Development of external surfaces of human cerebellar lobes in the fetal period

Abstract

In the fetal period, development of cerebellar lobes may proceed dissimilarly due to possible differentiated origins of the cells and diversified times of their migration to certain cerebellum regions. This can cause various growth trajectories for the external surfaces of cerebellar lobes. The goal of the study was to describe the development of the external surface of cerebellum lobes and fissures delineating them in the fetal period. The material consisted of 101 fetuses (48 males and 53 females)-crown rump length 89-229 mm corresponding to 15-28 weeks of fetal life. The methods were based on anthropometric measurements and preparation techniques combined with elicited image computer analysis. At the largest values of the cerebellum posterior lobe surface, the most dynamic growth rate was observed in the case of the anterior lobe. Among the cerebellar lobes, proportional change was observed as well as a gradual increase in anterior lobe surface area and a simultaneous decrease in the surface area of the flocculonodular lobe part of the cerebellum total external surface. This paper presents the different growth trajectories of cerebellar lobes and demonstrates the importance of the primary fissure as a delineating mark for two regions with different dynamics of development.

Fig. 1

Schematic presentation of cerebellar lobe boundaries: a primary fissure separating the anterior lobe (A) from posterior lobe (P) (superior view), b posterolateralis fissure separating the posterior lobe (P) from flocculonodular lobe (Fn)

Fig. 2

Schematic presentation of linear measurements of fissures: envelope of fissure (L solid line) and the shortest line joining the end points of the fissure (x dotted line) of a primary fissure (superior view) and b posterolateralis fissure (posterior view)

Fig. 3

Correlation diagram of analysed features and week of fetal life, as well as parameters of the model of feature variability along with age for a P _s area of superior surface of cerebellum, b P _i area of inferior surface of cerebellum

Fig. 4

Correlation diagram of analysed features and week of fetal life, as well as parameters of the model of feature variability along with age for: a P _a anterior lobe surface area, b P _p posterior lobe surface area, c P _fn flocculonodular lobe surface area

Fig. 5

Correlation diagram of analysed features with the week of fetal life a dimension ratio of anterior (P _a) and posterior cerebellar (P _p) lobe areas b dimension ratio of flocculonodular lobe (P _fn) and cerebellar inferior (P _i) surface areas c dimension ratio of anterior lobe (P _a) area and flocculonodular lobe (P _fn) area

Fig. 6

Proportions of the anterior (P _a), posterior (P _p) and flocculonodular lobe (P _fn) at a 15th and b 27th weeks of gestation

Fig. 7

Shape of the human cerebellum at a 15th week and b 27th week of gestation (posterior view), with marked anterior lobe (asterisk), posterior lobe (plus sign) and flocculonodular lobe (ex symbol). Scale white square is 1 mm²

Fig. 8

Correlation diagram of analysed coefficient L/x with the week of fetal life of a primary fissure (L1/x1), b posterolateral fissure (L2/x2). NS non statistically important