Fetal head anomaly restricted to the eye, the mandible, and the pterygoid process of the sphenoid: A histological study

Abstract

A report on an unusual combination of anomalies in the head of a female fetus. The authors examined whole body semiserial paraffin sections of a female fetus (155 mm CRL; ∼18 weeks of gestation), with a particular focus on the head region. Cranial autonomic ganglia, nasal olfactory cells, and the orbital muscle were investigated using immunohistochemistry for tyrosine hydroxylase, vasoactive intestinal peptide, calretinin, and smooth muscle actin expression. The surface gross anatomy of the fetus appeared normal. The left eyeball lacked a lens (the eyeballs were otherwise normal). The orbital muscle was very thick and located in the anterolateral side of the extraocular muscles. Conversely, the extraocular muscles made a cluster in the superoposterior side of the orbit. The infratemporal fossa was small due to the bulky, transversely extended lateral pterygoid process in contrast to the small coronoid process of the mandible. The bilateral mandibular bases overlapped at the midline symphysis. The thin orbitosphenoid and thick alisphenoid provided an almost flat, anterior cranial base. Nasal olfactory cells and cranial autonomic ganglia appeared to be normal. No major anomaly was observed in the brain. Because of the changes in topographical anatomy, the orbital muscle probably lost its normal bony attachment and appeared to push the extraocular muscles superoposteriorly. A gene function redundancy rather than mutation may explain the present restricted anomalies in the mandible and pterygoid process.

Association between the developing sphenoid and adult morphology: A study using sagittal sections of the skull base from human embryos and fetuses

“…These included the PT and the first and second branchial arch skeletons in Hoxa‐2 KO mice (Rijli et al, 1993) and the OS and the nasal capsule in mutant 3H1 Br / Br mice (McBratney et al, 2003). Similarly, we observed a histological fetal anomaly with an absent PT and OSpost (Jin et al, 2011). Conversely, each element of the cartilaginous sphenoid seemed not to be determined by a single signal.…”

“…Most photographs were taken with a Nikon Eclipse 80, whereas photographs at ultra‐low magnification (objective lens less than ×1) were obtained using a high‐grade flat scanner with translucent illumination (Epson scanner GTX970). In addition to the sagittal sections from 25 specimens, structures requiring identification were assessed by reexamining photographs of horizontally or frontally sectioned sphenoids taken for previous studies (Cho et al, 2010, 2013; Honkura et al, 2017; Jin et al, 2011; Katori, Kawamoto, et al, 2013; Katori, Kawase, et al, 2013; Kim et al, 2020; Kiyokawa et al, 2012; Osanai et al, 2011; 2011, 2017; Yamamoto et al, 2017, 2018). In these previous specimens, horizontal and frontal sections from 25 late‐term fetuses (GA 28–40 weeks and CRL 217–340 mm; Kim et al, 2020) were especially useful for detailed understanding of topographical anatomy.…”

The palatomaxillary suture revisited: A histological and immunohistochemical study using human fetuses

“…Also at 16-18 weeks, the shape of the lateral part of the palatomaxillary suture changed drastically, a change that may be associated with growth of the pterygoid. A case report of a pterygoid anomaly found in a human fetus of 155 mm CRL (GA 18 weeks) showed a figure incidentally displaying the double layered bony palate (Jin et al, 2011). Thus, development of the pterygoid seems not to be committed to maintenance of the double layered hard palate.…”

The anatomy of fetal peripheral lymphatic vessels in the head‐and‐neck region: an immunohistochemical study

“…in press). However, we did not assess head‐and‐neck LVs in the 18‐week‐old fetus because we observed anomalies restricted to the eyes, the pterygoid, and the mandibular coronoid process (Jin et al. 2011a).…”