a scheme of nine creases introduced by Schenk and Patzer (1959). Two transversal (No. 1 and No. 9) and three longitudinal (Nos. 3, 6, and 7) creases are always or predominantly present, a finding corresponding with the data of Schenk on 52 male and 48 female newborns from Germany. In addition, the nine plantar creases were evaluated according to six degrees of expression, and some typical crease combinations are shown. Bilateral and bisexual similarity prevails. The results of this study might serve investigations of different populations and of medical disorders.     

Seed dispersal spectra: a comparison of temperate plant communities

Abstract. We compare the dispersal spectra of diaspores from varied plant communities in Australia, New Zealand, and North America, assigning dispersal mode to each diaspore type on the basis of apparent morphological adaptations. Species with ballistic and external dispersal modes were uncommon in most communities we surveyed. Ant dispersal was also rather uncommon, except in some Australian sclerophyll vegetation types. The frequency of vertebrate dispersal ranged up to 60% of the flora, the highest frequencies occurring in New Zealand forests. Wind dispersal ranged as high as 70% of the flora, with the highest values in Alaska, but usually comprised 10–30% of the flora. Many species in most communities had diaspores with no special morphological device for dispersal. Physiognomically similar vegetation types indifferentbiogeographic regions usually had somewhat dissimilar dispersal spectra. The frequency of dispersal by vertebrates often increased and the frequency of species with no special dispersal device decreased along gradients of increasing vertical diversity of vegetation structure. Elevation and moisture gradients also exhibited shifts in dispersal spectra. Within Australia, vertebrate- and wind-dispersal increased in frequency along a soil-fertility gradient, and dispersal by ants and by no special device decreased. Habitat breadths (across plant communities) and microhabitat breadths (within communities) for species of each major dispersal type did not show consistent differences, in general. Ant-dispersed species often had lower cover-values than other species in several Australian vegetation types. We discuss the ecological bases of these differences in dispersal spectra in terms of the availability of dispersal agents, seed size, and other ecological constraints. Seed size is suggested to be one ecological factor that is probably of general relevance to the evolution of dispersal syndromes.     

Role of gastrocnemius activation in knee joint biomechanics: gastrocnemius acts as an ACL antagonist

Gastrocnemius is a premier muscle crossing the knee, but its role in knee biomechanics and on the anterior cruciate ligament (ACL) remains less clear when compared to hamstrings and quadriceps. The effect of changes in gastrocnemius force at late stance when it peaks on the knee joint response and ACL force was initially investigated using a lower extremity musculoskeletal model driven by gait kinematics—kinetics. The tibiofemoral joint under isolated isometric contraction of gastrocnemius was subsequently analyzed at different force levels and flexion angles (0°–90°). Changes in gastrocnemius force at late stance markedly influenced hamstrings forces. Gastrocnemius acted as ACL antagonist by substantially increasing its force. Simulations under isolated contraction of gastrocnemius confirmed this role at all flexion angles, in particular, at extreme knee flexion angles (0° and 90°). Constraint on varus/valgus rotations substantially decreased this effect. Although hamstrings and gastrocnemius are both knee joint flexors, they play opposite roles in respectively protecting or loading ACL. Although the quadriceps is also recognized as antagonist of ACL, at larger joint flexion and in contrast to quadriceps, activity in gastrocnemius substantially increased ACL forces (anteromedial bundle). The fact that gastrocnemius is an antagonist of ACL should help in effective prevention and management of ACL injuries.     

Two novel methods to assess ulnar nerve conduction across the elbow

PurposeNerve conduction studies (NCS) are used as an electrodiagnostic method for diagnosing ulnar neuropathy of the elbow (UNE). The purpose of this study was to determine normal and reliability values of across elbow ulnar nerve conduction velocity using two novel methods.MethodsUlnar nerve conduction studies were performed on both upper extremities of 104 healthy subjects. Two different techniques were used to evaluate ulnar nerve function at the elbow: Technique 1 (W-BE-AE) determined mixed NCV across the elbow indirectly while Technique 2 (BE-AE) measured conduction time directly. Twenty subjects returned within one week for re-testing to generate reliability data.ResultsThe mean NCV for the BE-AE segment using Technique 1 was 59.68 m/s (±8.91 m/s). The mean peak latency for the BE-AE segment using Technique 2 was 2.03 ms (±0.24 ms). The interrater and intrarater reliability intraclass correlation coefficient (ICC) for Technique 1 was 0.454 and 0.756, respectively. For Technique 2, the interrater and intrarater reliability ICC was 0.76 and 0.814, respectively.ConclusionThis study identified normal values for ulnar nerve conduction across the elbow with reliability ranging from poor to good, depending on the technique. These two novel techniques provide alternative methods to traditional techniques to measure ulnar nerve conduction across the elbow.     

Patients with chronic,but not episodic,migraine display altered activity of their neck extensor muscles

The current study aimed to investigate differences in activity of neck flexor and extensor muscles in women with migraine considering the chronicity of their condition. Thirty-one subjects with episodic migraine, 21 with chronic migraine and 31 healthy controls participated. Surface electromyography signals were recorded bilaterally from the sternocleidomastoid, anterior scalene, splenius capitis and upper trapezius muscles as subjects performed 5 stages of cranio-cervical flexion (CCF), representing a progressive increase in range of CCF motion. Comparison of normalized root-mean-square among groups was conducted with 3 × 5 ANCOVA with task level as the within-subject variable, group as the between-subject variable, and the presence of neck pain and disability as co-variates. The group with chronic migraine exhibited increased activity of their extensor muscles compared to the control and episodic migraine groups (splenius capitis: F = 3.149, P = 0.045; upper trapezius: F = 3.369, P = 0.041). No significant between-group differences were found for the superficial neck flexors (sternocleidomastoid: F = 1.161, P = 0.320; anterior scalene: F = 0.135, P = 0.874). In conclusion, women with chronic migraine exhibit increased activity of their superficial neck extensor muscles when acting as antagonists during low-load isometric CCF contractions in comparison to non-headache subjects.     

“Sensory Switching” in Elbow Reconstruction

In the treatment of the soft tissue defect of the elbow, flap reconstruction is necessitated in many cases because of thinness of soft tissue at this region. In addition, reacquirement of tactile sensation is desirable because of the anatomical and specific functions of the elbow. Of three cases treated for elbow defects, one was reconstructed with a pedicled island forearm flap containing the lateral cutaneous nerve of the forearm, another was reconstructed with a venoneuro-accompanying artery fasciocutaneous flap (VNAF flap) containing the basilic vein, and the third with the VNAF flap containing the cephalic vein. The three cases demonstrated a sudden change of sensory territory 4 to 6 months after surgery, which was confirmed by touching the reconstructed region with patients'' eye-closed: from its original territory to the elbow in a “switching”-like action. Here we describe and discuss the concept of “sensory switching.”     

The predatory behaviour of the thylacine: Tasmanian tiger or marsupial wolf?

The extinct thylacine (Thylacinus cynocephalus) and the extant grey wolf (Canis lupus) are textbook examples of convergence between marsupials and placentals. Craniodental studies confirm the thylacine's carnivorous diet, but little attention has been paid to its postcranial skeleton, which would confirm or refute rare eyewitness reports of a more ambushing predatory mode than the pack-hunting pursuit mode of wolves and other large canids. Here we show that thylacines had the elbow morphology typical of an ambush predator, and propose that the 'Tasmanian tiger' vernacular name might be more apt than the 'marsupial wolf'. The 'niche overlap hypothesis' with dingoes (Canis lupus dingo) as a main cause of thylacine extinction in mainland Australia is discussed in the light of this new information.     

Elbow joint adductor moment arm as an indicator of forelimb posture in extinct quadrupedal tetrapods

Forelimb posture has been a controversial aspect of reconstructing locomotor behaviour in extinct quadrupedal tetrapods. This is partly owing to the qualitative and subjective nature of typical methods, which focus on bony articulations that are often ambiguous and unvalidated postural indicators. Here we outline a new, quantitatively based forelimb posture index that is applicable to a majority of extant tetrapods. By determining the degree of elbow joint adduction/abduction mobility in several tetrapods, the carpal flexor muscles were determined to also play a role as elbow adductors. Such adduction may play a major role during the stance phase in sprawling postures. This role is different from those of upright/sagittal and sloth-like creeping postures, which, respectively, depend more on elbow extensors and flexors. Our measurements of elbow muscle moment arms in 318 extant tetrapod skeletons (Lissamphibia, Synapsida and Reptilia: 33 major clades and 263 genera) revealed that sprawling, sagittal and creeping tetrapods, respectively, emphasize elbow adductor, extensor and flexor muscles. Furthermore, scansorial and non-scansorial taxa, respectively, emphasize flexors and extensors. Thus, forelimb postures of extinct tetrapods can be qualitatively classified based on our quantitative index. Using this method, we find that Triceratops (Ceratopsidae), Anhanguera (Pterosauria) and desmostylian mammals are categorized as upright/sagittally locomoting taxa.     

Kinematic data on primate head and neck posture: Implications for the evolution of basicranial flexion and an evaluation of registration planes used in paleoanthropology

Kinematic data on primate head and neck posture were collected by filming 29 primate species during locomotion. These were used to test whether head and neck posture are significant influences on basicranial flexion and whether the Frankfurt plane can legitimately be employed in paleoanthropological studies. Three kinematic measurements were recorded as angles relative to the gravity vector, the inclination of the orbital plane, the inclination of the neck, and the inclination of the Frankfurt plane. A fourth kinematic measurement was calculated as the angle between the neck and the orbital plane (the head-neck angle [HNA]). The functional relationships of basicranial flexion were examined by calculating the correlations and partial correlations between HNA and craniometric measurements representing basicranial flexion, orbital kyphosis, and relative brain size (Ross and Ravosa [1993] Am. J. Phys. Anthropol. 91:305–324). Significant partial correlations were observed between relative brain size and basicranial flexion and between HNA and orbital kyphosis. This indicates that brain size, rather than head and neck posture, is the primary influence on flexion, while the degree of orbital kyphosis may act to reorient the visual field in response to variation in head and neck posture. Regarding registration planes, the Frankfurt plane was found to be horizontal in humans but inclined in all nonhuman primates. In contrast, nearly all primates (including humans) oriented their orbits such that they faced anteriorly and slightly inferiorly. These results suggest that for certain functional craniometric studies, the orbital plane may be a more suitable registration plane than Frankfurt “Horizontal.” Am J Phys Anthropol 108:205–222, 1999. © 1999 Wiley-Liss, Inc.