Normal Finger Research Articles

Optimal 3-T MRI for depiction of the finger A2 pulley: comparison between T1-weighted, fat-saturated T2-weighted and gadolinium-enhanced fat-saturated T1-weighted sequences

To compare three spin-echo sequences, transverse T1-weighted (T1WI), transverse fat-saturated (FS) T2-weighted (T2WI), and transverse gadolinium-enhanced (Gd) FS T1WI, for the visualisation of normal and abnormal finger A2 pulley with magnetic resonance (MR) imaging at 3 tesla (T). Sixty-three fingers from 21 patients were consecutively investigated. Two musculoskeletal radiologists retrospectively compared all sequences to assess the visibility of normal and abnormal A2 pulleys and the presence of motion or ghost artefacts. Normal and abnormal A2 pulleys were visible in 94% (59/63) and 95% (60/63) on T1WI sequences, in 63% (40/63) and 60% (38/63) on FS T2WI sequences, and in 87% (55/63) and 73% (46/63) on Gd FS T1WI sequences when read by the first and second observer, respectively. Motion and ghost artefacts were higher on FS T2WI sequences. Seven among eight abnormal A2 pulleys were detected, and were best depicted with Gd FS T1WI sequences in 71% (5/7) and 86% (6/7) by the first and the second observer, respectively. In 3-T MRI, the comparison between transverse T1WI, FS T2WI, and Gd FS T1WI sequences shows that transverse T1WI allows excellent depiction of the A2 pulley, that FS T2WI suffers from a higher rate of motion and ghost artefacts, and transverse Gd FS T1WI is the best sequence for the depiction of abnormal A2 pulley.

Flexor Tendon Grafting Using a Plantaris Tendon with a Fragment of Attached Bone for Fixation to the Distal Phalanx: A Preliminary Cohort Study

Secure methods of graft attachment ensure safe early motion after flexor tendon grafting. This has been achieved at the proximal graft juncture using Pulvertaft's technique. For secure distal attachment, we investigate the results of flexor tendon grafting using the plantaris tendon with a fragment of attached bone fixed with a screw to the distal phalanx. Thirteen digits from 10 patients with longstanding flexor tendon injuries in zone II had surgical reconstruction. A plantaris tendon-bone graft was attached to the distal phalanx using a mini-screw. This was followed by immediate active motion. At 3 and 8 months after surgery, total active motion was calculated as the sum of the degrees of active flexion in the proximal and distal interphalangeal joints minus the sum of the degrees of extension deficits for each of these joints. The results of total active motion were compared to the normal contralateral digit. Three months after surgery, the mean rate of recovery, relative to the normal contralateral finger, was 74%, whereas 8 months after surgery, this value was 70%. This difference was statistically significant. There were no failures or poor results (ie, less than 50% recovery). The tendon-bone plantaris graft employed here ensured immediate active motion and early use of the involved hand in daily activities. Therapeutic IV.

EMLA and Water Immersion Cause Similar Vasodilatation in Replanted Fingers

Skin wrinkling on water immersion is a reliable and simple test of sympathetic innervation. The eutectic mixture of local anesthetic (EMLA) cream has been shown to induce near identical clinical wrinkling scores and reduction in digit blood flow as that following water immersion in people with normal sympathetic innervation. This study was designed to investigate the vasomotor response to EMLA in replanted fingers that had poor sympathetic innervation. Laser Doppler imaging (PeriScan PIM II; Perimed AB, Stockholm, Sweden) was used to detect perfusion changes in the pulps of fourteen replanted fingers before and after 0.5 g of 5% EMLA cream application and water immersion in a 40 degrees C normal saline for 30 min, respectively. Comparisons were made with the contralateral corresponding normal fingers. After water immersion and EMLA application, all of the normal fingers showed a considerable and similar decrease in blood perfusion that demonstrated in the absolute perfusion units (pU) (baseline: 1.57 +/- 0.33 pU, after water-immersion, 1.19 +/- 0.22 pU, P < 0.001; decrease: 23.6 +/- 7.7%, after EMLA application: 1.20 +/- 0.18 pU, P < 0.001; decrease: 22.4 +/- 8.9%). In contrast, all of the replanted fingers showed a statistically significant vasodilatatory response (baseline: 1.20 +/- 0.29 pU, after water-immersion: 1.36 +/- 0.28 pU, P < 0.001; increase: 15.2 +/- 9.1%, after EMLA application: 1.38 +/- 0.27 pU, P < 0.001; increase: 16.8 +/- 9.1%). EMLA and water immersion both cause vasodilatation and no skin wrinkling in replanted fingers. These results imply that intact sympathetic nerve function is required to induce the vasoconstrictive effect of EMLA.

Quantitative analysis of asymmetrical cortical activity in motor areas during sequential finger movement

Brain asymmetry is a phenomenon well known for handedness and has been studied in motor cortices. However, few quantitative studies on asymmetrical cortical activity in motor areas have been conducted. In this study, we systematically investigated asymmetrical cortical activity in motor areas during sequential finger movement by quantitatively analyzing functional magnetic resonance imaging (fMRI) blood oxygenation level-dependent (BOLD) responses. The norm of BOLD signal percentage of change was introduced to quantitatively measure the BOLD signal intensity change difference between the left and right motor areas. The results of the data collected from six subjects show that the norm of BOLD signal percentage of change in the right motor area is higher than that in the left motor area for two-hand movement (P=.0059) and single-hand movement (P=.0279) with right-handedness. These results from fMRI show the asymmetry of motor areas and may suggest that the left hemisphere motor area comes into being as an adaptation system that needs few neuron cells only to finish any movement task for right-handedness. The activation intensity in the left motor area is reduced with normal right finger movement. The activation intensity in the right motor area is obviously higher than that in the left motor area.

True ulnar artery aneurysm of the hand in an 18-month-old boy: A case report

True aneurysms of the hand arteries are rare and are exceedingly uncommon in children. Presented is a case of a true ulnar artery aneurysm in an 18-month-old boy in which there was no history of trauma. The aneurysm was resected without reconstruction because of the normal preoperative Allen test result, normal preoperative finger pressure measurement with ulnar artery occlusion, the angiographic evidence that the radial artery was the dominant artery of the hand, and intraoperative evidence of adequate hand perfusion after excluding the aneurysm from the hand circulation as documented by good Doppler signals in all digital arteries.

Factors That Influence the Outcome of Zone I and Zone II Flexor Tendon Repairs in Children

To evaluate the factors that influenced the clinical results of zone I and II flexor tendon repairs in children at a single institution. Forty-one fingers (35 patients) in patients ages 2 to 14 years with zone I or II flexor tendon injuries were identified. There was a zone I tendon injury in 16 fingers and a zone II tendon injury in 25 fingers. Concomitant injuries to the digital nerves were seen in 18 fingers. Primary repair was performed within 1 week in 35 fingers and delayed repair (2-9 wk) was performed in 6 fingers. After surgery 22 fingers (21 patients) were treated with early controlled mobilization and 19 fingers (14 patients) were treated with plaster immobilization. All patients were available for evaluation at a mean follow-up period of 42 months. Patients were subdivided into 2 age groups: (1) 0 to 7 years and (2) 8 to 15 years. Digital performance was evaluated by determining the percentage return of normal finger function according to a total active motion formula. Functional evaluation of all digits in both groups showed excellent or good results. Zone I repairs had better results than zone II repairs and isolated tendon repairs had better results than those with associated nerve repairs. The age of the patients nor postoperative protocol did not influence the final digital motion. A good outcome can be expected after repair of zone I or II flexor tendon injuries in children. Prognostic III.

The relationship between the extensor tendon enthesis and the nail in distal interphalangeal joint disease in psoriatic arthritis--a high-resolution MRI and histological study

Diffuse swelling of the distal interphalangeal (DIP) joint beyond the joint margin is a common feature of arthritis in psoriatic arthritis (PsA). The purpose of this study was to explore the microanatomical basis for the inflammation and nail disease in PsA using a combined high-resolution magnetic resonance imaging (MRI) and histological studies. High-resolution MRIs of the DIP joint were obtained in 30 subjects [10 PsA, 10 osteoarthritis (OA) and 10 normal volunteers]. The relationship between the DIP joint capsule and associated tendon enthesis and the nail bed and root were evaluated. Histological studies to define the relationship between the normal cadaveric DIP joint capsule and the nail root were performed on the middle and ring fingers of 10 dissecting room cadavers. On MRI, the dorsal capsular enthesis was the epicentre of an inflammatory reaction. This extended to involve the soft tissues adjacent to the nail in 8 of 10 cases in PsA, but only 4 of 10 cases in OA where the inflammation is less intense and in none of the normal fingers. The DIP joint capsule was intimately linked with the nail complex on histology, with the dorsal, volar and lateral aspects of the nail bed being ensheathed in fibres extending from the entheses. The study suggests that the extended nature of the enthesis organ associated with the DIP joint may explain the diffuse nature of the inflammatory response around the nail in PsA. Therefore the nail is as much an integral part of the enthesis organ as it is of the skin, which has implications for a better understanding of the disease.

Phase field approach to spatial perturbations in normal Saffman-Taylor fingers

We make a numerical study of the effect that spatial perturbations have in normal Saffman-Taylor fingers driven at constant pressure gradients. We use a phase field model that allows for spatial variations in the Hele-Shaw cell. We find that, regardless of the specific way in which spatial perturbations are introduced, a lateral instability develops on the sides of the propagating Saffman-Taylor finger. Moreover, the instability exists regardless of the intensity of spatial perturbations in the cell as long as the perturbations are felt by the finger tip. If, as the finger propagates, the spatial perturbations felt by the tip change, the instability is nonperiodic. If, as the finger propagates, the spatial perturbations felt by the tip are persistent, the instability developed is periodic. In the later case, the instability is symmetrical or asymmetrical depending on the intensity of the perturbation.

Paradoxical response to water immersion in replanted fingers

When the fingers are immersed in water digital blood flow is reduced and the skin wrinkles, suggesting that vasoconstriction plays a role. However, is wrinkling due to sympathetic activation or some intrinsic property of the skin? To define the role of autonomic innervation in skin wrinkling we measured changes in blood perfusion (Laser Doppler Perfusion Imager) in 20 successfully replanted fingers (mean time after complete amputation 17.5 +/- 5.2 months). We compared responses in replanted fingers with those in corresponding contralateral normal fingers before and immediately after immersion in saline (0.5 mol/l NaCl at 40 degrees C). In the normal fingers, immersion caused a decrease in blood flow by 27.6 +/- 11.5% and skin wrinkling. However, in the replanted fingers blood flow increased by 22.8 +/- 19.6% and the skin did not wrinkle. The paradoxical cutaneous vasodilatation and absence of wrinkling in the denervated fingers suggests that sympathetic innervation is important in water-immersion skin wrinkling.

Fluctuations in Saffman-Taylor fingers with quenched disorder

We make an experimental characterization of the effect that static disorder has on the shape of a normal Saffman-Taylor finger. We find that static noise induces a small amplitude and long wavelength instability on the sides of the finger. Fluctuations on the finger sides have a dominant wavelength, indicating that the system acts as a selective amplifier of static noise. The dominant wavelength does not seem to be very sensitive to the intensity of static noise present in the system. On the other hand, at a given flow rate, rms fluctuations of the finger width, decrease with decreasing intensity of static noise. This might explain why the sides of the fingers are flat for typical Saffman-Taylor experiments. Comparison with previous numerical studies of the effect that temporal noise has on the Saffman-Taylor finger, leads to conclude that the effect of temporal noise and static noise are similar. The behavior of fluctuations of the finger width found in our experiments, is qualitatively similar to one recently reported, in the sense that, the magnitude of the width fluctuations decays as a power law of the capillary number, at low flow rates, and increases with capillary number for larger flow rates.

Analysis of Intrinsic–Extrinsic Muscle Function Through Interactive 3-Dimensional Kinematic Simulation and Cadaver Studies

To revisit the analysis of intrinsic muscle function and its relationship to the overall flexion moment at the index metacarpophalangeal (MCP) joint. Prior studies reported inconsistent levels of intrinsic contribution varying from 12.5% to 73% of the total flexion moment at the index MCP joint. This study hypothesized that 26% is a more realistic figure using computer simulation moment arms combined with known muscle-tension fractions. This study tested the hypothesis using a 2-part fresh cadaver study, the objectives of which were to measure actual muscle moment arms throughout index MCP range of motion and then combine these measurements with tension fractions to calculate normal intrinsic minus and low ulnar nerve palsy moments and then using the same specimens to apply loads to the muscles and measure resultant moments directly. An interactive computer simulation was constructed to replicate the position and loading orientation of an earlier experiment reported in the literature and known muscle-tension fractions were combined with the resultant moment arm structure to calculate the moment at the index MCP joint for maximum isometric contraction of the normal, intrinsic minus, and low ulnar nerve palsy finger. Eleven fresh cadaver specimens were used. For experiment A the excursion and angle data were used to determine moment arms of each muscle and moments were calculated. For experiment B the muscles were connected to weights based on muscle-tension fractions and the resultant moment was measured at the fingertip. Experiment A determined the muscle-tendon moment arms at the index MCP joint throughout the flexion-extension range of motion. Combining the flexor moment arms with known tension fractions determined that the intrinsics contributed 24% to the total flexion moment, the dorsal and palmar interossei contributed 22%, and the lumbrical contributed 2%. The results of experiment B confirmed the results of experiment A. Intrinsic muscle contribution to flexion moment at the index MCP joint is not as high or as low as previously reported. The relative moment production is governed by both the moment arms and tension produced by the muscle; thus a more precise knowledge of moment arms is essential to understand muscle balance at a joint. Clinically the hand surgeon should expect a loss of 24% of index MCP flexion moment-generating capacity in the intrinsic-minus index finger and a loss of 22% in the index finger on a hand with low ulnar nerve palsy. Furthermore the flexion moment from the lumbrical of only 2% appears to be adequate to prevent clinical clawing of the digit.

A comparison of video and autofluorescence bronchoscopy in patients at high risk of lung cancer

The aim of this study was to compare the diagnostic yield of flexible video bronchoscopy (FVB) and autofluorescence bronchoscopy (i.e. lung imaging fluorescence endoscopy (LIFE)) in 151 patients at a high risk of lung cancer and with moderate dysplasia or worse on sputum cytology mass screening. Findings from FVB and LIFE were classified as either normal, abnormal or suspicious for cancer. Endobronchial biopsies (EBX) were obtained from abnormal or suspicious areas on FVB and/or LIFE, or randomly when FVB and LIFE were normal. Moderate dysplasia and worse were defined as pathologically positive. Overall, 83 out of 343 (24%) EBX were pathologically positive. The sensitivity of FVB was 72% and LIFE 96%. Relative sensitivity of LIFE over FVB was 1.33. Specificities of FVB and LIFE were 53 and 23%, respectively. The numbers of pathologically positive EBX from sites designated normal, abnormal or suspicious were: from FVB, 23 out of 162 (14%), 37 out of 151 (25%) and 23 out of 30 (77%); from LIFE, three out of 69 (4%), 44 out of 212 (21%) and 36 out of 62 (58%). In normal or abnormal areas at FVB, there was a significant increase in the yield of EBX guided by abnormal and suspicious sites noted at LIFE. In conclusion, endobronchial biopsies of suspicious findings from lung imaging fluorescence endoscopy and flexible video bronchoscopy have a good diagnostic yield. Lung imaging fluorescence endoscopy is more useful when flexible video bronchoscopy is either normal or abnormal.

Internal forces during object manipulation

Internal force is a set of contact forces that does not disturb object equilibrium. The elements of the internal force vector cancel each other and, hence, do not contribute to the resultant (manipulation) force acting on the object. The mathematical independence of the internal and manipulation forces allows for their independent (decoupled) control realized in robotic manipulators. To examine whether in humans internal force is coupled with the manipulation force and what grasping strategy the performers utilize, the subjects (n=6) were instructed to make cyclic arm movements with a customized handle. Six combinations of handle orientation and movement direction were tested. These involved: parallel manipulations (1) VV task (vertical orientation and vertical movement) and (2) HH task (horizontal orientation and horizontal movement); orthogonal manipulations (3) VH task (vertical orientation and horizontal movement) and (4) HV task (horizontal orientation and vertical movement); and diagonal manipulations (5) DV task (diagonal orientation and vertical movement) and (6) DH task (diagonal orientation and horizontal movement). Handle weight (from 3.8 to 13.8 N), and movement frequency (from 1 to 3 Hz) were systematically changed. The analysis was performed at the thumb-virtual finger level (VF, an imaginary finger that produces a wrench equal to the sum of wrenches produced by all the fingers). At this level, the forces of interest could be reduced to the internal force and internal moment. During the parallel manipulations, the internal (grip) force was coupled with the manipulation force (producing object acceleration) and the thumb-VF forces increased or decreased in phase: the thumb and VF worked in synchrony to grasp the object more strongly or more weakly. During the orthogonal manipulations, the thumb-VF forces changed out of phase: the plots of the internal force vs. object acceleration resembled an inverted letter V. The HV task was the only task where the relative phase (coupling) between the normal forces of the thumb and VF depended on oscillation frequency. During the diagonal manipulations, the coupling was different in the DV and DH tasks. A novel observation of substantial internal moments is described: the moments produced by the normal finger forces were counterbalanced by the moments produced by the tangential forces such that the resultant moments were close to zero. Implications of the findings for the notion of grasping synergies are discussed.

Acupuncture Treatment of Compression Neuropathy of the Radial Nerve: A Single Case Report of "Saturday Night Palsy"

Evidence that acupuncture is effective for any type of motor nerve injury is limited to case reports and case series but these findings indicate benefit. Observation that the radial nerve has the most rapid recovery of all peripheral nerves suggests that acupuncture might benefit treatment of "Saturday Night Palsy," a syndrome of radial-nerve compression. A 41-year-old female with a 1-week history of inability to write or extend the right wrist received 1 acupuncture treatment utilizing the Lung and Large Intestine meridians in the forearm, with the 2 meridians interconnected using the Luo and Yuan points. A cockup wrist splint was then applied. Wrist motion with gravity neutralized returned immediately after treatment. As the day progressed, the patient reported increasing strength in wrist and finger extension. The next day, the patient cancelled the second acupuncture treatment, as her hand had recovered. Examination 4 months later revealed normal wrist and finger extension, sensation, and return of the brachioradialis reflex. The patient was symptom-free 1-year postinjury. Acupuncture potentially facilitates recovery and may enhance treatment of peripheral motor nerve injury.

Lateral instability in normal viscous fingers

We study a low-amplitude, long-wavelength lateral instability of the Saffman-Taylor finger by means of a phase-field model. We observe such an instability in two situations in which small dynamic perturbations are overimposed to a constant pressure drop. We first study the case in which the perturbation consists of a single oscillatory mode and then a case in which the perturbation consists of temporal noise. In both cases the instability undergoes a process of selection.

Quantitative assessment of periarticular osteopenia in patients with early rheumatoid arthritis: a preliminary report

Background: Involvement of the metacarpophalangeal (MP) joints is one of the major problems in patients with rheumatoid arthritis (RA). Although several data about the cumulative influence of steroid intake on bone are available, the course of demineralisation in RA has not been described by quantitative methods until now.Patients and methods: Computed tomography (CT) sections of 96 MP joints in 12 RA patients and of 32 MP joints in four age‐matched healthy controls were investigated. Patients were classified according to Steinbrocker. Densitometric evaluation of subchondral bone density was performed by CT osteoabsorptiometry (CT‐OAM). Quantitative CT‐OAM was used to evaluate mineralisation of the articular surfaces in MP joints.Results: In the distal articular surface of MP joints, the number of density maxima was reduced from 3 to 2.1±0.3, 1.9±0.5 and 1.3±0.3 in RA patients with early, mild to moderate, and severe disease, respectively. Means of calcium concentrations were 633.4±35. 3 mg Ca2+/mL, 518.9±56.2 mg Ca2+/mL, 497.7±23.8 mg Ca2+/mL and 455.1±28.6 mg Ca2+/mL for controls and RA patients with early, mild to moderate, and severe RA, respectively. Mineralisation of the distal articular surface was significantly reduced in all groups of RA patients [probability (p)=0.005]. Regarding the number of density maxima, no differences were detected in the proximal articular surface of normal and RA fingers. However, mineralisation of the proximal articular surface was significantly reduced in all groups of RA patients (p=0.004). Means of calcium concentrations of the proximal articular surface were 494.1±48.5 mg Ca2+/mL, 413.0±16.2 mg Ca2+/mL, 406.0±51.4 mg Ca2+/mL, 390,4±41.1 mg Ca2+/mL for controls and RA patients with early, mild to moderate, and severe RA, respectively.Conclusion: Patients with early and untreated RA show loss of mineralisation and altered morphology of the MP joints of the hand, even before corticosteroid therapy. CT‐OAM provides evidence for an early alteration of functional anatomy in MP joints.

Measurement of Finger Posture and Three-Axis Fingertip Touch Force Using Fingernail Sensors

When the human fingertip is pressed against a surface or bent, the hemodynamic state of the fingertip is altered due to mechanical interactions between the fingernail and bone. Normal force, shear force, and finger extension/flexion all result in different patterns of blood volume beneath the fingernail. This phenomenon has been exploited in order to detect finger forces and finger posture by creating a photoplethysmograph "fingernail sensor," which measures the two-dimensional pattern of blood volume beneath the fingernail. In this paper, a filter is designed to predict the normal force, lateral shear force, longitudinal shear force, and bending angle based on readings from the fingernail sensor. Linear, polynomial, and neural network models relating the bending angle and touch forces to optical sensor outputs are developed and tested. A method is developed to uniformly calibrate the predictor for each user. Calibration experiments are performed to train and validate the predictor for seven human subjects. Results show that on average, shear forces can be predicted with 0.5 N root mean square (rms) error, normal force with 1 N rms error, and posture angle with 10 degrees rms error. Applications and methods for improving performance are discussed.

A new method for interosseous muscle elasticity scoring

A new method for interosseous muscle elasticity scoring

Primary use of the index finger for reconstruction of amputated thumbs

Seven cases of primary reconstruction of traumatic amputation of the thumb using the index finger are reported. In six cases, the reconstruction was done using an injured index finger, while in one case where the amputation of the thumb was through the carpometacarpal joint, an intact index finger was primarily pollicised. This reduces cost of treatment, hospitalisation period and allows earlier rehabilitation without a period of a ‘no thumb experience’. We have followed all the patients for a minimum period of 2 years and all of them have excellent functional results. We believe that pollicisation of a normal index finger, if thumb amputation is through the carpometacarpal joint or an injured index finger at the time of initial management of a severely traumatised hand with thumb amputation is an excellent technique for thumb reconstruction.

Prehension synergies: effects of object geometry and prescribed torques.

We studied the coordination of forces and moments exerted by individual digits in static tasks that required balancing an external load and torque. Subjects ( n=10) stabilized a handle with an attachment that allowed for change of external torque. Thumb position and handle width systematically varied among the trials. Each subject performed 63 tasks (7 torque values x 3 thumb locations x 3 widths). Forces and moments exerted by the digit tips on the object were recorded. Although direction and magnitude of finger forces varied among subjects, each subject used a similar multidigit synergy: a single eigenvalue accounted for 95.2-98.5% of the total variance. When task parameters were varied, regular conjoint digital force changes (prehension synergies) were observed. Synergies represent preferential solutions used by the subjects to satisfy mechanical requirements of the tasks. In particular, chain effects in force adjustments to changes in the handle geometry were documented. An increased handle width induced the following effects: (a). tangential forces remained unchanged, (b). the same tangential forces produced a larger moment T (t), (c). the increased T (t) was compensated by a smaller moment of the normal forces T(n), and (d). normal finger forces were rearranged to generate a smaller moment. Torque control is a core component of prehension synergies. Observed prehension synergies are only mechanically necessitated in part. The data support a theory of hierarchical organization of prehension synergies.