Mandibular canal versus inferior alveolar canal: A Delphi study.

The general principles of anatomical terminology indicate that the "mandibular canal" should be named the "inferior alveolar canal" as it accommodates the inferior alveolar neurovascular bundles. Therefore, we performed a Delphi study to evaluate the current understanding and use of the terminology in different geographical regions and areas of expertise and to determine the appropriate terminology for this bony canal. A Delphi panel was formed and questions sent and answered via email about: field of expertise (anatomy, oral surgery/oral and maxillofacial (OMF) surgery, oral radiology/OMF radiology, plastic surgery, ENT surgery, or dentistry with the exception of oral/OMF surgery and oral/OMF radiology), years of experience in the field of expertise, country currently working in, "what is the name of the bony canal that contains the inferior alveolar neurovascular bundle," and "what should the structure above be called, in general?" A total of 52 participants responded to the questionnaire. Half or more of the experts in anatomy, oral/OMF surgery, and ENT/plastic surgery considered "mandibular canal" to be the most appropriate name for this bony canal. In contrast, more than half of all experts in oral/OMF radiology and dentistry, that is, most fields of dentistry, considered "either mandibular canal or inferior alveolar canal" to be the appropriate name. The results of the Delphi study and general principles suggest that an alternative term for the "mandibular canal" should be "inferior alveolar canal."

The principles of anatomical nomenclature revision: They're more like guidelines anyway.

Revision of the international standard anatomical terminology is required periodically to add names for new entities, delete archaic terms, and correct errors in existing terms. In addition to a small set of nomenclature rules, three principles have guided revisions: names should not be changed unless they are wrong; corrections of perceived errors should not be pedantic; and inclusion of every minor structure should not be attempted. These principles have served well, and are expected to continue to do so, but they have also proven to be subjective because their application through the history of the international terminology has varied. Specific efforts to deal with existing problems and new organizational initiatives to prevent future issues are presented. Clin. Anat. 33:327-331, 2020. © 2019 Wiley Periodicals, Inc.

How many bones? Every bone in my body.

Textbooks frequently report that there are 206 human bones, or 200 bones and 6 auditory ossicles. The human bone counts in history and within adulthood were reviewed. Tallies of 197 to 307 bones have been reported over the past several centuries. The relatively low modern reckoning of 206 was due to exclusion of teeth and sesamoid ossicles, and to reassessments of the hyoid, sacrum, coccyx, and sternum as unitary bones. An audit of bone counts during adulthood failed to confirm a rational justification for the total of 206. The number is higher in young adults and lower in the elderly. Difficulties in establishing a definitive bone count include individual differences and the inconsistency of viewing the adult cranium as a collection of 21 bones. Clin. Anat. 33:187-191, 2020. © 2019 Wiley Periodicals, Inc.

Survey of body donation programs in the US concerning the use of donor personal information with medical students.

Body donor programs need to balance ethical concerns and educational needs. Among donor programs in the US, there is variability in the amount of donor personal information that is provided to medical students. This study assesses this variability and investigates the reasons for the variability among donor programs. Telephone interviews and email surveys were used to collect information concerning the provision and use of donor personal information with medical students. One hundred fifty-one donor programs in the US were contacted via email or telephone interview or both. Fifty-three donor programs responded to the survey or participated in the telephone interview. The survey results show variation, not only in the amount of donor personal information provided to medical students, but also in the attitudes and beliefs of the donor program personnel concerning donor personal information. This research documents the variability of the educational use of donor personal information. It is hoped that this description of the various approaches to using donor information will encourage the ethical use of donor information within the context of medical education. Clin. Anat. 30:445-449, 2017. © 2017 Wiley Periodicals, Inc.

Persistent double dorsal aorta: A systematic review of the literature.

Our discovery of a case of persistent double dorsal aorta prompted us to systematically review the literature of all previously reported cases of this anomaly. For our case, we present a completely separated double dorsal aorta, with the right accessory aorta arising from the abdominal aorta and ascending through the aortic hiatus to supply posterior intercostal arteries (PIAs) to the 9th-3rd spaces bilaterally. We examined and compiled data from the 10 previously reported cases, along with our observations from our cadaver, into a systematic review of all known cases of persistent double dorsal aorta. In addition to our case report and systematic review, we investigated the literature focusing on formation of the dorsal aorta in the embryo in order to postulate potential mechanisms for formation of this anomaly. Two variants of persistent double dorsal aorta have been reported in the literature. The first type is characterized by a double-lumen descending aorta with a central dividing septum, and the second features complete separation of the two dorsal aortae. The completely separated variant shows further heterogeneity in the origins of the PIAs and the iliac arteries, and the majority of the reported cases also demonstrate additional anatomical anomalies. We outline the events in embryonic dorsal aorta formation as well as discuss several potential mechanisms that could underlie persistent double dorsal aorta formation. Clin. Anat. 30:517-524, 2017. © 2017 Wiley Periodicals, Inc.

Effectiveness of various methods of formaldehyde neutralization using monoethanolamine.

Formaldehyde is the most commonly used fixative chemical for the preservation of human cadavers used for educational purposes in the United States. Formaldehyde is also a known carcinogenic agent whose exposure level is regulated by guidelines of the Occupational Safety and Health Administration. Various methods for formaldehyde neutralization exist, yet many donations programs do not take any steps to neutralize the formaldehyde in embalmed donor bodies. The effectiveness of monoethanolamine (MEA) in neutralizing formaldehyde is well documented when used as a final injection during embalming. The purpose of this study is to report the effectiveness of several post-embalming techniques of formaldehyde neutralization. Twenty-four donor bodies were assigned to four experimental groups of six. For the three experimental groups, the techniques tested involve delivery of a 20:1 dilution of deionized water:MEA via recannulization and gravity flow infusion, compartment injection, and alternate wetting solution containing four percent MEA. Our results indicated that spray bottle delivery was not effective in neutralization of formaldehyde compared to the control group, but that formaldehyde levels decreased when recannulization or compartment injection were used. The most effective method of formaldehyde neutralization was compartment injection of MEA solution (P < 0.01). The results of this study indicate that, in situations where MEA is not used as a final infusion during embalming, compartment injection of MEA solution is an effective method of formaldehyde neutralization.

Clinical considerations of the glandular branch of the lacrimal artery.

The lacrimal artery is classically described as a branch of the ophthalmic artery supplied by the internal carotid. In this study, 25 orbits were dissected to identify variations in glandular branching and to compare them to previously published accounts. The glandular branching patterns of the lacrimal artery fall into two categories, those that branch (56%) and those that do not branch (44%). We found the medial and lateral glandular branches to be equal in diameter with a divergence of 2.67-40.58 mm proximal to the gland parenchyma. The long glandular branches run alongside the superolateral aspect of the orbit. The lateral branch runs lateral to the lateral rectus muscle. The medial branch runs superomedial to the lateral rectus muscle and lateral to the superior rectus muscle. In relation to the lacrimal gland, the medial branch enters the superior aspect of the gland parenchyma and the lateral branch enters its inferior aspect. The average branch lengths were 17.88 mm (medial) and 13.51 mm (lateral) as measured with a Mitutoyo Absolute 1/100 mm caliper. We could not confirm the existence of a third branch supplying the lacrimal gland, as posited by other authors. The key finding in this study is that the lacrimal gland is predominantly supplied by two significant arterial branches, both of which must be identified during procedures involving the lateral orbit.

Pancreas divisum: a common developmental variant that deserves attention in preclinical medical education.

Clinical literature indicates that pancreas divisum (PD) is present in 3-22% of the population and may be associated with an increased risk of pancreatitis. PD is a developmental variant wherein the duct systems derived from the dorsal and ventral pancreatic buds are not fused. Hence secretions from the head, neck, body, and tail, which develop from the dorsal bud, must pass through the minor duodenal papilla. The smaller uncinate process, derived from the ventral bud, drains through the major duodenal papilla. The purpose of this study was: (1) to do a cadaveric dissection to confirm whether PD is common in donors who had not been selected because they had pancreatitis and (2) to determine the frequency of PD descriptions in anatomy, embryology, pathology, and surgery books in our libraries. For our anatomical study, pancreata of eight human donors were dissected. Dye was injected into the ducts so that any communications between main and accessory ducts could be easily located. For our literature review, 22 anatomy, 14 embryology, 11 pathology, and 26 surgery books were examined for mention of PD. PD was unambiguously identified in two donor cadavers. However, only 14% of the anatomy plus embryology books compared to 70% of the surgery plus pathology books describe PD. Cadaveric dissection confirms that PD is indeed prevalent. The prevalence of PD with its increased risk of pancreatitis merits inclusion of this topic in textbooks of anatomy and embryology.

Patterns of innervation of the lacrimal gland with clinical application.

Parasympathetic stimulation of the lacrimal gland is responsible for tear production, and this innervation originates from fibers conveyed in the facial nerve. After synapse in the pterygopalatine ganglion, postsynaptic parasympathetic fibers travel within the zygomatic and zygomaticotemporal nerves (ZTN) into the orbit. As described in most anatomy texts, ZTN communicates with the lacrimal nerve (LN) posterior to the gland and then secretomotor fibers enter the gland. This study was performed to gain a better understanding of the innervation of the lacrimal gland. Seventeen cadaver heads were bisected for a total of 34 sides, which then underwent dissection of the superolateral orbital region to observe the course for the LN and ZTN. Three variations of the course of the LN and ZTN were found. In 20 (60.6%) dissections it was documented that the ZTN entered directly into the lacrimal gland with no communication with the LN. In 12 (36.4%) of the bisected heads, ZTN had both a direct connection into the gland and a communicating branch with the LN. In only one (3.0%) bisected head, ZTN communicated with the LN before entering the gland as it is commonly described in anatomy texts. Our study reveals that the ZTN usually takes a different course than is classically described in most anatomy textbooks. A greater understanding of the typical course these nerves take may help surgeons identify them more easily and avoid damaging them.

Superior rectal artery origin from the median sacral artery--angiographic appearance, developmental anatomy, and clinical implications.

Two angiographic observations of significant rectal vascularization by branches originating from the median sacral artery (MSA) are reported. In the first case, the MSA provided a complete superior rectal trunk, with left and right branches, while in the second, the MSA only contributed superior rectal branches to the right side of the rectum, the left side being supplied by left internal iliac branches. The angiographic appearance, developmental anatomy, and clinical significance of these variants are discussed.

Self-guided clinical cases for medical students based on postmortem CT scans of cadavers.

In the summer of 2009, we began full body computed tomography (CT) scanning of the pre-embalmed cadavers in the University of Michigan Medical School (UMMS) dissection lab. We theorized that implementing web-based, self-guided clinical cases based on postmortem CT (PMCT) scans would result in increased student appreciation for the clinical relevance of anatomy, increased knowledge of cross-sectional anatomy, and increased ability to identify common pathologies on CT scans. The PMCT scan of each cadaver was produced as a DICOM dataset, and then converted into a Quicktime movie file using Osirix software. Clinical cases were researched and written by the authors, and consist of at least one Quicktime movie of a PMCT scan surrounded by a novel navigation interface. To assess the value of these clinical cases we surveyed medical students at UMMS who are currently using the clinical cases in their coursework. Students felt the clinical cases increased the clinical relevance of anatomy (mean response 7.77/10), increased their confidence finding anatomical structures on CT (7.00/10), and increased their confidence recognizing common pathologies on CT (6.17/10). Students also felt these clinical cases helped them synthesize material from numerous courses into an overall picture of a given disease process (7.01/10). These results support the conclusion that our clinical cases help to show students why the anatomy they are learning is foundational to their other coursework. We would recommend the use of similar clinical cases to any medical school utilizing cadaver dissection as a primary teaching method in anatomy education.

Resident perceptions of anatomy education: a survey of medical school alumni from two different anatomy curricula and multiple medical specialties.

In 2004, the University of Michigan Medical School reduced its gross anatomy curriculum. To determine the effect of this reduction on resident perceptions of their clinical preparedness, we surveyed alumni that included residents from the original and new shortened curricula. A Likert-scale survey was sent to four classes of alumni. Respondents were compared in old curriculum (OC) and new curriculum (NC) groups, surgical specialty (SS) and nonsurgical specialty (NS) groups, and subgroups of SS and NS were compared for differences between OC and NC. Mean response scores were compared using independent samples T-tests. As a single population (n = 110), respondents felt their anatomy education prepared them well for residency, that a more robust anatomy curriculum would be helpful, that dissection was important to their residency preparation, and that a 4th year anatomy elective was effective in expanding their anatomy education and preparing them for residency. No significant difference existed between OC and NC groups, neither as a whole nor as SS and NS subgroups. The SS group felt dissection was more important to their residency preparation than the NS group (P = 0.001) and that a more robust anatomy curriculum would have better prepared them for residency (P = 0.001). Thirty percent of SS respondents who did not take a 4th year elective commented that they wish they had. Fourth year anatomy electives were highly valued by residents, and respondents felt that they should be offered to students as a way of revisiting anatomy following the 1st year of clinical training.

Posterior interosseous nerve of the elbow: normal appearances simulating entrapment.

OBJECTIVE: In our clinical practice, we have noted a caliber change of the posterior interosseous nerve (PIN) at the elbow as seen in the long axis on sonography simulating nerve entrapment. The objective of this study was to characterize the PIN using sonography in asymptomatic individuals. METHODS: Our study retrospectively characterized the PIN in 50 elbows of 47 asymptomatic patients with sonography. Measurements of the PIN in a short-axis cross section using the circumferential trace technique and the anteroposterior (AP) dimension in the long axis were made proximal, at, and distal to the arcade of Frohse. RESULTS: There was reduction of the AP dimension of the PIN distal to the arcade of Frohse when compared with the measurements at the arcade of Frohse and proximal to the arcade (P < .0001); however, there was no significant difference between the cross-sectional area of the PIN at all 3 levels (P = .59). CONCLUSIONS: The PIN normally flattens as it enters into the supinator muscle without a notable change in the cross-sectional area. This appearance should not be misinterpreted as nerve entrapment when imaged in the long axis.

A need for logical and consistent anatomical nomenclature for cutaneous nerves of the limbs.

The system of anatomical nomenclature needs to be logical and consistent. However, variations in translation to English of the Latin and Greek terminology used in Nomina Anatomica and Terminologia Anatomica have led to some inconsistency in the nomenclature of cutaneous nerves in the limbs. An historical review of cutaneous nerve nomenclature reveals that there are two general naming conventions: one primarily American and one primarily British. The American convention presents cutaneous nerves of the limbs in the format "medial brachial cutaneous nerve," while the British convention presents the same nerve as "medial cutaneous nerve of the arm," thereby translating "brachii" to "of the arm." If logically and consistently applied throughout the body, the British convention would rename the sural nerve to the "nerve of the calf," the brachial artery would become the "artery of the arm," the femoral nerve would be "nerve of the thigh," and femur would be "bone of the thigh" or "thigh bone." The British convention leads to many other nomenclatural inconsistencies, which would seem to make learning anatomy more difficult for the beginning student. In this era of contracting anatomy curricula, every effort should be made to keep anatomical nomenclature simple, logical, and consistent.

Spectrum of normal and pathologic findings in the region of the first extensor compartment of the wrist: sonographic findings and correlations with dissections.

OBJECTIVE: The purpose of this presentation is to review pathologic conditions that lead to pain at the radial aspect of the distal radius and to address anatomic variations of the first extensor compartment that exist and may have diagnostic and therapeutic implications. METHODS: Our presentation is based on a review of cases from teaching files and observations made in anatomic specimens. RESULTS: The discussed conditions include de Quervain tenosynovitis, intersection syndrome, and Wartenberg syndrome. Sonographic diagnosis of these conditions is addressed, and correlations are provided with anatomic specimens. CONCLUSIONS: Sonography is able to depict and differentiate between these conditions.

The impact of interactive, computerized educational modules on preclinical medical education.

Interactive computerized modules have been linked to improved retention of material in clinical medicine. This study examined the effects of a new series of interactive learning modules for preclinical medical education, specifically in the areas of quiz performance, perceived difficulty of concepts, study time, and perceived stress level. We randomly allocated 102 medical student volunteers into control and experimental groups. All participants studied selected anatomical and physiologic concepts using existing material (lecture notes, textbooks, etc.), while those in the experimental groups used the new interactive modules as well. All participants completed a quiz to test their knowledge of the assigned concepts and a survey to assess their subjective experiences in studying with the modules. We found a trend toward higher quiz scores in the experimental group relative to the control group, though it did not reach statistical significance (P = 0.31). Perceived concept difficulty was significantly reduced among those who studied with the modules (P < 0.001), and the number of hours spent studying the concepts was significantly increased (P = 0.028). Of those who used the modules, 83% rated them as "very helpful" or "extremely helpful." No significant differences existed between participants' reported stress levels during the course of the study (P = 0.44). Our data suggest that medical students may learn more effectively and feel less intimidated by difficult concepts when interactive modules supplement traditional instruction.

Sonography of inguinal region hernias.

OBJECTIVE: The purpose of this article is to describe the anatomy of the inguinal region in a way that is useful for sonographic diagnosis of inguinal region hernias, and to illustrate the sonographic appearance of this anatomy. We show sonographic techniques for evaluating inguinal, femoral, and spigelian hernias and include surgically proven examples. CONCLUSION: Understanding healthy inguinal anatomy is essential for diagnosing inguinal region hernias. Sonography can diagnose and differentiate between various inguinal region hernias.

Embryonic origin of the caudal mesenteric artery in the mouse.

It is commonly held that the caudal mesenteric artery (CaMA, or inferior mesenteric artery in humans) arises in the same manner as the celiac and cranial mesenteric artery (CrMA, or superior mesenteric artery in humans), i.e., from the remodeling of the vitelline system of arteries that surrounds and supports the yolk sac. Conflicting evidence about the precise manner in which the CaMA arises was presented in studies of the luxate syndrome (Carter: J. Genet. 1954;52:1-35) and sirenomelia (Schreiner and Hoornbeek: J. Morphol. 1973;141:345-358) in the mouse. These studies suggested that the CaMA arises from the remodeling of the medial umbilical arterial roots. Later studies of blood vessel development in the hindlimb of the Dominant hemimelic mouse (Gest: Anat. Rec. 1984;208:296; Anat. Rec. 1987;218:49A; Gest and Roden: Anat. Rec. 1988;220:37-38A) also supported the results of the previous studies. The present investigation tests the hypothesis that the CaMA arises as a result of the regression and remodeling of the medial umbilical arterial roots. Vascular corrosion casts of 9.5-13.5-day-old mouse embryos were observed by scanning electron microscopy (SEM). The results of the present investigation agree with the aforementioned studies. The medial umbilical roots initially conduct the blood to the placenta. On days 10-12 the medial umbilical roots regress and remodel into the CaMA, while the lateral umbilical roots take over the blood supply to the placenta. On the basis of our results, we conclude that the CaMA arises from the medial umbilical roots and not from the remodeling of the vitelline system of arteries, as previously assumed.