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Biomedical subjects

S C Whiten

Publications and source records attributed to S C Whiten.

5 recordsLinked to original sources
PubMed2002

The anatomical and neurophysiological basis of the sensate free TRAM and DIEP flaps.

Recent developments in autogenous breast reconstruction using the rectus abdominis myocutaneous free flap include attempts to reinnervate the flap tissue. We have carried out anatomical studies to determine the nature of abdominal-wall cutaneous innervation, with particular emphasis on the harvesting of sensate flaps. Dissections were performed on four embalmed and 12 fresh human cadavers (32 sides). The lowest five intercostal nerve trunks were identified and traced to the lateral border of the rectus sheath. A detailed dissection of the intramuscular course of the nerves and associated vasculature was performed. The relationship of the nerves to the vascular perforators used for rectus abdominis myocutaneous flaps was determined visually, and confirmed histologically. In contrast to previous studies, we show that nerves supplying cutaneous sensation can travel with both medial and lateral vascular perforators. In order to confirm clinically useful innervation, the abdominal flap skin of five patients undergoing TRAM flap reconstruction was stimulated electrically, and sensory recordings were made directly from the related intercostal nerve just prior to flap harvest. These studies represent, to our knowledge, the first clinical application of neurophysiological techniques to outline the perforator neurosomes of flaps based on the deep inferior epigastric vascular axis. We provide the first comprehensive study of abdominal-wall innervation with regard to sensate free-flap harvest. Our dissections show complex patterns of abdominal skin innervation that have not been previously described. The implications for sensate free TRAM and DIEP flap reconstructions, as well as the potential for more accurate inclusion of innervated flap skin, are discussed.

Abdominal Muscles↗
PubMed2000

Marks, scores and grades: scaling and aggregating student assessment outcomes.

The term marks conflates the concepts of scores (raw test performance) and grades (level of performance). Neither scores nor grades represent interval scales, and therefore properly speaking arithmetic means should not be calculated during aggregation. The distributions of scores from a variety of kinds of assessment are considered, and ways of converting scores to grades are discussed. Methods of aggregation are also considered, and several strategies for implementing these via spreadsheets are made available. It is recommended that: 1 Scores should always be converted to grades before aggregation. The process of converting scores to grades requires both subject-specific skills, and familiarity with educational principles. 2 Whatever grade scale is used, it should be readily distinguishable from scores. 3 The median should be calculated as the measure of overall performance, not the arithmetic mean. 4 The interquartile range should be calculated as the measure of dispersion. 5 Students should be informed of both their score and grade for each assessment. 6 Where possible, assessment should report performance by individual assessment, not by a single aggregated mark. 7 When aggregation takes place, it should be possible to aggregate student performance by type of assessment as well as by academic subject. 8 Students who perform inconsistently should receive particular scrutiny during assessment.

Education, Medical, Undergraduate↗
PubMed1998

Cartilaginous development of the human craniovertebral junction as visualised by a new three-dimensional computer reconstruction technique.

Serial transverse histological sections of the human craniovertebral junction (CVJ) of 4 normal human embryos (aged 45 to 58 d) and of a fetus (77 d) were used to create 3-dimensional computer models of the CVJ. The main components modelled included the chondrified basioccipital, atlas and axis, notochord, the vertebrobasilar complex and the spinal cord. Chondrification of the component parts of CVJ had already begun at 45 d (Stage 18). The odontoid process appeared to develop from a short eminence of the axis forming a third occipital condyle with the caudal end of the basioccipital. The cartilaginous anterior arch of C1 appeared at 50-53 d (Stages 20-21). Neural arches of C1 and C2 showed gradual closure, but there was still a wide posterior spina bifida in the oldest reconstructed specimen (77 d fetus). The position of the notochord was constant throughout. The normal course of the vertebral arteries was already established and the chondrified vertebral foramina showed progressive closure. The findings confirm that the odontoid process is not derived solely from the centrum of C1 and that there is a 'natural basilar invagination' of C2 during normal embryonic development. On the basis of the observed shape and developmental pattern of structures of the cartilaginous human CVJ, we suggest that certain pathologies are likely to originate during the chondrification phase of development.

Basilar Artery↗
PubMed1997

The study of early human embryos using interactive 3-dimensional computer reconstructions.

Tracings of serial histological sections from 4 human embryos at different Carnegie stages were used to create 3-dimensional (3D) computer models of the developing heart. The models were constructed using commercially available software developed for graphic design and the production of computer generated virtual reality environments. They are available as interactive objects which can be downloaded via the World Wide Web. This simple method of 3D reconstruction offers significant advantages for understanding important events in morphological sciences.

Computer Communication Networks↗