Ulnar Side Research Articles

Injury of ulnar branch of palmar cutaneous branch of median nerve: an important cause of pillar pain after surgical treatment for carpal tunnel syndrome

Objective To find out the possible causes of pillar pain after surgical treatment for carpal tunnel syndrome through anatomical and clinical study. Methods Through the anatomical study of the surgical area of carpal tunnel syndrome in 6 cadavers (12 sides), the distribution rule of the nerve branches in this area was found. According to this rule, the incision design and entry route were improved and applied to the clinic, and the occurrence of pillar pain was analyzed. A statistical comparison was made between the occurrence of pillar pain in routine surgical and modified surgical in order to find out the possible causes of the occurrence of pillar pain. Results The nerve innervation in the surgical area of carpal tunnel syndrome was derived from the palmar cutaneous branch of the median nerve. The palmar cutaneous branch of the median nerve emerged off the palmar fascia 8.1 mm at the distal side to the zero point. There were 3 types of main branch including 16.7% in single branch, 33.3% in double branches and 50% in three branches. The nerve trunk of the single and double branches walked in the radial side of the thenar crease with several irregular fine branches to the ulnar side. The ulnar branch of the three branches went from the main trunk to the ulnar side at the site to zero point averaging 11.2 mm and crossed the thenar crease at the site to zero point averaging 14.6 mm. According to this, the operative method was designed: the incision was located at 0.5 cm of the ulnar side of the thenar crease. The incision was about 3.0 cm long, and the proximal end of the incision was at least 2.0 cm to zero point. After incision, only the transverse carpal ligament was cut to protect the palmar aponeurosis at the proximal end of the incision to zero point and avoid the injury of the ulnar branch of palmar cutaneous branch. 102 patients were performed with the improved surgery while 110 cases were treated by routine surgery. The incidence of pillar pain in the improved group was 12.7%, and that in the control group was 34.5% one month after the operation. The incidence of pillar pain in the improved group was 14.7%, and that in the control group was 41.0% 3 months after the operation. The two groups had significant differences (P<0.05). There was no significant differences between the two groups 6 months after the operation, and the pillar pain disappeared in all the patients one year after the operation. Conclusion The injury of the ulnar branch of the palmar cutaneous branch of median nerve may be an important cause of pillar pain after surgical treatment for carpal tunnel syndrome. Key words: Carpal tunnel syndrome; Anatomy; Palmar cutaneous branch; Pillar pain

Trabecular bone patterning across the human hand

Hand bone morphology is regularly used to link particular hominin species with behaviors relevant to cognitive/technological progress. Debates about the functional significance of differing hominin hand bone morphologies tend to rely on establishing phylogenetic relationships and/or inferring behavior from epigenetic variation arising from mechanical loading and adaptive bone modeling. Most research focuses on variation in cortical bone structure, but additional information about hand function may be provided through the analysis of internal trabecular structure. While primate hand bone trabecular structure is known to vary in ways that are consistent with expected joint loading differences during manipulation and locomotion, no study exists that has documented this variation across the numerous bones of the hand. We quantify the trabecular structure in 22 bones of the human hand (early/extant modern Homo sapiens) and compare structural variation between two groups associated with post-agricultural/industrial (post-Neolithic) and foraging/hunter-gatherer (forager) subsistence strategies. We (1) establish trabecular bone volume fraction (BV/TV), modulus (E), degree of anisotropy (DA), mean trabecular thickness (Tb.Th) and spacing (Tb.Sp); (2) visualize the average distribution of site-specific BV/TV for each bone; and (3) examine if the variation in trabecular structure is consistent with expected joint loading differences among the regions of the hand and between the groups. Results indicate similar distributions of trabecular bone in both groups, with those of the forager sample presenting higher BV/TV, E, and lower DA, suggesting greater and more variable loading during manipulation. We find indications of higher loading along the ulnar side of the forager sample hand, with high site-specific BV/TV distributions among the carpals that are suggestive of high loading while the wrist moves through the ‘dart-thrower's’ motion. These results support the use of trabecular structure to infer behavior and have direct implications for refining our understanding of human hand evolution and fossil hominin hand use.

Anatomic Relationship Between the Hook of the Hamate and the Distal Transverse Carpal Ligament: Implications for Ultrasound-Guided Carpal Tunnel Release.

During ultrasound-guided carpal tunnel release, osseous landmarks may supplement direct visualization of the distal transverse carpal ligament (dTCL) to ensure a complete release. The purpose of this study was to determine the relationship between the apex of the hook of the hamate (aHH) and the dTCL within the transverse safe zone (TSZ) of the carpal tunnel. Twenty unembalmed cadaveric specimens were dissected to determine the aHH-dTCL distance and the aHH-SPA distance (the distance between the aHH and the superficial palmar arch) at the ulnar and radial limits of the TSZ (the distance between the hook of the hamate or ulnar artery to the median nerve). The aHH-dTCL distance averaged 11-12 mm across the TSZ (maximum, 18.2 mm), whereas the aHH-SPA distance was significantly greater on the radial side of the TSZ compared with the ulnar side (22.6 ± 3.6 mm vs. 14.0 ± 4.0 mm). The dTCL lies approximately 11-12 mm distal to the aHH across the TSZ, with an upper limit of 18.2 mm. Along with direct sonographic visualization of the dTCL, the aHH can be used with other osseous landmarks to estimate the position of the dTCL during ultrasound-guided carpal tunnel release.

A rare case report of bilateral dupuytren's contracture of hand

Dupuytren’s contracture (DC) is painless flexion contracture of ulnar side of palm where fingers bend towards palm and cannot be straightened. It is a fibrosing disorder that results in slowly progressive thickening and shortening of the palmar fascia, leading to the debilitating digital contractures. We report the case of a 60-year-old male with bilateral contractures on ulnar side of hands, suggestive of DC.

Application of free superficial palmar branch of radial artery flap in repairing of soft tissue defect of fingers

To evaluate the surgical technique and the effectiveness of the free superficial palmar branch of the radial artery flap to repair soft tissue defect of fingers. Between June 2014 and June 2017, 10 cases (10 fingers) of soft tissue defects of fingers were repaired with the free superficial palmar branch of the radial artery flaps. There were 8 males and 2 females with an average age of 29.8 years (range, 23-42 years). The causes of injury included the chainsaw cutting injury in 6 cases, the machine crush injury in 2 cases, and the glass scratching in 2 cases. The time from injury to admission was 1-8 hours with an average of 3 hours. The locations were the volar of the middle of index finger in 3 cases, the volar of the distal of index finger in 1 case, the volar of the distal of middle finger in 3 cases, the ulnar side of distal interphalangeal joint of ring finger in 1 case, and the volar of the distal of the little finger in 2 cases. The area of soft tissue defect ranged from 1.8 cm×0.9 cm to 2.8 cm×2.1 cm, and the area of flap ranged from 2.0 cm×1.0 cm to 3.0 cm×2.3 cm. The donor sites were sutured directly. All flaps survived after operation, and the wounds healed by first intention. The incisions of donor site also healed by first intention with a linear scar. All cases were followed up 6-12 months (mean, 9 months). The appearance and texture of the flaps were satisfactory. The pain sensation, warm sensation, and touch sensation of the flap recovered. At last follow-up, the two-point discrimination of the flap was 6-13 mm (mean, 7.5 mm). According to the assessment of the upper limb function issued by tha Hand Surgery Society of Chinese Medical Association, the results were graded as excellent in 8 cases and good in 2 cases. The free superficial palmar branch of the radial artery flap is easy to harvest and anastomose and has small injury. It is an ideal method in repairing of soft tissue defects of fingers.

New technique of ultrasound-guided injection in the carpal tunnel syndrome

In conventional ultrasound-guided corticosteroid injection in carpal tunnel syndrome (CTS), the entry point is usually at the distal crease of the wrist. However, actual pathology of CTS is caused by thickening of the transverse carpal ligament (TCL). Injection of corticosteroid can reduce inflammation and ameliorate the symptoms, but it cannot reduce the thickness of TCL. If we change the entry point to just 10 mm below the distal crease rather than at the distal crease, we can inject corticosteroid around the median nerve and into the TCL. Five patients with CTS treated with ultrasound-guided corticosteroid injection around median nerve and into the TCL. The diagnosis of CTS was made by history, physical examination, sonographic evaluation, and electrophysiologic confirmation. Sonographic examinations were performed by one physiatrist using Samsung scanner with a 5–12 MHz linear transducer. Standard 23-gauge needles were used for administration of local anesthetics and triamcinolone mixture (total 1 cm 3 ). After transverse view and longitudinal view, the entry point was determined. The entry point was below the distal crease, where the needle could easily introduce the injection material into the thickened TCL. The direction of the needle entry point was from lateral to ulnar side. Total of five female patients with CTS were included. The mean age was 55.4 ± 3.6 years. The mean duration of disease was 4.6 (range 3–8 mo) months. The results were good to excellent in all patients. There were no complications during the procedure. Ultrasound-guided corticosteroid injection in CTS, combined with injection at the thickened TCL may be a good method and further research is needed to confirm the usability.

Injuries of the Sportsman’s Hand

Injuries of the Sportsman’s Hand

Correlation Between Referred Pain Region and Sensitized Acupoints in Patients with Stable Angina Pectoris and Distribution of Sensitized Spots in Rats with Myocardial Ischemia

To observe the correlation between the referred pain regions of stable angina pectoris (SAP) and the acupoints in coronary heart disease (CHD) patients and to investigate the rule of regional sensitized point distribution in rats. A total of 1 046 CHD patients with SAP from 8 hospitals in China were recruited in the present study. The tenderness was palpated along the left and right chest, back, shoulder, upper limb, etc. by a specially-assigned researcher in each hospital. Among them, 77 patients accepted pain threshold (PT) measurement by using a hand-held esthesiometer. In animal experiments, 14 SD rats were subjected to occlusion of the left anterior descending branch of the left coronary artery for 4 h for establishing myocardial ischemia (MI) model, and other 4 normal rats were used as the sham-operation control group. Four hours after MI, all the rats accepted tail venous injection of 5% Evans blue (50 mg/kg) for examining the distribution of the blue dye exudation spots at the body surface where the mechanical PT was also detected by a von Frey. In 1 046 CHD patients, 987 (94.36%) were found to have at least one tenderness spot. The tenderness spots were found at the left chest (87.47%), right chest (13.67%), left arm (ulnar side, 41.30%), right upper limb (4.68%), left shoulder back (30.21%), right shoulder back (7.07%), etc., accompanied with rash or pigmentation, subcutaneous induration, cord-like tissue contracture, skin sag, etc. The mechanical PT level was significantly lower at the tenderness spots of the left upper limb than at non-tender points of the right upper limb in CHD patients (P<0.001). Tenderness and cutaneous abnormal changes in angor pectoris patients distributed mostly on the left chest, back, shoulder and upper limb, and some also on the right. Tender points scattered on, near or outside acupoints. A similar distribution of the blue exudation spots and lower mechanical PT spots were found in MI rats, but not in sham-MI rats. In the case of MI, a regular "referred sensitization" response frequently occurs in the dermatomere area innervated by the corresponding segments (T 1－T 5) in both CHD patients and MI rats, which may be closely associated with the formation of acupoints in ancient China.

Arthroscopy of the distal radioulnar joint

The aim of the procedure is to visualize the proximal pouch of the DRUJ, the joint surfaces of the sigmoid notch and the ulnar head, the convexity of the ulnar head and the proximal ulnar side surface of the triangular fibrocartilage complex (TFCC). Arthroscopy of the distal radioulnar joint is applied for the evaluation of joint pathologies in ulnar-sided wrist pain, especially in cases without diagnostic findings in standard X‑rays and MRIs and arthroscopically assisted procedures. In vertical extension, two portals of the wrist are created on the dorsal side of the DRUJ between the extensor digiti minimi and extensor carpi ulnaris tendons. By insertion of asmall joint arthroscope via these portals visualization of the ulnar head, the sigmoid notch, the proximal pouch of the DRUJ and the proximal surface of the TFCC is accomplished. Arthroscopy of the DRUJ is ararely and not routinely performed procedure for the diagnosis and therapy of ulnar-sided wrist pain. It is technical demanding with aflat learning curve and anatomy-related obstacles. Acomplete view of the joint is not always accessible. Rare complications are injuries of the extensor digiti minimi tendon, as well as contusion or sectioning of the transverse branch of the dorsal branch of the ulnar nerve. In distinct cases, this procedure offers important additional information about the distal radioulnar joint. The procedure is especially valuable for the detection of proximal TFCC injuries that are missed otherwise.

A solitary osteochondroma of middle phalanx of the hand in an adult: A case report and differential diagnosis

Introduction: Solitary osteochondroma of phalanx of the hand in an adult are extremely rare and have different presentations depending on the site of origin. Most adult solitary tumour arises either from the distal phalanx or in the carpal bones. Importance of the lesion lies in its various differential diagnoses. We present a rare case report of solitary osteochondroma of the middle phalanx left index finger in an adult. Management and differential diagnosis is discussed. Presentation of Case: 32 year old male presented with osteochondroma arising from dorsal ulnar side of middle phalanx left index finger with limitations of movements at PIP and DIP joint. Patient achieved full finger movements after excision and no recurrence at 18 month follow-up. Conclusion: Solitary osteochondroma of the middle phalanx in an adult is a rare osteocartilaginous lesion. In view of a varied differential diagnosis and a high rate of local recurrence, an early identification and a wide excision is essential.

Second Commentary on "Partial Wrist Denervation: The Evidence Behind a Small Fix for Big Problems".

Second Commentary on "Partial Wrist Denervation: The Evidence Behind a Small Fix for Big Problems".

Mind the Gap: The Effects of Temporal and Spatial Separation in Localization of Dual Touches on the Hand.

In this study, we aimed to relate the findings from two predominantly separate streams of literature, one reporting on the localization of single touches on the skin, and the other on the distance perception of dual touches. Participants were touched with two points, delivered either simultaneously or separated by a short delay to various locations on their left hand dorsum. They then indicated on a size-matched hand silhouette the perceived locations of tactile stimuli. We quantified the deviations between the actual stimulus grid and the corresponding perceptual map which was constructed from the perceived tactile locations, and we calculated the precision of tactile localization (i.e., the variability across localization attempts). The evidence showed that the dual touches, akin to single touch stimulations, were mislocalized distally and that their variable localization error was reduced near joints, particularly near knuckles. However, contrary to single-touch localization literature, we observed for the dual touches to be mislocalized towards the ulnar side of the hand, particularly when they were presented sequentially. Further, the touches presented in a sequential order were slightly “repelled” from each other and their perceived distance increased, while the simultaneous tactile pairs were localized closer to each other and their distance was compressed. Whereas the sequential touches may have been localized with reference to the body, the compression of tactile perceptual space for simultaneous touches was related in the previous literature to signal summation and inhibition and the low-level factors, including the innervation density and properties of receptive fields (RFs) of somatosensory neurons.

Polydactyly of the Hand.

Polydactyly is one of the most common congenital hand deformities managed by orthopaedic surgeons. It is most often found in isolation; however, rarely, it may be associated with genetic syndromes. Polydactyly is classified as postaxial, preaxial, or central depending on the radioulnar location of the duplicated digits. Postaxial polydactyly, which affects the ulnar side of the hand, is most common and is typically managed with excision or suture ligation of the supernumerary digit. Preaxial polydactyly, which affects the thumb or radial side of the hand, often requires reconstructive techniques to ensure a functional, stable thumb. Central polydactyly is much less common, and reconstruction can be challenging.

Extensor digitorum brevis manus - its incidence and clinical insight

Abstract Background and aims: Extensor digitorwn brevis manus is an accessory muscle on the dorsum of the hand. It lies in the fourth extensor compartment of the wrist. Its occurrence is relatively rare. Incidence of this muscle is 4% in the general population. Presence of this muscle is usually asymptomatic but rarely it may produce painful swelling which can be misdiagnosed as lipoma or ganglion or synovial cyst. Aim of the present study was to find out the incidence of extensor digitorwn brevis manus muscle in Indian cadavers. Material and Methods : Study was conducted on 64 human hands of adult Indian cadavers of unknown age and sex in the department of anatomy. A longitudinal incision was placed on the dorsum of hand along the axis of middle finger, skin flaps were raised both on radial and ulnar side. A transverse incision was taken at metacarpo-phalangeal joints from second to fifth fingers. Dorsum of each hand was dissected carefully to see the presence of extensor digitorwn brevis manus. Results: We found extensor digitorum brevis manus muscle in 3 hands [rt.-1; It. - 2] out of 64, i.e. 4.68%. Conclusion: Anatomical knowledge of this muscle present in the extensor compartment may be helpful in planning tendon transfer or graft surgeries Therefore, the knowledge of these variant muscles may be important.

Vascular Analysis of Radial Artery Perforator Flaps.

Background:Radial forearm free flap with all its present day modifications is the workhorse of soft tissue reconstruction in head & neck. Although there are several advantages, it requires the sacrifice of a major artery of forearm. There are several modifications of harvesting a forearm flap based on perforator principles. A clear understanding of vascular anatomy of individual perforators relative to its vascular territory & flow characteristics is essential for both flap harvest & design. The purpose of this cadaveric observational anatomical study was to determine the location, size & vascular territory of the radial artery cutaneous perforators.Materials and Methods:12 fresh human cadavers & 24 cadaveric forearms were dissected to determine the total number, location, size & vascular territory of radial artery adipo-fascio cutaneous perforator. The cutaneous territory of distally dominant perforators was analyzed using methylene blue injections & three-dimensional computed tomographic angiogram.Results:In the 12 fresh human cadavers & 24 forearm specimens, a total of 222 perforators were dissected for an average of 18.5 radial artery perforators per forearm. Of the total 222 perforators dissected 118 were smaller than 0.5mm in diameter (53.15%) these were not clinically significant. 104 perforators were greater than 0.5mm in diameter (46.84%) these were clinically significant. Of the 222 radial artery perforators dissected, 127 perforators (57.20%) were radially distributed & 95 perforators (42.79%) had ulnar distribution. A total of 90 perforators (40.54%) were identified on distal side (Radial styloid) & 132 perforators (59.45%) were identified on proximal side (Lateral epicondyle). Mean number of perforators on radial side was 10.6 & 7.9 on ulnar side, a comparison of both using student t paired test gives a P value of 0.006, which was statistically significant. Comparison of mean number of perforators on the distal side was 7.5 & proximal side was 11.0, Student Paired t test gives a P value of 0.003, which was statistically significant. Comparison of mean Diameter of perforators between the Distal side (1.11) & Proximal side (0.86) using Student Paired t test gives a P value of 0.01 which was statistically significant. A chi square test was done to compare mean diameter of perforators on distal side, which were more than 1mm (80%) & less than 1mm (20%) & on proximal side more than 1mm (35.6%) & less than 1mm (64.4%). Chi square value of 42.406 was obtained, degree of freedom value was 1& P value of <0.001 was achieved which was found to be highly significant. Methylene blue injections into the proximal part of radial artery demonstrated clusters both in proximal & distal forearm & also cutaneous territory of flap. Three- dimensional computed tomographic angiography reveals a network of linking vessels found to communicate between adjacent perforators & running parallel to radial artery. Large network of linking vessels could be found between fascia & dermis, which also explains the ability to harvest forearm flap at the supra-fascial level.Conclusion:Increase in knowledge of vascular territory of radial artery perforators with regards to numbers, size, location, and cutaneous territory can lead to expanded use of radial forearm flap based on either distal or proximal perforator alone, without sacrificing the radial artery.

Anatomical Relationships between Muscles Overlying Distal Transverse Carpal Ligament and Thenar Motor Branch of the Median Nerve.

BackgroundThe purpose of the current study is to investigate anatomical relationships between the muscle overlying the distal transverse carpal ligament (TCL) and the thenar motor branch of the median nerve.MethodsOf the 192 wrists that underwent open carpal tunnel release, a muscle belly overlying the TCL was observed on the distal margin of TCL in 25 wrists and ligament exposure could not be achieved without transection of it. We recorded surgical findings of these 25 wrists. The origin of the recurrent motor branch arising from the major median nerve was marked on the axial and coronal section diagrams of the wrist.ResultsThe presence of muscle overlying the TCL was seen in 25 wrists (21 patients, 13%). The locations of origin were distributed not only on the radial side but anterior or ulnar side of the major median nerve. Abnormal branches originated from the unusual side in 14 cases (56% of those with a muscle overlying the TCL): central-anterior side in eight cases, ulnar-anterior side in five cases, and ulnar side in one case. These anomalous branches were frequently associated with the muscle belly overlying the TCL in our study regardless of the origin site. The branches were prone to cut if careless midline incision along the third web space was performed. Unusual origin and aberrant pathway of the recurrent thenar motor branch were associated with the presence of a muscle overlying the TCL.ConclusionsA thorough knowledge of the standard and variant anatomy of the muscle belly and recurrent motor branch in the carpal tunnel is fundamental to prevention of complications such as muscle wasting or atrophy by iatrogenic motor branch injury during carpal tunnel release.

Adipo Fascio Cutaneous Perforator Based, Shape Modified Radial Forearm Flap: Vascular Analysis of Perforators &amp;amp; Its Clinical Applications in Head &amp;amp; Neck Reconstruction

Resume of the study & Background: Radial forearm free flap with all its present day modifications is the workhorse of soft tissue reconstruction. Although there are several advantages, it requires sacrifice of a major artery of forearm. Several modifications are described in harvesting a forearm flap. In order to achieve a reliable, safe flap harvest & design one must have a very clear understanding of radial artery perforators, relative to its distribution, territory & flow. The purpose of this study is to determine the location, size & vascular territory of the radial artery cutaneous perforators & to demonstrate application of shape modification of radial forearm free flap based on its distal & proximal perforators in various head & neck defects. Materials & Methods: Anatomical Study: 12 fresh human cadavers & 24 cadaveric forearms were dissected to determine the number, location, size & vascular territory of radial artery perforator. The cutaneous territory of distally dominant perforators was analyzed using methylene blue injections & three-dimensional computed tomographic angiogram to determine the vascular network. Clinical Study: 15 patients with various head neck defects following oncological resections were reconstructed with shape modified adipo-fascio cutaneous free forearm flap. All these patients were prospectively followed for donor site healing, motor & sensory nerve deficit, function & quality of life questioner for donor site assessment. Results: 12 fresh human cadavers & 24 cadaveric forearms were dissected, and a total of 222 perforators were dissected for an average of 18.5 perforators per forearm. 118 were smaller than 0.5 mm in diameter (53.15%) & were not clinically significant. 104 perforators were greater than 0.5 mm in diameter (46.84%) & were clinically significant. 127 perforators (57.20%) were radially distributed & 95 perforators (42.79%) had ulnar distribution. 90 perforators (40.54%) were identified on distal side (Radial styloid) & 132 perforators (59.45%) were identified on proximal side (Lateral epicondyle). Mean number of perforators, on radial side was 10.6 & 7.9 on ulnar side; comparison of both using student t paired test gives a P value of 0.006, which is significant. Comparison of mean number of perforators on the distal side was 7.5 & proximal side was 11.0; Student Paired t test gives a P value of 0.003, which was statistically significant. Comparison of mean diameter of perforators on Distal side (1.11) & Proximal side (0.86), side using Student Paired t test gives a P value of 0.01 which was statistically significant. A chi square test was done to compare mean diameter of perforators on distal side, which was more than 1 mm (80%) & less than 1 mm (20%) & on proximal side more than 1 mm (35.6%) & less than 1 mm (64.4%). Chi square value of 42.406 was obtained, degree of freedom value was 1 & P value of <0.001 was achieved which was found to be highly significant. Methylene blue injections demonstrated clusters both in proximal & distal forearm & also marked the cutaneous territory of flap. Three-dimensional computed tomographic angiography reveals a network of linking vessels found to communicate between adjacent perforators & running parallel to radial artery. A total of 15 patients were reconstructed with shape modified radial forearm flap following oncologic resections. Wound healing in all 15 patients was good, with scar assessment faring better than traditional radial forearm flap. There was no sensory or motor nerve deficit. Although pedicle length was comparatively shorter in shape-modified flap, there was no problem in anastomosing to neck vessels. Conclusion: Increase in knowledge of vascular territory of radial artery perforators with regards to numbers, size, location, & cutaneous territory can lead to expanded use of radial forearm flap based on either distal or proximal perforator alone. Shape modified technique for harvesting radial forearm flap allows primary closure of donor site. Donor site is better healed and shows a predicted pattern, which is functionally and aesthetically good.

Gender identification from thumbprint ridge thickness among Hausa population of Nigeria using likelihood ratio and posterior probability density

The objectives of the present study were to identify sex from thumbprints ridge thickness using likelihood ratio and posterior probability density as well as to determine which of the three areas of thumb has more potential in sex determination. This was a cross sectional study which involved 194 subjects (97 males and 97 females) within the age range 18-25 years. Ridge thickness was examined within the 25 mm2 areas (ulnar, radial and proximal) which made up of 1164 areas of the thumbprints. Females exhibited finer ridge count compared to males in ulnar area of both sides of the thumbs. In the radial area females were found to have finer ridge counts as in ulnar side, but with some coarse ridge. For the right proximal ridge thickness, a similar trend to that in the radial area was noticed, however, in the left thumbprint, males tend to have finer ridge counts compared to females. It was noticed that chance of sex inference from likelihood ratio decreased in the following order: proximal ridge thickness < radial ridge thickness < ulnar ridge thickness as ridge thickness decreases in favor of females but left proximal ridge thickness showed increased in likelihood ratio as ridge thickness decreased in favor of males. In conclusion, considering equal probability for each sex, likelihood ratio reveals the applicability of ridge thickness in sex inference among Hausa population. Ridge thickness in ulnar area showed more discrimination power compared to other two areas.

Design and Evaluation of a Wearable Skin Stretch Device for Haptic Guidance

We present a wearable skin stretch device for the forearm. It is composed of four cylindrical end effectors, evenly distributed around the user's forearm. They can generate independent skin stretch stimuli at the palmar, dorsal, ulnar, and radial sides of the arm. When the four end effectors rotate in the same direction, the wearable device provides cutaneous stimuli about a desired pronation/supination of the forearm. On the other hand, when two opposite end effectors rotate in different directions, the cutaneous device provides cutaneous stimuli about a desired translation of the forearm. To evaluate the effectiveness of our device in providing navigation information, we carried out two experiments of haptic navigation. In the first one, subjects were asked to translate and rotate the forearm toward a target position and orientation, respectively. In the second experiment, subjects were asked to control a 6-DoF robotic manipulator to grasp and lift a target object. Haptic feedback provided by our wearable device improved the performance of both experiments with respect to providing no haptic feedback. Moreover, it showed similar performance with respect to sensory substitution via visual feedback, without overloading the visual channel.

Seguridad de los portales metacarpofalángicos. Estudio anatómico

AimTo quantify the risk of dorsal innervation injury when performing direct metacarpophalangeal joint portals of the second to fifth fingers. Material and methodAn anatomical study of 11 upper limbs of fresh corpses was carried out. After placing them in a traction tower, the metacarpophalangeal portals were developed on both sides of the extensor tendon. The dorsal sensory branches were dissected and the distances between the portal and the nearest nerve were measured by a digital caliper. The portals of all the fingers were compared globally to assess the safest finger and two to two radial and ulnar portals were compared in each of the fingers to assess the safest portal within each finger. ResultsThe overall comparison of all portals and fingers showed that the third finger is the safest in any of its portals, while the ulnar side of the second and radial of the fourth are the portals with the highest risk of nerve injury (P=8.96·10-5). Comparing two to two of the radial and ulnar portals in each of the fingers showed that the ulnar portal is safer than the radial on the fourth finger (P=.042), while the radial is safer than the ulnar on the fifth finger (P=.003). ConclusionsThe third finger was the safest to perform metacarpophalangeal portals, while the ulnar side of the second finger and radial side of the fourth had the highest risk of nerve injury.