Search PubMed⌕ Search

Biomedical subjects

S W Carmichael

Publications and source records attributed to S W Carmichael.

At least 19 recordsLinked to original sources
PubMed2005

Assessing professionalism in early medical education: experience with peer evaluation and self-evaluation in the gross anatomy course.

INTRODUCTION: As today's healthcare model moves toward more streamlined and corporate industrialism, it is our responsibility, as doctors, to ensure the integrity of medicine's foundation in professionalism. The erosion of professional values not only creates a climate of animosity, but reverberates negatively to impact the development of students, who model their behaviour after those they most respect. This hazard has spurred an evaluation of medical school curricula, with a new emphasis on professionalism in the philosophy of medical education. Courses such as Gross Anatomy that, in the past, offered "pure content," are now being used to teach and evaluate professionalism. The goal of this study was to determine if peer evaluation and self-evaluation used in conjunction and implemented early in the medical curriculum, can serve as useful tools to assess and provide feedback regarding professional behaviour in first-year medical students. MATERIALS AND METHODS: From 1999 to 2003, students at Mayo Clinic College of Medicine evaluated themselves and their peers during the Gross and Developmental Anatomy Course. Numerical evaluations and written comments were statistically analysed within established categories of professionalism and correlated with academic performance, gender, and peer rating and self-rating. RESULTS: The majority of written comments pertained to inter-professional respect, responsibility, and excellence. Students who gave higher peer evaluation and self-evaluation scores provided more positive comments, and students performing well in the course provided more positive comments about their peers and themselves than did those struggling academically. Students consistently rated their peers higher than themselves, and male students rated themselves higher than did female students. CONCLUSIONS: Implementing peer evaluation and self-evaluation early in the medical curriculum is a valuable exercise in teaching first-year medical students assessment skills when evaluating their behaviour, as well as the behaviour of their colleagues.

Anatomy↗
PubMed2000

Animated PowerPoint as a tool to teach anatomy.

Anatomy is a visual science. For centuries, anatomic information has been conveyed through drawings that have been presented to students through every available medium. The projection of animated images from a computer is a medium that offers great promise in effecting improved communication of anatomic information. Using Microsoft PowerPoint software, we have developed animated presentations for all of our lectures in Gross and Developmental Anatomy. As a starting point, we scan pen-and-ink drawings to create a digital image. The image may be edited and manipulated in an image processing program. Next, the image is imported into a PowerPoint slide where it is labeled and otherwise enhanced (arteries overlaid with red color, veins in blue, etc.) and the enhancements are animated, as we describe here step by step. For the lecture, the file is loaded on a server that is accessible through a network from a computer in the lecture hall. The output is directed to a video projector and the PowerPoint presentation is projected in the "Slide Show" mode. We use a wireless mouse that allows us to control the presentation from anywhere in the room. Before the lecture, students are provided with the same unlabeled drawings as handouts, and during the lecture the students are actively engaged in labeling the drawings and making related notes. After the lecture, the file is saved in HTML format and posted on our course web site where students can access the slides. Evaluation by the students at the end of the course demonstrated that this style of presentation was very favorably received.

Anatomy↗
PubMed1999

Biomechanics of total hip arthroplasty.

The biomechanics of the hip joint provide an understanding of the development, evolution, and treatment of many disabling conditions of this joint. The available methods of biomechanical analysis include in vitro studies, in vivo studies, and theoretical mathematic analyses. The information obtained from these analyses have enabled the design of therapeutic programs to alleviate the symptoms of, and possibly delay the progression of, hip disease. The design of surgical procedures has been based on alterations of the biomechanics of the hip. These procedures have proven useful for treating pathologies such as osteoarthritis, hip dysplasia, and hip fractures. The study of biomechanics and biomaterials are integral to the current success of total hip arthroplasty in achieving pain relief and functional restoration.

Animals↗
PubMed1998

Isolated paralysis of the extensor digitorum communis associated with the posterior (Thompson) approach to the proximal radius.

Seven patients presented with an isolated extensor digitorum communis (EDC) palsy immediately after undergoing surgery in which the posterior (Thompson) approach to the proximal radius was used. All had normal neurologic examination findings documented prior to surgery. In an attempt to localize this lesion, the authors studied the arborization of the terminal motor branches of the posterior interosseous nerve (PIN) at the distal edge of the supinator. A common innervation pattern to the superficial extensor muscles was observed in 29 of 30 cadaveric limbs. In 10 of 10 specimens, when the EDC was subdivided into its individual bellies, a reproducible pattern emerged: the proximal EDC muscles of the middle and ring fingers were supplied primarily by the recurrent nerve branch(es) and the EDC muscles of the index and little fingers, by separate nerve branches. Consistent with our anatomic findings, perioperative stimulation of the recurrent branch in 1 neurologically intact patient resulted in middle and ring finger extension. Electromyography in 8 normal limbs showed that the middle and ring fingers could be activated together without the index and little fingers in all cases. We believe that these patients with isolated EDC nerve palsy may have sustained an iatrogenic injury to EDC motor branches, distal to the supinator rather than to a PIN fascicle near the proximal supinator.

Cadaver↗
PubMed1997

The adrenal medulla as a wet sponge: a role for the intramedullary venous vasculature?

Synchronous contractions in the intramedullary venous vasculature have been postulated to assist in the discharge of hormones from the stimulated adrenal medulla in a manner analogous to the squeezing of a wet sponge. This study reports on two experimental approaches to support the hypothesis that contractions in the venous vasculature may contribute to the hormonal efflux. Firstly, the bovine adrenal medulla was perfused retrogradely via the bovine central adrenomedullary vein end changes in the vascular volume were assessed as changes in wet weight of the perfused tissue. Stimulation with acetylcholine and carbachol resulted in repetitive, transient weight losses, suggesting cholinergically mediated reductions in the vascular volume. Secondly, the contractile properties of the longitudinal layers of smooth muscle cells in the intramedullary venous system were characterized, using the bovine central adrenomedullary vein as a model. The results showed that the longitudinal layers of this vein were, similarly to the circular layers, selectively contracted by endothelin-1 via an ETA-like receptor, by neuropeptide Y and by membrane depolarization (high K+). However, the vein was insensitive to electrical stimulation acetylcholine and carbacho, as well as to catecholamines. These results suggest neuropeptide Y, released from the cholinergically stimulated chromaffin cells, as the most likely mediator of stimulus-evoked synchronous contractions of the venous vasculature in the bovine adrenal medulla. Together, these experiments provide support for the 'wet sponge' hypothesis for hormonal discharge from the adrenal gland.

Adrenal Medulla↗
PubMed1997

An anatomic comparison of septocutaneous free flaps from the thigh region.

Various free flaps have been utilized in the thigh region, however there are few systematic clinicoanatomic studies of the thigh region. The purpose of this study is to clarify the clinicoanatomic characteristics of the free septocutaneous thigh flap. Forty-two dissections were carried out in unenbalmed cadavers. The pedicle was observed in all specimens in the anterolateral thigh (ALT), medial thigh, gluteal thigh, and lateral thigh flaps. The pedicle was observed in 46% of the specimens in the anteromedial thigh flap. The pedicle was observed in 86% of the specimens in the posterior thigh flap. The pedicle length (153 +/- 23 mm) of the ALT flap was the longest pedicle in the thigh flaps. The internal diameter of the pedicle of the ALT flap (3.0 +/- 1.0 mm), which could be used for anastomosis, is the largest in the septocutaneous thigh flaps. The clinicoanatomic characteristics of thigh flaps are clarified.

Aged↗
PubMed1996

Guyon's canal revisited: an anatomic study of the carpal ulnar neurovascular space.

The boundaries of the space through which the ulnar neurovascular bundle crosses the wrist have been reinvestigated. Using gross dissections, transverse and sagittal sections, and histologic study, we determined that the roof of Guyon's canal, the "carpal ulnar neurovascular space," does not directly connect to the hamate bone, as is currently accepted. The roof of this space extends radially to the hook of hamate and attaches to the flexor retinaculum. This anatomic arrangement allows the ulnar artery and sensory component of the ulnar nerve to course radially to the hook of hamate, where they lie on the flexor retinaculum (transverse carpal ligament). The roof and radial border have three segments: (1) a proximal segment that begins near the pisiform and extends distally to the level of the hook of hamate but does not attach directly to it, (2) a central segment that contains only adipose tissue, and (3) a distal fascial layer that includes the palmaris brevis muscle. The floor of the space consists of the muscles of the hypothenar eminence, their fibers of origin, and the flexor retinaculum (transverse carpal ligament). Guyon accurately described the proximal portion of the carpal ulnar neurovascular space, but his description has been misinterpreted; the hook of hamate does not serve as the radial boundary of Guyon's canal. The anatomic relationships of the "carpal ulnar neurovascular space" need to be appreciated to avoid complications during carpal tunnel surgery.

Cadaver↗
PubMed1996

Surgical anatomy for endoscopic subfascial division of perforating veins.

PURPOSE: This study was undertaken to define the surgical anatomy of the medial perforating veins (PVs) of the leg and to provide information on how to gain access to all medial PVs from the superficial posterior compartment during a subfascial endoscopic procedure. METHODS: The venous anatomy of 40 limbs (from 23 cadavers) were studied. Medial PVs located between the ankle and the tibial tuberosity were dissected. None of the subjects had pathologic evidence of venous disease. Each PV's type (direct or indirect), size (< 1 mm, 1 to 2 mm, > 2 mm), location (distances from ankle [D1], and tibia [D2]), and accessibility from the superficial posterior compartment were recorded. RESULTS: Five hundred fifty-two PVs were identified (mean, 13.8; range, 7 to 22). Two hundred eighty-seven PVs (52%) directly connected the superficial with the deep systems, 228 (41%) were indirect muscle perforators, and 37 PVs (7%) were undetermined. One hundred thirty-seven PVs (25%) were > 2 mm. Sixty-three percent of PVs were accessible from the superficial posterior compartment. In the distal half of the leg, two groups of direct PVs could be identified (Cockett II: D1, 7 to 9 cm; Cockett III: D1, 10 to 12 cm). In the proximal half of the leg, paratibial direct PVs (D2 < or = 1 cm) were found clustered in three groups (D1, 18 to 22 cm; D1, 23 to 27 cm; D1, 28 to 32 cm). CONCLUSIONS: Our study confirmed the presence of the Cockett II and III PVs and three groups of proximal paratibial PVs, including the "24-cm" perforators. Two thirds of the medial direct PVs are accessible for endoscopic division from the superficial posterior compartment. To divide paratibial PVs, however, incision of the paratibial deep fascia is frequently required.

Cadaver↗
PubMed1996

Ulnar nerve anatomy and compression.

Compression of the ulnar nerve can be understood in terms of the anatomic and dynamic factors. Although the ulnar nerve may be compressed at any point along its course, it is particularly susceptible at the elbow and the wrist. Clinically relevant anatomy will be reviewed in an attempt to provide the reader with a logical framework for successfully diagnosing and managing typical and atypical ulnar nerve compression lesions.

Humans↗
PubMed1995

Morphology of the torn rotator cuff.

The morphological characteristics of shoulders with torn rotator cuffs were determined using 41 embalmed specimens. The following parameters were measured in the supraspinatus (SSP), infraspinatus (ISP) and subscapularis (SSC) muscles: the length, thickness and width of the extramuscular tendon; the length of the intramuscular tendon; the length and width of a tear, if present, muscle fibre length; and muscle volume. The cross-sectional area (CSA) of the tendon was measured on the photographic image of slices of the tendon using an image analysis system, and the CSA of the muscle was calculated by dividing the muscle volume by muscle fibre length. The rotator cuff was intact in 11 shoulders. A partial-thickness tear of the cuff was present in 12 shoulders, a full-thickness tear of the SSP in 11 shoulders, and a full-thickness tear of more than 2 tendons in 7. Overall incidence of full-thickness tears of the rotator cuff was 44%, and that of partial-thickness tears 29%. With increase of tear size, the functional tendon length (extramuscular tendon length plus tear length) increased by a statistically significant amount in the SSP, ISP and SSC, whereas muscle fibre length decreased in SSP and ISP. It is concluded that the increased functional tendon length and decreased muscle fibre length are the main morphological changes that make the rotator cuff a physiologically abnormal unit. Surgical repair of the torn cuff would be expected to improve these anatomical changes and restore the kinetics of the glenohumeral joint.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Adrenal medulla and Parkinson's disease.

Parkinson's disease has been described as a multisystem disorder that includes alterations in the function of the autonomic nervous system. The activity of the adrenal medulla in this disease has not been thoroughly investigated. Previous reports are reviewed that demonstrate that the adrenal medullae of parkinsonian patients are compromised, having a decreased content of all catecholamines and several neuropeptides. An animal model was used to investigate whether the observations made in human patients were related to extended treatment with antiparkinsonian medications or were a natural concomitant of the disease. Administration of L-dopa and/or carbidopa to C57BL mice for 4-16 weeks had no significant effect on the level of any of the adrenal medullary catecholamines. Treatment with MPTP 4-16 weeks prior to sacrifice did not deplete adrenal medullary catecholamines in these animals, thus not fully mimicking Parkinson's disease in this animal model. The only significant effect was an interaction between group (MPTP or control) and treatment with antiparkinsonian medications; L-dopa, in the absence and presence of carbidopa, had opposite effects in the two groups. Based primarily on the lack of effect of antiparkinsonian medications on adrenal medullary catecholamines, it was concluded that the adrenal medullary depletion observed in human patients was a peripheral concomitant of Parkinson's disease.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1994

The ulnar neurovascular bundle at the wrist. A technical note on endoscopic carpal tunnel release.

The boundaries of Guyon's canal have recently been redefined by a series of anatomical dissections. These showed that the confines of this space do not extend from the pisiform to the hook of the hamate, as currently accepted. The fascial roof extends radial to the hook of the hamate, which allows the ulnar neurovascular bundle to course radial to the hamate hook. The position of the ulnar nerve and artery is of particular significance for endoscopic carpal tunnel release. Most endoscopic devices are designed to divide the flexor retinaculum just to the radial aspect of the hamate hook. Utilizing cross-sectional analysis of nine cadaver specimens, we found the ulnar artery to course radial to the hamate hook in five and palmar to it in four. Therefore, the ulnar artery may be at greater risk of injury during endoscopic procedures than previously recognized.

Carpal Bones↗
PubMed1994

Flexor carpi radialis tendinitis. Part I: Operative anatomy.

The anatomical characteristics of the flexor carpi radialis tendon, the tendon sheath, the tunnel boundaries, and the adjacent structures were examined in twenty-five adult cadaveric specimens. Transverse and sagittal sections of the wrist and forearm, tenograms, and histological sections of the tendon were made from two additional specimens each. The musculotendinous portion of the flexor carpi radialis tendon begins an average of fifteen centimeters (range, twelve to seventeen centimeters) proximal to the radiocarpal joint; the muscular fibers end an average of eight centimeters (range, six to nine centimeters) proximal to the wrist. The synovial sheath extends from the origin to the insertion. The tendon enters a fibro-osseous tunnel at the proximal border of the trapezium and is separated from the carpal canal by a thick septum that functions, at its distal border, as a pivot point for the flexor pollicis longus. Within the tunnel, the tendon occupies 90 per cent of the available space and is in direct contact with the slightly roughened surface of the trapezium. The tendon lies within a few millimeters of the distal aspect of the radius, the scaphoid tubercle, the scaphoid-trapezium-trapezoid joint, and the carpometacarpal joint of the thumb. In most patients, the flexor carpi radialis tendon is inserted at three locations. A small slip is connected to the trapezial crest or tuberosity; 80 per cent of the remaining tendon is inserted on the base of the second metacarpal and 20 per cent, on the base of the third metacarpal. The deep palmar arch is located two to three millimeters distal to the insertion of the tendon.

Humans↗
PubMed1993

Variations of the arterial anatomy of the foot.

Reconstruction of the arteries of the foot in patients with severe chronic arterial occlusive disease has become a routine and valuable procedure. However, it is frequently difficult to select the optimal site for the distal arterial anastomosis. In order to determine the most important anatomic variations of foot arteries and the relationship of the dorsalis pedis artery to crossing tendons, the following study was performed in 30 cadaver limbs of 17 persons (9 men and 8 women). Their mean age at death was 69.8 years (range: 42 to 93 years). Methods to evaluate anatomy included anatomic dissection, arteriography, and preparation of corrosion cast models. The latter was performed by injection of liquid plastic and catalyst into the tibial arteries followed by chemical débridement of the soft tissue of the foot. Photographs of the corrosion cast models were taken at various stages of soft tissue dissolution. The dorsalis pedis artery was absent in 6.7% of the cases, and the arcuate artery was absent in 33%. The dorsalis pedis artery arose from the peroneal artery in 6.7%. The dorsalis pedis artery crossed under the extensor hallucis longus tendon at the ankle in 54%, above the ankle in 43%, but below the ankle in only 3%. Our study suggests that the optimal site for the dorsalis pedis artery anastomosis on the foot is the segment distal to the ankle.

Adult↗
PubMed1992

Inorganic thiophosphate effects on chromaffin cell structure and function.

The effect was determined of replacing medium inorganic phosphate with thiophosphate on the structure and function of cultured bovine chromaffin cells. Cell cultures were incubated in normal medium containing fetal bovine serum, phosphate free medium or similar medium supplemented with inorganic phosphate or thiophosphate. In contrast to the other media, cells cultured with thiophosphate medium for 3-4 days showed seriously compromised structure and functions. The cells lost 75% of their catecholamine content and their ability to secrete remaining catecholamines in response to nicotine stimulation. Radiolabelled thiophosphate was rapidly taken up by the cells and, in long-term experiments, was incorporated largely into a 97-121 kDa protein band on SDS-PAGE. Additional minor bands were found to a lesser, variable extent. Transmission electron micrographs of cells treated with thiophosphate showed extensive depletion of chromaffin vesicles and disruption of mitochondria, suggesting that the functional damage noted with these cells could be associated with damage to mitochondria. Analysis of general cell metabolic activity by conversion of the dye (3-[3,4-dimethylthiazol-2-yl]-3,5-diphenyltetrazolium bromide) to its formazan derivative indicated increased metabolic activity at early stages of exposure to thiophosphate followed by a decline with continued exposure, supporting the argument for an overall depression of cell metabolism. Uptake of the dye neutral red, which is avidly accumulated by chromaffin cells, was also reduced for cells exposed to thiophosphate. The data suggest that thiophosphate enters chromaffin cells and disrupts energy dependent cell functions, including catecholamine storage and secretion.

Animals↗