Cadaveric Observation Research Articles

Anatomy and Microsurgical Relevance of the Outer Arachnoid Envelope around the Olfactory Bulb Based on Endoscopic Cadaveric Observations.

There is high risk of injury to the olfactory tract and olfactory bulb during surgery of the anterior cranial fossa. The goal of this study was to describe the outer arachnoid envelope around the olfactory bulb, which plays a significant role in approach-related injury of the nerve. A total of 20 fresh human cadaveric heads were examined. Five cadaveric heads were used to describe a gross overview of the topographic anatomy of the outer arachnoid cover of the olfactory bulb. In 15 cadaveric heads, endoscopic surgical approaches were performed to examine the in situ undisrupted anatomy of the outer arachnoid around the olfactory bulb. Four cadaveric heads were used for the lateral subfrontal approach, 5 heads for the medial subfrontal approach, 3 heads for the median subfrontal approach, and 3 heads for the anterior interhemispheric approach. The outer arachnoid membrane of the frontal lobe attaches the olfactory bulb strongly to the above lying olfactory sulcus. Only the most rostral portion of the olfactory bulb became slightly detached from the frontal lobe. The outer arachnoid forms a decent protrusion around the tip of the olfactory bulbs. The fila olfactoria have their own outer arachnoid cover as a continuation of the same layer of the olfactory bulb. The effect of brain retraction and manipulation forces on the olfactory bulb and the role of the arachnoid membranes located here were visually analyzed and described in detail through the four different neurosurgical approaches we performed. The results of our observations provide important anatomical details for preserving the sense of smell during neurosurgical procedures.

A cadaveric observation of infraorbital and accessory infraorbital foramen in the Indian population

A cadaveric observation of infraorbital and accessory infraorbital foramen in the Indian population

Ultrasound-guided injection of the elbow: Cadaveric description for the proximal to distal approach.

Ultrasound (US) guided intra-articular elbow injections are commonly performed in clinical practice. To describe a proximal to distal approach for US-guided intra-articular elbow injection. Cadaveric study. Academic institution. Both elbows of a single cadaver were injected with green-colored water-diluted latex dye using the US-guided proximal to distal approach. In the left elbow, the needle was kept in situ; in the right elbow, the needle was removed. Subsequently, a layer-by-layer anatomical dissection was performed in both elbows. Presence and distribution of the latex dye and location of the needle tip within the elbow joint capsule. Anatomical dissection of both elbows confirmed the correct intra-articular position of the needle tip in the left elbow as well as correct placement of the latex dye bilaterally. During layer-by-layer dissection of the left elbow, the position of the radial nerve was observed anterior to the needle. This cadaveric observation demonstrated that the US-guided proximal to distal approach is a convenient technique to access the elbow joint. Compared to the previously described techniques, the in-plane, proximal to distal approach may provide excellent needle visibility during the entire procedure, precisely targeting the articular space. The preliminary data need to be validated in additional clinical studies.

Cerebral hemiatrophy associated with Chronic Subdural Hematoma- Rare Cadaveric Observations

Cerebral hemiatrophy is an infrequent neuroimaging observation of varied etiologies, classified into two wide categories: congenital and acquired. Chronic subdural hematoma is hypothesised to be associated with the aetiology of brain atrophy. We present a case of an 85-year-old female with history of seizures, right hemiplegia and behavioural changes. Gross left cerebral hemiatrophy with evidence of associated chronic subdural hematoma, anatomical bony and brain parenchymal changes were observed during routine dissection of the brain.

Anatomical observation and clinical significance of the prostatic part of neurovascular bundle in total mesorectal excision

Objective: To observe the anatomical architecture of the prostatic part of the neurovascular bundle (NVB) in total mesorectal excision (TME). Methods: A descriptive cohort study and an anatomical observation study were carried out. A total of 38 male patients with rectal cancer who underwent TME in the Department of Colorectal Surgery at the affiliated Union hospital of Fujian Medical University between November 2013 and March 2015 were included. A total of 4 hemipelvis were examined at the Laboratory of Clinical Applied Anatomy, Fujian Medical University. The following outcomes were observed: 1) the clinical significance of bleeding of the prostatic part of NVB: surgical videos were reviewed and the incidence of bleeding was recorded. The urogenital function was assessed using the International Prostate Symptom Score (IPSS) and International Index of Erectile Function (IIEF) score. The correlation between prostatic part bleeding and postoperative urogenital function was evaluated. 2) anatomical observation: the vessels, nerve fibers, as well as their surrounding fatty tissue from the prostatic part were treated as a whole, namely, the fat pad of the prostatic part. The anatomical architecture of the prostatic part in the surgical videos was reviewed and interpreted with the cadaveric findings. Categorical variables were compared between groups using a Fisher exact probability. while continuous variables with skewed distribution were compared between groups using the Mann-Whiteny U test. Results: The median age of the included 38 patients was 57 years (range, 31-75), and the median tumor distance to the anal verge was 6 cm (range, 1-8). Of them, a total number of 21 (55.3%) patients had bleeding of the prostatic part of NVB (bleeding group), while the rest had not (17 cases, 44.7%, non-bleeding group). 1) the clinical significance of bleeding of the prostatic part of NVB. The urinary function significantly decreased in patients in the bleeding group according to IPSS score after the 3rd month and the 6rd month of the surgery [7 (0-16) vs. 2 (0-3), Z=-1.787, P=0.088; 2 (0-15) vs. 0 (0-2), Z=-2.270, P=0.028]. There was no difference regarding the IPSS score between the two groups after 1 year of the surgery (P>0.05). With a total of 23 patients with normal preoperative sexual activity included, 87.5% (7/8) of patients in the non-bleeding group can expect to return to their preoperative baseline, this incidence was significantly higher than that of only 40% (6/15) in the bleeding group (P=0.029). 2) anatomical observation: for cadaveric observation, the prostatic part of NVB was located in the narrow triangular space composed of anterolateral walls of the rectum, the posterolateral surface of the prostate and the medial surface of the levator ani musculature. The tiny vascular branches and nerve fibers from the prostatic part were hard to identify. The cavernosal nerves cannot reliably be distinguished from the neural supply to the prostate, rectum and levator ani. In the cross-section of levels of prostatic base and mid-prostate in cadaveric hemipelvis specimens, the boundary of the prostatic part fat pad was partly overlapped and merged with the boundary of the mesorectum. Intraoperative observation showed that the areas of overlap referred to the rectal branches from the prostatic part piercing the proper fascia to supply the mesorectum, which carried the largest tension and high risk of bleeding during circumferential dissection toward the perirectal plane. The ultrasonic scalpel was required to pre-coagulate the rectal branches at the point close to the proper fascia of the rectum to prevent bleeding. In the cross-section of the prostatic apex level, the prostatic part approached ventrally and its boundary was away from the boundary of the mesorectum. Conclusions: NVB prostatic part injury is one of the causes of urogenital dysfunction after TME. The nerve fibers from the prostatic part were tiny, and its functional zones cannot be distinguished during operation. Therein, the fat pad of the prostatic part should be protected as a whole. Understanding the morphology of the fat pad of the prostatic part provides invaluable surgical guidance to dissect this critical area. When dissecting around the anterolateral rectal wall, appropriate anti-traction tension should be maintained and the rectal branches from the prostatic part should be coagulated with an ultrasonic scalpel to prevent bleeding.

Anatomy of the perirectal fascia at the level of rectosacral fascia revisited

BackgroundThe relative anatomical understanding of the perirectal fasciae is of paramount importance for the proper performance of total mesorectal excision (TME). This study was to demonstrate the planes of TME and validates the intraoperative findings using cadaveric observations.MethodsIn this combined retrospective and prospective study, bilateral attachment of the rectosacral fascia (RSF) was observed in 28 cadaveric specimens (male, n = 14; female, n = 14). From January 2018 to December 2019, surgical videos of 67 patients who underwent laparoscopic TME at the Affiliated Union Hospital of Fujian Medical University (Fuzhou, China) were reviewed and interpreted with the cadaveric findings.ResultsThe RSF (synonym: Waldeyer's fascia) is the end of the pre-hypogastric fascia at the level of S4 and comprises two layers (upper and lower). These two layers provide double fascial protection for the venous sacral plexus. It inserts into the fascia propria of the rectum along a broad horizontal arc that merges anterolaterally in an oblique downward direction until it meets the posterolateral merge of Denonvilliers' fascia at the lateral rectal ligament (LRL). This ligament does not look like a true ligament but is more likely to be a fascial combination that cushions the rectal innervation and middle rectal vessels.ConclusionsUnderstanding the lateral attachment of RSF and its contribution to LRL provides invaluable surgical guidance to dissect this critical area. Therefore, lateral dissection is proposed from the anterior to the posterior direction to find the correct plane that guarantees an intact mesorectal envelope to protect the important nearby nerve structures.

CADAVERIC STUDY OF KATIKTARUN MARMA WITH DETAILED DESCRIPTION OF ITS LOCATION AND AGHAT LAKSHANS

Marma Science is one of the most distinctive concepts of Ayurveda. There are 107 marma sites in the body, and they are the conglomeration of muscles, veins, ligaments, bones, and joints. This peculiarity makes Marmamarma a somewhat vulnerable point, and any injury can lead to disability, dysfunction and demise. The cause of the damage can either be traumatic or iatrogenic; therefore, it becomes a necessity to rule out the exact location of the marma and anatomical structure responsible for the traumatic effects. Katiktarun being a Prishthagata marma, is prone to get injured during significant surgeries of the gluteal region and spine. Its injury can lead to delayed death. The aim of this study revolves around the anatomical entity responsible for delayed death caused by katiktarun injury. By identifying the location and structure involved in the marma, it might be possible to repair the structure and deferment the delayed end. Based on Ayurvedic literature and cadaveric observations, the superior margin of the sciatic notch (suprapiriform foraman) is considered as the position of Katiktarun Marma, whereas the neurovasculature associated with suprapiriform foramen is the causative structure of marma trauma symptoms.

Variations of Median Nerve Formation in North Indian Population.

Introduction: The median nerve is usually formed by two roots contributed from the medial and lateral cords of the brachial plexus. Morphological variations of the median nerve can have clinical implications from the anesthetic and surgical points of view. In this cadaveric observation study, we report the variations of median nerve formation in the North Indian population.Methods: We observed the formation of the median nerve in 40 human cadaveric upper limb specimens. The specimens belonged to 20 right and 20 left upper limbs. Variations in the formation of the median nerve were noted.Results: Of the 40 dissected specimens, six (15%) had triple roots including a supernumerary root contributing to the medial nerve formation. The supernumerary root was a branch of the lateral cord in five cases, and it had an additional contribution from the medial cord in one case. The median nerve formation and continuation were located anterior or laterally in 39 specimens (97.5%) and medial in one (2.5%) in relation to the axillary artery.Conclusion: We observed supernumerary roots of varying morphology contributing to the median nerve formation. These variations should be considered during the administration of regional anesthesia and during the management of brachial plexus injuries. Further large multi-region studies will help in a better understanding of these variations.

Comparison of Single- Versus Dual-Vector Technique Using Facial Suspension Threads: A Cadaveric Study Using Skin Vector Displacement Analysis.

Facial suspension threads have been successfully used for facial soft-tissue repositioning. When using facial suspension threads, it is unclear which technique and/or material has the greatest lifting effect for the middle and lower face or which technique/material best reduces the appearance of the jowls. Three female and 2 male cephalic specimens of Caucasian ethnicity (65.2 ± 8.3 years; 20.72 ± 2.6 kg/m) were analyzed in an upright secured position. Polydioxanone and polycaprolactone bidirectional barbed facial suspension threads were introduced by an 18 G, 100 mm cannula. The single-vector technique aimed toward the labiomandibular sulcus, and the dual-vector technique aimed toward the labiomandibular sulcus and the mandibular angle. Computation of vertical lifting, horizontal lifting, and volume reduction at the jowls and along the jawline were calculated using 3D imaging. The dual-vector technique effected a greater vertical lifting effect (4.45 ± 2.78 mm vs 2.99 ± 2.23 mm) but a reduced horizontal lifting effect (0.33 ± 1.34 mm vs 0.49 ± 1.32 mm). The dual-vector technique effected less volume reduction at the jowls 0.32 ± 0.24 cc versus 0.41 ± 0.46 cc and less volume reduction along the jawline 0.46 ± 0.48 cc versus 0.87 ± 0.53 cc (dual-vector vs single-vector). This study provides evidence resulting from cadaveric observations for the overall nonsuperiority of the dual-vector technique compared with the single-vector technique.

Assessment of Coolant Delivery Techniques for Irrigation During Bone Drilling: A Cadaveric Observation.

Assessment of Coolant Delivery Techniques for Irrigation During Bone Drilling: A Cadaveric Observation.

The Endoscopic Relationship of the Stapedius Muscle to the Facial Nerve: Implications for Retrotympanic Surgery.

The stapedius muscle, tendon, and pyramidal eminence are structures within the retrotympanum. In cholesteatoma surgery, the retrotympanum is a common site of residual disease. The removal of the pyramidal eminence during surgery is sometimes necessary to obtain better visualization of the superior retrotympanum during surgery. Understanding the relational anatomy of structures in the region to the facial nerve allows the surgeon to safely access regional disease. This study aims to better understand the anatomical relationship between the mastoid portion of the facial nerve, the pyramidal eminence, and the stapedius muscle. A secondary aim is to demonstrate that removal of the stapedius muscle in the cadaver model, can increase exposure to the retrotympanic space. Anatomical cadaveric observation study. Endoscopic dissection of cadaveric heads was undertaken. Classification of the superior and inferior retrotympanic area was performed. The anatomy of the stapedius muscle was described including relationships, depth, course, and angle with respect to the facial nerve. The pyramidal eminence and stapedius muscle were removed in all specimens and the exposure of the retrotympanum re-evaluated to determine if exposure of the region was increased. In all cases (11 ears), the stapedius muscle was located medial and anterior to the mastoid portion of the facial nerve, with the second genu superior. The mean antero-posterior distance from the apex of the pyramidal eminence, which the stapedius tendon enters, to the stapes itself was 4.10 mm (range, 2.92-5.73 mm; standard deviation [SD] 0.90 mm). In all cases, irrespective of sinus tympani conformation, removal of the pyramidal eminence and stapedial bony crest in proximity to the facial nerve allowed exposure of the whole retrotympanic region, using a 0-degree endoscope. The pyramidal eminence and stapedius muscle have a relatively constant relationship to the facial nerve. Removal of the stapedius muscle in the human cadaver model increases the exposure of the sinus tympani and subpyramidal space. Increased visualization in this region, may reduce risk of residual cholesteatoma in patients.

Structural and functional anatomy of the palmaris brevis: grasping for answers.

The palmaris brevis (PB) is a small cutaneous hand muscle that has been described as the most mysterious muscle from a functional and developmental perspective [Kaplan () Kaplan's Functional and Surgical Anatomy of the Hand]. Functionally, the PB is considered to deepen the hollow of the palm and to protect the neurovasculature of the ulnar canal. Although the function of the PB has been inferred from cadaveric observations, the electromyographic (EMG) activity of this muscle has not been explored systematically during specific movements of the hand. The purpose of this study was to record PB intramuscular EMG activity during dynamic grasping tasks, and to quantify the change in PB muscle length (ML ) and thickness (MT ) incurred during maximal contraction using ultrasound imaging. Intramuscular EMG was recorded from the PB in the dominant hands of 12 healthy participants (11 males, one female; age: 27 ± 4 years) during maximal abduction, flexion and opposition of the 5th digit, and two grasping tasks. Abduction of the 5th digit yielded the greatest EMG activity in most individuals (seven out of 11), and produced significantly less PB EMG activity when compared with grasping a cylindrical-shaped object (P = 0.003) but not a spherical-shaped object (P=0.130). During maximal abduction of the 5th digit, PB ML decreased in both the left (28±11%; P=0.002) and right (32±5%; P=0.002) hands. Similarly, a concomitant increase in PB MT was observed in the left (68±30%; P=0.002) and right (85±44%; P=0.002) hands during the same contraction. These EMG results indicate that the PB is voluntarily activated during prehensile and non-prehensile movements of the hand with significant changes in muscle architecture. The study supports the preservation of the PB in surgical procedures based on its proposed protective role as a muscular barrier to the neurovasculature within the ulnar canal.

Fiber type composition of the palmaris brevis muscle: implications for palmar function.

The palmaris brevis (PB) is a small muscle of variant morphology located on the ulnar aspect of the palm, superficial to the hypothenar eminence. Functionally, the PB has been proposed to protect the neurovasculature of the ulnar canal from compressive forces during repetitive or intermittent trauma associated with grasping. Although PB function has been inferred from cadaveric observations, it is unknown whether it has the contractile capacity and fatigue-resistance necessary to withstand these functional demands. Insight into the functional specialization of the PB can be provided through investigating the proportions of type I and type II muscle fibers by staining for myosin heavy chain (MHC) isoforms using immunohistochemical methods. Therefore, the purpose of this study was to quantify the proportion of type I and type II muscle fibers to provide insight into the role of the PB in palmar function based on its gross histological structure. Sixteen PB specimens were harvested from the hands (eight right, eight left) of eight formalin-embalmed cadavers (mean age: 75±14years; three males, five females). PB muscle composition was determined by labeling serial cross-sections with MHC type I and type II monoclonal antibodies. The results indicate that the PB is primarily composed of type I muscle fibers (72.2±13.7%), with no significant differences between left and right hands. Given the predominance of type I muscle fibers, our findings indicate the PB may be fatigue-resistant and thus, capable of contracting for prolonged durations. This supports cadaveric observations indicating that the PB functions to protect the ulnar neurovasculature of the palm by providing a muscular barrier in addition to serving as a functional anchor to the hypothenar fat pad when objects are firmly compressed into the palm.

Morphology of Anterolateral Ligament of the Knee: A Cadaveric Observation with Clinical Insight.

Background. The morphology and function of anterolateral ligament (ALL) of the knee are not clearly understood even today with all the sophisticated techniques available. There have been differing descriptions of the ALL of the knee in literature, and not all of them have been named or described clearly. Aim. The present study was undertaken to provide a clear structure/relationship description on ALL. Materials and Methods. We used 24 formalin-fixed cadaveric limbs. Knee regions of the all the limbs were neatly dissected and the ALL was exposed. Its proximal and distal attachments were traced carefully. Middle portion of ALL was removed and processed for histological analysis. Results. ALL was found in one right knee (4.16%). It extended distally from the lateral femoral condyle to the lateral tibial plateau margin. Its attachment on the tibial plateau was located between head of the fibula and Gerdy's tubercle. A strong connection was identified between the ALL and the periphery of the middle third of the lateral meniscus. Histological analysis of ALL confirmed the presence of true ligamentous structure in it with dense connective tissue and plenty of fibroblasts. Conclusion. The prevalence of ALL in different populations along with its clinical significance has been discussed in detail in this paper.

Anastomosis Between the Ascending Pharyngeal Artery and the Posterior Inferior Cerebellar Artery Through the Jugular Foramen: A Cadaveric Observation.

The ascending pharyngeal artery (APA) may, in very rare cases, supply the posterior inferior cerebellar artery (PICA). In reported cases, when such is the case, the ipsilateral vertebral artery (VA) does not supply the PICA, and most of the time it is hypoplastic. To describe a unique cadaveric observation of a direct anastomosis between the posterior division (neuromeningeal) of the jugular branch of the APA and the PICA, where the PICA is also supplied by a normal-size VA. A direct connection between the APA and the PICA was examined in a cadaveric specimen using a 3-dimensional endoscope and a surgical microscope. The enlarged jugular branch of the posterior division of the APA entered intracranially via the jugular foramen in its pars vascularis. It then connected directly with the lateral medullary segment of the PICA. The first segment of the PICA originated from a left vertebral artery of normal size and continued its normal course beyond the junction with the jugular branch of the APA. Both the VA and the jugular branch of the APA may simultaneously supply the PICA territory. Recognition of this anatomic variant is relevant when planning surgical or endovascular treatments.

Trabecular Pattern of the Proximal Ulna: A Morphological Study

Background The trabecular architecture of the olecranon and proximal ulna has not been studied in detail. We undertook a primarily cadaveric study aiming to link with the theory of biomechanics. Methods Eight pairs of ulnae were obtained from cadavers. Half of the ulnae were sliced longitudinally, each slice 2 mm to 3 mm thick (Group I), and the remaining half were sliced vertically (Group II) and radiographed to study the trabecular orientation of the olecranon and proximal ulna. Computerized tomography (CT) scans of eight patients (Group III) were studied to determine the real-life trabecular pattern. Results In Group I, two main sets of trabeculae were observed. The first set of trabeculae consists of three bundles, which arise from the anterior cortex. Anterior and middle bundles support the subarticular subchondral area. The posterior bundle curves and spreads to posterior cortex. The second set arises from posterior cortex and terminates under subchondral area. In Group II, trabeculae subtend a 90° angle to the articular surface. CT (Group III) confirmed the cadaveric observations. Conclusions Trabeculae of the olecranon and proximal ulna comprise a cluster that resists compressive loading and a further cluster that resists tensile stresses, which should be taken into consideration in the prosthetic design of elbow replacement to facilitate stress absorption.

Is portable ultrasonography accurate in the evaluation of Schanz pin placement during extremity fracture fixation in austere environments?

The purpose of this study was to investigate the efficacy of ultrasonography to confirm Schanz pin placement in a cadaveric model, and the interobserver repeatability of the ultrasound methodology. This investigation is a repeated measures cadaveric study with multiple examiners. Cadaveric preparation and observations were done by an orthopaedic traumatologist and resident, and two general surgery traumatologists. A total of 16 Schanz pins were equally placed in bilateral femora and tibiae. Four examiners took measurements of pin protrusion beyond the distal cortices using first ultrasonography and then by direct measurement after gross dissection. Distal Schanz pin protrusion length measurements from both ultrasonography and direct measurement post dissection. Schanz pin protrusion measurements are underestimated by ultrasonography (p < 0.01) by an average of 10 percent over the range of 5 to 18 mm, and they display a proportional bias that increases the under reporting as the magnitude of pin protrusion increases. Ultrasound data demonstrate good linear correlation and closely represent actual protrusion values in the 5 to 12 mm range. Interobserver repeatability analysis demonstrated that all examiners were not statistically different in their measurements despite minimal familiarity with the ultrasound methodology (p > 0.8). Despite the statistical imparity of pin protrusion measurement via ultrasound compared to that of gross dissection, a consideration of the clinical relevance of ultrasound measurement bias during an austere operating theatre leads to the conclusion that ultrasonography is an adequate methodology for Schanz pin protrusion measurement.

Verification of a standardized method for inserting intramuscular EMG electrodes into uniquely oriented segments of gluteus minimus and gluteus medius

Guidelines for assessing the function of gluteus minimus and gluteus medius with electromyography (EMG) traditionally offer one electrode placement site per muscle. However, anatomical studies suggest that there are two uniquely oriented segments within gluteus minimus (anterior and posterior), and three within gluteus medius (anterior, middle, and posterior) with potential for independent function. Assessment of these muscles with one electrode may therefore provide only a limited account of their role. Thus, the aim of this cadaveric study was to verify guidelines for placing intramuscular electrodes into two uniquely oriented segments of gluteus minimus, and three segments of gluteus medius. The guidelines were developed with reference to anatomical reports, cadaveric observation and real-time ultrasound imaging in vivo. Five cadaveric gluteal regions were marked for intramuscular electrode insertions based on these guidelines. Intramuscular electrodes were inserted into the marked regions of gluteus minimus (2×) and gluteus medius (3×) with the aid of a 15 cm biopsy needle. Systematic dissection revealed that electrodes were successfully inserted into uniquely oriented segments of gluteus minimus and medius. The orientation of fascicles surrounding each electrode was also consistent with segmental descriptions in past anatomical research. The findings of this research suggest that the guidelines described may be used to assess the functional role of segments within gluteus minimus and medius in health and dysfunction using EMG. Finally, electromyographers intent on investigating the role of posterior gluteus minimus must be cautious of the superior gluteal neurovascular bundle.

Cadaveric observation of an aberrant left subclavian artery: A possible cause of thoracic outlet syndrome

We report a rare anomaly of the left subclavian artery, coursing through the scalenus anterior muscle, that may cause thoracic outlet syndrome. We also discuss the anatomical basis of the possible diagnostic maneuvers for patients with thoracic outlet syndrome.

Prevention of cubitus varus deformity in supracondylar fractures of the humerus

Based on cadaveric experiments, peroperative observations and clinical study, an exact mechanism is described by which full pronation of the forearm prevents cubitus varus deformity in supracondylar fractures of the humerus. The significance of the position of the upper limb in relation to the chest is described, and it has been demonstrated that even the posterolaterally displaced supracondylar fractures are better reduced and maintained in pronation.