Sherry A. Downie

Innervation of the levator ani muscles: description of the nerve branches to the pubococcygeus, iliococcygeus, and puborectalis muscles

We described the innervation of the levator ani muscles (LAM) in human female cadavers. Detailed pelvic dissections of the pubococcygeus (PCM), iliococcygeus (ICM), and puborectalis muscles (PRM) were performed on 17 formaldehyde-fixed cadavers. The pudendal nerve and the sacral nerves entering the pelvis were traced thoroughly, and nerve branches innervating the LAM were documented. Histological analysis of nerve branches entering the LAM confirmed myelinated nerve tissue. LAM were innervated by the pudendal nerve branches, perineal nerve, and inferior rectal nerve (IRN) in 15 (88.2%) and 6 (35.3%) cadavers, respectively, and by the direct sacral nerves S3 and/or S4 in 12 cadavers (70.6%). A variant IRN, independent of the pudendal nerve, was found to innervate the LAM in seven (41.2%) cadavers. The PCM and the PRM were both primarily innervated by the pudendal nerve branches in 13 cadavers (76.5%) each. The ICM was primarily innervated by the direct sacral nerves S3 and/or S4 in 11 cadavers (64.7%).

Impact of cadaver dissection: working toward solutions.

Netterstrom and Kayser’s study (2008), ‘‘Learning to be adoctor while learning anatomy,’’ beautifully documents a classicproblem in medical education: the adverse impact that tradi-tional dissection of the cadaver has had on students’ professio-nal development. In their study, medical students report that‘‘faculty donotencouragecommonreflectionontheexperi-ence ...asaconsequence,studentslearn ...toendureandtocontrol and master anatomy and feelings alone ...cop(ing)by detaching themselves from the experience ...they onlyfocus on finding the anatomic structures they have learnedabout ...separated and isolated from everyday life ...learn(ing)tobe ...cold ...’’(NetterstromandKayser,2008).At the Albert Einstein College of Medicine in the Bronx,anatomists and clinicians have collaborated to harness thepower of this rite of passage and effectively use it to trans-form impressionable young students into physicians who canmore fully care for patients.In the anatomy course at Albert Einstein College of Medi-cine, general internists and family practitioners have beenrecruited to join the Generalist Physician Anatomy Faculty(GPAF) Program. The goal of this program is to promote aclinically relevant patient-centered approach to learning anat-omy by having practicing physicians help students appreciatethe unique humanness of the person who once possessed thephysical remains that are being examined and exploredthrough dissection (Richardson, 2000; Francis and Lewis,2001).The GPAF Program begins with the students’ first encounterwith the cadaver. The generalist physician brings her or his stu-dent team into the dissection lab and introduces them to theircadaver. Together, students and physician perform a physicalexamination of the completely nude supine cadaver. Modelingcomfort with comprehensive care of the whole patient, the phy-sician facilitates discussion of the divergent feelings that the dis-section and the care of patients evoke: close human connection,alternating with objective professional distance (Lachman andPawlina, 2006; Montross, 2007; Arraez-Aybar et al., 2008).Over the course of the full dissection, the GPAFs help studentsfocus on variation and pathology, alongside normal anatomy,and teach them to engage in clinical reasoning as they identifyfindings. They work with students to develop hypotheses aboutthe disease and how the observed conditions may have im-pacted the daily activities, medical care, and end-of-life issuesof the person when he or she was alive (Marks et al., 2007).Throughout the anatomy dissection course the GPAF interactwith their students via on-line discussions (Grinspan et al., 2007)and three face-to-face meetings. It has been our experience thatthecorevalueoftheGPAF programisfoundin thegeneralistphy-sician–student relationship that develops through these interac-tions and meetings. This unique relationship not only motivatesstudents to learn patient-centered clinical anatomy but also whetstheir appetite for the time when they will actually care for the liv-ingwhocangivehistoriesthatputphysicalfindingsintocontext.

Nerve injury during uterosacral ligament fixation: a cadaver study

Introduction and hypothesisThe objective of this study was to identify nerve(s) vulnerable to entrapment during uterosacral ligament fixation (USLF), which could cause postoperative lower extremity pain previously described in the literature.MethodsPreserved cadavers in a medical anatomy course were used. Before the students’ pelvic dissections, a 2-0 prolene suture was placed in the middle third of each left uterosacral ligament visualized. The sutures were re-evaluated at the end of the course.ResultsNine sutures remained in place after the course, and one entrapped a nerve. It was part of the inferior hypogastric plexus, included fibers from S2 and S3, and radiated to the bladder and rectum. The posterior femoral cutaneous nerve was lateral and posterior to this nerve.ConclusionsThe inferior hypogastric plexus is vulnerable during USLF. Entrapment of S2 and S3 fibers could cause pain in their respective dermatomes and could be responsible for the postoperative pain previously described.

Safe and successful bone marrow biopsy: an anatomical and CT-based cadaver study.

Bone marrow biopsy is generally a safe procedure. However, infrequently the procedure is associated with serious injuries that are attributed to inadvertent needle penetration of the iliac bones inner cortex. An evidence‐based approach to needle orientation during iliac crest biopsy does not exist. In our study, the posterior to anterior path of the bone marrow needle from the posterior superior iliac spine (PSIS) was studied in human cadavers in two orientations: (1) perpendicularly to the coronal plane (the perpendicular approach) and (2) laterally toward the ipsilateral anterior superior iliac spine (ASIS) (the lateral approach). The biopsy needle was deliberately advanced through the inner ilial cortex in both approaches. Dissections and imaging studies were done to identify the relationship of the penetrating needle to internal structures. Both approaches begin with a perpendicular puncture of the outer cortex at the PSIS. The perpendicular approach proceeds anteriorly whereas in the lateral approach the needle is reoriented toward the ipsilateral ASIS before advancing. The lateral approach caused less damage to neurovascular structures and avoided the sacroiliac joint compared to the perpendicular approach. This procedure is best done in the lateral decubitus position. Proper use of the lateral approach should obviate many of the complications reported in the literature. Am. J. Hematol. 89:943–946, 2014.

Localization of the Lateral Retinacular Nerve for Diagnostic and Therapeutic Nerve Block for Lateral Knee Pain: A Cadaveric Study

The lateral retinacular nerve (LRN) is a branch of the superior lateral genicular nerve (SLGN) and is believed to contribute to anterolateral knee pain. The precise anatomical pathway of the LRN, however, has not been demonstrated as it relates to the performance of targeted nerve block procedures.

Early and prolonged opportunities to practice suturing increases medical student comfort with suturing during clerkships: Suturing during cadaver dissection: Suturing during Cadaver Dissection

Medical students are expected to perform common procedures such as suturing on patients during their third‐year clerkships. However, these experiences are often viewed by medical students as stressors rather than opportunities for learning. The source of this stress is the lack of instruction on common procedures prior to being asked to observe or perform the procedure on a patient. First‐time exposures to procedures in stressful environments may result in decreased confidence in medical students and decrease the frequency with which they perform these procedures in the future. The authors sought to change this paradigm by: (1) introducing a suturing module to first‐year medical students in the context of the anatomy dissection laboratory and (2) measuring its effects on student attitudes and behavior over the course of their third‐year clerkships when they encounter patients. The authors found that early and prolonged introduction to suturing was associated with increased student confidence relative to suturing a patient. Participation in the suturing module was associated with increased student confidence in identifying suturing instruments (P < 0.001) and suturing patients (P = 0.013). Further it positively affected their behavior as demonstrated by increased performance of suturing events from students exposed to the suturing module. (P < 0.001) This study demonstrates that early and prolonged opportunities to practice a procedural skill in a low‐stress environment increases student confidence during patient interactions and alters student behavior.

Unilateral Complete Agenesis of Mesonephric Duct Derivatives in an 82-year-Old Male Cadaver: Embryology, Anatomy and Clinical Considerations

Development of urogenital anatomy in the human fetus is the result of a complex interplay between multiple different tissues. The time course of development is well documented and the morphologic outcomes of insults at various time points during development are predictable. We present a cadaveric case of unilateral agenesis of the left kidney, ureter, bladder hemitrigone, ureteric opening, seminal vesicle, vas deferens, and epididymis. Failure of development of the mesonephric duct early during embryogenesis, likely between the third and fifth week, caused ipsilateral urogenital organ agenesis.

Lumbar Medial Branch Block Volume-Dependent Dispersion Patterns as a Predictor for Ablation Success: A Cadaveric Study

Lumbar facet arthropathy is a common cause of low back pain. Literature supports treatment with radiofrequency ablation (RFA) of associated nerves that innervate lumbar facets when alternative conservative therapies have failed. Diagnostic local anesthetic blocks precede therapeutic ablation, but have a false‐positive rate of 27%‐63%, and some authors have questioned their utility in predicting therapeutic response to RFA. The authors of the current study believe that injectate volume may be a contributing factor to false positivity.

The Anatomic Relationship of the Tibial Nerve to the Common Peroneal Nerve in the Popliteal Fossa: Implications for Selective Tibial Nerve Block in Total Knee Arthroplasty.

Background. A recently described selective tibial nerve block at the popliteal crease presents a viable alternative to sciatic nerve block for patients undergoing total knee arthroplasty. In this two-part investigation, we describe the effects of a tibial nerve block at the popliteal crease. Methods. In embalmed cadavers, after the ultrasound-guided dye injection the dissection revealed proximal spread of dye within the paraneural sheath. Consequentially, in the clinical study twenty patients scheduled for total knee arthroplasty received the ultrasound-guided selective tibial nerve block at the popliteal crease, which also resulted in proximal spread of local anesthetic. A sensorimotor exam was performed to monitor the effect on the peroneal nerve. Results. In the cadaver study, dye was observed to spread proximal in the paraneural sheath to reach the sciatic nerve. In the clinical observational study, local anesthetic was observed to spread a mean of 4.7 + 1.9 (SD) cm proximal to popliteal crease. A negative correlation was found between the excess spread of local anesthetic and bifurcation distance. Conclusions. There is significant proximal spread of local anesthetic following tibial nerve block at the popliteal crease with possibility of the undesirable motor blocks of the peroneal nerve.

Axillobifemoral Bypass: A Brief Surgical and Historical Review

Peripheral artery disease (PAD) occurs when plaque accumulates in the arterial system and obstructs blood flow. Narrowing of the abdominal aorta and the common iliac arteries due to atherosclerotic plaques restricts blood supply to the lower limbs. Clinically, the lower limb symptoms of PAD are intermittent claudication, discoloration of the toes, and skin ulcers, all due to arterial insufficiency. Surgical revascularization is the primary mode of treatment for patients with severe limb ischemia. The objective of the surgical procedure is to bypass a blockage in an occluded major vessel by constructing an alternate route for blood flow using an artificial graft. This article presents information on aortoiliac reconstruction, with an emphasis on axillobifemoral bypass grafting.