Ronan O'Rahilly

A survey of carpal and tarsal anomalies.

1. The carpus and tarsus are subject to the same types of anomalous development.2. Congenital anomalies may or may not be hereditary; they may be bilateral or unilateral; and they may undergo pathological changes.3. Teratological data are commonly misused for the fabrication of unsubstantiated phylo

The onset of ossification in the human calcaneus

SummaryA (silver) radiographic and microscopic study of the onset of ossification in the calcaneus of 177 human fetuses between 49 and 150 mm C.-R. length has revealed the presence of two independent and developmentally different ossific sites. A lateral locus, intramembranous (parachondral) in origin and precocious in appearance, was observed in slightly over 16% of the fetuses examined between 93 mm (the first appearance of this bone) and 150 mm C.-R. It occupied the vascular connective tissue within the anterior portion of a distinct groove on the inferolateral wall of the cartilaginous calcaneus between the retrotrochlear eminence anterosuperiorly, and the lateral process of the tuber posteroinferiorly. A centrally situated, primary ossific centre, endochondral in origin, was detected in only 11% of the fetuses between 118 mm (the initial appearance of this centre) and 150 mm C.-R. It was situated in the centre of the anterior third of the cartilaginous calcaneus in relatin to the sustentaculum tali medially and to a distinct cartilaginous prominence on its lateral surface. Only four fetuses possessed both ossific sites (lateral and central): at 122, 143, 145, and 150 mm C.-R., and in only one of these was continuity established between them. One fetus (122 mm) possessed two independent endochondral centres (superior and inferior).

The normal cardiac apex and apex beat: A critical review of recent data

Abstract 1. 1. There is a lack of agreement concerning the clinical localization of the apex beat. A commonly used definition employs the farthest inferolateral point of maximal pulsation. Only a certain proportion of apex beats can be localized by palpation; this varies from 24 to 98 per cent in the recorded literature. 2. 2. As regards horizontal localization, the mean distance of the adult apex beat (as defined above) from the midsternum is 3.25 or 3.5 in. in the recumbent posture, 3 in. when erect. The variation is commonly from 2.5 to 4 in. from midsternum, recumbent, and 2.25 to 3.5 in., erect, but extremes ranging from 2 to 5.5 in. have been found in apparently normal subjects. Here, as elsewhere, the wide range of physiologic values compatible with health should be stressed. The existence of a direct relationship between the width of the thorax and the position of the apex beat is disputed; its possibility is allowed for by “heart angle” measurements. 3. 3. As regards verticle localization, the apex beat is commonly in the fifth, or perhaps in either the fourth or fifth, intercostal space, rarely in the third or sixth. 4. 4. The apex cordis is formed by either the left ventricle or the ventricular septum, rarely by the right ventricle. Radiologically, the apex is influenced by the orientation of the heart and body, and the cardiac contour is frequently such that no apex is definable. This is in agreement with the observation that 16 per cent of normal hearts have been found to show no anatomic apex post mortem. The radiologic apex has been defined either in terms of cardiac geometry or variously as being above, at, or below the diaphragmatic shadow; the relationship between the heart and diaphragm is too inconstant to be satisfactory, however. An acceptable definition of the radiologic apex cordis does not seem to be available and it is questionable whether the term “apex” has any value as a localized landmark in many cases. 5. 5. The mean position of the apex, definied (however questionably) as the inferior left corner of the heart, is recorded as being in the fifth intercostal space, 2.75 in. from midsternum. 1 in. below the level of the xiphisternal joint, recumbent; sixth costal arch, 2.75 in. from midsternum, 2 in. below the joint level, erect. It appears that the apex beat is usually above the apex, and that it may be lateral (commonly) or medial to the apex or to the left cardiac margin. 6. 6. The apical region of the heart is affected by a number of factors, such as posture, respiration, and habitus. The intrinsic cardiac movements are exceedingly complicated and much further work remains to be done toward their elucidation. The mechanism of the apical impulse appears to be in doubt.