Correction to: Are Clerks Proficient in the Basic Sciences? Assessment of Third-Year Medical Students' Basic Science Knowledge Prior to and at the Completion of Core Clerkship Rotations.

[This corrects the article DOI: 10.1007/s40670-021-01249-3.].

Are Clerks Proficient in the Basic Sciences? Assessment of Third-Year Medical Students' Basic Science Knowledge Prior to and at the Completion of Core Clerkship Rotations.

Basic sciences are a cornerstone of undergraduate medical education (UME), yet research indicates that students' basic science knowledge is not well retained. Many UME curricula are increasing the integration between the basic and clinical sciences with the goal of enhancing students' knowledge levels; however, the impact of clerkship training on students' basic science knowledge remains inconclusive. Thus, using clerkship directors' expectations as framework, we aimed to assess third-year medical students' basic science knowledge during clerkship training and evaluate the influence of clerkship training on their basic science knowledge. Using concepts deemed necessary by clerkship directors, we created a basic science assessment for each clerkship rotation. Assessments were distributed to third-year medical students as a pre- and post-test to assess their basic science knowledge prior to and at the completion of each rotation. On average, students retained ≥ 60% of relevant basic science knowledge from pre-clerkship, and neither clerkship rotation order, nor the basic science discipline being assessed, impacted students' basic science knowledge levels. Post-test data revealed that students, on average, reinforced fundamental concepts during clerkship. Interestingly, even though lower-performing students demonstrated the greatest post-test improvement, they still left each rotation with knowledge deficits compared with their highest-performing peers, suggesting that the clinical experience of clerkship appears to be particularly beneficial for lower-performing students, in regard to enhancing their basic science knowledge. Overall, results indicate that earlier exposure to clinical learning in UME, along with integration of basic science education into clerkship, could promote students' basic science knowledge acquisition and retention.

Lateral subvastus approach: A cadaveric examination of its potential for total knee arthroplasty.

BACKGROUND: Lateral approaches to total knee arthroplasty (TKA) provide good surgical exposure and may provide greater ease of soft tissue balancing in patients with a valgus deformity; however, little is known about the versatility in non-valgus knees. The present study evaluated if a lateral subvastus approach can achieve adequate surgical exposure while maintaining less soft tissue damage compared with the medial parapatellar approach in knees without any significant deformity. METHODS: Using paired fresh-frozen cadaveric knees, the present study provides the first specimen-matched, side-by-side comparison of the lateral subvastus approach to the standard medial parapatellar approach to TKA. Ten knees were selected to undergo a lateral subvastus approach; the contralateral knee had a medial parapatellar approach as control. Incision length, surgical exposure and iatrogenic soft tissue damage were compared between the two approaches. RESULTS: The lateral subvastus approach was successfully performed using an incision length that was not different from that used in the medial parapatellar approach (p > 0.05). The resultant surgical exposure was comparable between approaches (p > 0.05). The risk of the approach included tearing of the vastus lateralis fibers, and/or abrasion of the iliotibial tract/patellar ligament. CONCLUSIONS: The lateral subvastus approach to TKA provided a comparable method to the standard medial parapatellar approach. Despite adequate exposure, the approach did risk soft tissue injury. Caution needs to be exercised to reduce the risk of iatrogenic injury to the vastus lateralis and surrounding ligaments. The successful implementation in this cadaveric study substantiates the need for further consideration of this approach in clinical practice.

Does endoscopic sinus surgery alter the biomechanics of the orbit?

OBJECTIVE: The purpose of this study is to determine if removal of ethmoid cell septations as commonly performed in endoscopic sinus surgery leads to a change in orbital wall fracture patterns and the force required to create them. METHODS: Six fresh-frozen cadaveric heads were acquired and underwent endoscopic uncinectomy, maxillary antrostomy, and anterior and posterior ethmoidectomy on one, randomized, side. The contralateral sinuses were used as intra-specimen control. Hyaluronic acid gel globe injections were performed to simulate normal intra-ocular pressure. Post-op CT scans confirmed no orbital fractures or violation of the lamina papyracea prior to trauma testing. Orbital trauma was induced using a guided weight-drop technique. Both orbits were tested in random order, and sequentially higher drops were performed until both the test and control side demonstrated an orbital fracture on CT scan. RESULTS: In all six heads, the post-sinus surgery side incurred a medial orbital wall fracture, and no orbital floor fractures were identified. On the other hand, on the control side, all six heads incurred orbital floor fractures at drop heights equal to, or higher than, the surgical side. Fisher's exact test demonstrated a significant difference in fracture pattern (p <  0.001). CONCLUSIONS: To our knowledge, this is the first demonstration that the structures removed during sinus surgery may act as a buttress for the medial orbital wall. The anatomic changes of sinus surgery may alter the biomechanics of the orbit and affect the pattern of subsequent traumatic blowout fractures.

Expectations and Perceptions of Students' Basic Science Knowledge: Through the Lens of Clerkship Directors.

Basic sciences are a cornerstone of undergraduate medical education (UME) as they provide a necessary foundation for the clinical sciences to be built upon and help foster trainees' competency. However, research indicates that students' basic science knowledge is not well retained, and as a result, students are ill-prepared, with respect to their basic science knowledge, when entering clerkship. One potential reason why students may not be prepared for clerkship is a lack of understanding as to which basic science concepts are critical for medical students to retain from pre-clerkship. We facilitated interviews with all core UME clerkship directors to establish which basic science concepts they expect students to know prior to each clerkship rotation, along with student's basic science strengths and areas of improvement. Interviews revealed that students are expected to have some knowledge of every basic science prior to clerkship, with pharmacology being a strong focus, as many specialties deal with common drugs and classes of drugs. Additionally, general anatomy and physiology knowledge were deemed student strengths in two rotations. Clerkship directors focused on perceived areas of improvement more than perceived strengths, with the most prevalent areas being pharmacology, microbiology, and detailed anatomy. These results represent views of clerkship directors from one Canadian institution; however, since clerks rotate through institutions across Canada, this data provides the impetus for creating a national discussion to help foster standardization of UME curricula, with the overarching goal of ensuring all graduates are proficient in the necessary fundamentals as they transition into residency.

Time to Return to School After 10 Common Orthopaedic Surgeries Among Children and Adolescents.

BACKGROUND: Return to school among adolescents is often overlooked in orthopaedic outcome studies. The purpose was to measure the time missed from school after 10 common orthopedic surgeries. METHODS: Patients, 5 to 19 years old enrolled in elementary, middle, or high school, who underwent treatment for fixation of type III supracondylar humerus fracture, midshaft femur fracture fixation, isolated anterior cruciate ligament reconstruction, isolated partial menisectomy, adolescent idiopathic scoliosis fusion, closed reduction of both-bone forearm fracture, arthroscopic Bankart repair, hip arthroscopy with femoroacetabular impingement correction, limb length discrepancy correction, or surgical fixation of slipped capital femoral epiphysis during the 2014/2015 and 2015/2016 school years were identified for this Institutional Review Board-approved study. All patients were contacted after surgery to determine date of return to school, number of days in session, and number of school days missed. RESULTS: Two hundred six patients met the inclusion criteria for this study. Mean age at time of surgery was 13.0±3.8 years. There were 105 males (51%). Mean time to return to school overall was 13.0±15.2 days. Very few students (n=9; 4%) did not miss any school days during recovery from the procedure of interest. The average number of days missed from school for males was 6.6 days compared with 8.4 days in females (P=0.20). There was no difference between patients aged 5 to 12 years compared with those aged 13 to 19 years (7.1 vs. 7.7 d, respectively; P=0.69). On average, patients who underwent closed reduction of a both-bone forearm fracture returned to school the quickest following surgery (3.4±1.2 d) and missed the least amount of in-session school days (1.9±0.9 d), and those who underwent adolescent idiopathic scoliosis fusion were out of school the longest (42.3±21.4 d) and missed the greatest number of in-session school days (27.6±14.7 d). CONCLUSIONS: Information regarding average time missed from school for 10 common orthopaedic surgeries can be used by clinicians to counsel patients and their families regarding expected recovery time. LEVEL OF EVIDENCE: Level IV.

Ultrasound-guided subomohyoid suprascapular nerve block and phrenic nerve involvement: a cadaveric dye study.

BACKGROUNDS AND OBJECTIVES: The anterior approach to the subomohyoid suprascapular (SOS) nerve is a new, technically easy and reliable regional anesthesia technique for postoperative shoulder analgesia. However, due to its proximity, the injectate may spread to the brachial plexus and phrenic nerve. The goal of this anatomic study with dye injection in the subomohyoid space and subsequent cadaver dissection was to establish the likely spread of local anesthesia and the extent of brachial plexus and phrenic nerve involvement resulting from ultrasound-guided SOS nerve block. METHODS: The suprascapular nerve (SSN) under the inferior belly of omohyoid muscle in the posterior triangle of the neck was identified. Using a contrast dye, 10 ultrasound-guided SOS nerve injections of 5 mL were done bilaterally, in five fresh cadavers. The area was then dissected to evaluate the spread of the contrast dye in the immediate proximity of the brachial plexus, phrenic and SSN. RESULTS: The SSN and omohyoid muscle were easily identified on each cadaver. SOS nerve staining with contrast dye was seen in 90% of dissections. The superior trunk was stained in 90% and the middle trunk was stained in 80% of dissections. The inferior trunk was stained in 20% of dissections. A spread of dye around the SSN was observed in 90% and the phrenic nerve was mildly stained in 20% of the dissections. CONCLUSION: In-plane ultrasound-guided needle injection with a 5 mL volume for SOS block was sufficient to stain the SSN. This conservative volume involved other parts of the brachial plexus and may potentially spread to the phrenic nerve. Further clinical studies are required for confirmation.

The biomechanical and morphological characteristics of the ligamentum mucosum and its potential role in anterior knee pain.

BACKGROUND: The ligamentum mucosum is composed of dense regular connective tissue and traverses from the distal femur to the infrapatellar fat pad. While the gross and histologic morphology has been studied, there is currently no evidence concerning the biomechanical properties of the ligamentum mucosum and the potential of anterior knee pain. The purpose of this study was to determine the anatomical, mechanical and histological properties of the ligamentum mucosum. METHODS: Dissections were performed on cadaveric knee specimens (N = 18) and histological analysis (n = 6) was performed to define the anatomical characteristics of the ligamentum mucosum using standard hematoxylin and eosin (H&E), Masson's trichrome, and immunohistochemical methods. Biomechanical testing (n = 5) was conducted to determine the tensile properties of the ligamentum mucosum. The peak load at failure, stiffness, and strain were analyzed. RESULTS: Sixty-four percent of the knees had a ligamentum mucosum and the histological analysis confirmed it to be composed of dense regular connective tissue. Small peripheral nerves were identified in the junction between the ligamentum mucosum and the fat pad. The average (SD) peak force of failure, stiffness, and strain were 31.9 N (19.0), 5.1 N/mm (3.59), and 0.83 (0.14), respectively. CONCLUSIONS: The tensile strength and stiffness of the ligamentum mucosum is considerably less than the primary stabilizers of the knee joint. Based on these findings, it is improbable that the ligamentum mucosum has a meaningful effect on the kinematics of the extensor mechanism; perturbations of the tissue and the connected infrapatellar fat pad could potentially play a role in the pathogenesis of anterior knee pain.

Ultrasound-guided lateral-medial transmuscular quadratus lumborum block for analgesia following anterior iliac crest bone graft harvesting: a clinical and anatomical study.

BACKGROUND: The anterior iliac crest (AIC) is one of the most common sites for harvesting autologous bone, but the associated postoperative pain can result in significant morbidity. Recently, the transmuscular quadratus lumborum block (TQL) has been described to anesthetize the thoraco-lumbar nerves. This study utilizes a combination of cadaveric models and clinical case studies to evaluate the dermatomal coverage and analgesic utility of TQL for AIC bone graft donor site analgesia. METHODS: Ten ultrasound-guided TQL injections were performed in five cadaver specimens using a lateral-to-medial transmuscular approach. Twenty mL of 0.5% methylcellulose was injected on each side after ultrasound confirmation of the needle tip ventral to the quadratus lumborum muscle (QLM). Cranio-caudal and medial-lateral extent of the dye spread in relation to musculoskeletal anatomy and direct staining of the thoraco-lumbar nerves were recorded. Following the anatomical findings, continuous catheter TQL blocks were performed in four patients undergoing ankle surgery with autologous AIC bone graft. The dermatomal anesthesia and postoperative analgesic consumption were recorded. RESULTS: In the anatomical component of the study, 9/10 specimens showed a lateral spread anterior to the transversalis fascia and medially between the QLM and psoas major muscle. Direct staining of the branches of the T12, L1, and L2 nerves was noted ventral to the QLM, while variable staining of the T9-T11 nerves was seen laterally in the transversus abdominis plane and the transversalis fascia. The vertical spread of injectate anterior to the QLM was T12 to the iliac crest (n = 5/10) and L1 to the iliac crest (n = 4/10). In the four patients who received TQL, the T9-L2 dermatomal anesthesia correlated with the injectate spread seen in the cadavers and provided effective analgesia at the bone graft donor site. CONCLUSION: Ultrasound-guided TQL injections consistently cover the thoraco-lumbar innervation relevant to the AIC graft donor site. The injectate spread seen in anatomical dissections correlated with the dermatomal anesthesia clinically. The TQL has the potential to provide reliable analgesia for patients undergoing AIC bone graft harvesting.

The anatomy of the infrarenal lumbar splanchnic nerves in human cadavers: implications for retroperitoneal nerve-sparing surgery.

Injury to the nerves of the aortic- and superior hypogastric plexuses during retroperitoneal surgery often results in significant post-operative complications, including retrograde ejaculation and/or loss of seminal emission in males. Although previous characterizations of these plexuses have done well to provide a basis for understanding the typical anatomy, additional research into the common variations of these plexuses could further optimize nerve-sparing techniques for retroperitoneal surgery. To achieve this, the present study aimed to document the prevalence and positional variability of the infrarenal lumbar splanchnic nerves (LSNs) through gross dissection of 26 human cadavers. In almost all cases, two LSNs were observed joining each side of the aortic plexus, with 48% (left) and 33% (right) of specimens also exhibiting a third joining inferior to the left renal vein. As expected, the position of the LSNs varied greatly between specimens. That said, the vast majority (98%) of LSNs joining the aortic plexus were found to originate from the lumbar sympathetic trunk above the level of the inferior mesenteric artery. It was also found that, within specimens, adjacent LSNs often coursed in parallel. In addition to these nerves, 85% of specimens also demonstrated retroaortic LSN(s) that were angled more inferior compared with the other LSNs (P < 0.05), and exhibited a unique course between the aorta/common iliac arteries and the left common iliac vein before joining the superior hypogastric plexus below the aortic bifurcation. These findings may have significant implications for surgeons attempting nerve-sparing procedures of the sympathetic nerves in the infrarenal retroperitoneum such as retroperitoneal lymphadenectomies. We anticipate that the collective findings of the current study will help improve such retroperitoneal nerve-sparing surgical procedures, which may assist in preserving male ejaculatory function post-operatively.

Eligibility for Minimally Invasive Coronary Artery Bypass: Examination of Epicardial Adipose Tissue Using Computed Tomography.

OBJECTIVE: A variable that necessitates conversion to a conventional full-sternotomy coronary artery bypass procedure from a robotic-assisted endoscopic single-vessel small thoracotomy is the inability to visualize the left anterior descending coronary artery within the surrounding epicardial adipose tissue using the endoscopic camera. The purpose of this study was to determine whether anatomical properties of the epicardial adipose tissue examined using preoperative computed tomography (CT) images are able to predict and thus reduce the need for intraoperative conversion based on effective preoperative exclusion criteria. METHODS: Retrospective analysis of patient preoperative CT angiography scans from both converted (n = 17) and successful robotic-assisted (n = 17) procedures was performed. Where possible, measurements of epicardial adipose tissue were acquired from axial slices, at the most accessible segment of the left anterior descending coronary artery. RESULTS: Results indicate that patients who successfully underwent the endoscopic single-vessel small thoracotomy procedure (mean ± SD depth, 4.9 ± 1.9 mm) had significantly less epicardial adipose tissue (38%, P = 0.002) overlying the vessel toward the lateral chest wall than those who were converted to the full-sternotomy approach intraoperatively (mean ± SD depth, 7.9 ± 3.2 mm). Using this as a retrospective exclusion criterion reduces the conversion rate for this group by 47%, while maintaining a high specificity (94%). No significant differences exist between the two groups with respect to the remaining epicardial adipose tissue measurements or body mass index. CONCLUSIONS: The addition of CT angiography measurements of the epicardial adipose tissue overlying the left anterior descending coronary artery may enhance preoperative surgical planning for this procedure, thereby reducing the instances of procedural changes.

Bikini versus traditional incision direct anterior approach: is there any difference in soft tissue damage?

INTRODUCTION: The direct anterior approach for total hip replacements has reported advantages of improved early function and muscle preservation. In an effort to improve healing and cosmesis, a change in the orientation of the incision has been proposed. Traditionally, the skin incision is in-line with the tensor fasciae latae muscle belly. The bikini incision is orthogonal to this orientation. The hypothesis was that muscle damage would be increased by using the bikini incision. METHODS: A traditional or bikini incision was performed on 18 cadaveric hips. On each of the 9 specimens, the traditional incision was performed on 1 side, and a bikini incision on the contralateral hip, with an even distribution of right or left side. Blinded anatomists performed the hip dissections, and assessed for muscle damage as well as for damage to the lateral femoral cutaneous nerve. RESULTS: No difference in muscle damage was identified in the tensor fasciae latae between muscle groups. Muscle damage was very minimal to the gluteus medius and minimus. Damage to the lateral femoral cutaneous nerve occurred equally for both the bikini and traditional skin incisions. CONCLUSIONS: The bikini incision for the direct anterior approach to the hip can be performed safely, with no increase in muscle damage or damage to the lateral femoral cutaneous nerve compared to the traditional incision.

A Peer-Reviewed Instructional Video is as Effective as a Standard Recorded Didactic Lecture in Medical Trainees Performing Chest Tube Insertion: A Randomized Control Trial.

OBJECTIVE: Online medical education resources are becoming an increasingly used modality and many studies have demonstrated their efficacy in procedural instruction. This study sought to determine whether a standardized online procedural video is as effective as a standard recorded didactic teaching session for chest tube insertion. DESIGN: A randomized control trial was conducted. Participants were taught how to insert a chest tube with either a recorded didactic teaching session, or a New England Journal of Medicine (NEJM) video. Participants filled out a questionnaire before and after performing the procedure on a cadaver, which was filmed and assessed by 2 blinded evaluators using a standardized tool. SETTING: Western University, London, Ontario. Level of clinical care: institutional. PARTICIPANTS: A total of 30 fourth-year medical students from 2 graduating classes at the Schulich School of Medicine & Dentistry were screened for eligibility. Two students did not complete the study and were excluded. There were 13 students in the NEJM group, and 15 students in the didactic group. RESULTS: The NEJM group׳s average score was 45.2% (±9.56) on the prequestionnaire, 67.7% (±12.9) for the procedure, and 60.1% (±7.65) on the postquestionnaire. The didactic group׳s average score was 42.8% (±10.9) on the prequestionnaire, 73.7% (±9.90) for the procedure, and 46.5% (±7.46) on the postquestionnaire. There was no difference between the groups on the prequestionnaire (Δ + 2.4%; 95% CI: -5.16 to 9.99), or the procedure (Δ -6.0%; 95% CI: -14.6 to 2.65). The NEJM group had better scores on the postquestionnaire (Δ + 11.15%; 95% CI: 3.74-18.6). CONCLUSIONS: The NEJM video was as effective as video-recorded didactic training for teaching the knowledge and technical skills essential for chest tube insertion. Participants expressed high satisfaction with this modality. It may prove to be a helpful adjunct to standard instruction on the topic.

Complete Obliteration of the Left Atrial Appendage: An Analysis of Epicardial Excision and Novel Pericardial Patch Exclusion.

OBJECTIVE: Conventional epicardial excision is believed to be the most effective method of surgically obliterating the left atrial appendage (LAA), although incomplete resection and residual LAA volume may undermine its effectiveness. We sought to compare the impact of conventional epicardial excision with a novel LAA pericardial patch exclusion on residual LAA volume. METHODS: We performed LAA obliteration using pericardial patch exclusion, followed by conventional epicardial excision, in 27 cadaveric hearts. After each procedure, residual LAA volume was measured by two different techniques and compared with baseline volume. There was no difference in baseline LAA volume between each procedure. RESULTS: Procedural success was achieved in all hearts. Conventional epicardial excision left a residual LAA volume of 0.95 mL (24%), as compared with pericardial patch exclusion, which left a residual volume of 0.17 mL (4%, P = 0.0001). Further analysis of fixed and fresh hearts showed that reduction of LAA volume was more pronounced in the fresh hearts, suggesting effectiveness in live patients. Neither technique resulted in any significant change in the endocardial shape of the LAA orifice or injury to the circumflex artery. CONCLUSIONS: Conventional epicardial excision of the LAA results in significantly more residual LAA volume, which may have important implications in persistent stroke risk. Pericardial patch exclusion seems to achieve near-total elimination of the LAA and may be a superior surgical option.

Retroperitoneal Lymph Node Dissection: Anatomical and Technical Considerations from a Cadaveric Study.

PURPOSE: Metastatic testis cancer in the retroperitoneum presents a technical challenge to urologists in the primary and post-chemotherapy settings. Where possible, bilateral nerve sparing retroperitoneal lymph node dissection should be performed in an effort to preserve ejaculatory function. However, this is often difficult to achieve, given the complex neurovascular anatomy. We performed what is to our knowledge the first comprehensive examination of the anatomical relationships between the sympathetic nerves of the aortic plexus and the lumbar vessels to facilitate navigation and nerve sparing during bilateral retroperitoneal lymph node dissection. MATERIALS AND METHODS: The relative anatomy of the infrarenal vasculature (lumbar vessels, right gonadal vein and inferior mesenteric artery) was investigated in 21 embalmed human cadavers. The complex relationships between these vessels and the sympathetic nerves of the aortic plexus were examined by dissection of an additional 8 fresh human cadavers. RESULTS: Analysis of the infrarenal vasculature from 21 cadavers demonstrated that the position of the right gonadal vein and the inferior mesenteric artery may be useful to locate the right superior lumbar vein and the first pair of infrarenal lumbar arteries as well as the common lumbar trunk (vein) and the second pair of infrarenal lumbar arteries, respectively. Furthermore, the lumbar splanchnic nerves supplying the aortic plexus were most often positioned anteromedial to the respective lumbar vein. CONCLUSIONS: The current study describes the complex neurovascular relationships that are crucial to performing successful nerve sparing retroperitoneal lymph node dissection. Surgical techniques are also discussed. Collectively, these results may help surgeons decrease the rate of postoperative retrograde ejaculation and/or anejaculation.

A Three-dimensional Analysis of Zygomatic Symmetry in Normal, Uninjured Faces.

Current approaches to facial reconstruction are based on the assumption of facial symmetry, though this has yet to be established in the literature. Through quantitative and qualitative analysis, symmetry of normal, male faces is examined here using the zygomatic complex as a bellwether for the rest of the facial skeleton. Three-dimensional models reconstructed from the computed tomography scans of 30 adult male patients displaying normal facial skeletal anatomy were analyzed. Seven zygomatic landmarks were identified on all craniofacial models, and asymmetry scores were calculated based on the average deviation distance upon reflection of 1 hemiface across the midfacial plane. Deviation maps were then generated for each zygomatic pair to enable visualization of the asymmetry. All landmarks displayed a slight (<3 mm) deviation from perfect symmetry, and analysis of zygomatic form asymmetry revealed an average of 0.4 mm of surface deviation between hemifaces. The presence of such slight asymmetries in the zygoma warrants further investigation as to the clinical relevance of such skeletal asymmetries from both an esthetic and biomechanical consideration to provide insight as to the proper approach to zygomatic restoration in cases of zygomatic fracture.

Histological verification of the prehypogastric and ovarian ganglia confirms a bilaterally symmetrical organization of the ganglia comprising the aortic plexus in female human cadavers.

The aortic plexus is a network of sympathetic nerves positioned along the infrarenal abdominal aorta. Recently, we characterized the aortic plexus and its ganglia (inferior mesenteric, left/right spermatic, and prehypogastric ganglion) in males; however, the literature minimally describes its anatomy in females. In the present study, we conducted the first histological examination of the left and right ovarian ganglia, while also investigating whether females, like males, exhibit a prehypogastric ganglion. The ganglia were dissected from embalmed (n = 32) and fresh (n = 1) human cadavers, and H&E staining was used to confirm the presence of a left ovarian ganglion in 31/31 specimens, a right ovarian ganglion in 29/29 specimens and a prehypogastric ganglion in 25/28 specimens. Comparable to the topographic arrangement in males, there is a bilateral organization of the ganglia comprising the aortic plexus in females. More specifically, the left and right ovarian ganglia were positioned in close relation to their respective ovarian artery, whereas the prehypogastric ganglion was positioned within the right cord of the aortic plexus, contralateral to the inferior mesenteric ganglion. Using immunohistochemistry, it was shown that all ganglia from the fresh cadaver stained positive for tyrosine hydroxylase, thereby confirming their sympathetic nature. Having provided the first topographical and histological characterization of the ovarian and prehypogastric ganglia in females, future studies should seek to determine their specific function.

Regional Variations in Cartilage Thickness of the Radial Head: Implications for Prosthesis Design.

PURPOSE: To characterize the regional variations in cartilage thickness around the radial head. METHODS: We dissected 27 cadaveric radii and scanned them with computed tomography in neutral position. Three-dimensional cartilage and subchondral bone surface models were generated from computed tomography scans and 2 independent observers processed them through a computer program to obtain cartilage thickness measurements. These measurements were taken at 41 predetermined landmarks around the periphery of the radial head and within the articular dish. RESULTS: At the periphery of the radial head, cartilage was thickest in the posteromedial region. Thickness values within the articular dish were similar but increased toward the rim. Regional variations within the rim (range, 0.76-1.73 mm) were also detected with the thickest region located anteriorly and thinnest region laterally. In addition, cartilage was significantly thicker in male relative to female specimens. CONCLUSIONS: Regional variations in cartilage thickness are present around the periphery and rim and within the articular dish of the radial head. CLINICAL RELEVANCE: Cartilage thickness across the articular dish may contribute to dish depth and the radius of curvature. This may be clinically important for the design of anatomic implants, because accounting for such subtle contours could help to restore radiocapitellar concavity-compression stability better.