Quantitative anatomy of the ulna’s shaft primary ossification center in the human fetus

Abstract

PurposeThere has been little information in the medical literature regarding the growing ulna in the human fetus, though such knowledge appears to be potentially useful in diagnosing skeletal dysplasias, characterized by a disrupted or completely halted growth of the fetus. Therefore, longitudinal measurements of long bones are extremely conducive in assessing both pregnancy and fetal anatomy.Materials and methodsUsing methods of CT, digital-image analysis and statistics, the size of the ulna’s shaft primary ossification center in 48 (26 males and 22 females) spontaneously aborted human fetuses aged 17–30 weeks was studied.ResultsWith no sex differences, the best fit growth dynamics for the ulna’s shaft primary ossification center was modeled by the following functions: y = − 8.476 + 1.561 × age ± 0.019 for its length, y = − 2.961 + 0.278 × age ± 0.016 for its proximal transverse diameter, y = – 0.587 + 0.107 × age ± 0.027 for its middle transverse diameter, y = − 2.865 + 0.226 × age ± 0.295 for its distal transverse diameter, y = − 50.758 + 0.251 × (age)2 ± 0.016 for its projection surface area, and y = − 821.707 + 52.578 × age ± 0.018 ± 102.944 for its volume.ConclusionsThe morphometric characteristics of the ulna’s shaft primary ossification center show neither sex nor bilateral differences. The ulna’s shaft primary ossification center grows linearly with respect to its length, transverse dimensions and volume, and follows a quadratic function with respect to its projection surface area. The obtained morphometric data of the ulna’s shaft primary ossification center is considered normative for respective prenatal weeks and may be of relevance in both the estimation of fetal ages and the diagnostic process of congenital defects.

Quantitative anatomy of the primary ossification center of the radial shaft in human fetuses

“…It is noteworthy to emphasize that the examined ossification center demonstrated no differences with respect to sex and laterality. Such a finding closely corresponded with the results of Baumgart et al [1] concerning the primary ossification center of the clavicle, and those of Wiśniewski et al [19, 20] regarding the ossification centers of the humerus and ulna in human fetuses. The present study emphasized that in fetuses aged 17–30 weeks, the radial shaft ossification center increased proportionately to fetal age, following the functions: y = − 10.988 + 1.565 × age ± 0.018 for its length, y = − 2.969 + 0.266 × age ± 0.01 for its proximal transverse diameter, y = − 0.702 + 0.109 × age ± 0.018 for its middle transverse diameter, y = − 2.358 + 0.203 × age ± 0.018 for its distal transverse diameter, and y = − 798.174 + 51.152 × age ± 0.018 for its volume.…”

“…Using our previous numerical data regarding the length of the ulnar shaft ossification center [20], the ulna-to-radius length index was calculated as a quotient of the length of ossification centers of the ulna and radius. The mean ulna-to-radius length index in the analyzed study period attained the value of 0.9 ± 0.1.…”

“…On the other hand, the projection surface area of the radial shaft ossification center increased following the quadratic function of fetal age in weeks: y = − 189.992 + 11.788 × (age) 2 ± 0.018. It should be emphasized that the growth dynamics of the radial shaft ossification center were related to those of the ulnar shaft ossification center [20], which grew in a proportionate fashion to fetal age, as follows: y = − 8.476 + 1.561 × age ± 0.019 for length, y = − 2.961 + 0.278 × age ± 0.016 for proximal transverse diameter, y = − 0.587 + 0.107 × age ± 0.027 for middle transverse diameter, y = − 2.865 + 0.226 × age ± 0.295 for distal transverse diameter, y = − 821.707 + 52.578 × age ± 0.018 for volume. However, it is noteworthy that an increase in projection surface area of the ulnar shaft ossification center followed the quadratic function of fetal age in weeks: y = − 50.758 + 0.251 × (age) 2 ± 0.016.…”

“…Having reviewed the professional literature about the ossification of the upper limb bones, we found those of the clavicle [1], humerus [19] and ulna [20] to be precisely quantified and expressed by growth curves. However, we failed to find any mathematical models concerning the primary ossification center of the radial shaft.…”

Novel imaging techniques to study postmortem human fetal anatomy: a systematic review on microfocus-CT and ultra-high-field MRI

“…Magnetic resonance imaging (MRI) and computed tomography (CT) have been extensively used to study fetal anatomy for research and diagnostic purposes, enabling minimally invasive autopsy and giving insight in human fetal development [1][2][3][4]. However, postmortem MR imaging using clinical routine magnets (1.5-3 Tesla (T)) demonstrates a low diagnostic accuracy, especially in fetuses below 20 weeks of gestation [5][6][7], as result of low resolution in small samples.…”