Dissection: a positive experience.

First-year medical students were surveyed by questionnaire to assess levels of stress and physical symptoms resulting from their experience of the anatomy room. There was a 100% response rate from the 188 students. Most students (95%) found the prospect of their first visit to the anatomy room exciting. A small number initially experienced physical symptoms, but these had improved significantly 10 weeks later. Most students suffered very little or no stress (80%) on their first visit with only 2% of respondents rating their stress levels as high. Ten weeks later, 87% experienced little or no stress with only 1% stating that they had high stress levels. The anatomy room was rated to be less stressful than workload and assessments. Students reported that the anatomy room provoked thoughts of mortality, and 27% suggested that there should be more preparation before the first visit to the anatomy room. Our findings support previous studies suggesting that American/Canadian students in particular find anatomy stressful. However, the wisdom of interpreting adverse reactions as symptomatic of post-traumatic stress disorder is questioned. This study shows the anatomy room to be a positive learning experience for the students of the Royal College of Surgeons in Ireland.

Helical CT evaluation of the perirenal space and its boundaries: a cadaveric study.

PURPOSE: To determine whether the perirenal spaces communicate across the midline and with the pelvic extraperitoneal spaces. MATERIALS AND METHODS: Helical CT was used to guide the sequential injection of 100-mL intravenous boluses of dilute contrast medium, up to 300 mL, into the perirenal space of eight embalmed cadavers (three male, five female; mean age at death, 82 years; range, 72-93 years), with four left-sided and four right-sided injections. All images were acquired after the final injection (300 mL total) to facilitate coronal and sagittal reconstruction of relevant images. All images were reviewed to assess the flow pathways of contrast medium from the perirenal space to other retroperitoneal spaces. RESULTS: In three cadavers that received left perirenal space injections and in two cadavers that received right perirenal space injections, communication was seen with the contralateral perirenal space through an area anterior to the aorta and inferior vena cava. In three cadavers that received right perirenal space injections, contrast material flowed from the right perirenal space to outline the bare area of the liver. Communication between the perirenal and pelvic extraperitoneal spaces was seen in all eight cadavers; contrast material extended into the pelvic extraperitoneal and presacral spaces. CONCLUSION: These findings show that the perirenal spaces communicate with each other across the midline and with the pelvic extraperitoneal spaces. Clinical implications are that perinephric collections can potentially flow into the pelvis or across the midline.

Tomorrow's doctors: today's mistakes?

Tomorrow's Doctors, published by the General Medical Council of the UK in December 1993, has prompted far-reaching changes to medical education in Britain. We draw attention to some inconsistencies in the document and to those aspects of it that we maintain are undesirable. We question the emphasis in Tomorrow's Doctors on change in view of the unchanging nature of the structure and function of the human body. We doubt the wisdom of exhorting students to learn through curiosity and experiment, such methods being wasteful of time and resources when used in the context of accepted core material. We do not accept that the information overload is an automatic result of traditional methods of delivering education, and we are by no means convinced that the university model is the right one for medical education. In the face of experts being unable to agree on or to define scientific method, we wonder if consideration of this is appropriate in an undergraduate medical course, and we doubt that ethics and criticism are rightly placed in the undergraduate curriculum. The drawbacks of systems-based teaching are considered in the light of the disease process, and we draw attention to the lack of evidence for the document's condemnation of departmental structures and its uncritical espousal of integration. Finally, we consider some of the ways in which these changes have affected anatomy.

Anatomy of the peritoneal aspect of the deep inguinal ring: implications for laparoscopic inguinal herniorrhaphy.

There are a number of important structures to be avoided in suturing or stapling during laparoscopic inguinal herniorrhaphy, not all of which are easily identifiable at laparoscopy. This is particularly so of the ductus deferens. Measurements were taken of the angle made by the ductus deferens with testicular vessels, and of the thickness of tissue in the vicinity of the internal ring into which sutures or staples are likely to be inserted. The angle (mean +/- SD) made by the ductus with testicular vessels was 38.6 degrees +/- 4.4 degrees on the right, and 48.6 degrees +/- 7.2 degrees on the left (P < 0.05) (measurements for right and left sides taken from different cadavers). Thickness of tissue around the ring (peritoneum, transversalis fascia and intervening connective tissue) varies at different sites, being greatest lateral to the testicular vessels (2.2 +/- 0.4 mm) and least over the ductus (0.2 +/- 0.1 mm). The angle measured constitutes the apex of the "triangle of doom" (Spaw et al., 1991. J. Laparoendoscopic Surg. 1:269-277) and with its use the position of the ductus deferens may be predicted and the underlying external iliac vessels avoided when stapling during herniorrhaphy.

Innervation of the rat external auditory meatus: a retrograde tracing study.

The innervation of the rat external auditory meatus has contributions from several nerves. Fluoro-gold, a retrograde neuronal tracer, was used to determine the relative contributions from neurons in cranial and spinal ganglia, and to distinguish any difference in the sensory and motor innervation between the outer cartilaginous and inner bony portions. The following ganglia were examined: the trigeminal, geniculate, glossopharyngeal, vagal, superior cervical, and dorsal root (C2-C4) ganglia. All selected ganglia demonstrated innervation of the external ear canal, particularly the trigeminal, glossopharyngeal, facial, and vagal ganglia. The geniculate and glossopharyngeal ganglia contributed more innervation to the inner osseous portion than to the outer cartilaginous portion of the external ear canal, and the vagal ganglion contributed relatively equally.

The anatomy of the facial nerve.

The facial (seventh cranial) nerve arises from the pontomedullary junction by two roots: (1) the motor root conveying fibers to muscles derived from second branchial arch mesoderm and (2) the nervus intermedius conveying visceral sensory fibers from the tongue and palate, and preganglionic parasympathetic fibers to the pterygopalatine and submandibular ganglia. The roots pass into the internal acoustic meatus where they join. At the lateral end of the meatus, the facial nerve passes into the facial canal. The nerve then turns sharply posteriorly at the geniculum. The geniculate (sensory) ganglion is situated here, and the greater petrosal nerve to the pterygopalatine ganglion arises from this region. The facial canal continues posteriorly on the medial wall of the tympanic cavity, passing above the fenestra vestibuli and arching downward and laterally to emerge at the stylomastoid foramen just after giving off the chorda tympani nerve. The posterior auricular nerve and the nerves to the stylohoid and posterior digastric muscles arise before the facial nerve enters the substance of the parotid gland. In the gland, the nerve divides into five groups of branches (temporal, zygomatic, buccal, mandibular, and cervical) that supply the muscles of facial expression.

The heart of the newborn child: an anatomical study based upon transverse serial sections.

This study of the newborn child heart is based mainly on observations made on thin (0.2 mm) serial transverse sections of an entire thorax. Several features of the cardiovascular system associated with the fetal circulation are discussed. Despite considerable differences between the cardiac form in the newborn child and that in later postnatal life, the orientation of the heart in the newborn child has already attained many of its postnatal features. For example, it lies more nearly in the horizontal than the vertical plane and the atrial and ventricular septa are in line with each other at an angle of about 45 degrees to the median plane. This angulation of the septa determines that the right atrium and ventricle lie as much in front of the corresponding chambers of the left heart as they do to their right side. The cardiothoracic ratio and thoracic index are derived from a section through the thorax of the newborn child and these values are compared with those from a section through an adult man. A major purpose of this communication is to make a plea that the nomenclature given to all cardiac structures, even in the newborn child, should be consistent with the heart in situ in the anatomical position.

A fraction of labelled mitoses study on adrenal chromaffin tissue in the newborn mouse and the effect of hydrocortisone.

Hydrocortisone was administered to gravid mice from the thirteenth day of pregnancy until term. In vivo fraction of labelled mitoses experiments on intra-adrenal chromaffin tissue of newborn mice were performed to assess the effect of hydrocortisone on the cell cycle in this tissue. In untreated mouse intra-adrenal chromaffin tissue the total cell cycle time was 7 hours, being made up as follows: S phase 1 1/2 hours, G2 phase 1 hour, M phase 4 hours (by analysis of results, not by assumption) and G1 phase 1/2 hour (by subtraction). Hydrocortisone administration was without marked effect on these values. These results are discussed in the context of the influence of corticosteroids on the development biology of chromaffin tissue, both intra- and extra-adrenal.

The histological effects on the guinea pig external ear of several constituents of commonly used aural preparations.

Medicament contact dermatitis can be troublesome in external ear disease. In this work the effects on the guinea pig external ear of instillation twice daily for 3 weeks of benzalkonium chloride, Cerumol, gentamicin, the pharmaceutical base for Gentisone HC, hydrocortisone and propylene glycol were studied using light microscopy, thickness measurements of tympanic membrane and meatal epidermis, and the mitotic index of meatal epidermis. Benzalkonium chloride induced severe inflammatory changes and markedly increased the thickness measurements and meatal mitotic index. Cerumol also increased the thickness measurements and the mitotic index; there was additionally low grade chronic inflammation in the dermis. Prophylene glycol increased the mitotic index and thickness measurements though no signs of inflammation were seen. Other compounds did not produce significant changes except that hydrocortisone reduced the mitotic index. Contact dermatitis to benzalkonium chloride may be important in persistent ear disease. Cerumenolytic agents ought not to be used for prolonged periods or as prophylaxis.

The effect of Otosporin and Gentisone HC on the mitotic index and thickness of the tympanic membrane and meatal skin in the guinea pig.

Otosporin and Gentisone HC ear drops were inserted twice daily for 3 weeks into the external auditory meatuses of guinea pigs. An intraperitoneal injection of vincristine (1 mg/kg.) was given to each animal three hours before it was killed. Temporal bones and attached external auditory meatuses were dissected, tissues were fixed in 10 per cent buffered formalin, decalcified in EDTA, and embedded in JB4 plastic for sectioning at 4 micron. The proliferative activity in the epidermis of the bony meatus and in the lateral surface of the tympanic membrane was obtained by deriving the mitotic indices. After both types of ear drops there was a statistically significant reduction in mitotic indices, the values being about half the control values. The proliferative activity in the tympanic membrane was too low to permit statistical analysis, but no differences were apparent between the groups. The thicknesses of the epidermis and dermis of the bony canal, and of the tympanic membrane, were measured using a Kontron MOP-AMO3 analyser. Although the dermis was thinner as a result of the administration of ear drops, both the epidermis of the bony meatus and that of the tympanic membrane were thicker, all these changes being statistically significant.

The effect of hydrocortisone on the para-aortic body of the newborn mouse: an in vivo fraction of labelled mitoses study.

Information about the cell cycle of the mouse para-aortic body within the first 24 hours of postnatal life was derived from a fraction of labelled mitoses study. The total cell cycle time was 8 1/2 hours, being made up as follows: S phase-2 hours; G2 phase-1 hour; M phase-3 1/2 hours (by analysis of the results, not by assumption) and G1 phase-2 hours (by subtraction). Problems are discussed regarding the length of G2 and M phases and the consequences for G1. After hydrocortisone administration (40 mg/kg/day) to female mice for the last seven days of pregnancy, the pattern in newborn mice was disrupted. Values for G2 and M were similar to those of the untreated group, but no values were obtainable for the other phases of the cell cycle or for the total cell cycle time. These results after hydrocortisone treatment could be explained by the superimposition of the cell cycles of two or more different groups of cells. They are discussed with regard to the life span of the para-aortic body, and their implications are considered in the light of previously reported glucocorticoid-induced transformations of small granule cells from cervical sympathetic ganglia into catecholamine-storing chromaffin cells. The established hyperplastic effect of hydrocortisone on the para-aortic body is therefore not the result simply of an acceleration of the cell cycle, but it may involve the incorporation into the proliferative compartment of cells previously either moribund or nonproliferating.

The adrenal and renal veins of man and their connections with azygos and lumbar veins.

There exist many variations in the manner of formation, dimensions and place of termination of the central adrenal veins. In addition, some superficial adrenal veins may be substantial in size and may themselves drain directly into the renal veins and/or into other vessels which communicate with azygos and lumbar veins. This provides a route for venous adrenal blood to the heart via the azygos system and the superior vena cava rather than via the inferior vena cava. Variations in the formation and disposition of the renal veins are also described and the patterns of communication between somatic veins (including veins of the azygos and lumbar systems) and the left renal vein are illustrated and discussed in relation to the findings of others.

Variations in the composition of the human rectus sheath: a study of the anterior abdominal wall.

Three modes of construction of the rectus sheath above the arcuate line were found in a study of 40 cadavers. The classical description occurred most frequently, in 24 cases. The other constructions conformed to those described in earlier studies although the incidences were different. The accessory internal oblique muscle was found in none of the 40 cadavers, and pyramidalis muscle occurred on one or both both sides in only 3 out of 56 specimens. The shape and position of the arcuate line were neither symmetrical nor constant, and neither was the arrangement of the nerve supply to the rectus abdominis muscle or to the overlying skin.

The effect of in vivo hydrocortisone administration on the labelling index and size of chromaffin tissue in the postnatal and adult mouse.

Hydrocortisone administration in vivo to neonatal mice for seven days led to a significant increase in both the size and the labelling index of extra-adrenal chromaffin tissue (as represented by the para-aortic body) of 8 days old mice. In untreated animals at this age, the para-aortic body was in most cases too small to obtain a valid labelling index. In the para-aortic bodies of 14 days old, 21 days old and adult mice, the extra-adrenal chromaffin tissue was too dispersed to obtain values for either volumetric analysis or labelling indices, and hydrocortisone was without significant effect in promoting a hyperplastic response. In the postnatal adrenal medulla at all ages studied, hydrocortisone had no effect on the medullary size or on the labelling indices of either adrenaline- or noradrenaline-storing cells, although it led to a marked diminution of adrenocortical volume. The relative proportion of adrenaline-storing cells increased between the values for 8 days old animals and those for adults; this was unaffected by hydrocortisone. The cortico-medullary ratio remained unchanged from the eighth postnatal day onwards. The results are discussed and related to those of other workers. It is suggested that factors as yet unknown might modulate the response to corticosteroids of developing intra- and extra-adrenal chromaffin tissue.