An assessment of the effects of variations in the Palmaris longus tendon and the fifth superficial flexor digitorum on pinch and grip strength.

INTRODUCTION: The effect of the absence or presence of the Palmaris longus tendon on pinch and grip strength was investigated in this study. Similarly, the effect of the presence or absence of the fifth superficial flexor digitorum on grip strength in the hand was studied. The aim of the present study was to assess the combined effect of these anatomical variations on pinch and grip strength. MATERIALS AND METHODS: In this cross-sectional study, 523 volunteers and their 1046 hands were enrolled. Each hand was assessed for the presence or absence of the Palmaris longus tendon and for variations in the fifth superficial flexor digitorum function. Then the grip and pinch power of the hands were measured with the Jammar Dynamometer. RESULTS: The presence or absence of Palmaris longus had no effect on grip strength in the individuals studied. Likewise, variations in fifth superficial flexor digitorum function had no effect on grip and pinch strengths. But the results of statistical testing showed the effect of the presence of Palmaris longus on pinch strength (25.38 lbs in hands with Palmaris present vs 24.43 lbs in hands without Palmaris). Pinch and grip power was higher in men than in women and in the right hand than in the left. CONCLUSION: Based on the findings of the present study, it seems that absence of the Palmaris longus tendon is associated with a reduction in pinch strength but has no effect on grip strength, and the variations in the fifth superficial flexor digitorum (flexor digitorum superficialis, or FDS) have no effect on pinch and grip strengths.

Anthropometry-corrected exposure modeling as a method to improve trunk posture assessment with a single inclinometer.

Measuring trunk posture in the workplace commonly involves subjective observation or self-report methods or the use of costly and time-consuming motion analysis systems (current gold standard). This work compared trunk inclination measurements using a simple data-logging inclinometer with trunk flexion measurements using a motion analysis system, and evaluated adding measures of subject anthropometry to exposure prediction models to improve the agreement between the two methods. Simulated lifting tasks (n=36) were performed by eight participants, and trunk postures were simultaneously measured with each method. There were significant differences between the two methods, with the inclinometer initially explaining 47% of the variance in the motion analysis measurements. However, adding one key anthropometric parameter (lower arm length) to the inclinometer-based trunk flexion prediction model reduced the differences between the two systems and accounted for 79% of the motion analysis method's variance. Although caution must be applied when generalizing lower-arm length as a correction factor, the overall strategy of anthropometric modeling is a novel contribution. In this lifting-based study, by accounting for subject anthropometry, a single, simple data-logging inclinometer shows promise for trunk posture measurement and may have utility in larger-scale field studies where similar types of tasks are performed.

Anatomical study and clinical relevance of the flexor superficialis synovial flap: an assessment of 31 hand dissections.

PURPOSE: The authors present an anatomical study of the flexor digitorum superficialis synovial flap and its clinical application for palmar soft tissue defects in hand trauma. METHODS: Green latex was injected into the brachial artery of thirty-one human upper limbs from corpses donated to science. Anatomical features of this pedicled flap were assessed: arterial vascularization, dimensions and covering surface. RESULTS: The anatomical support of this flap is the synovial tissue of the flexor tendons, and particularly the superficial layer of the synovial system, covering the flexor digitorum superficialis (FDS) tendons in the forearm. It is vascularized by four different arteries: a constant collateral branch of the ulnar artery, and three inconstant arterial supports: from collateral branches of the superficial palmar arch, from the radial artery, and from the vasa nervorum of the median nerve. The flap is harvested from proximal to distal on the ulnar pedicle to cover the palmar soft tissue defects of the hand. A clinical application of this synovial flap is presented via a case report for covering a palmar skin defect secondary to a hand injury. CONCLUSIONS: The synovial flap contains a constant ulnar pedicle and could be considered a useful alternative to cover palmar soft tissue defects.

Assessment of individual finger muscle activity in the extensor digitorum communis by surface EMG.

The extensor digitorum communis (ED) is a slender muscle group in the dorsal forearm from which tendons arise to the index (D2), medius (D3), ring (D4), and little (D5) fingers. Limited independence has been attributed to the parts that actuate the individual fingers. However, in a detailed anatomical analysis, it was found that the ED parts to the different fingers have constant and widely spaced anatomical locations that promote independent function. These observations and the superficial muscle belly locations prompted the hypothesis that these ED parts would be individually assessable by small anatomically placed surface EMG electrodes. In the present study, this hypothesis was evaluated by measuring electromyography (EMG) from the ED parts and surrounding muscles during individual finger tapping tasks with the forearm resting on a flat surface. It was found that individual ED activity can be well measured in ED2, ED3, ED4, and extensor digiti minimi (EDM). ED3 did not give nor did its electrodes receive significant crosstalk from other ED parts. ED4 electrodes recorded an EMG level of 30 +/- 19% (mean +/- SD) ED2 EMG in D2 tapping and ED2 electrodes a level of 53 +/- 22% ED4 EMG in D4 tapping, by hypothesis mostly crosstalk. EDM electrodes may record EMG at the level of ED4 EMG in D4 tapping. In D2 tapping, the mutual ED2 and extensor indicis redundancy reflected in large intersubject EMG differences with sometimes one or the other almost silent. The results may expand the possibilities of EMG analysis and finger muscle electrostimulation in ergonomic and clinical applications.

Morphologic assessment of the tendon graft donor sites: palmaris longus, plantaris, tensor fascia lata.

The purpose of this study is to compare and measure the tendon graft donor sites and to predict the sizes of these tendons preoperatively. Seventeen cadavers were included in the study. The morphologic evaluation of the palmaris longus (n = 29), plantaris (n = 32), and tensor fascia lata (n = 34) tendons were done. The length of the forearm, leg, and thigh and the width of the wrist, ankle, and knee joints were noted. The length, width, and the thickness of the tendons were measured. Degree of association between measurements was calculated by Pearson's correlation coefficient. We found statistically significant correlation between the length of the extremities and the length of the muscle tendons, and we formulated these correlations. The correlation between the length or width of the extremity and the tendon to be harvested could be designated as the ratios presented, and this could ease the preoperative planning at the craniofacial and other areas of surgery.

Multiprobe laser reflectometry in imaging and characterization of biological tissues.

Laser backscattered radiation from human forearm and foot were measured by multi-probe reflectometer, which consisted of one input probe and three output probes placed at distances of 2, 4 and 6 mm from the input probe. The normalized backscattered intensity (NBI) signals from the tissue surface, measured by the output probes, after digitization, were used to reconstruct the reflectance images of tissues in various layers below the skin surface. From NBI profiles measured at various locations of the tissues on the forearm the corresponding optical parameters, the scattering (mu(s)) and absorption (mu(a)) coefficients and the anisotropy parameter g, by matching these with profiles as simulated by Monte Carlo procedure were determined. From these data the optical parametric images of forearm were reconstructed which show the variation of these parameters at various locations. Similarly, the NBI data were collected from the foot sole region of healthy and diabetes subjects and their images reconstructed. These images showed the variation in the NBI in the diabetic foot sole compared to that of healthy subject, indicating the tissue structural changes. These procedures could be useful for diagnostic and therapeutic applications of lasers.

[Radiometric assessment of wrist angle values, linear parameters of the forearm and wrist ratios]. / Normy wybranych katów nadgarstka, dlugosci przedramienia i wspólczynników nadgarstka.

With the device of our own invention suitable for static X-ray examination of the wrist 12 radiographic parameters were evaluated. 100 radiograms regarded normal were analyzed, obtained as a comparative in unilateral wrist trauma patients group. Age of the patients ranged from 18 to 60 years. No comparative studies in regard to sex were performed. Obtained data were statistically analyzed. Subsequent values of the radiometric parameters were obtained: scaphoid-lunate angle (SL) 48.61 degrees, radio-lunate angle (RL): -0.83 degrees, palmar inclination of the distal radius metaphysis (RI): 25.96. The most significant linear parameters measured: ulnar length 0.18 mm, ulnar transposition (UT): 0.339 mm.

Pre-operative assessment of K-nail length in fracture shaft of femur.

INTRODUCTION: Internal fixation of diaphyseal fracture of shaft of femur in an adult by Kuntscher nail is the most common operative method of treatment in Nepal where operative facilities for the same exist. Since the complete range of K-nail sizes and length are not available in most operation theatres in Nepal, most orthopaedic surgeons assess the size and length of the K-nail pre-operatively by various methods and keep one size above and below the assessed length for the planned surgery. MATERIALS AND METHODS: The following measurements were taken in five hundred people involved in the study: Measurement No. 1: Tip of the greater trochanter to lateral knee joint line minus 2 cm. Measurement No. 2: Tip of the olecranon process to the tip of little finger, and Measurement No. 3: Tip of the greater trochanter to the upper pole of patella. An average of all three lengths were analysed to see if there were any differences in their mean lengths. RESULTS: Analysis showed that there were significant differences between the mean lengths measured by the three different methods. The average length of measurement no: 2 was 3 cm longer than the average length of measurement no: 1, which is the reference pre-operative length of K.nail. CONCLUSION: However, in practice since measurement no:2 is more convenient to perform and can also be used when the patient has sustained bilateral fractures of femur, an accurate pre-operative K-nail length assessment can be done by subtracting 3 cm from measurement no:2, i.e. the tip of the olecranon process to the tip of the little finger.

Assessment by bioimpedance of forearm cell mass: a new approach to calibration.

OBJECTIVE: Changes in skeletal muscle mass are involved in several important clinical disorders including sarcopenia and obesity. Unlike body fat, skeletal muscle is difficult to quantify in vivo, particularly without highly specialized equipment. The present study had a two-fold aim: to develop a regional (40)K counter for non-invasively estimating cell mass in the arm, mainly skeletal muscle cell mass, without radiation exposure; and to test the hypothesis that cell mass in the arm is highly correlated with electrical impedance after adjusting for the arm's length. METHODS: Forearm cell mass was estimated using a rectangular lead-shielded (40)K counter with 4-NaI crystals; impedance of the arm was measured at multiple frequencies using a segmental bioimpedance analysis (BIA) system. The system's within- and between-day coefficient of variation (CV) for (40)K-derived elemental potassium averaged 1.8+/-1.3 and 5.8+/-1.2%, respectively. The corresponding BIA system's CVs were 1.0+/-0.4 and 2.1+/-1.0%, respectively. SUBJECTS AND RESULTS: Participants in the study were 15 healthy adults (eight females, seven males; age 39+/-2.8 y, BMI 22.9+/-4.5 kg/m(2)). The right arm's K (5.2+/-1.7 g) was highly correlated with length-adjusted impedance (r(2)=0.81, 0.82, and 0.83 for 5, 50 and 300 kHz, respectively; all P<0.001); multiple regression analysis showed no additional improvement by adding age or sex to the prediction models. CONCLUSION: These results demonstrate the feasibility of calibrating BIA-measured electrical properties of the arm against estimates of arm cell mass, mainly of skeletal muscle, obtained by regional (40)K counting. This simple and practical approach should facilitate the development of BIA-based regional cell mass prediction formulas

Quantitative assessment of forearm muscle size, forelimb grip strength, forearm bone mineral density, and forearm bone size in determining humerus breaking strength in 10 inbred strains of mice.

Bone strength is an important clinical endpoint of osteoporosis research. The evaluation of the relative importance of bone and muscle components to bone strength has widespread implications for the understanding and preventing of osteoporosis. The objectives of this study were to understand the interrelationship between the different components of the muscular skeletal system and to determine the effect of forearm muscle size, forelimb grip strength, forearm bone mineral density (BMD), and forearm bone size on the humerus breaking strength among 10 inbred strains of mice. The forearm muscle size was measured using a peripheral quantitative computed tomography (pQCT). The forearm BMD and forearm bone size were measured using a PIXIMUS Densitometer. The forelimb grip strength and humerus breaking strength were measured using an Instron Mechanical Tester. Significant correlations were found among the five regional phenotypes. All variables have a moderately high genetic component with heritability estimates of 0.83 for forelimb grip strength, 0.76 for forearm muscle size, 0.6 for forearm BMD, 0.63 for forearm bone size, and 0.68 for humerus breaking strength. Forward stepwise multiregression analysis showed that the forearm BMD, forelimb grip strength, and forearm bone size were three major determinants of bone strength and explained 61% of the variation in bone breaking strength. These data suggest that evaluation of these three parameters together, rather than BMD alone, is a more effective, noninvasive approach for predicting fracture risk.

What happens to the triangular fibrocartilage complex during pronation and supination of the forearm? Analysis of its morphology and diagnostic assessment with MR arthrography.

OBJECTIVE: To evaluate the dynamic morphologic changes of the triangular fibrocartilage complex (TFCC) during pronation and supination of the forearm using high-resolution MR arthrography in cadavers and to evaluate the impact of these changes on the diagnostic assessment of the normal and abnormal TFCC. DESIGN AND SPECIMENS: High-resolution MR arthrography of 10 wrists of cadaveric specimens was obtained in maximum pronation, in the neutral position, and in maximum supination of the forearm. The structures of the TFCC were evaluated by two musculoskeletal radiologists and correlated with anatomic sections. The position of the forearm that allowed the best visualization of normal structures and lesions of the TFCC was determined. RESULTS: The shape and extent of the articular disc as well as the radial portions of the radioulnar ligaments did not change with pronation and supination. The articular disc was horizontal in the neutral position and tilted more distally to align with the proximal carpal row in pronation and supination. The fibers of the ulnar part of the radioulnar ligaments (ulnar attachment of the articular disc) revealed the most significant changes: their orientation was coronal in the neutral position and sagittal in positions of pronation and supination. The ulnomeniscal homologue was largest in the neutral position and was reduced in size during pronation and supination. The extensor carpi ulnaris tendon was centered in its groove in the neutral position and pronation. In supination this tendon revealed subluxation from this groove. The dorsal capsule of the distal radioulnar joint was taut in pronation, and the palmar capsule was taut in supination. The preferred forearm position for analysis of most of the structures of the TFCC was the neutral position, followed by the pronated position. The neutral position was rated best for the detection of ulnar and radial detachments of the TFCC, followed by the pronated position, except for two central perforations of the TFCC which were best seen with supination. CONCLUSION: The articular disc and the surrounding radial portions of the radioulnar ligaments form a rigid, unified complex with the radius without change in their shape in positions of pronation and supination of the forearm, while the ulnar attachment of the TFCC shows important dynamic changes. The neutral forearm position is the best position to analyze both the normal and the abnormal TFCC.

A cadaveric and radiologic assessment of catheter placement for the measurement of forearm compartment pressures.

The diagnosis of compartment syndrome is essentially a clinical one. In recent years, much interest and research has focused on the development of intracompartmental pressure monitoring devices to help in the diagnosis of this condition. Proper placement of the catheter is essential for accurate monitoring, because an incorrect result is potentially more dangerous than no reading at all. In the forearm, measurement in the flexor digitorum profundus is thought to be a more sensitive way of assessing rising pressure. One of the risks of catheter placement is inadvertent damage to a neurovascular structure, particularly when monitoring pressures in deeper muscle bellies. Standard anatomic texts and outpatient magnetic resonance scans of the forearm were studied to define a safe pathway for the introduction of a catheter into the volar forearm. An approach from the midline to the ulna, between the tendons of the flexor carpi radialis and palmaris longus, seemed the safest. Ten cadaveric forearms had 100 cc of gastrograffin injected into the deep forearm through a dorsal approach. The median and ulnar nerves were cannulated with a fine wire from the elbow to the wrist. Two cannulae were passed, using the suggested approach, at 2 locations between the wrist and the mid forearm. All limbs then were scanned with computed tomography, and the images were reviewed. In all forearms, the cannulae passed between the median and ulnar nerves into the belly of the flexor digitorum profundus and posed no risk to the neurovascular structures.