Surface Landmarks Research Articles

Evaluation of the Safety and Effectiveness of Ultrasound-guided Internal Jugular Vein Catheterization in Critically Ill Patients

Background:Central venous catheterization is a frequently performed procedure in intensive care units (ICU) for diagnostic and therapeutic purpose. As an invasive procedure it carries some risk and should be performed with few attempts. Traditionally this procedure is performed blindly by considering body surface landmark, but this procedure can be done with the help of ultrasound machine as an alternative of landmark procedure. Objectives: Evaluation of the safety and effectiveness of USG-guided internal jugular vein(IJV) catheterization in critically ill patients. Methods: This prospective observational study was conducted in the ICU of Dhaka Medical College Hospital, from May 2017 to October 2018. Patients scheduled for central venous catheterization via the IJV were included based on selection criteria and randomly allocated into two groups of 50 patients each using card sampling. Group A received ultrasound-guided catheterization, while the landmark technique was used in Group B. Results: The analysis revealed that in the ultrasound group 49 out of 50 (98.0%) patients were successfully catheterized while the landmark method was successful in 45 out of 50 (90.0%) patients. Successful catheterization by first attempt was possible in 29 patients of group A, where as it was 5 in group B. The average number of attempts for successful catheterization in Group A was 1.7 (SD=0.2) and in the landmark group it was 2.8 (SD=0.1). On the average, 4.9 minutes (SD=1.3) were needed for catheterization in ultrasound group. The time was significantly increased in the landmark group 11.4 (SD=5.8). Total number of complication was 2 in Group A and it was 8 in Group B. After considered all the above parameter, by using four points safety and effectiveness rating scale, safety and effectiveness mean score was 10.3 for Group A and 8.2 for Group B. Conclusion: Two-dimensional ultrasound offers improved safety and quality when compared with an anatomical landmark technique for IJV catheterization. Bangladesh Crit Care J September 2024; 12 (2): 96-104

Risk of Nerve Injury Following Peroneus Longus Harvest is Very Low: A Prospective Cohort of 600 Patients.

Peroneus longus (PL) graft harvest has gained popularity in recent years for a variety of ligament surgeries. One of the common apprehensions regarding its more widespread usage has been the risk of injury to the common peroneal nerve or the sural nerve during graft harvest. The purpose of the current study is to assess the rate of injury to the peroneal and sural nerve following PL harvest using our technique in a large cohort of patients. A prospective cohort of 600 consecutive patients undergoing PLG harvest over a period from January 2022 to December 2022 at a single tertiary referral centre were included for analysis. Patients had baseline screening of nerve function prior to surgery and were regularly followed up at 3 weeks, 6 weeks, 3 months and 6 months post-harvest. Grouped variables for the sural and peroneal nerve were completed and analysis was carried out using Cochrane's Q test and McNemar's test. We found that only 0.01% of patients had any nerve complications at 6 months follow-up, and three times more patients had sural nerve complaints than peroneal nerve complaints at the end of the 6 months follow-up. Peroneus longus harvest is a safe and reproducible technique with low complication rate. The rate of nerve complications post-harvest is grossly overestimated in the literature secondary to low-powered and low evidence studies. We believe that using our safe surgical technique for PL harvest with respect to surface landmarks allows for PL harvest with a low nerve complication rate.

Pre-surgical Tumor Marking by Tattooing in Patients Offered with Neoadjuvant Chemotherapy (Nact) for Advance Staged Oral Carcinomas.

We described a novel technique of marking the oral squamous cell carcinoma (OSCC) tumors before the pre-operative neoadjuvant chemotherapy (NACT). The pre-operative NACT may shrink the tumor, making it difficult for the oncosurgeon to identify the pre-NACT tumor area to be included in the surgical resection. Difficulty lies in exact topographic replication/documentation of examination findings on superficial or mucosal surface levels, primarily due to limited surface landmarks. This technique helps to identify the pre-NACT tumor margins during surgical resection and to achieve maximum oncological safety and refining surgical planning.

Orthodontic maxillary molar movement-induced zygomatic pillar remodeling and its consequences on occlusal characteristics and stress distribution

ObjectiveWe aimed to evaluate changes in the zygomatic pillar during orthodontic treatment involving premolar extraction, analyze the effects of maxillary first molar movement on zygomatic pillar remodeling, and examine occlusal characteristics and stress distribution after remodeling.MethodsTwenty-five patients who underwent premolar extraction were included in the study. The zygomatic pillar measurement range was defined, and cross-sectional areas, surface landmark coordinates, alveolar and cortical bone thicknesses, and density changes were assessed using Mimics software based on the cone-beam computed tomography scans taken before (T0) and after the treatment (T1). Multiple linear regression analysis was performed to determine the correlation between changes in the zygomatic pillar and maxillary first molar three-dimensional (3D) movement and rotation. Additionally, the correlation between pillar remodeling and occlusal characteristics was analyzed by Teetester. Pre- and post-reconstruction 3D finite element models were constructed and loaded with an average occlusal force of two periods.ResultsThe morphological and structural remodeling of the zygomatic pillar after orthodontic treatment involving premolar extraction showed a decreased cross-sectional area of the lower segment of the zygomatic pillar. The zygomatic process point moved inward and backward, whereas the zygomatico-maxillary suture point moved backward. The thicknesses of the zygomatic pillar alveolar and cortical bones were thinner, and reduced alveolar bone density was observed. Simultaneously, the movement and angle change of the maxillary first molar could predict zygomatic pillar reconstruction to a certain extent. With decreasing the total occlusal force and the occlusal force of the first molar, occlusal force distribution was more uniform. With zygomatic pillar remodeling, occlusal stress distribution in the zygomatic alveolar ridge decreased, and occlusal stress was concentrated at the junction of the vertical and horizontal parts of the zygomatic bone and the posterior part of the zygomatic arch.ConclusionsOrthodontic treatment involving premolar extraction led to zygomatic pillar remodeling, making it more fragile than before and reducing the occlusal force of the maxillary first molar and the entire dentition with stress concentrated in weak areas.Clinical relevanceNo other study has focused on the effects of orthodontics on pillar structures. The present study indicates that the mesial movement of the maxillary first molar weakened the zygomatic pillar and reduced occlusal function, thereby providing insights for inserting anchorage screws and facial esthetics.

Obturator Nerve Block: An Anatomical Perspective.

Background A comprehensive understanding of the anatomy of the obturator nerve after its emergence from the obturator foramen is essential when undertaking an obturator nerve block effectively. This study was conducted to provide precise anatomical guidance of the obturator nerve block with surface landmarks in the inguinal region. Materials and methods A cross-sectional observational study was carried out on 34 dissected embalmed cadaveric lower limbs to investigate anatomic variability of obturator nerve localization concerning bony/ligamentous landmarks viz. the pubic tubercle, anterior superior iliac spine, inguinal ligament, and femoral artery as well as the adductor longus. Results The pubic tubercle and inguinal ligamentwere found to be the "least variable indicator" and palpable landmark for localization of the main trunk of the obturator nerve exhibiting lesser standard deviation of the mean distance from the obturator nerve exit. Among the soft tissue (vessel/muscle) parameters, the shortest distance of the adductor longus muscle from the obturator nerve exit was found to have the lowest standard deviation, thus making it the most reliable parameter for obturator nerve localization. Conclusion High anatomic variability in the obturator nerve's localization does exist, and this explains the difficulty frequently encountered in the application of regional anesthetic techniques. The pubic tubercle and inguinal ligament points were found to be the least variable and most reliable landmarks for localization of the main trunk of the obturator nerve.

Anatomic location of the first dorsal extensor compartment for surgical De-Quervain's tenosynovitis release: A cadaveric study.

De-Quervain's tenosynovitis is a disorder arising from the compression and irritation of the first dorsal extensor compartment of the wrist. Patients who fail conservative treatment modalities are candidates for surgical release. However, risks with surgery include damage to the superficial radial nerve and an incomplete release due to inadequate dissection. Currently, there is a paucity of literature demonstrating the exact anatomic location of the first dorsal extensor compartment in reference to surface anatomy. Thus, this cadaveric study was performed to determine the exact location of the first extensor compartment and to devise a reliable surgical incision to prevent complications. To describe the location of the first dorsal compartment in relation to bony surface landmarks to create replicable surgical incisions. Six cadaveric forearms, including four left and two right forearm specimens were dissected. Dissections were performed by a single fellowship trained upper extremity orthopaedic surgeon. Distance of the first dorsal compartment from landmarks such as Lister's tubercle, the wrist crease, and the radial styloid were calculated. Other variables studied included the presence of the superficial radial nerve overlying the first dorsal compartment, additional compartment sub-sheaths, number of abductor pollicis longus (APL) tendon slips, and the presence of a pseudo-retinaculum. Distance from the radial most aspect of the wrist crease to the extensor retinaculum was 5.14 mm ± 0.80 mm. The distance from Lister's tubercle to the distal aspect of the extensor retinaculum was 13.37 mm ± 2.94 mm. Lister's tubercle to the start of the first dorsal compartment was 18.43 mm ± 2.01 mm. The radial styloid to the initial aspect of the extensor retinaculum measured 2.98 mm ± 0.99 mm. The retinaculum length longitudinally on average was 26.82 mm ± 3.34 mm. Four cadaveric forearms had separate extensor pollicis brevis compartments. The average number of APL tendon slips was three. A pseudo-retinaculum was present in four cadavers. Two cadavers had a superficial radial nerve that crossed over the first dorsal compartment and retinaculum proximally (7.03 mm and 13.36 mm). An incision that measures 3 mm proximal from the radial styloid, 2 cm radial from Lister's tubercle, and 5 mm proximal from the radial wrist crease will safely place surgeons at the first dorsal compartment.

Defining the Safe Entry Point in Deep Plane Facelifting with Novel Landmark for the Buccal Branch of the Facial Nerve.

In deep facial surgery, accurate preoperative landmarking of branches of the facial nerve is helpful in avoiding inadvertent facial nerve injury. The objective of our study was to determine the accuracy at which the intersection point of two bisecting lines that join facial surface landmarks can be used to accurately locate the buccal branch(es) of the facial nerve, specifically at the deep plane entry point (ie, intercept landmark). Thirty-three cadavers were dissected to determine the position of the buccal rami relative to the intercept. Buccal rami crossed the intercept in 12.12% of specimens (0 mm from intercept, n = 4). Buccal rami passed superiorly in 66.67% of specimens (3.71 ± 3.28 mm from intercept, n = 7) and inferiorly in 21.21% of specimens (2.44 ± 0.92 mm from intercept, n = 7). Noteworthy, buccal rami were located within 1 cm of the intercept landmark with 96.97% accuracy (32/33 cadavers). These data suggest that this novel intercept (1) reliably locates the buccal branch of the facial nerve as it courses distal to the parotid gland, and (2) helps define a "safe zone" for entry into the deep plane where the likelihood of encountering the facial nerve is extremely low.

Anterior approach for sciatic nerve localization: A novel observational pilot study utilizing sonoanatomical landmarks

Abstract Background: Anterior approach to sciatic nerve (SN) block has been an underutilized technique due to the technical difficulties and lack of accurate landmarks to guide the localization of the nerve. This prospective, observational study was planned to evaluate the sonoanatomical relationship of SN with femoral neurovascular complex and femoral shaft by anterior approach for easy identification. Materials and Methods: After ethics committee approval and written informed consent, sonoanatomy of SN in anteromedial thigh was observed in 30 American Society of Anesthesiologists I–III patients. Measurements of distance between SN, femoral shaft, and femoral neurovascular complex were taken. Surface landmark for probe positioning was also noted. Results: We observed that SN was consistently located in a triangular arrangement with femoral shaft and femoral neurovascular complex. Distance of SN from femoral shaft located superolaterally was 43.4 ± 12 mm. Distance of SN from femoral neurovascular complex located superiorly was 44.8 ± 11.4 mm. Distance between femoral shaft and femoral neurovascular complex was 39.1 ± 9.4 mm and distance of ultrasound probe placement for optimal visualization of SN from inguinal crease was 167 ± 29 mm. Conclusion: We propose a new and more distal sonoanatomical landmark for ultrasound-guided approach to anterior SN block which consistently localizes the SN in relation to femoral shaft and femoral neurovascular complex and can be easily performed in all patients in the supine position.

Variability in the distance between the suprascapular notch with the spine of the scapulae and the acromion.

The suprascapular notch lies in the superior border of the scapula and is a passageway for the suprascapular nerve that is sensory to the shoulder joint. Suprascapular nerve block involves injection of local anaesthetic into the suprascapular notch, either ultrasound guided or blind, using the spine of scapula and/or the medial border of the acromion as surface landmarks. To investigate the anatomic variations that exist between the distance of the notch from the spine of scapula and acromion. Ninety-two dry scapulae were measured with a digital calliper for their length of the spine, distance between the midpoint of the spine and base of the suprascapular notch and distance between the medial border of the acromion and the base of the suprascapular notch. These measurements were compared for variations in the scapular bony landmarks, the spine and the acromion to determine the site for the injection. Measurement reliability was assessed by intraclass correlation, Cronbach's alpha being 0.99, 0.97 and 0.91 for length of spine, distance from spine and distance from acromion respectively. The distance from the acromion had less variation in measurement (3.73 ± 0.42cm) but a flatter distribution when compared to distance from the spine of the scapula (3.32 ± 0.39cm). Length of the spine of the scapula appeared not to influence either distance from the acromion or distance from the spine of scapula. There is potential for greater variability in placement of nerve blocks that use acromion as the bony reference. Key Points • Dry scapular measurement using electronic Vernier callipers is accurate (0.91-0.97). • There is potential for greater variability in placement of blind nerve blocks that use acromion as the bony reference to locate the suprascapular notch.

Nasal Measurements in Indian Population of North-East Region: Angular Parameters with Literature Review.

Just like linear nasal parameters, angular nasal parameters form the basis of any rhinoplasty, especially in various ethnic groups to maintain the specific racial characteristics while creating an aesthetic nose. The objective of this study was to measure and study the outcomes of angular nasal parameters in north-east Indians and to contrast them with available literature on Oriental, Caucasian and Indian population in general. This cross-sectional study was carried out in 150 young adults from north-east region of India. Surface landmarks were marked, and standard photographs were taken. Nine angular parameters were measured from the left lateral and basal view photographs of the face using computer software. Data were analysed by Student's 't'-test for parametric data and Mann-Whitney U-test for non-parametric data using SPSS v.25. All the angular measurements were found to be greater in females except nasofacial angle, columella tip angle and interaxial angle. Differences in nasofrontal angle, columella labial angle, nasofacial angle and columella tip angle between males and females were statistically significant. Nasofrontal and columella labial angles were more acute in the study population compared to Caucasians, Orientals and other Indians while nasofacial, interaxial and interalar angles were larger. The north-east Indian nose is dissimilar to that of rest of the country as well as that of Caucasians and Orientals with respect to angular parameters.

Rib region detection for scanning path planning for fully automated robotic abdominal ultrasonography.

Scanning path planning is an essential technology for fully automated ultrasound (US) robotics. During biliary scanning, the subcostal boundary is critical body surface landmarks for scanning path planning but are often invisible, depending on the individual. This study developed a method of estimating the rib region for scanning path planning toward fully automated robotic US systems. We proposed a method for determining the rib region using RGB-D images and respiratory variation. We hypothesized that detecting the rib region would be possible based on changes in body surface position due to breathing. We generated a depth difference image by finding the difference between the depth image taken at the resting inspiratory position and the depth image taken at the maximum inspiratory position, which clearly shows the rib region. The boundary position of the subcostal was then determined by applying training using the YOLOv5 object detection model to this depth difference image. In the experiments with healthy subjects, the proposed method of rib detection using the depth difference image marked an intersection over union (IoU) of 0.951 and average confidence of 0.77. The average error between the ground truth and predicted positions was 16.5 mm in 3D space. The results were superior to rib detection using only the RGB image. The proposed depth difference imaging method, which measures respiratory variation, was able to accurately estimate the rib region without contact and physician intervention. It will be useful for planning the scan path during the biliary imaging.

Robotic-Assisted Single-Position Prone Lateral Lumbar Interbody Fusion: Indications, Techniques, and Outcomes.

Robotic-Assisted Single-Position Prone Lateral Lumbar Interbody Fusion: Indications, Techniques, and Outcomes.

A standardized protocol for needle placement in the infraspinatus muscle: an anatomical perspective.

This study aimed to evaluate the morphology of the three parts of the infraspinatus muscle based on surface landmarks for precise and effective access, and to propose the most effective fine-wire electrode insertion technique and sites. Fifteen Asian fresh cadavers were used. We investigated the probability of the presence of the superior, middle, and inferior parts in each infraspinatus muscle based on surface landmarks. Based on the positional characteristics of the muscle, we determined the needle insertion method and confirmed its effectiveness by dissection. The superior part was mostly observed near the spine of the scapula. The middle part was broadly observed within the infraspinous fossa. The inferior part showed variable location within the infraspinous fossa. The injection accuracy of the superior, middle, and inferior parts in the infraspinatus muscle was 95.8%, 100%, and 91.7%, respectively. Targeting the superior and middle parts for injection of the infraspinatus muscle is relatively more straightforward than targeting the inferior part. Targeting the inferior part of the infraspinatus muscle in this study was more challenging than targeting the superior and middle parts. Needling for electromyography should be performed with special care to avoid unintended muscle parts, which could lead to inaccurate data acquisition and affect the conclusions about muscle function.

Safety considerations for treating the parotid and submandibular glands with neuromodulators for facial slimming.

Neuromodulators have predominantly been used for the treatment of upper facial lines, but their use has expanded to include lower face and neck treatments. However, the injection sites for these treatments are based on skin surface landmarks, which may pose risks to nearby structures and result in undesired outcomes. To investigate the spatial relationship between the FDA-approved skin surface landmarks for neuromodulator injections in the parotid and submandibular glands and the topographical anatomy of critical facial structures such as the facial artery, facial vein, external carotid artery, and retromandibular vein. A cross-sectional retrospective analysis was conducted on contrast-enhanced cranial CT scans. The scans were analyzed for the morphology and location of the parotid and submandibular glands. Measurements were taken for gland volume, craniocaudal extent, anterior-posterior extent, and distances between the skin surface and gland capsule or nearby structures such as arteries. The study sample consisted of 53 subjects, including 7 males and 46 females, with a mean age of 36.91 years and a mean BMI of 23.28 kg/m2 . The mean volume of the parotid gland was 31.9 ± 3.0 cc in males and 28.5 ± 3.6 cc in females with p < 0.001, while the mean volume of the submandibular gland was 18.2 ± 2.0 cc in males and 14.5 ± 3.4 cc in females with p < 0.001. The mean distances between skin surface and the gland capsule were 5.98 ± 2.2 and 8.84 ± 4.0 mm for the parotid and submandibular gland, respectively. This distance increased with higher age and higher BMI values in a statistically significant manner with p < 0.001. The distances between FDA-approved skin surface landmarks and the parotid and submandibular glands varied significantly depending on gender, age, and BMI. Optimal injection depth and location for neuromodulator treatments cannot be generalized based on these landmarks alone, emphasizing the need for real-time ultrasound imaging guidance.

Subcutaneous Dorsomedial Triangle of Forearm: Surgical Anatomy and Clinical Implication.

Background The purpose of the study was to provide a practical landmark for localizing the dorsal branch of the ulnar artery and nerve, to approach for microsurgical flaps, for harvesting nerve grafts and also to avoid these nerves during insertion of wrist arthroscopy portals. Material and methods Forty adult cadaveric upper limbs (20 right and 20 left) were dissected for localizing the dorsal branches of the ulnar artery and nerve. The ramification patterns of the nerve were mapped. The wrist arthroscopy portals are located radial and ulnar to the tendon of extensor carpi ulnaris at the level of the wrist joint, and their designated names are '6R & 6U', respectively. The distance of branches of the nerve from the 6U and 6R portals for wrist arthroscopy was recorded. Results The present study has delineated asubcutaneous dorsomedial triangular area in the distal forearm. The construction of this triangle uses palpable landmarks, i.e. pisiform bone, styloid process and subcutaneous border of the ulna. The measure of the sides of the triangle uses proportion rather than absolute measurements and hence is person specific. The dorsal branches of the ulnar nerve and artery are consistently given off in the triangle's upper third and middle third, respectively. Four branching patterns have been mapped, with one dominant pattern in 67.5% of limbs. In three-fourths of cases, one branch of the dorsal branch of the ulnar nerve consistently overlies the 6U portal and hence runs a higher risk of injury. Conclusion The study suggests more practical, accurate, reliable and consistent surface landmarks for the localization of the dorsal branch of the ulnar artery and nerve for reconstructive microsurgery for distal hand defects.

Evaluation of Sthapani Marma: A Review

Marma points represent crucial areas within the human body, as described in various Ayurvedic texts. These points are more than just surface landmarks; they are deeply rooted physio-anatomical structures. Defined as the intersection of Mamsa, Sira, Snayu, Asthi, and Sandhi in a specific location, Marma serves as the focal point of Prana. Ayurveda identifies 107 such Marma points in the body. Prominent scholars like Acharya Sushruta and Vagbhatta have classified them into different categories based on location, structure, prognosis, number, and measurement. When injuries occur to certain Vishlyaghna Marma points, an individual can survive as long as the foreign object remains lodged there; however, death is imminent once it is removed. Life can be sustained if the object naturally falls out post-suppuration. Vishalyaghna Marma points are closely related to Vayu dominance. Among these vital points is the Sthapani Marma, situated between the two eyebrows or superciliary arches. In Tamil, both "Varmam" and "Marmam" refer to these vital points. Varmalogy therapy manipulates Varmam locations where Pranic energy is concentrated or blocked. Stimulating specific Varmam points releases trapped energy that restores balance in affected regions due to trauma. Siddha science recognizes Tilartha Kalam at the same position as Sthapani Marma in Ayurveda – the glabella region.&#x0D; This article will delve deeper into the structures underlying the Sthapani Marma and attempt to draw correlations with Siddha science while exploring ways to stimulate this particular Varmam point effectively.

Identifying Palmar Skin Surface Landmark for Locating A2 Pulley during Cadaveric Dissection of the Hand.

We performed cadaveric dissection of 62 hands. For 248 fingers, the measurement of distance A, which is half the distance between the palmar digital crease and proximal interphalangeal crease reflected in the palm, and distance B, which is the distance between the A2 pulley's starting point and the palmar digital crease, were taken by a caliber. Statistical analysis was performed using the paired sample t test to determine whether there was a significant difference between distances A and B. Our study revealed that there was no significant difference (p>0.05) between the measured starting point of the A2 pulley and its proposed surface landmark for the index, middle, and small fingers. Conversely, the ring finger showed a statistically significant difference of 1 mm more proximal. By measuring the distance between the palmar digital crease and proximal interphalangeal crease and reflecting it proximally in the palms, one can anticipate the location of the A2 pulley's starting point for each digit, except for the ring finger. The ring finger's starting point is 1 mm more proximal than the other digits. Knowing the starting point of the A2 pulley will help hand surgeons limit incisions and avoid accidental injury during hand surgery.

Retrosigmoid Craniotomy and Intradural Variations: Role of Patient-Specific Preoperative Imaging to Identify Landmarks and Relevant Structures

There are several landmarks to safely identify the limits of the retrosigmoid approach and its intradural variations, however, little has been discussed about how those landmarks may vary among patients. We provided a review of patient positions, surface landmarks for the retrosigmoid craniotomy, and structures to recognize for transmeatal, suprameatal, suprajugular and transtentorial extensions. The position of the dural sinuses in relation with the zygomatic-inion line, and digastric notch line is readily identified on MRI. For transmeatal drilling, the position of the semicircular canals, vestibular aqueduct and jugular bulb is best evaluated on CT. For suprameatal drilling, the labyrinth and the position and integrity of the carotid canal are relevant to plan the anterior extension of the approach. For transtentorial extension, it is desirable to identify incisural structures. For suprajugular drilling, the position of the jugular bulb, invasion of venous structures, and integrity of the roof of the jugular foramen must be checked preoperatively. The retrosigmoid approach is the workhorse of posterior skull base surgery. By recognizing patient-specific variations in known landmarks, the approach may be tailored prevent complications.

Ulnar shape of extant primates: Functional signals and covariation with triquetrum shape.

In this study, we investigated the shape differences of the distal ulna in a phylogenetic context among a broad range of primate taxa. Furthermore, we evaluated covariation between ulnar and triquetrum shape and a possible association between ulnar shape and locomotor behavior. We applied 3D geometric morphometrics on a large dataset comprising the distal ulna of 124 anthropoid primate specimens belonging to 12 different genera. For each species, a mean shape was calculated using 11 Procrustes-aligned surface landmarks on the distal ulna. These mean shapes are used in a bgPCA, pPCA, and PACA and 3D morphs were used to visualize more subtle differences between taxa. A p2B-PLS analysis was performed to test the covariance between distal ulnar and triquetrum shape. The results show that more closely related species exhibit a similar distal ulnar shape. Overall, extant hominid ulnae show a shape shift compared to those of extant monkeys and hylobatids. This includes a shortening of the ulnar styloid process and dorspalmarly widening of the ulnar head, shape characteristics that are independent of phylogeny. Within the hominids, Pongo pygmaeus seem to possess the most plesiomorphic distal ulnar shape, while Gorilla and Homo sapiens display the most derived distal ulna. Cercopithecoids, hylobatids, and P. pygmaeus are characterized by a relatively deep ECU groove, which is a shape trait dependent of phylogeny. Although there was no significant covariation between distal ulnar shape and triquetrum shape, the shape differences of the distal ulna between the different primate taxa reveal a possible link with locomotor behavior. The comparative analyses of this study reveal different shape trends in a phylogenetic context. Highly arboreal primates, such as hylobatids and Ateles fusciceps, show a distal ulnar morphology that appears to be adapted to tensile and torsional forces. In primates that use their wrist under more compressive conditions, such as quadrupedal cercopithecoids and great apes, the distal ulnar morphology seems to reflect increased compressive forces. In modern humans, the distal ulnar shape can be associated to enhanced manipulative skills and power grips. There was no significant covariation between distal ulnar shape and triquetrum shape, probably due to the variation in the amount of contact between the triquetrum and ulna. In combination with future research on wrist mobility in diverse primate taxa, the results of this study will allow us to establish form-function relationships of the primate wrist and contribute towards an evidence-based interpretation of fossil remains.

Pterion topography in dry human skulls: A comprehensive institutional analysis from Kashmir valley, Northern India

The pterion is an important boane marker due to its frequent proximity to Broca's Area and the anterior branch of the middle meningeal artery. The aim of the study was to examine the different types of pterions and gauge the distance between bony landmarks on the skull and the midpoint of the pterion. The study used 30 adult dried human skulls of undetermined age and sex. Bilateral observation of pterion types and locations was made. The fronto-zygomatic suture, the center of the zygomatic arch, the tip of the mastoid process, the glabella, the anterosuperior edge of the external auditory meatus, and the asterion were all measured using a digital Vernier caliper. A total of five varieties of pterions were observed; Spheno-parietal, frontotemporal, stellate, epipteric, and atypical pterion. Bilaterally Sphenoparietal was the most prevalent form of skull among those examined. The mean distances from the midpoint of the pterion to the fronto-zygomatic suture were 30.99±5.48 mm and 30.21±5.72 mm, respectively. The average distances to the middle of the zygomatic arch were 37.77± 3.61 mm and 37.94±3.89 mm, respectively. The average distances to the asterion were 82.54±7.18 mm and 84.43±6.78 mm. The mean distances to the external acoustic meatus were 50.70±3.18 mm and 51.35±3.37 mm; to the glabella, it was 78.01±6.15 mm and 75.66±6.73mm; to the tip of the mastoid process, it was 80.27±6.20 mm on the right side and 78.98±5.45 mm on the left side. The pterion is the most popular surface landmark. Neurosurgeons, radiologists, anthropologists, and forensic pathologists will benefit from the study's findings about the classification of pterion.