The External Oblique Intercostal Block: Anatomic Evaluation and Case Series.

STUDY OBJECTIVE: We report a modified block technique aimed at obtaining upper midline and lateral abdominal wall analgesia: the external oblique intercostal (EOI) block. DESIGN: A cadaveric study and retrospective cohort study assessing the potential analgesic effect of the EOI block. SETTING: Cadaver lab and operating room. PATIENTS: Two unembalmed cadavers and 22 patients. INTERVENTIONS: Bilateral ultrasound-guided EOI blocks on cadavers with 29 mL of bupivacaine 0.25% with 1 mL of India ink; single-injection or continuous EOI blocks in patients. MEASUREMENTS: Dye spread in cadavers and loss of cutaneous sensation in patients. MAIN RESULTS: In the cadaveric specimens, we identified consistent staining of both lateral and anterior branches of intercostal nerves from T7 to T10. We also found consistent dermatomal sensory blockade of T6-T10 at the anterior axillary line and T6-T9 at the midline in patients receiving the EOI block. CONCLUSIONS: We demonstrate the potential mechanism of this technique with a cadaveric study that shows consistent staining of both lateral and anterior branches of intercostal nerves T7-T10. Patients who received this block exhibited consistent dermatomal sensory blockade of T6-T10 at the anterior axillary line and T6-T9 at the midline. This block can be used in multiple clinical settings for upper abdominal wall analgesia.

External Approach to Buccal Fat Excision in Facelift: Anatomy and Technique.

BACKGROUND: Masculinization of the face is a common finding in facelift patients. It is attributed to deflation and decent of the midface-jowls coupled with skin laxity. Fullness is evident lateral to the jowl in a small percentage due to prominent buccal fat pad (BFP). OBJECTIVES: The authors sought to examine the anatomy of the BFP, triangulate the prominent BFP with surgical landmarks, and describe an external approach to excise the BFP during facelift surgery. METHODS: Eighteen cadaveric dissections were performed. Facelift flap was elevated and the prominent buccal extension of the BFP protruding through the superficial-musculo-aponeurotic-system was identified. Measurements were taken from the BFP to surgical landmarks: zygomatic arch, tragus, and gonial angle. The locations of the facial nerve, parotid duct, and vascular pedicle relative to the BFP were calculated. RESULTS: BFP was 4.1 cm inferior to the zygomatic arch, 7.5 cm anterior the tragus, and 4.5 cm medial the gonial angle. The middle facial artery supplied the BFP on the inferior-lateral quadrant in 61% and inferior-medial quadrant in 39% of specimens . In all specimens, the parotid duct traversed the BFP superiorly, and the buccal branches of the facial nerve traversed the capsule superficially. CONCLUSIONS: The buccal extension of the BFP can pseudoherniate in the aging face. Excision may improve lower facial contour. Measurements from facial landmarks may help surgeons identify the buccal extension of the BFP intraoperatively. The surgeon must be careful of the vascular pedicle, parotid duct, and the facial nerve. The external approach safely excises buccal fat during facelift dissection while avoiding intraoral incisions and unnecessary contamination.

Discovery of a sensory organ that coordinates lunge feeding in rorqual whales.

Top ocean predators have evolved multiple solutions to the challenges of feeding in the water. At the largest scale, rorqual whales (Balaenopteridae) engulf and filter prey-laden water by lunge feeding, a strategy that is unique among vertebrates. Lunge feeding is facilitated by several morphological specializations, including bilaterally separate jaws that loosely articulate with the skull, hyper-expandable throat pleats, or ventral groove blubber, and a rigid y-shaped fibrocartilage structure branching from the chin into the ventral groove blubber. The linkages and functional coordination among these features, however, remain poorly understood. Here we report the discovery of a sensory organ embedded within the fibrous symphysis between the unfused jaws that is present in several rorqual species, at both fetal and adult stages. Vascular and nervous tissue derived from the ancestral, anterior-most tooth socket insert into this organ, which contains connective tissue and papillae suspended in a gel-like matrix. These papillae show the hallmarks of a mechanoreceptor, containing nerves and encapsulated nerve termini. Histological, anatomical and kinematic evidence indicate that this sensory organ responds to both the dynamic rotation of the jaws during mouth opening and closure, and ventral groove blubber expansion through direct mechanical linkage with the y-shaped fibrocartilage structure. Along with vibrissae on the chin, providing tactile prey sensation, this organ provides the necessary input to the brain for coordinating the initiation, modulation and end stages of engulfment, a paradigm that is consistent with unsteady hydrodynamic models and tag data from lunge-feeding rorquals. Despite the antiquity of unfused jaws in baleen whales since the late Oligocene (∼23-28 million years ago), this organ represents an evolutionary novelty for rorquals, based on its absence in all other lineages of extant baleen whales. This innovation has a fundamental role in one of the most extreme feeding methods in aquatic vertebrates, which facilitated the evolution of the largest vertebrates ever.

Continuous Positive Airway Pressure Thresholds for Nasolacrimal Air Regurgitation in a Cadaveric Model.

PURPOSE: To elucidate the mechanisms underlying nasolacrimal air regurgitation (AR) in the setting of continuous positive airway pressure therapy. METHODS: Twelve nasolacrimal systems of 6 fresh female human cadavers were evaluated individually for AR using continuous positive airway pressure therapy before any nasolacrimal procedure. Cadavers were then randomly assigned to undergo nasolacrimal duct probing or endoscopic dacryocystorhinostomy and then each hemisystem was again evaluated for AR. The pressure where AR was first observed (discovery pressure) or maximum possible pressure in systems without AR was recorded. In systems that demonstrated AR, the pressure was then gradually decreased to the lowest pressure where regurgitation persisted. This pressure was recorded as the secondary threshold pressure. RESULTS: None of the 12 unoperated nasolacrimal systems or the 6 systems that underwent nasolacrimal duct probing demonstrated AR through the maximum continuous positive airway pressure therapy (30 cm H2O). After endoscopic dacryocystorhinostomy, all 6 nasolacrimal systems demonstrated AR. The mean discovery pressure was 16.0 cm H2O (range, 14.0-18.0 cm H2O) and mean secondary threshold pressure was 7.25 cm H2O (range, 6.5-8.0 cm H2O). CONCLUSIONS: Air regurgitation during continuous positive airway pressure therapy in the setting of prior endoscopic dacryocystorhinostomy can be replicated in a cadaver model. The secondary threshold pressures required for AR in this model were similar to AR pressures reported clinically. Prior to dacryocystorhinostomy, patients using continuous positive airway pressure therapy should be counseled on AR, and physicians should consider this phenomenon when evaluating ophthalmic complaints in postoperative patients on positive airway pressure therapy.

Injectate spread following anterior sub-costal and posterior approaches to the quadratus lumborum block: A comparative cadaveric study.

BACKGROUND: The dermatomal level of analgesia achieved with quadratus lumborum blocks varies according to the location of injection. The most commonly used approaches are either at the postero-lateral aspect or anterior to the quadratus lumborum muscle. OBJECTIVE: To determine whether the site of injection of contrast dye around the quadratus lumborum muscle of cadavers affects the extent and mechanism of dye spread. DESIGN: Observational human cadaver study. SETTING: Cleveland Clinic cadaveric laboratory. PARTICIPANTS: Six fresh human cadavers. INTERVENTIONS: The cadavers received either a posterior quadratus lumborum block or an anterior subcostal quadratus lumborum block on each side. MAIN OUTCOME MEASURES: Cadavers were dissected to determine the extent of dye spread. RESULTS: The posterior quadratus lumborum block approach revealed consistently deep staining of the iliohypogastric, ilioinguinal, subcostal nerve, T11 to 12 and L1 nerve roots. In addition, staining of the middle thoracolumbar fascia was seen in all specimens but only variable staining of T10 nerve roots. The anterior subcostal quadratus lumborum block approach in all specimens demonstrated predictable deep staining of the iliohypogastric and ilioinguinal nerves, subcostal nerves, T11 to 12 and L1 nerve roots, and in addition traversing the arcuate ligaments to involve T9 to 12 nerve roots with variable staining of higher thoracic nerve roots. CONCLUSIONS: Our cadaveric study demonstrates that injection of dye on the posterior aspect of quadratus lumborum muscle led to injectate spread through the lateral and posterior abdominal wall but with limited cranial spread, whereas the anterior approach produced broader coverage of the lower to mid-thoracic region. Clinical translation of these findings to determine the practical significance is warranted.

The Simultaneous Use of Breast Reduction and Internal Mammary Artery Perforator Flap in Sternal Wound Reconstruction.

Internal mammary artery perforator (IMAP)-based fasciocutaneous flaps have recently gained popularity in sternal wound reconstruction due to their decreased donor site morbidity. However, patients with significant macromastia or who are obese present a challenge when using these flaps due to their anatomy and associated comorbid conditions. Despite the prevalence of this population, there is a relative paucity of data on the use of local fasciocutaneous flaps and techniques to close sternotomy wounds in the obese population with hypertrophic or ptotic breasts. The authors describe a novel technique using simultaneous unilateral breast reduction with a fifth intercostal IMAP-based flap for closure of a median sternotomy wound through a case presentation, an anatomical injection study, and review of the literature. Five fresh female cadavers were used to conduct 8 trials of injection of the IMAP arteries, isolation of the fifth IMAP branch, and elevation of a local flap. The literature was comprehensively reviewed with a total of 33 cases of IMAP flaps for sternal reconstruction being described. The most commonly used perforators with the second and sixth IMAPs. Overall complication rate was reported to be 9.1% (3/33), with 2 cases reporting dehiscence and 1 with flap tip necrosis. No cases reported use of the fifth IMAP or formal breast reduction procedures, which was successfully performed in a 40-year-old diabetic female patient history of multiple left-sided thoracic surgeries and radiation with a chronic sternal wound.

Longitudinal cohort study on medical student retention of anatomical knowledge in an integrated problem-based learning curriculum.

BACKGROUND: When modifying a curriculum to accommodate changes in the methods of subject matter presentation or fit within a shortened time frame, student retention of knowledge remains an important issue. AIM: This study evaluates medical student retention of anatomical knowledge as they matriculate through an anatomy curriculum where the instruction hours are less than half of the current national average. METHOD: Medical students completed an assessment tool developed to evaluate their baseline level of anatomical knowledge at the beginning of the first year. They then completed the instrument at the end of their 1st, 2nd, 3rd, and 4th years to assess their retention of anatomical knowledge during medical school. Data collection began in September 2010 and concluded in June 2015. RESULTS: Results demonstrate that students began medical school with a low level of anatomical knowledge (baseline), that knowledge increased during their first year (p < 0.001), continued to increase during their second year (p < 0.001), but was over 90% maintained through years 3 and 4. CONCLUSION: In conclusion, an anatomy course with reduced hours (∼60), using active learning methods, contextual learning, cadaver demonstrations, increased exposure to imaging, and longitudinal reinforcement can help students build a strong foundation of anatomical knowledge.

Microsurgical Anatomy of the Terminal Hypoglossal Nerve Relevant for Neurostimulation in Obstructive Sleep Apnea.

BACKGROUND: Neurostimulation of the hypoglossal nerve has shown promising results in the treatment of obstructive sleep apnea. This anatomic study describes the detailed topography of the hypoglossal nerve's motor points as a premise for super-selective neurostimulation in order to optimize results and minimize the risk of complications related to main nerve trunk manipulation. METHODS: Thirty cadaveric hypoglossal nerves were dissected and characterized by number of branches, arborization pattern, and terminal branch motor point location. For each motor point, the distance to cervical midline (x axis), distance to posterior aspect of the symphysis (y axis), and depth from the plane formed by the inferior border of symphysis and anterior border of hyoid (z axis) were recorded. RESULTS: The average number of distal branches for each hypoglossal nerve was found to be 9.95 ± 2.28. The average number of branches per muscle was found to be 3.3 ± 1.5 for the hyoglossus muscle, 1.8 ± 0.9 for the geniohyoid muscle, and 5.0 ± 1.6 for the genioglossus muscle. It was found that branches to the genioglossus and geniohyoid muscles were located closer to midline (relative lengths of 0.19 ± 0.07 and 0.19 ± 0.05, respectively) while hyoglossus branches were located more laterally (0.38 ± 0.10 relative length). On the y-axis, the branches to the genioglossus were the most anterior and therefore closest to the posterior symphysis of the mandible (relative length of 0.48 ± 0.11), followed by the geniohyoid (0.66 ± 0.09), and the hyoglossus (0.76 ± 0.16). The branches to the geniohyoid were the most superficial (relative length of 0.26 ± 0.06), followed by the genioglossus (0.36 ± 0.09), and finally, the hyoglossus branches (0.47 ± 0.11), which were located deeply. CONCLUSION: A topographical map of the hypoglossal nerve terminal motor points was successfully created and could provide a framework for the optimization of the neurostimulation techniques.

A retrospective and prospective look at medical education in the United States: trends shaping anatomical sciences education.

During the last decade of the 20th century and the first decade of the 21st century, curricular reform has been a popular theme. In fact, reform on the current scale has not occurred since the early 1900s, when Abraham Flexner released his landmark report 'Medical Education in the United States and Canada'. His report, suggesting major changes in how physicians were educated, became the norm and few changes occurred until the last quarter of the 20th century. During this period increased demands on medical school curriculums due to the explosion of knowledge in biomedical sciences and the pressure to add additional clinical experiences increased the momentum for curriculum reform. In 1984 an Association of American Medical Colleges (AAMC) report, 'Physicians for the Twenty-First Century: The Report of the Panel on the General Professional Education of the Physician (GPEP) and College Preparation for Medicine', discussed many items related to reforming medical education including the value of integration, increased use of active learning formats, more self-directed learning, improved communication skills and increased problem-solving activities. This was followed by a report released in 1993 entitled 'Educating Medical Students: Assessing Change in Medical Education - The Road to Implementation' (ACME-TRI), which identified educational problems by surveying medical school deans, suggested ways to deal with these issues and presented a plan of action. Recently, the Carnegie Foundation for the Advancement of Teaching released 'Education Physicians: A Call for Reform of Medical School and Residency' with additional suggestions. At this point the question that might be asked is - Where is all this going and how is it going to affect anatomy education?

International association for the study of lung cancer (IASLC) lymph node map: radiologic review with CT illustration.

Accurate clinical or pretreatment stage classification of lung cancer leads to optimal treatment outcomes and improved prognostication. Such classification requires an accurate assessment of the clinical extent of regional lymph node metastasis. Consistent and reproducible regional lymph node designations facilitate reliable assessment of the clinical extent of regional lymph node metastasis. Regional lymph node maps, such as the Naruke lymph node map and the Mountain-Dresler modification of the American Thoracic Society lymph node map, were proposed for this purpose in the past. The most recent regional lymph node map to be published is the International Association for the Study of Lung Cancer (IASLC) lymph node map. The IASLC lymph node map supersedes all previous maps and should be used in tandem with the current seventh edition of the tumor, node, metastasis stage classification for lung cancer.

A failsafe method to avoid injury to the great auricular nerve.

BACKGROUND: The great auricular nerve (GAN) is the most commonly injured nerve during facelift surgery. Although rare, injury can result in long-term sequelae. OBJECTIVES: Previous reports have described the nerve's location at the midbelly of the sternocleidomastoid muscle (SCM) or at its emergence from underneath the SCM. The purpose of our study was to identify the superior course of the great auricular nerve as it applies to facelift. METHODS: Thirteen fresh cadavers were dissected. A vertical line through the midlobule was drawn perpendicular to the Frankfort's horizontal, acting as a reference to the course of the GAN. Transparent paper overlay tracings were then done to record each nerve's location. The distance from the bony external auditory canal (EAC) to the nerve was measured at the anterior muscle border, at the midbelly of the SCM, and as the nerve emerged from under the SCM. Branching patterns of the nerve and its relation to the external jugular vein were identified. RESULTS: In 100% of the dissections, the superior course of the GAN fell within a 30-degree angle constructed using the vertical limb perpendicular to the Frankfurt horizontal and a second limb drawn posteriorly from the midlobule. The distance from the EAC to the nerve was 4.9 ± 1.1 cm at the anterior muscle border, 7.3 ± 1.0 cm at the midbelly of the SCM, and 9.8 ± 1.2 cm at the GAN's emergence from under the SCM. Four types of branching patterns were identified. CONCLUSIONS: The 30-degree angle described above rapidly and accurately identifies the nerve's location.

Cervical erector spinae plane block: a cadaver study.

BACKGROUND: Cervical erector spinae plane (ESP) block has been described to anesthetize the brachial plexus (BP), however, the mechanism of its clinical effect remains unknown. As the prevertebral fascia encloses the phrenic nerves, BP and erector spinae muscles to form a prevertebral compartment, a local anesthetic injected in the cervical ESP could potentially spread throughout the prevertebral compartment. This study utilizes cadaveric models to evaluate the spread of ESP injections at the C6 and C7 levels to determine whether the injection can reach the BP and its surrounding structures. METHODS: For each of the five cadavers, an ESP injection posterior to the transverse process of C6 was performed on one side, and an ESP injection posterior to the transverse process of C7 was performed on the contralateral side. Injections were performed under ultrasound guidance and consisted of a 20 mL mixture of 18 mL water and 2 mL India ink. After cadaver dissection, craniocaudal and medial-lateral extent of the dye spread in relation to musculoskeletal anatomy as well as direct staining relevant nerves was recorded. The degree of dye staining was categorized as "deep," "faint," or "no." RESULTS: The phrenic nerve was deeply stained in 1 injection and faintly stained in 2 injections. Caudally, variable staining of C8 (100%) and T1 (50%) roots were seen. Faintly staining at C4 root was only seen in one sample (10%). There was variable staining of the anterior scalene muscles (40%) anterior to the BP and the rhomboid intercostal plane caudally (30%). CONCLUSIONS: Ultrasound-guided cervical (C6 and C7) ESP injections consistently stain the roots of the BP and dorsal rami. This study supports the notion that the cervical ESP block has the potential to provide analgesia for patients undergoing shoulder and cervical spine surgeries.

Full Facial Allotransplantation Including the Temporomandibular Joints: A Radiologic and Anatomical Cadaveric Study.

BACKGROUND: Facial allotransplantation including the temporomandibular joints may improve the functional outcomes in face transplant candidates who have lost or damaged this joint. METHODS: Linear and angular measurements were taken in 100 dry skulls and mandibles and in 100 three-dimensionally-reconstructed facial computed tomographic scans to determine the variability of the temporomandibular joint, glenoid fossa, and mandible. A vascular study was performed in six fresh cadaveric heads, followed by harvest of the face allograft in three heads. Next, four heads were used for mock transplantation (two donors and two recipients). The full facial allograft included four different segments: a Le Fort III, a mandibular tooth-bearing, and two condyle and temporomandibular joint-bearing segments. Statistical analysis was performed using SAS software. RESULTS: In only one-third of the skulls, the condylar shape was symmetric between right and left sides. There was a wide variability in the condylar coronal (range, 14.3 to 23.62 mm) and sagittal dimensions (range, 5.64 to 10.96 mm), medial intercondylar distance (range, 66.55 to 89.91 mm), and intercondylar angles (range, 85.27 to 166.94 degrees). This high variability persisted after stratification by sex, ethnicity, and age. The temporomandibular joint was harvested based on the branches of the superficial temporal and maxillary arteries. The design of the allograft allowed fixation of the two condyle and temporomandibular joint-bearing segments to the recipient skull base, preserving the articular disk-condyle-fossa relationship, and differences were adjusted at the bilateral sagittal split osteotomy sites. CONCLUSION: Procurement and transplantation of a temporomandibular joint-containing total face allograft is technically feasible in a cadaveric model.

The use of simulation in medical education to enhance students' understanding of basic sciences.

Simulation! The deans talk about its use in medical education regularly. But how can it be used to teach the basic sciences to first- and second-year medical students? This article will help answer that question by providing information about various types of simulation activities being used in medical education and examples of their application to basic science education. The next step depends on your creativity.

Comparing two posterior quadratus lumborum block approaches with low thoracic erector spinae plane block: an anatomic study.

BACKGROUND AND OBJECTIVES: Both posterior quadratus lumborum (QL) and erector spinae plane (ESP) blocks have been described as new truncal interfascial plane blocks. Distribution of injectate is influenced by fascial anatomy; therefore, different injection sites may produce similar spread. This anatomic study was designed to test the hypothesis that a posteromedial QL block at L2 level will more closely resemble a low thoracic ESP block when compared with the posterolateral approach at L2 level. METHODS: Left-sided ESP blocks were performed in six cadavers at T10-11. Three of these cadavers received right-sided posteromedial QL block at L2, while the other three received right-sided posterolateral QL block at L2. All injections were composed of 20 mL methylcellulose 0.5 % mixed with India ink and 10 mL of Omnipaque (Iohexol) 240 mg/mL. CT 24 hours after injection and cadaver dissection were used to evaluate injectate spread. RESULTS: Cephalocaudal spread of injectate by CT and cadaveric dissection was highly correlated (r=0.85 [95% CI 0.51 to 0.95]). Cadaver dissection showed ESP injectate spread deep to the muscle (mean [SD]) 11.7 (2.3) levels compared with 7.3 (1.2) levels for posterolateral QL and 9.7 (1.5) for posteromedial QL (p=0.04 overall, with a statistically significant pairwise difference between ESP and posterolateral QL only). The subcostal nerve and dorsal rami were commonly involved in most blocks, but the paravertebral space and ventral rami had inconsistent involvement. The lumbocostal ligament limited cranial spread from the posterlateral QL block approach. CONCLUSIONS: The posteromedial QL block at L2 produces more cranial spread beyond the lumbocostal ligament than the posterolateral QL block, and this spread is comparable with a low thoracic ESP block. Both posterior QL and ESP blocks show unreliable spread of injectate to the paravertebral space and ventral rami, but the dorsal rami were frequently covered.

Regurgitation and pulmonary aspiration during cardio-pulmonary resuscitation (CPR) with a laryngeal tube: A pilot crossover human cadaver study.

BACKGROUND: High-quality chest compressions are imperative for Cardio-Pulmonary-Resuscitation (CPR). International CPR guidelines advocate, that chest compressions should not be interrupted for ventilation once a patient's trachea is intubated or a supraglottic-airway-device positioned. Supraglottic-airway-devices offer limited protection against pulmonary aspiration. Simultaneous chest compressions and positive pressure ventilation both increase intrathoracic pressure and potentially enhances the risk of pulmonary aspiration. The hypothesis was, that regurgitation and pulmonary aspiration is more common during continuous versus interrupted chest compressions in human cadavers ventilated with a laryngeal tube airway. METHODS: Twenty suitable cadavers were included, and were positioned supine, the stomach was emptied, 500 ml of methylene-blue-solution instilled and laryngeal tube inserted. Cadavers were randomly assigned to: 1) continuous chest compressions; or, 2) interrupted chest compressions for ventilation breaths. After 14 minutes of the initial designated CPR strategy, pulmonary aspiration was assessed with a flexible bronchoscope. The methylene-blue-solution was replaced by 500 ml barium-sulfate radiopaque suspension. 14 minutes of CPR with the second designated ventilation strategy was performed. Pulmonary aspiration was then assessed with a conventional chest X-ray. RESULTS: Two cadavers were excluded for technical reasons, leaving 18 cadavers for statistical analysis. Pulmonary aspiration was observed in 9 (50%) cadavers with continuous chest compressions, and 7 (39%) with interrupted chest compressions (P = 0.75). CONCLUSION: Our pilot study indicate, that incidence of pulmonary aspiration is generally high in patients undergoing CPR when a laryngeal tube is used for ventilation. Our study was not powered to identify potentially important differences in regurgitation or aspiration between ongoing vs. interrupted chest compression. Our results nonetheless suggest that interrupted chest compressions might better protect against pulmonary aspiration when a laryngeal tube is used for ventilation.

Nonuniform pressure generation in the optic chiasm may explain bitemporal hemianopsia.

PURPOSE: To measure the pressure in the temporal and central aspects of the chiasm simultaneously during compression of the optic chiasm from below with an expanding simulated tumor. DESIGN: Experimental study. METHODS: Craniotomies were performed on 5 unfixed cadaveric specimens ranging in age from 49 to 89 years, and the optic chiasm was exposed. After a pediatric gauge Foley catheter was inserted into the sellar region, the temporal side of the chiasm (temporal aspect uncrossed fibers) was impaled with a 30-gauge needle connected to a pressure transducer. In like fashion, the central portion of the chiasm (crossed fibers) was impaled with another 30-gauge needle connected to a pressure transducer on a separate channel. The Foley catheter was inflated for a period of 30 seconds to 1 minute and the pressure in each channel continuously monitored. Multiple trials were performed on each of the 5 specimens. MAIN OUTCOME MEASURE: Pressure change between the temporal and nasal aspects of the optic chiasm. RESULTS: In all cases in which intrachiasmal pressure could be measured, higher pressures were always generated in the central aspect of the chiasm than in the temporal aspect of the chiasm. In cadaver 1, the mean central pressure was 19.75 mmHg, whereas the mean temporal pressure was 6 mmHg. In cadaver 5, the mean central pressure was 4 mmHg, whereas the mean temporal pressure was zero. Donors 70 and older demonstrated abnormally thin and frail chiasms that were unable to support a sustained pressure increase during simulated tumor expansion. CONCLUSIONS: During deformation of the optic chiasm from below by a radially expanding mass analogous to a pituitary tumor, the central aspect of the optic chiasm consistently manifests a higher pressure than the temporal aspect. It is hypothesized that the peculiar geometry of the optic chiasm renders the crossing nasal fibers more prone to a deformation stress exerted from below. Nonuniform pressure generation between the central and temporal aspects of the chiasm results in a greater effective stress on the crossing fibers of the chiasm and may be responsible for the clinical phenomenon of bitemporal hemianopsia.

National survey on anatomical sciences in medical education.

The drivers for curricular change in medical education such as the addition of innovative approaches to teaching, inclusion of technology and adoption of different assessment methods are gaining momentum. In an effort to understand how these changes are impacting and being implemented in gross anatomy, microscopic anatomy, neuroanatomy/neuroscience, and embryology courses, surveys were sent out to course directors/discipline leaders at allopathic Medical Schools in the United States during the 2016-2017 academic year. Participants in the study were asked to comment on course hours, student experiences in the classroom and laboratory, amount of faculty participation, the use of peers as teachers in both the classroom and laboratory, methods used for student assessment and identification of best practices. Compared to data published from a similar survey in 2014, a number of changes were identified: (1) classroom hours in gross anatomy increased by 24% and by 29% in neuroanatomy/neuroscience; (2) laboratory hours in gross anatomy decreased by 16%, by 33% in microscopic anatomy, and by 38% in neuroanatomy/neuroscience; (3) use of virtual microscopy in microscopic anatomy teaching increased by 129%; and (4) the number of respondents reporting their discipline as part of a partially or fully integrated curriculum increased by greater than 100% for all four disciplines. Anat Sci Educ 11: 7-14. © 2017 American Association of Anatomists.

Rhomboid Intercostal and Subserratus Plane Block: A Cadaveric and Clinical Evaluation.

BACKGROUND AND OBJECTIVES: Fascial plane blocks are rapidly emerging to provide safe, feasible alternatives to epidural analgesia for thoracic and abdominal pain. We define a new option for chest wall and upper abdominal analgesia, termed the rhomboid intercostal and subserratus plane (RISS) block. The RISS tissue plane extends deep to the erector spinae muscle medially and deep to the serratus anterior muscle laterally. We describe a 2-part proof-of-concept study to validate the RISS block, including a cadaveric study to evaluate injectate spread and a retrospective case series to assess dermatomal coverage and analgesic efficacy. METHODS: For the cadaveric portion of the study, bilateral ultrasound-guided RISS blocks were performed on 6 fresh cadavers with 30 mL of 0.5% methylcellulose with india ink. For the retrospective case series, we present 15 patients who underwent RISS block or RISS catheter insertion for heterogeneous indications including abdominal surgery, rib fractures, chest tube-associated pain, or postoperative incisional chest wall pain. RESULTS: In the cadaveric specimens, we identified staining of the lateral branches of the intercostal nerves from T3 to T9 reaching the posterior primary rami deep to the erector spinae muscle medially. In the clinical case series, dermatomal coverage was observed in the anterior hemithorax with visual analog pain scores less than 5 in patients who underwent both single-shot and continuous catheter infusions. CONCLUSIONS: Our preliminary cadaveric and clinical data suggest that RISS block anesthetizes the lateral cutaneous branches of the thoracic intercostal nerves and can be used in multiple clinical settings for chest wall and upper abdominal analgesia.

Procurement of Extended Vascularized Skin Flaps from the Donor Enables Hand Transplantation in Severe Upper Extremity Burns: An Anatomical Study.

BACKGROUND: Hand transplantation in patients with severe upper extremity burns can be associated with an increased risk of exposure of vessels, tendons, and nerves because of extensive skin and soft-tissue deficit. This study evaluated how to reliably transfer additional extended skin flaps with a standard hand allograft. METHODS: Twenty-five upper extremities were used. Sixteen were injected with latex to map the perforating branches of the brachial, superior ulnar collateral, radial, ulnar, and posterior interosseous arteries. Nine hand allografts were procured, injected with blue ink through the brachial artery to assess the perfusion of the skin flaps, and then mock transplanted. RESULTS: Sizable perforators from the brachial, superior ulnar collateral, radial, ulnar, and posterior interosseous arteries were used to augment the vascularization of the skin flaps. The average stained area of the medial arm flap was between 85.7 and 93.9 percent. The stained area of the volar forearm flap was the smallest when based on perforators within 6 cm from the wrist crease (51.22 percent). The dorsal forearm flap showed the least amount of staining (34.7 to 46.1 percent). The average time to repair tendons, nerves, and vessels was longer when a single volar forearm-arm flap was harvested (171.6 minutes). Harvest of the allograft associated with a distally based forearm flap and islanded arm flap was the fastest (181.6 ± 17.55 minutes). CONCLUSION: Extended skin flaps, based on perforators of the main axial vessels, can be reliably transplanted with a standard hand allograft based on the brachial or axillary vascular pedicle.