Non-embalmed Cadavers Research Articles

Ultrasound for the detection of the pyramidal lobe of the thyroid gland

PurposeThe pyramidal lobe (PL) is an ancillary lobe of the thyroid gland that can be affected by the same pathologies as the rest of the gland. We aimed to assess the diagnostic performance of high-resolution sonography in the detection of the PL with verification by dissection and histological examination.MethodsIn a prospective, cross-sectional mono-center study, 50 fresh, non-embalmed cadavers were included. Blinded ultrasound examination was performed to detect the PL by two investigators of different experience levels. If the PL was detected with ultrasound, dissection was performed to expose the PL and obtain a tissue sample. When no PL was detected with ultrasound, a tissue block of the anterior cervical region was excised. An endocrine pathologist microscopically examined all tissue samples and tissue blocks for the presence of thyroid parenchyma.ResultsThe prevalence of the PL was 80% [40/50; 95% CI (68.9%; 91.1%)]. Diagnostic performance for both examiners was: sensitivity (85.0%; 42.5%), specificity (50.0%; 60.0%), positive predictive value (87.2%; 81.0%), negative predictive value (45.5%; 21.0%) and accuracy (78.0%; 46.0%). Regression analysis demonstrated that neither thyroid parenchyma echogenicity, thyroid gland volume, age nor body size proved to be covariates in the accurate detection of a PL (p > .05).ConclusionWe report that high-resolution ultrasound is an adequate examination modality to detect the PL. Our findings indicate a higher prevalence than previously reported. Therefore, the PL may be regarded as a regular part of the thyroid gland. We also advocate a dedicated assessment of the PL in routine thyroid ultrasound.

Austere Fasciotomy: Alternative Equipment for Performance in the Field.

Acute compartment syndrome (ACS) following extremity trauma requires rapid fasciotomy to avoid significant morbidity and limb loss. Four-compartment fasciotomy of the leg is a surgical procedure typically performed in the operating room; however, casualties who cannot be rapidly transported may need fasciotomies in the prehospital setting. In the absence of traditional operating instruments (e.g., scalpel, long Metzenbaum scissors, electrocautery), alternative means of fasciotomy may be needed. We undertook a proof-of-concept study using cadaver models to determine whether leg fasciotomies could be performed with alternative devices compared with the surgical standard. Two-incision, four-compartment fasciotomies were performed on fresh, never-frozen, non-embalmed cadaver legs using a scalpel for the initial skin incision, followed by release of the fascia using one of the following instruments: 5.5-in curved Mayo scissors; Benchmade rescue hook (model BM-5BLKW); rescue hook on the Leatherman Raptor multitool (model 831741-FFP); Leatherman Z-Rex multitool rescue hook (model LM93408); or No. 10 PenBlade (model PB-M-10- CAS). The procedures were performed by a surgeon. Skin and fascia incisional lengths were recorded along with a subjective impression of the performance for each device. Post-procedural dissection was performed to identify associated injuries to the muscle, superficial peroneal nerve, and the greater saphenous vein (GSV). All devices were able to adequately release the fascia in all four compartments. All rescue hooks (Benchmade, Raptor, and Z-Rex) required a "pull technique" and a skin incision of equal length to the fascia incision. The PenBlade was used in a "push technique," similar to the standard scissor fasciotomy through a smaller skin incision. There was one superficial peroneal nerve transection with the rescue hooks, but there were no GSV injuries or significant muscle damage with any instrument. Four-compartment fasciotomy can be performed with readily available alternative equipment such as rescue hooks and the PenBlade. Hook-type devices require longer skin incisions compared with scissors and the PenBlade. In contested environments, patients with ACS may require fasciotomy prior to evacuation to surgical teams; training combat medics in the use of these alternative instruments in the field may preserve life and limb.

Elastic Fibres in the subcutaneous tissue: Is there a difference between superficial and muscular fascia? A cadaver study.

In last years the role of fascia in proprioception and pain has been confirmed in numerous papers, but the real structure of fasciae is not still entirely known. To date, many studies have evaluated the elastic fibres in arteries, ligaments, lungs, epidermis and dermis, but only two studies exist about the elastic fibres in the fasciae, and they did not distinguish between superficial (in the subcutaneous tissue) and deep/muscular fasciae. The aim of the study was to assess the percentage of elastic fibres between superficial and deep fascia. Three full thickness specimens (proximal, middle and distal respectively) were taken from each of four regions of the thigh of three non-embalmed cadavers: the anterior (Ant), the lateral (Lat), the posterior (Post) and the medial (Med) aspect. Thus, a total of 12 specimens were collected from each analysed thigh and histological Weigert Van Gieson stains was performed. Three sections per specimen were considered for the morphometric analysis. In all the specimens the superficial and deep fasciae were clearly recognizable. The difference in percentage of elastic fibres between superficial and deep fasciae in same region for all four was highly significant (p<0.001). They are abundant in the superficial fascia than deep fascia. In the light of these findings is evident that the superficial (in the subcutaneous tissue) and deep fasciae have different elasticity. This difference may improve grading of fascial dysfunction in dermatological diseases as burns, scars and lymphedema to better plan treatments.

Femoral Intercondylar Notch: Gross Anatomy and Histology of the Connective Tissue Lining of its Roof: A Pilot Study.

We have consistently observed a connective tissue lining over the intercondylar notch's roof (CTLINR) during arthroscopic surgeries of the knee joint. As there is a strong association of the intercondylar fossa with the anterior cruciate ligament (ACL), we believe that this tissue must be having some role in the functioning of the ACL. The purpose of this pilot study was to investigate the anatomic characteristics of the CTLINR. In this observational anatomical study, we have investigated the gross anatomical and histological features of the CTLINR in four knees of two fresh frozen non-embalmed cadavers. We have also studied its ultrastructural characteristics by obtaining an arthroscopic biopsy of the tissue from a patient undergoing ACL reconstruction. At gross examination, the CTLINR had a typical glistening white surface with transversely oriented fibres. It entirely covered the roof of the intercondylar notch and was soft to touch. Histological examination with haematoxylin-eosin stain revealed fibro-collagenous tissue with intervening blood vessels. Transmission electron microscopy manifested loosely arranged collagen fibres of variable diameter. The histological and electron microscopic characteristics of the tissue differentiate it from the ACL and its femoral enthesis, suggesting that it was a distinct anatomical structure. As it entirely covered the roof of the intercondylar fossa and had a smooth surface and soft consistency, it may protect the reconstructed ACL from graft abrasion. Furthermore, as it had a characteristic arthroscopic appearance, future research can investigate its role in femoral tunnel positioning.

Direct measurement of radiation exposure dose to individual organs during diagnostic computed tomography examination

Ionizing radiation from Computed tomography (CT) examinations and the associated health risks are growing concerns. The purpose of this study was to directly measure individual organ doses during routine clinical CT scanning protocols and to evaluate how these measurements vary with scanning conditions. Optically stimulated luminescence (OSL) dosimeters were surgically implanted into individual organs of fresh non-embalmed whole-body cadavers. Whole-body, head, chest, and abdomen CT scans were taken of 6 cadavers by simulating common clinical methods. The dosimeters were extracted and the radiation exposure doses for each organ were calculated. Average values were used for analysis. Measured individual organ doses for whole-body routine CT protocol were less than 20 mGy for all organs. The measured doses of surface/shallow organs were higher than those of deep organs under the same irradiation conditions. At the same tube voltage and tube current, all internal organ doses were significantly higher for whole-body scans compared with abdominal scans. This study could provide valuable information on individual organ doses and their trends under various scanning conditions. These data could be referenced and used when considering CT examination in daily clinical situations.

Innervation and vascular supply of the first dorsal interosseous muscle and palmar interosseous muscle of the index: An anatomic descriptive study

The first dorsal interosseous muscle (FDI) and palmar interosseous muscle of the index (P2I) are essential for the strength and mobility of the index finger. This study aims to describe the course of the deep branch of the ulnar nerve (DBUN) and the blood supply to these muscles. An anatomical cadaver study was carried out with 14 upper limbs from fresh, non-embalmed cadavers. All limbs were filled with an equal amount, based on weight, of colored silicone and diluent that was combined and catalyzed with 5% curing agent. The location of the DBUN's termination was specified relative the carpometacarpal joint. Every artery supplying either muscle was identified and documented. The DBUN had a slightly convex path, distal to the hook of the hamate and penetrated the FDI muscle at an average 41% of the second metacarpal length. An average of 1.3 branches to the P2I and 2.6 branches to the FDI were found. Four artery pedicles coming from the deep palmar arch supply the FDI with an average of one consistent and exclusive pedicle to the FDI and three pedicles heading to the P2I. According to the classification of Mathes and Nahai, the FDI has a type 2 blood supply and the P2I has a type 3 blood supply. In-depth knowledge of the vascular network supplying the FDI and P2I muscles and the course of the DBUN is essential when the DBUN is damaged or when dissecting these muscles for index pollicization.

Reconstructive surgery of thefacial nerve (step-by-step modeling of the technique using cadaveric materials)

The study objective is to develop and test on cadaveric materials a new technique for reinnervation of facial muscles at an early stage from the moment of paralysis occurrence for introduction into neurosurgical practice. Materials and methods . Eighteen (18) fresh non-embalmed cadavers (10 men and 8 women, ages between 18 and 67 years without pathology of the craniomaxillofacial area) were used. During the intervention, a cadaver was put on its back, access to the area of interest was performed in esthetically insignificant areas. For plastic surgery of the facial nerve, the masseteric branch of the trigeminal nerve and the subtotal hypoglossal nerve, calf sural nerve and great auricular nerve autotransplants were used as donor material. Results . The presented technique inflicts minimal damage to the patient during autotransplant collection as no functionally significant structures are affected. Conclusion . It is anticipated that in clinical practice the technique will result in movement of the mimic muscles of the upper and middle areas of the face (closure of the eyelids, raising of the eyebrows, etc.) concurrent with swallowing, because upper group of the facial nerve branches is reconstructed using the hypoglossal nerve. Mimic movements of the lower part of the face (smile, lip pursing, teeth baring, etc.) will be performed during teeth clenching as lower group of the facial nerve branches are repaired using the masseteric branch of the trigeminal nerve.

Ultrasound-Guided Injections at the Lateral Femoral Cutaneous Nerve: The Inguinal Ligament as a Barrier

Ultrasound-guided perineural injections at the lateral femoral cutaneous nerve (LFCN) may confirm the correct diagnosis and provide symptom relief in meralgia paresthetica. Although correct visualization of the nerve is generally described as feasible, failure rates of the procedure may be as high as 30%. This study investigated the spread of injected fluids in ultrasound-guided perineural injections at the LFCN. The aim of the study was to evaluate whether the inguinal ligament impedes the distribution of injected fluids along the course of the LFCN. We used a descriptive research design. Research was conducted at an anatomical research facility. In fresh, nonembalmed cadavers, 2 mL of ink were injected with ultrasound-guidance at the LFCN below the inguinal ligament. The course of the nerve was then dissected to show the extent of nerve staining. Spread of the injected ink proximal to the inguinal ligament was found in 67.65% of specimens, while the ink did not pass the inguinal ligament in 32.35%. Concerning proximal spread, specimen body mass index was not of any relevance. This cadaver study is only a simulation of the real clinical setting and does not allow any insight into the efficacy of the injection in living patients. The inguinal ligament is a barrier in the distribution of injected fluids in about one-third of specimens. This might be a major cause of failure in ultrasound-guided injections. The results from our study are in line with previously published failure rates and our findings might provide the anatomic basis to advance injection techniques. Cadaver study; injection; lateral femoral cutaneous nerve; LFCN; meralgia paresthetica; nerve entrapment; sonography; ultrasound.

The injection site in the tarsal tunnel to minimize neurovascular injury for heel pain: an anatomical study.

The aim of this study was to investigate the location and distribution patterns of neurovascular structures and determine the effective injection point in the tarsal tunnel for heel pain. Fifteen adult non-embalmed cadavers with a mean age of 71.5 years were studied. The most inferior point of the medial malleolus of the tibia (MM) and the tuberosity of the calcaneus (TC) were identified before dissection. A line connecting the MM and TC was used as a reference line. The reference point was expressed in absolute distance along the reference line using the MM as the starting point. For measurements using MRI, the depth from the skin was measured to inferior at an interval of 1 cm from the MM. The posterior tibial artery, lateral plantar nerve, and medial plantar nerve were located from 29.0 to 37.3% of the reference line from the MM. The distribution frequencies of the medial calcaneal nerve on the reference line from the MM were 0%, 8.60%, 37.15%, 37.15%, and 17.10%, respectively. The mean depth of the neurovascular structures was 0.3 cm. This study recommended an effective injection site from 45.0 to 80.0% of the reference line.

Factors Related to Successful Energy Transmission of Focused Ultrasound through a Skull : A Study in Human Cadavers and Its Comparison with Clinical Experiences.

ObjectiveAlthough magnetic resonance guided focused ultrasound (MRgFUS) has been used as minimally invasive and effective neurosurgical treatment, it exhibits some limitations, mainly related to acoustic properties of the skull barrier. This study was undertaken to identify skull characteristics that contribute to optimal ultrasonic energy transmission for MRgFUS procedures. MethodsFor ex vivo skull experiments, various acoustic fields were measured under different conditions, using five non-embalmed cadaver skulls. For clinical skull analyses, brain computed tomography data of 46 patients who underwent MRgFUS ablations (18 unilateral thalamotomy, nine unilateral pallidotomy, and 19 bilateral capsulotomy) were retrospectively reviewed. Patients' skull factors and sonication parameters were comparatively analyzed with respect to the cadaveric skulls. ResultsSkull experiments identified three important factors related skull penetration of ultrasound, including skull density ratio (SDR), skull volume, and incidence angle of the acoustic rays against the skull surface. In clinical results, SDR and skull volume correlated with maximal temperature (Tmax) and energy requirement to achieve Tmax (p<0.05). In addition, considering the incidence angle determined by brain target location, less energy was required to reach Tmax in the central, rather than lateral targets particularly when compared between thalamotomy and capsulotomy (p<0.05). ConclusionThis study reconfirmed previously identified skull factors, including SDR and skull volume, for successful MRgFUS; it identified an additional factor, incidence angle of acoustic rays against the skull surface. To guarantee successful transcranial MRgFUS treatment without suffering these various skull issues, further technical improvements are required.

Thoracic paravertebral block: comparison of different approaches and techniques. A study on 27 human cadavers

Background and objectivesThe success rate and spread of thoracic paravertebral block (TPVB) are variable and difficult to predict. It is now recommended that an ultrasound guidance technique should replace the traditional landmark technique. The objective was to compare anatomical outcomes of both techniques on cadavers. MethodsA landmark technique (loss of resistance technique [LOR]) and a USG technique (three approaches: sagittal, transversal in-plane, transverse out-of-plane) were performed on 27 thawed non-embalmed cadavers. Each of the four approaches was performed in each body (T3–T5 and T9-T11 × right and left). A coloured solution (13 mL, saline 0.9%) was injected in the targeted thoracic paravertebral space (TPVS). A successful thoracic paravertebral injection (TPVI) was defined by the presence of dye in at least one TPVS during anatomical dissection. ResultsIn 104 TPVIs analysed, the overall success rate was 78%. Factors associated with success were: USG versus LOR technique (85% vs. 52%, P < 0.0007), sagittal versus both transversal approaches (93%/81%/83%, P < 0.0007) and right side (86% vs. 66%). The median spread was 2 TPVS (min – max 1–5) with a median cephalad-caudal spread of 5 cm (min - max 1-18). By multivariate analysis, the sagittal approach was an independent factor of success (OR 2.75). Dye spread and pleural entry were influenced by neither the approach nor the site of injection. ConclusionsParavertebral spread of TPVI is variable. USG technique has higher anatomical success rates than the LOR technique, the sagittal USG approach being the most successful.

Laparoscopic pectopexy: a follow-up cyclic biomechanical analysis determining time to functional stability.

Pectopexy, a laparoscopic method for prolapse surgery, showed promising results in previous transient testing by this group. It was shown that a single suture, yielding an ultimate load of 35N, was equivalent to continuous suturing. This was demonstrated in an in vitro cadaver study. This transient data were used to establish an elastic stress-strain envelope. It was now possible to proceed to dynamic in vitro analysis of this surgical method to establish time to functional stability. Cyclic testing of this fixation method was performed on human female embalmed cadaver (cohort 1) and fresh, non-embalmed cadaver (cohort 2) pelvises. The testing envelope was 5-25N at a speed of 1mm/s. 100 load regulated cycles were applied. 100 cycles were completed with each model; no overall system failure occurred. Steady state, i.e., functional stability was reached after 14.5 (± 2.9) cycles for the embalmed group and after 19.1 (± 7.2) cycles for the non-embalmed group. This difference was statistically significant p = 0.00025. This trial showed in an in vitro cyclic testing of the pectopexy method that functional stability may be achieved after no more than 19.1 cycles of load exposure. When remaining within the established load envelope of below 25N, patients do not need to fear global fixation failure. Testing did demonstrate differences in non-embalmed and embalmed cadaver testing. Embalmed cadaver testing tends to underestimate time to steady state by 26.3%.

US-guided temporomandibular joint injection: Validation of an in-plane longitudinal approach

Ultrasonography of the temporomandibular joint is a non-invasive imaging technic, easy to perform in daily practice. It can be used for diagnosis and to guide intra-articular injections. The objective was to validate a longitudinal in-plane US injection approach of the joint and assess its accuracy. We performed a study in 13 non-embalmed cadavers. The injection was done under real-time US guidance using a needle inserted in-plane with an angulation of 30°and positioned under the capsule until the injection was feasible without resistance. The intra-articular injection was successful in all cases and confirmed by a liquid backflow in 96% of cases. The median duration between skin puncture and the intra-articular injection was 23 seconds. Our technique allows a direct visualization of the needle throughout its course to the joint with a high accuracy. Other studies will be needed to confirm its feasibility and usefulness in patients with TMJ disorders.

Axon numbers and landmarks of trigeminal donor nerves for corneal neurotization.

PurposeCorneal anesthesia leads to chronic corneal injury. This anatomical study characterizes the donor nerve branches of the supratrochlear and supraorbital nerves used for corneal neurotization.MethodsIn 13 non-embalmed cadavers, the supratrochlear and supraorbital nerves were dissected and distances to anatomical landmarks measured. Cross-sections of supratrochlear and supraorbital donor nerves were harvested and histomorphometrically analyzed to assess the number of myelinated axons.ResultsThe donor axon counts were 3146 ± 1069.9 for the supratrochlear and 1882 ± 903 for the supraorbital nerve distal to the supraorbital notch. The supratrochlear nerve was dissected on the medial upper eyelid 2 cm lateral to the facial midline and the branch of the supraorbital nerve 1 cm medial to the mid-pupillary line.ConclusionThe supraorbital and supratrochlear branches of the trigeminal nerve are potent donor nerves for corneal neurotization in the treatment of neuropathic keratopathy and can be reliably dissected using anatomical landmarks.

Anatomical study of jugular foramen in the neck

IntroductionThe anatomical complexity of the jugular foramen makes surgical procedures in this region delicate and difficult. Due to the advances in surgical techniques, approaches to the jugular foramen became more frequent, requiring improvement of the knowledge of this region anatomy. ObjectiveTo study the anatomy of the jugular foramen, internal jugular vein and glossopharyngeal, vagus and accessory nerves, and to identify the anatomical relationships among these structures in the jugular foramen region and lateral-pharyngeal space. MethodsA total of 60 sides of 30 non-embalmed cadavers were examined few hours after death. The diameters of the jugular foramen and its anatomical relationships were analyzed. ResultsThe diameters of the jugular foramen and internal jugular vein were greater on the right side in most studied specimens. The inferior petrosal sinus ended in the internal jugular vein up to 40mm below the jugular foramen; in 5% of cases. The glossopharyngeal nerve exhibited an intimate anatomical relationship with the styloglossus muscle after exiting the skull, and the vagal nerve had a similar relationship with the hypoglossal nerve. The accessory nerve passed around the internal jugular vein via its anterior wall in 71.7% of cadavers. ConclusionAnatomical variations were found in the dimensions of the jugular foramen and the internal jugular vein, which were larger in size on the right side of most studied bodies; variations also occurred in the trajectory and anatomical relationships of the nerves. The petrosal sinus can join the internal jugular vein below the foramen.

Ultrasound-guided versus blind temporomandibular joint injections: a pilot cadaveric evaluation

Temporomandibular disorders are painful conditions that require precise injection therapy in selected patients. This pilot cadaveric study was undertaken to compare the accuracy of temporomandibular joint (TMJ) injection between the anatomical landmark-based (blind) technique and an ultrasound-guided technique. TMJ injections using the blind technique or the ultrasound-guided technique were performed in 10 non-embalmed cadavers. After dissection, the accuracy of the TMJ injections was found to be significantly greater for the ultrasound-guided injections than for the blind technique (blind 55% vs. ultrasound 95%, P=0.008). For injections into the upper joint space of the TMJ, the success rate of the injection was comparable for the two techniques (blind 80% vs. ultrasound 100%, P=0.474). However, ultrasound-guided injections into the lower joint space had a much higher success rate than the blind technique (blind 30% vs. ultrasound 90%, P=0.020). The blind technique was associated with a considerable proportion of failed or inappropriate injections, especially for lower joint space injections. Ultrasound-guided TMJ injections were accomplished with a higher accuracy than the conventional blind technique, especially in the case of injections targeting the lower joint space of the TMJ.

The distributed pattern of the neurovascular structures around clavicle to minimize structural injury in clinical field: anatomical study.

The aim of this study was to determine the location and distribution pattern of neurovascular structures superior and inferior to the clavicle by detailed dissection. Fifteen adult non-embalmed cadavers with a mean age of 71.5years were studied. For measurements, the most prominent point of the sternal end of the clavicle (SEC) on anterior view and the most prominent point of the acromial end of the clavicle (AEC) were identified and divided five equal sections before dissection. A line connecting the SEC and AEC was used as a reference line. The surrounding neurovascular structures were investigated. The supraclavicular nerve was mainly distributed in the second and the third sections (distribution frequency: 41.30% and 30.43%, respectively) from AEC. Branches of the thoracoacromial artery were mainly distributed in the second, third, and fourth sections (distribution frequency: 21.15%, 26.92%, and 28.85%, respectively). Branches of the subclavian vein were mainly distributed in the third and fourth sections (distribution frequency: 23.26 and 30.23%, respectively). Distribution frequency of subclavian vein, subclavian artery, and brachial plexus ranged from 31.3 to 57.5%. When the clavicle was divided into five sections, there was relatively little distribution of neurovascular damage in the first section or the fifth section. This study reveals the average location of subclavian vein with artery and brachial plexus. Results of this study could be used as reference during surgery.

Feasibility of Bone Perfusion Evaluation in Cadavers Using Indocyanine Green Fluorescence Angiography.

Bone perfusion evaluation methods in cadaver studies have yet to be established. The aim of this report was to introduce and validate the feasibility of indocyanine green (ICG) fluorescence angiography for evaluation of bone perfusion in the femoral medial condyle in cadavers. In 4 fresh nonembalmed cadavers (2 female), the descending genicular artery was dissected and carefully cannulated bilaterally. A 10 mL solution containing 5 mL ICG solution and 5 mL methylene blue solution was injected into the descending genicular artery. After the injection, the medial femoral condyle was cut with an oscillating saw. A photograph was taken of the cut ends of the bone. The cut ends of the bones were observed using a near-infrared camera. Images corresponding to the previously taken photographs of the cut ends were captured for comparative analysis. After injection of methylene blue and ICG, the blue dye could be seen in the periosteum in all specimens, but not inside the cortex or the cancellous region of the bone. When observed with ICG fluorescence angiography, however, the cancellous region was highlighted through small perforators penetrating the periosteum. Perfusion inside the medial femoral condyle in cadavers was confirmed using ICG fluorescence angiography. Our method can be especially beneficial in confirming the bone perfusion of a new bone flap based on a particular artery, both in cadavers as well as in patients, because ICG can be injected into specific arteries.

Ultrasound imaging of the thenar motor branch of the median nerve: a cadaveric study

IntroductionAnatomic variations of the median nerve (MN) increase the risk of iatrogenic injury during carpal tunnel release surgery. We investigated whether high-frequency ultrasonography could identify anatomic variations of the MN and its thenar motor branch (MBMN) in the carpal tunnel.MethodsFor each volar wrist of healthy non-embalmed cadavers, the type of MN variant (Lanz classification), course and orientation of the MBMN, and presence of hypertrophic muscles were scored by 18-MHz ultrasound and then by dissection.ResultMBMN was identified by ultrasound in all 30 wrists (15 subjects). By dissection, type 1, 2 and 3 variants were found in 84%, 3%, and 13% of wrists, respectively. Ultrasound had good agreement with dissection in identifying the variant type (kappa =0.9). With both techniques, extra-, sub-, and transligamentous courses were recorded in 65%, 31%, and 4% of cases, respectively. With both techniques, the bifid nerve, hypertrophic muscles, and bilateral symmetry for variant type were identified in 13.3%, 13.3%, and 86.7% of wrists, respectively. Agreement between ultrasound and dissection was excellent for the MBMN course and orientation (kappa =1).ConclusionUltrasound can be used reliably to identify anatomic variations of the MN and MBMN. It could be a useful tool before carpal tunnel release surgery.Key Points• Ultrasound can identify variations of the motor branch of the median nerve.• Ultrasound mapping should be used prior to carpal tunnel release surgery.• All sub-, extra-, and transligamentous courses were accurately identified.• Type 3 variants (bifid nerve), hypertrophic muscles, and bilateral symmetry were accurately identified.

Cadaver-based Necrotizing Fasciitis Model for Medical Training.

Necrotizing fasciitis is a devastating infectious disease process that is characterized by extensive soft tissue necrosis along deep fascial planes, systemic toxicity, and high mortality. Ultrasound imaging is a rapid and non-invasive tool that can be used to help make the diagnosis of necrotizing fasciitis by identifying several distinctive sonographic findings. The purpose of this study is to describe the construction of a realistic diagnostic training model for necrotizing fasciitis using fresh frozen cadavers and common, affordable materials.Presently, fresh non-embalmed cadavers have been used at medical institutions for various educational sessions including cadaver-based ultrasound training sessions. Details for the preparation and construction of a necrotizing fasciitis cadaver model are presented here. This paper shows that the images obtained from the cadaver model closely imitate the ultrasound appearance of fluid and gas seen in actual clinical cases of necrotizing fasciitis.Therefore, it can be concluded that this cadaver-based model produces high-quality sonographic images that simulate those found in true cases of necrotizing fasciitis and is ideal for demonstrating the sonographic findings of necrotizing fasciitis.