Arches of the hand in reach to grasp

Topographically, the hand is described by its anterior (palmar) and posterior (dorsal) surfaces that encompass a hollow cavity that changes its shape during hand preshaping and grasping according to the object to be grasped. The hollow cavity has been described as consisting of three arches that run in different directions: transverse, longitudinal and oblique, spanning the anterior surface of the hand. Although described anatomically, the modulation in the palmar arches has not been investigated kinematically during actual grasping. In this study, we describe and compare biomechanical formulations of the palmar arch, specifically, the distal transverse and the oblique arches. In addition, we introduce another biomechanical formulation of the palmar arch, called the kinematic transverse arch that takes account of the thenar and hypothenar involvement in arch formation. Hand shape modulation during two natural power-grasping tasks was studied in eight healthy adults. Results showed a significant influence of the overall contribution of thenar and hypothenar movement during hand shape modulation. While there was relatively more thenar contribution during transport shaping, more hypothenar contribution was evident during preshaping and contact shaping-the two phases of grasping during which the hand establishes contact with the object. The advantage of the new formulation is that it better described the contributions from thenar and hypothenar movement to palmar arch formation which may be a more accurate depiction of hand preshaping during grasping.     

Innervated radial thenar flap combined with radial forearm flap transfer for thumb reconstruction

A radial thenar flap combined with radial forearm flap was used for the reconstruction of the ipsilateral thumb in four patients. Vascular supply of the combined flap was based on the radial artery and extending the vascular pedicle to the superficial palmar branch of the radial artery. The flap was sensated by the palmar branch of the superficial radial nerve. The size of the flap averaged 15 x 5 cm and the innervated region of the thenar eminence was an area approximately 5 x 3 cm located over the proximal parts of the abductor pollicis brevis and opponens pollicis muscles. The flap was transferred as a free flap in three patients and as an advancement flap in one patient. The flaps survived completely without complications. Satisfactory restoration of sensation was achieved in the flap area, as shown by 6 mm of average moving two-point discrimination. This combined flap may be a feasible reconstructive option for large palmar defects of the fingers such as degloving injuries.     

Thenar and hypothenar muscles and their innervation by the ulnar and median nerves in the human hand.

The thenar and hypothenar muscles as well as their supplying nerves were analyzed with an improved dissecting method. Among the four thenar muscles, the m. abductor pollicis brevis (AbPB) has a separate muscle belly, whereas the m. opponens pollicis (OP), the superficial and deep heads of the flexor pollicis brevis (sFPB and dFPB), and the adductor pollicis (AdP) are fused with each other to make a single mass (deep thenar muscle group). These muscles are innervated by branches of the recurrent nerve and the accessory recurrent nerve from the median nerve as well as by terminal branches of the deep branch (ramus profundus) of the ulnar nerve. These three nerves frequently form a loop within the deep thenar muscle group (thenar loop), and a branch to the OP and one to deep parts of the sFPB often make a smaller loop (intrathenar loop), whereas the AbPB receives a separate nerve branch. Among the hypothenar muscle, the m. abductor digiti minimi and the m. flexor digiti minimi brevis are fused with each other, and their supplying nerves frequently form a loop in these muscles (intrahypothenar loop), whereas the m. opponens digiti minimi is separated from the others and receives a separate nerve branch. In the distribution pattern of supplying nerves to the thenar and hypothenar muscles, we find regularities in that they branch off in a regular manner from the ulnar and the median nerve, and that nerve branches to those muscles with fused bellies frequently communicate with each other to make loops.     

Simian crease incidence and the correlation with thenar and hypothenar pattern types in Swedish patients with trisomy 21 (Down's syndrome)

In the present study the frequency of the simian crease among 57 Down patients is compared to the corresponding figures of related and unrelated individuals. A study of the correlation with the dermatoglyphic patterns of the thenar and hypothenar areas is presented, the palm print classification being carried out according to a Swedish method.     

Finger and palmar dermatoglyphics in Seminole Indians of Florida

Hand prints of 146 Florida Seminoles were obtained at the Brighton, Big Cypress and Dania reservations and at the Indian Agency in Dania. Comparisons with other tribes of North American Indians (Comanche, Arapahoe, Navaho, Hopi and Pueblo) reveal similarities with respect to fingerprint indices, frequencies of patterns in all palmar areas, and transverseness of palmar ridges. Comparisons of Seminoles and other North American tribes with the Mayans of southern Mexico and Guatamala show striking differences in pattern frequencies in the thenar/first interdigital area of the palm. Among North American Indians, the frequency varies from 18.49% among Seminoles to 28.5% among Navahoes, whereas all Mayan tribes which have been studied range between 40 and 50%. Pattern frequencies are higher in the thenar/first interdigital area than in the hypothenar area among all Amerindians who have been tested. This trend is the reverse of that found in other racial groups. North, Central and South American Indians are similar with respect to relatively high finger pattern indices, low frequencies of patterns in the hypothenar area, low frequencies of accessory triradii in the interdigital areas and moderately transverse palmar ridges.     

Complete achromatopsia associated with skeletal anomalies: a new autosomal recessive syndrome

Complete achromatopsia associated with skeletal anomalies: a new autosomal recessive syndrome: Achromatopsia or rod monochromatism is the complete absence of color discrimination, with an estimated frequency of 1 in 100,000. To date the McKusick Catalogue includes more than 10 entities related to Achromatopsia. This paper describes four Mexican sibs with a stationary rod monochromatism, associated with long fingers and toes, hypothenar and thenar hypoplasia and pes planus, suggesting a new genetic entity probably inherited in an autosomal recessive mode.     

Wrist dosimeter in nuclear medicine – An alternative for the ring dosimeter?

PurposeIndividual dosimetry is undoubtedly one of the best methods of assessing the exposure of personnel to ionizing radiation, however in case of nuclear medicine, the method applied to measure the dose does not always present a picture of the worker’s actual exposure. The highly non-homogeneous dose distribution on the hand means that the ring dosimeter, routinely used to measure the Hp(0.07), provides only approximate dose values received by fingertips, the body part most exposed to ionizing radiation. This paper is an attempt to answer the question whether the wrist dosimeter used as a replacement for the ring dosimeter is able to provide information on doses for the most exposed fragments of the hand of an employee during handling procedures with the use of radiopharmaceuticals.MaterialsThroughout measurements performed in five nuclear medicine facilities, high-sensitivity thermoluminescent detectors were used.ResultsCorrection coefficients have been determined, which constitute an amendment to be made to move from the dose recorded by the wrist dosimeter to the doses received by the most exposed hand fragments. The fingertips received on average 25 times higher doses, compared to the values recorded by the wrist dosimeter.ConclusionsA wrist dosimeter can be used to measure the Hp(0.07) in nuclear medicine, including as a gauge of the most exposed parts of the hand – the fingertips. However, the applicability of correction coefficients makes it necessary to ensure a stable position of the wrist dosimeter during routine procedures.     

REPAIR OF INJURIES TO SOFT TISSUES OF FINGERS—Primary and Secondary Reconstruction

Preservation of maximum function and appearance of the finger can best be attained by wide excision of crushed or traumatized tissue and closure of defects by primary split thickness skin grafts. Primary pedicle flaps are rarely indicated and should be reserved for cover of denuded cortical bone or joint surfaces. In only 1 per cent of fresh injuries were primary pedicle flaps used. Finger length, nail bed and root, bone and tendon can be adequately preserved with minimal morbidity by split thickness skin grafts. Restoration of contour if necessary is best done secondarily, utilizing thenar or hypothenar flaps. These flaps are particularly indicated in the reconstruction of finger tips.     

Tripedal knuckle-walking: a proposal for the evolution of human locomotion and handedness.

A comparative morphological analysis of human and non-human hominoids was conducted in an attempt to determine the mode of locomotion of the protohominid. Although the generalized hominoid anatomy permits variation of locomotion: brachiation, knuckle-walking, etc., minor variations in structure determine which behavior is favored. Arboreal arm swinging requires a flexible forelimb while terrestrial fist or knuckle-walking demands more rigidity of the hand and wrist. It is demonstrated that the large human thumb accompanied by the strong adduction of the thenar, hypothenar, and palmar interosseous muscles offer powerful rigidity to the hand, while fusion of the os centrale with the scaphoid during gestation permits the formation of an arch of carpals which imbue the wrist with the stability necessary for weight bearing. Fascialization of the contrahentes and dorsiepitrochlearis muscles in the human as well as depilation of the middle phalanges; the webbing (syndactyly) of the palm; the direction of the fibers of the interosseous membrane of the forearm; the shape of the puerile annular ligament, and the direction of the human glenoid fossa strongly suggest that the ancestor of man used a knuckle-walking form of locomotion prior to becoming bipedal. A model is presented that suggests that bipedalism was attained through an intermediate stage of tripedalism. The model is based on the fact that man's anatomy is much more asymmetric than that of the great apes. A presumption is made that due to the absence of trees for climbing in the transition from forest to open plain, the protohominid needed to carry tools (stones) at all times for protection. Stones could be carried for long distances on the posterior iliac crest since the weight would be shifted posteriorly over the legs. Pick up, medial rotation and adduction of the stone would employ a two-muscle chain of biceps brachii and latissimus dorsi. On the iliac crest, the stone is posterior to the coronal plane of the glenohumeral joint, and with the contraction of this two-muscle chain, the shoulder on one side is moved posteriorly effecting a semi-erect posture. It is proposed that tripedalism of the protohominid may be an explanation for the handedness unique to hominids.     

Dermatoglyphic patterns and pattern intensities of the genus Cacajao (Cebidae,platyrrhini) with observations on interspecific and subspecific differentiation

Palmar and plantar dermatoglyphic pattern types, area and total pattern intensities (API and TPI), and pattern intensity (PI) profiles are presented for the South American genus Cacajao of the subfamily Pitheciinae. The data are based on prints from 41 bald-head uacaries (C. calvus), 9 white bald-head uacaries (C. c. calvus), and 15 black-head uacaries (C. melanocephalus). In each extremity, loops of differing orientation were the most frequent pattern type; whorls were dominant at palmar interdigital (I) area 3 in C. calvus and at both I3 and I4 in C. melanocephalus. Open fields characterized the palmar thenar and plantar proximal hypothenar, thenar, calcar, and I3 and I4. There was little evidence of significant sexual dimorphism as assessed from PI values. The genus displayed significant asymmetry at palmar I3 (P?0.001) and plantar distal hypothenar (P?0.004). There were significant group differences between C. calvus and C. c. calvus in the palmar thenar API and plantar TPIs. The combined bald-head sample of C. calvus and C. c. calvus differed from C. melanocephalus in API of palmar I4 and plantar distal thenar, I2, and distal hypothenar (marginally), and in plantar TPIs. In PI profiles, C. melanocephalus departed from the pattern shared by C. calvus and C. c. calvus in both palmar and plantar interdigital areas. As a genus, the uacaries have markedly low plantar TPI values relative to palmar values (palm-sole index > 195). Of eight comparison cebid genera, only Chiropotes, another pitheciine genus, approximated these values.     

Dermatoglyphic assessment of the genetic relationships of native American populations

Genetic distance techniques and cluster analysis were used to determine which dermatoglyphic parameters were most useful in assessing genetic relationships between native American populations. The dermatoglyphic parameters used for this analysis were those most completely reported in the papers examined in a literature survey we had carried out previously, and include digital patterns, modal types of the C-line and D-line terminations, and palmar patterns in the hypothenar, thenar/I, and interdigital areas. The populations examined were separated by sex and divided into seven major geographical groups: Eskimo; North American Indian; Maya and non-Maya (Central America); Amazonian; Quechua, and Aymara (South America). Mean frequencies of dermatoglyphic traits were computed for each group and pairwise “genetic” distances calculated using Cavalli-Sforza and Edward's D-test. Dendrograms were then generated from these D-values using Q-mode cluster analysis. Using the hypothenar, thenar/I and III and IV interdigital areas, the results of this analysis demonstrated a good fit to an expected phylogenetic tree. When digital patterns, patterns in the II interdigital area, and the modal types of the C-line were included in the analysis, the same phylogenetic relationships were observed. However, inclusion of the modal types of the D-line with the other parameters tended to introduce some distortion and a greater separation between sexes within the same populations.     

Dermatoglyphics of the nganasans and the forest entsy from the Taimir Peninsula

Dermatoglyphic data on 17 traits (digital arches, ulnar loops, whorls, patterns on the hypothenar and thenar/I,II,III, and IV interdigital areas, main line C absence and its incompleteness, mean digital ridge-count, a–b, b–c, and c–d ridge–counts, atd angle, pattern intensity index, and main line index) are presented in this paper for 194 males and 224 females from the Taimir Peninsula. Also presented is a population analysis of the Taimir aborigines based on quantitative traits, and comparisons of this population with some Siberian and North American populations.     

Noninformative vision improves the spatial resolution of touch in humans

Research on sensory perception now often considers more than one sense at a time. This approach reflects real-world situations, such as when a visible object touches us. Indeed, vision and touch show great interdependence: the sight of a body part can reduce tactile target detection times [1], visual and tactile attentional systems are spatially linked [2], and the texture of surfaces that are actively touched with the fingertips is perceived using both vision and touch [3]. However, these previous findings might be mediated by spatial attention [1, 2] or by improved guidance of movement [3] via visually enhanced body position sense [4--6]. Here, we investigate the direct effects of viewing the body on passive touch. We measured tactile two-point discrimination thresholds [7] on the forearm while manipulating the visibility of the arm but holding gaze direction constant. The spatial resolution of touch was better when the arm was visible than when it was not. Tactile performance was further improved when the view of the arm was magnified. In contrast, performance was not improved by viewing a neutral object at the arm's location, ruling out improved spatial orienting as a possible account. Controls confirmed that no information about the tactile stimulation was provided by visibility of the arm. This visual enhancement of touch may point to online reorganization of tactile receptive fields.     

Glucose monitoring at the thenar: evaluation of upper dermal blood glucose kinetics during rapid systemic blood glucose changes.

OBJECTIVE: We compared blood glucose measurements at the thenar with those at the fingertip during glucose increase and decrease that was rapid enough to induce glucose differences between the forearm and the fingertip. METHODS: A rapid glucose increase was induced by oral glucose; subsequently, a rapid glucose decrease was induced by intravenous insulin in 16 insulin-treated patients with diabetes. Capillary samples were taken in parallel from the thenar and fingertip. Different glucose monitors (FreeStyle, OneTouch Ultra, Soft-Sense) were used. Additional samples were taken from the forearm (n = 10 patients) in order to demonstrate that the blood glucose change achieved was rapid enough to principally induce glucose differences at alternative sites. RESULTS: Neither blood glucose at baseline (135 +/- 34 vs. 136 +/- 41 mg/dl, p = 0.86) nor glucose amplitude during increase (190 +/- 35 vs. 188 +/- 41 mg/dl, p = 0.65) or decrease (255 +/- 32 vs. 257 +/- 45 mg/dl, p = 0.83) differed significantly between the fingertip and the thenar. Intra-individual average thenar-fingertip glucose difference was - 2 +/- 12 (p = 1.00) and + 5 +/- 9 mg/dl (p = 0.11). In the subgroup, intra-individual average forearm-finger difference was - 50 +/- 19 (p < 0.01) and + 45 +/- 11 mg/dl (p < 0.01) during glucose-increase and decrease, respectively. There were no obvious device-specific differences. CONCLUSIONS: Blood glucose measurements at the thenar are a safe alternative to measurements at the fingertip at steady state as well as during blood glucose change that is sufficiently rapid to induce clinically relevant differences between forearm and fingertip.     

青海土族肤纹学研究

本文报道土族人群的肤纹参数,在知情同意手续下捺印对象的手纹和足纹,样本包括106名男性和108名女性,研究的项目有TFRC、a-b RC,atd,tPD、指纹、指间纹、手大小鱼际,猿线,大拇趾球纹,趾间纹,足小鱼际纹和足跟纹等。为人类学,遗传学和医学提供了较完整的数据集。     

新疆柯尔克孜族肤纹初步研究

本文报道新疆柯尔克孜族肤纹参数的正常值,样本中有男女各500例,本文的研究包括13类,它们是:指纹总嵴数,a-b间嵴数,指纹,指间花纹,大鱼际纹,小鱼际纹,猿线,掌指c三叉缺失,多个t三叉点,(足母)趾球部纹,足小鱼际纹,趾间纹,足跟纹。     

Manual digital pressures during knuckle‐walking in chimpanzees (Pan troglodytes)

Considerable attention has been given to hand morphology and function associated with knuckle‐walking in the African apes because of the implications they have for the evolution of bipedalism in early hominins. Knuckle‐walking is associated with a unique suite of musculoskeletal features of the wrist and hand, and numerous studies have hypothesized that these anatomical features are associated with the dynamics of load distribution across the digits during knuckle‐walking. We collected dynamic digital pressures on two chimpanzees during terrestrial and simulated arboreal locomotion. Comparisons were made across substrates, limb positions, hand positions, and age categories. Peak digital pressures were similar on the pole and on the ground but were distributed differently across the digits on each substrate. In young animals, pressure was equally high on digits 2–4 on the ground but higher on digits 3 and 4 on the pole. Older animals experience higher pressures on digits 2 and 3 on the ground. Hand posture (palm‐in vs. palm‐back) influenced the distribution and timing of peak pressures. Age‐related increases in body mass also result in higher overall pressures and increased variation across the digital row. In chimpanzees, digit 5 typically bears relatively little load regardless of hand position or substrate. These are the first quantitative data on digital pressures during knuckle‐walking in hominoids, and they afford the opportunity to develop hypotheses about variation among hominoids and biomechanical models of wrist and forearm loading. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.     

Palmar dermatoglyphics in different phenotypic manifestations of schizophrenia]

Palmar dermatoglyphics was studied in 1120 patients with schizophrenia with due regard for its form, and in 1240 healthy persons of the same population. The frequency of the AU/AC type of patterns in the hypothenar area was increased in women with schizophrenia and its paranoid form. Among men with schizophrenia and its simple form the frequency of dysplasia, true and defective patterns on the thenar was increased; in addition in men with the paranoid form the frequency of loops in the 3d interdigital areas was also increased.     

A reverse ulnar hypothenar flap for finger reconstruction

A reverse-flow island flap from the hypothenar eminence of the hand was applied in 11 patients to treat palmar skin defects, amputation injuries, or flexion contractures of the little finger. There were three female and eight male patients, and their ages at the time of surgery averaged 46 years. A 3 x 1.5 to 5 X 2 cm fasciocutaneous flap from the ulnar aspect of the hypothenar eminence, which was located over the abductor digiti minimi muscle, was designed and transferred in a retrograde fashion to cover the skin and soft-tissue defects of the little finger. The flap was based on the ulnar palmar digital artery of the little finger and in three patients was sensated by the dorsal branch of the ulnar nerve or by branches of the ulnar palmar digital nerve of the little finger. Follow-up periods averaged 42 months. The postoperative course was uneventful for all patients, and all of the flaps survived without complications. The donor site was closed primarily in all cases, and no patient complained of significant donor-site problems. Satisfactory sensory reinnervation was achieved in patients who underwent sensory flap transfer, as indicated by 5 mm of moving two-point discrimination. A reverse island flap from the hypothenar eminence is easily elevated, contains durable fasciocutaneous structures, and has a good color and texture match to the finger pulp. This flap is a good alternative for reconstruction of palmar skin and soft-tissue defects of the little finger.     

Clinical anatomy of the m. flexor carpi radialis tendon sheath

At the transitional zone from the forearm to the hand the insertion tendon of the m.flexor carpi radialis (FCR) glides on a fibrous and fatty cushion, which is connected dorsally with the joint capsule of the radiocarpal articulation. The tendon distally crosses the palmar side of the scaphoid tubercle and enters the dorsally curved rim of the trapezoid tubercle. At the level of the wrist joint the narrow tendon sheath begins, which extends to the insertion at the metacarpus. Immediately after entering the gliding tunnel the tendon branches off radially as a rule with an accessory fibre strand 8 mm in width to the scaphoid, trapezium and the joint capsule between these two bones. The insertion tendon regularly is attached to the palmar and radial surfaces of the second and third metacarpal bones. The wall of the osteofibrous gliding tunnel can be prominent following trauma, inflammation or arthrosis deformans in the trapezio-scaphoideal joint and may irritate the tendon (tendovaginosis stenosans). Against resistance forces pain will occur in the wrist joint during palmar flexion. The typical point of tenderness is situated at the entering of the tendon in the thenar region. Operative decompression will be effective by opening the radial wall of the tendon sheath from the carpal tunnel.