Head Distance Research Articles

Effects of the Laser Head Distance and Cutting Speed of the Laser Cutting Machine in the Polymethyl Methacrylate Cutting Process

Laser cutting is a process used as an alternative of conventional machinery that works by directing the output of the laser power on the would be-cut material. Material exposed to the laser light is then melted, burned, and evaporated by the gas. Thus, this laser cutting process produces high-quality edge surface. The research aimed to determine the effects of the laser head distance and cutting speed to obtain minimum width of gap and the laser cutting process with the 3 mm-thick polymethyl methacrylate. This experiment used a 60 Watt-powered laser cutting machine to take the specimen in the form of a 30 mm-long horizontal line. The laser head distance ranged from 6 to 10 mm and cutting speed varied from 4 to 8 mm/s. A stereo zoom microscope with 30 times magnification was used to measure the gap. The research resulted in 0.582 to 0.931 mm as the value of the width gap in the cutting of 3 mm thick 60 Watts-powered polymethyl methacrylate (PMMA). The laser head distance and cutting speed contributed to the gap width of the product. The increased cutting speed and gap distance resulted in the smaller gap width.

Paper #7 - The effects of latarjet reconstruction on glenohumeral instability in the presence of combined bony defects: a cadaveric model

Introduction: Recurrent glenohumeral instability often results from underlying bony defects in the glenoid and/or humeral head. Anterior glenoid augmentation with a bone block (i.e. Latarjet) has been recommended for glenoid bone loss in the face of recurrent instability. However, no study has investigated the effect of Latarjet augmentation in the setting of both glenoid and humeral head defects (Hill-Sachs Defects (HSD)). The purpose of this study was to evaluate the stability achieved through a Latarjet procedure in the presence of combined bony defects. Methods: Eighteen fresh-frozen cadaveric specimens were tested at all combinations of glenohumeral abduction (ABD) angles of 20°, 40°, and 60° and three external rotation (ER) levels (0°, 40°, and 80°). Each experiment comprised of anterior dislocation by translating the glenoid under a 50N medial load applied on the humerus, simulating the static load of soft tissues. Translational distance and medial-lateral displacement of the humeral head, along with horizontal reaction forces were recorded for every trial. Specimens were tested in an intact condition (no defect), different combinations of defects, and with Latarjet augmentation. The Latarjet was performed for 20% and 30% glenoid defects by transferring the specimen's coracoid process anterior to the glenoid flush with the articulating surface. Four different humeral head defects (sizes 6%, 19%, 31%, and 44% of humeral head diameter) were created. Repeated measures analysis of variance (ANOVA) was performed with statistical significance set at P < .05. Results: Results are summarized in Figure 1. The vertical axis represents the normalized distance to dislocation with respect to the values of the intact joint. The horizontal axis represents the varying sizes and combinations of bony defects. At 20° ABD and 0°ER, increasing HSD size did not affect percentage of intact translation with a constant glenoid defect of 20% before and after Latarjet augmentation (Fig. 1A). However, at an arm position of 60° ABD and 80° ER increasing HSD size led to a decrease in stability for both the defect state and post-Latarjet trials (Fig. 1C). Nevertheless, Latarjet augmentation helped in regaining stability for every combination of bony defects. With a HSD size of 44% the defect state had 0% intact translation for all 18 specimens. Conclusions: Clinically, these results demonstrate that some degree of stability can be regained for combined bony Bankart and Hill-Sachs defects with a Latarjet procedure. However, for humeral defects larger than 31%, the rotational effect of the HSD led to persistent instability. Thus, directly addressing the humeral defect to restore the articular surface should be considered in these cases.

The short-term effects of trigger point therapy, stretching and medicine ball exercises on accuracy and back swing hip turn in elite, male golfers – A randomised controlled trial

ObjectivesThis study aimed to compare the effect of myofascial trigger point therapy (MTPT) and stretching, MTPT and medicine ball exercises, and no intervention, on hip flexor length (HFL), golf swing biomechanics and performance in elite, male golfers. DesignSingle blind, randomised controlled trial with two experimental groups (stretch group: MTPT and stretching; and the ball group: MTPT, a single stretch and medicine ball exercises) and one control group (no intervention). SettingProfessional golf academy. ParticipantsOne hundred, elite, male golfers aged 16–25 years. Main outcome measuresHFL, 3D biomechanical analysis of the golf swing, club head speed (CHS), smash ratio, accuracy and distance at baseline and after the interventions. ResultsBackswing hip turn (BSHT) improved in the ball group relative to the control group (p = 0.0248). Accuracy in the ball group and the stretch group improved relative to the control group (Fisher's exact = 0.016). ConclusionsOther performance parameters such as: smash ratio, distance and CHS were not compromised by either intervention. This study advocates the use of MTPT combined with medicine ball exercises over MTPT combined with stretching in the treatment of golfers with shortened hip flexors – even immediately preceding a tournament.

Radiologic Changes by Early Motion in Neck Fractures of the Fifth Metacarpal Treated with Antegrade Intramedullary Fixation.

As intramedullary (IM) fixation is one of the fixation methods used in neck fractures of the fifth metacarpal, an early motion of injured finger can be allowed. The purpose of this study is to evaluate whether immediate active motion affects the stability of antegrade IM fixation in surgical treatment of neck fractures of the fifth metacarpal bone and to assess related factors. Thirty one patients treated by closed reduction and antegrade IM fixation were consecutively enrolled. All patients started active motion of the little finger since 7 postoperative days and only daily activities including writing, typing or washing were allowed until the union of fracture. All fractures were healed within four to eight weeks. The changes of angulation, fifth metacarpal length and tip to head distance of K-wire were compared between immediate postoperative radiographs and radiographs at eight weeks. In addition, the effects by age, gender, initial angulation and comminution of the metacarpal neck were assessed. The average change of angulation was 0.12°, 5th metacarpal length was 1.49mm and tip to head distance of K-wire was 1.31mm. There was no significant difference in the change of angulation (p = 0.137). But, there were significant differences in the change of 5th metacarpal length and tip to head distance of K-wire ([Formula: see text]). The change of angulation was related to a comminution of the metacarpal neck and that of 5th metacarpal length was related to age and sex. The change of 5th metacarpal length and tip to head distance of K-wire can occur by an early mobilization in the antegrade IM fixation for neck fractures of the fifth metacarpal. However, we thought that an early active motion after surgery is important to increase the patients' satisfaction, even though careful selection of candidates is necessary.

Collagenase Treatment for Dupuytren Disease of the Thumb and First Web

To evaluate the short-term effectiveness of collagenase Clostridium histolyticum to treat thumb and first web contractures in Dupuytren disease. We prospectively included 14 thumbs in 12 patients with a contracture at the metacarpophalangeal or interphalangeal joint of at least 20° with a palpable cord in the thumb (n= 8) or an adduction contracture of the thumb with palpable cords in the first web (n= 6). They received an injection containing 0.58 mg of collagenase Clostridium histolyticum in the fibrous cord divided over 3 spots. The contracture was released by carefully manipulating the thumb under local anesthesia 1 day later. The extension and abduction deficits were measured before and after the intervention (follow-up at 7 and 30 days and 6 months). Wilcoxon signed rank test was used to analyze the data. In the total sample, postintervention extension deficits were statistically significantly lower than preintervention deficits except in one patient who had a recurrence at 6 months compared with the 30-day posttreatment result. Intermetacarpophalangeal head distance (IMD) also improved significantly. In an analysis of subgroups, we compared the separate contributions of treatment of a pretendinous cord and a first web cord on both extension deficit and IMD. Treatment of pretendinous cords significantly affected both extension deficit and IMD. However, treatment of first web contractures did not significantly improve extension or IMD. Collagenase Clostridium histolyticum is a good treatment option for pretendinous cords in thumbs affected with Dupuytren disease because it provides good results, is minimally invasive, and has minor adverse events. Therapeutic IV.

プレッシャーが知覚および運動プランニングに及ぼす影響

The purpose of this study was to clarify how psychological pressure impacts on perception, motor planning and performance. Fourteen male college students (mean age 21.5, sd=1.6 years) performed 2 tasks in succession under both no-pressure and pressure conditions; the perception task required them to judge the perceptual distance to the target, while the action task required them to putt a golf ball, aiming for the perceived target location. We measured the perceived target distance (subjective perception), displacement and maximum velocity of the club head (motor planning), and putting distance (motor performance) during the tasks; the target was created using Muller-Lyer illusion figures that induced distorted depth perception. While this form of pressure did not affect subjective perception, the illusion influenced subjective perception, i.e. F (1, 13)=24.25, p

Influence of Train Location on Smoke Control in Tunnel Cross-passage

Theoretical analysis and numerical are used to investigate the critical velocity in tunnel cross-passage. Considering the effect of train blocking, several cases are built by FDS to verify whether the critical velocity can control the smoke in the cross-passage. Result indicates that the distance of the train head away from the cross-passage as 1/2 power of the tunnel velocity. With the train crossing the cross-passage, the value velocity of the cross door increase gradually and then decreases when the middle of the train stocking in the door of cross-passage. The maximum value of velocity is greater than the critical velocity calculated by Froude model and the smoke diffuse to the cross-passage. In other cases, the velocity fails to prevent the soot propagation from accident side of the tunnel and the gas full of the cross-passage cause risk of evacuation.

SEP에서 전송 거리 분배를 이용한 무선 센서 네트워크 수명 개선

In this paper, we propose a method for improving the lifetime of the sensor network SEP through the wireless sensor network divided into two spaces by reducing the transmission distance of the cluster head in the layer in the distance. With reference to the position information of the node, the base station divides the layer based on the midpoint of the nearest node and the furthest distance away from the base station node. And the cluster head in the outer layer far from the base station is transmitted the data to the base station via the cluster head in the inner layer base station to transmit data. That is, we are proposed the layered SEP by reducing the transmission distance of the cluster head in the outer layer for the energy consumption to a minimum. The proposed algorithm is verified by comparison with the existing SEP.

Theoretical Analysis of Total Hip Dislocation and Comparison of Hemispherical Cup and Newly Developed Cup

Dislocation remains a serious complication of total hip replacement. The aim of this study was to analyze the process by which the femoral head is levered out of the acetabular cup when the femoral component sustains a torque after prosthetic impingement. The jump distance of the femoral head and its trajectory were calculated and compared for the common hemispherical cup and a newly developed elongated cup with a preferred impact mode (ChenLin cup). The results show that the latter avoids the short jump distance seen with the former and makes it more difficult for the femoral head to follow a path resulting in dislocation. Thus, it is expected that the ChenLin cup will reduce the risk of dislocation. In addition, this study found that, with both types of cup, the femoral head diameter and the outer diameter of the cup affect the jump distance, whereas the head/neck ratio has almost no effect on the jump distance for the hemispherical cup, but may have a positive effect for the ChenLin cup. This study suggests that the use of a combination of a small cup, large femoral head, and large head/neck ratio will reduce the occurrence of total hip dislocation induced by torque.

The Study of the Electrothermal Heating Pipe Membrane Resistance Test Equipment

In order to detect the electrothermal heating tube internal electrothermal film resistance and the relationship between the two electrode gap, this thesis used design using a testing equipment: The two ends of the measurement period from two electrodes, and the probe spacing can be adjusted ; The two measuring points into hair heat pipe internal contact with the resistive film, using the bleeder circuit, the indirect measuring resistance membrane resistance and the relationship between the two measuring points spacing; then analyze the measurement data, the relationship between the two electrode gap and electrothermal film resistance. The use of such equipment, the measured data, we can analyze the electrothermal film heating pipe internal heating membrane resistance and two measurement of the end head distance is linear change. The linear relationship between the use of electrothermal film heating tube internal electrothermal membrane resistance, can estimate the range of internal electric heating film heating pipe resistance from two the distance between the electrodes, get the change range of heating tube power.

The Electrothermal Heating Tube Membrane Resistance Test Method Research

This thesis uses a kind of detection method: The two ends of the measurement period from two electrodes, and the probe spacing can be adjusted. Two measuring end head into the interior with electric heat pipe membrane contact ,used the voltage dividing circuit,relations indirect detection of electric resistance film ends with the two measuring pitch. Then the measured data analysis, obtains the relationship between the two electrode spacing and the electrothermal membrane resistance. Make this thought method may not be used to measure the electric heating film resistance, become a simple and practical method for measuring the electric heating film resistance. Using this method, the measured data can be analyzed, indirectly electrothermal film heating pipe internal resistance value and the two measurement of the end head distance is linear change. The linear relationship between the use of electrothermal film heating tube internal electric heating film resistance, the resistance can be estimated from the distance between the two electrodes, get the change range of heating tube power.

Controls on submarine canyon activity during sea-level highstands: The Biobío canyon system offshore Chile

Newly acquired high-resolution bathymetric data (with 5 m and 2 m grid sizes) from the continental shelf off Concepcion (Chile), in combination with seismic reflection profiles, reveal a distinctly different evolution for the Biobio submarine canyon compared to that of one of its tributaries. Both canyons are incised into the shelf of the active margin. Whereas the inner shelf appears to be mantled with unconsolidated sediment, the outer shelf shows the influence of strong bottom currents that form drifts of loose sediment and transport -material into the Biobio submarine canyon and onto the continental slope. The main stem of the Biobio Canyon is connected to the mouth of the Biobio River and currently provides a conduit for terrestrial sediment from the continental shelf to the deep seafloor. In contrast, the head of its tributary closest to the coast is located similar to 24 km offshore of the present-day coastline at 120 m water depth, and it is subject to passive sedimentation. However, canyon activity within the study area is interpreted to be controlled not only by the direct input of fluvial sediments into the canyon head facilitated by the river-mouth to canyon-head connection, but also by input from southward-directed bottom currents and possibly longshore drift. In addition, about 24 km offshore of the present-day coastline, the main stem of the Biobio Canyon has steep canyon walls next to sites of active tectonic deformation that are prone to wall failure. Mass-failure events may also foster turbidity currents and contribute to canyon feeding. In contrast, the tributary has less steep canyon walls with limited evidence of canyon-wall failure and is located down-system of bottom currents from the Biobio Canyon. It consequently receives neither fluvial nor longshore sediments. Therefore, the canyon's connectivity to fluvial or longshore sediment delivery pathways is affected by the distance of the canyon head from the coastline and the orientation of the canyon axis relative to the direction of bottom currents. The ability of a submarine canyon to act as an active conduit for large quantities of terrestrial sediment toward the deep sea during sea-level highstands may be controlled by several different conditions simultaneously. These include bottom current direction, structural deformation of the seafloor affecting canyon location and orientation as well as canyon-wall failure, shelf gradient and associated distance from the canyon head to the coast, and fluvial networks. The complex interplay between these factors may vary even within an individual canyon system, resulting in distinct levels of canyon activity on a regional scale.

The Effects of Latarjet Reconstruction on Glenohumeral Instability in the Presence of Combined Bony Defects

Objectives:Recurrent glenohumeral instability is often as a result of underlying bony defects in the glenoid and/or humeral head. Anterior glenoid augmentation with a bone block (i.e. Latarjet) has been recommended for glenoid bone loss in the face of recurrent instability. However, no study has investigated the effect of Latarjet augmentation in the setting of both glenoid and humeral head defects (Hill-Sachs Defects (HSD)). The purpose of this study was to evaluate the stability achieved through a Latarjet procedure in the presence of combined bony defects.Methods:Eighteen fresh-frozen cadaveric specimens were tested at all combinations of glenohumeral abduction (ABD) angles of 20°, 40°, and 60° and three external rotation (ER) levels (0°, 40°, and 80°). Each experiment comprised of anterior dislocation by translating the glenoid under a 50N medial load applied on the humerus, simulating the static load of soft tissues. Translational distance and medial-lateral displacement of the humeral head, along with horizontal reaction forces were recorded for every trial. Specimens were tested in an intact condition (no defect), different combinations of defects, and with Latarjet augmentation. The Latarjet was performed for 20% and 30% glenoid defects by transferring the specimen's coracoid process anterior to the glenoid flush with the articulating surface. Four different humeral head defects were created of sizes 6%, 19%, 31%, and 44% of humeral diameter. Repeated measures analysis of variance (ANOVA) was performed with statistical significance set at p <0.05.Results:Results are summarized in Fig. 1. The vertical axis represents the normalized distance to dislocation with respect to the values of the intact joint. The horizontal axis represents the varying sizes and combinations of bony defects. At 20° ABD and 0°ER, increasing HSD size did not affect percentage of intact translation with a constant glenoid defect of 20% before and after Latarjet augmentation (Fig. 1A). However, at an arm position of 60° ABD and 80° ER increasing HSD size led to a decrease in stability for both the defect state and post-Latarjet trials (Fig. 1B). Nevertheless, Latarjet augmentation helped in regaining stability for every combination of bony defects. With a HSD size of 44% the defect state had 0% intact translation for all 18 specimens.Conclusion:Clinically, these results demonstrate that some degree of stability can be regained for combined bony Bankart and Hill-Sachs defects with a Latarjet procedure. However, for humeral defects larger than 30%, the rotational effect of the HSD led to persistent instability. Thus, directly addressing the humeral defect to restore the articular surface should be considered in these cases. In conclusion, this study demonstrated that Latarjet procedure can restore the stability for combined defects, however for humeral defects greater than 31% may need attention.

A Multi-hop Cluster Routing Algorithm Based on Max-min Distances Method

With the purpose of reflning cluster head election and node single-hop in LEACH protocol under the environment of wireless sensor network energy heterogeneous, we propose a new routing algorithm named LEACH-3M. This algorithm generates K cluster centers spending max-min distances method which creates K clusters based on the distance from node to cluster center, selects cluster head with the principle of maximum weight, forms new cluster according to node and cluster head distance and this cluster head will be chose as next communication cluster center automatically. Constructing a chain with the shortest communication path between cluster head and SINK adopts continuous Hopfleld neural network and optimizes it to make multi-hop tree clustering chain with SINK central. Through MATLAB simulation analysis, this new algorithm improves prolonging network’s stability and energy equilibrium obviously compared with LEACH algorithm.

Radially Optimized Zone-Divided Energy-Aware Wireless Sensor Networks (WSN) Protocol Using BA (Bat Algorithm)

ABSTRACTThe problems of hot spot and energy consumption of nodes in wireless sensor networks (WSNs) have been tackled by the adoption of hybrid energy efficient distributed (HEED) and unequal clustering algorithm to prolong the network lifetime (UCAPN) protocols. These have involved the implementation of unequally sized clusters that are based on the distance of cluster head (CH) from the base station (BS). The BS partitions the network area into several radially divided zones depending on the distance from centre of the field and CHs are independently selected in each zone. Clustering, on the other hand, controls how data are transmitted and allows for aggregation in the clusters. However, whereas these topologies have been able to improve network life time, the problem of network void still persists. To address this, a radially optimized zone-divided energy-aware WSN protocol using bat algorithm is proposed. This protocol considers not only the distance from the BS, but also the angle at which the WSN develops. It gives a unique and equal opportunity for each sensor network to have ambience area for communicating and sensing necessary for its routing operations. Besides, it divides the sensing area into radial zones and employs the unequal clustering method in these zones to resolve the hot-spot problem. Based on the merits of zone-divided networks, CHs with great residual energy present in the high-energy regions are selected as the relay node in the inter-cluster multi-hop routing stage. Simulation results show that the proposed technique outperforms both HEED and UCAPN protocols. Bat algorithm is capable of predicting most critical nodes and generates a scalable and feasible energy-efficient routing technique for radially optimized zone-divided energy-aware WSN. By exploiting the angle at which the WSN develops, this protocol avails equal opportunity for each sensor network to have enough fields for communicating and sensing necessary for its routing operations. Using bat algorithm not only gives a superior packet delivery ratio, hence reducing voids, but also saves on energy consumption at the nodes. Sensor nodes are grouped into clusters to improve network performance.

Embodied Head Gesture and Distance Education

Traditional distance education settings are usually based on video teleconferencing scenarios where human emotions and social presence are only expressed by the facial and vocal expressions which are not enough for complete presence; our bodily gestures and actions play a vital role in understanding exact meaning of communication patterns; especially in teaching-learning scenarios. The bodily gestures especially head movements offer cues to understand contextual knowledge during conversational dialogue. In this work, we have considered the tutor's head gesture embodiment for educational assistive robot and compared the results with the standard audio-video tele-conferencing scenarios used in online education. We have used Embodied Telepresence System (ETS) to investigate the distance communication for online education setting. Our ETS emulates the head gestures of the human tutor for distance education scenario. Our experimental study includes ten able-bodied subjects (5 male and 5 female) from various countries. These participants were asked to participate in online education scenario through i) a traditional video conferencing tool, i.e. Skype and ii) an extended setup based on ETS. The statistical analysis is done on the results which indicates the effectiveness of our novel embodied head gesture based approach in distance education setting. Our experimental studies show that the proposed design of embodied head gesture based ETS is able to improve the user engagement in distance education.

Heart place and tail length evaluation in Naja oxiana, Macrovipera lebetina, and Montivipera latifii

ObjectiveTo evaluate a) heart place and tail length, b) their correlations with other biometrics, c) sexual differences in those features, in regard to cardiovascular system in a number of snakes from Iran, about which there is little information. MethodsWe studied the fresh mortalities of snakes including 14 Naja oxiana (N. oxiana), 23 Macrovipera lebetina, and one male Montivipera latifii acquired from the Serpentatium of Pasteur Institute of Iran. In this respect, each specimen first was weighted, and then its ventral side of the integument was incised, and heart place was measured. Subsequently, other biometrical features such as total length, TAL, and snout-vent length were measured. ResultsThe results showed that heart place in N. oxiana, Macrovipera lebetina and Montivipera latifii was about 18%, 32% and 30%, and also TAL constituted about 16%, 11% and 7% of total body length, respectively. Moreover, females indicated anterior heart place and shorter tail than males. Furthermore, the measures and correlations indicated few differences between N. oxiana and typical terrestrial species. ConclusionsThe results denoted that in order to overcome hemocirculatory perturbations in vertical orientation while hooding and head raising behavior, N. oxiana need to have more important features than short heart to head distance and long tail. In addition, it gave the sexual differences in heart place and tail length between males and females. It is suggested that in ophidian cardiovascular studies the animals be grouped based upon their sex.

Myofascial force transmission in sacroiliac joint dysfunction increases anterior translation of humeral head in contralateral glenohumeral joint

Abstract Introduction Posterior and anterior oblique muscle slings contribute to the force closure mechanisms that provide stability to sacroiliac joint. These global muscle slings consist of myofascial network of fascia, muscles and tendons from global muscles. It links the lumbopelvic region to other joints of musculoskeletal system especially the contralateral glenohumeral joint (GHJ). Any sacroiliac joint dysfunction (SJD) may likely disrupt the force transmission across the oblique slings and it can affect the contralateral GHJ. Aim The current study aims to investigate the effects of SJD on the contralateral GHJ. Material and methods An experimental study is designed recruiting 20 participants with SJD and 20 healthy participants as matched controls to test the hypothesis that SJD may cause excessive anterior translation of humeral head (ATHH) in contralateral GHJ. Using real time ultrasonography, resting position of humeral head (RPHH), ATHH and posttranslation distance of humeral head (PDHH) are compared between the GHJs among participants with SJD and the matched controls. Paired sample t-test and independent sample t-test are used to analyze the data. Results and discussion The paired sample t-test result showed statistically significant increase in ATHH (P = 0.03) and PDHH (P = 0.01) in contralateral GHJs among participants with SJD. The independent sample t-test showed a significant increase in RPHH (P = 0.01) and PDHH (P = 0.01) in SJD participants when compared to matched controls. Conclusion SJD contributes to excessive ATHH in the contralateral GHJ. This may occur due to altered myofascial force transmission across oblique sling muscles.

Distance Based Clustering Algorithm for Energy Efficiency in Wireless Sensor Networks

In wireless sensor networks Energy-efficient routing is an important issue due to the limited battery power within the network, Energy consumption is one of the important performance factors. Specifically for the election of cluster head selection and distance between the cluster head node and base station. The main objective of this proposed system is to reduce the energy consumption and prolong the network lifetime. This paper introduces a new clustering algorithm for energy efficient routing based on a cluster head selection

Ultrasound diagnosis of fetal head engagement

ObjectiveTo compare clinical data and transperineal ultrasound results for the diagnosis of fetal head engagement. MethodsThe present prospective longitudinal study enrolled 100 term women attending the Mongi Slim Hospital, La Marsa, Tunisia, between July and September 2012. The clinical assessment of fetal engagement was compared with ultrasound measurements. Ultrasound examination was performed in the delivery room. The probe was placed on the ano-vulvar area. The measure used was the distance between the perineum and external table of fetal skull. ResultsThe ultrasound measures of the perineum to external table of fetal skull ranged from 13 to 75mm. The measures of the perineum to succedaneum bump ranged from 22 to 68mm. A threshold of 55mm was determined as the perineum to fetal head distance above which a diagnosis of engagement would be reversed. This proposed threshold had a positive predictive value of 98.6%, a sensitivity of 86.7%, and a specificity of 94.1%. ConclusionTransperineal ultrasound is a simple, rapid, and reproducible method for the diagnosis of fetal head engagement. It can be used in the delivery room in addition to clinical examination and when the latter is hampered by a succedaneum bump.