Extraocular eye muscles in human fetuses with craniofacial malformations: Anatomical findings and clinical relevance

Abstract

Anomalies of the extraocular muscles have been suspected to be present frequently in patients with craniofacial malformations. We studied the extraocular musculature in the orbits of 15 anencephalic human fetuses between the 5th and 10th months after gestation, and in one fetus with an occipital meningocele and a large defect of the left cranial base. The findings were compared to those in nine normal age-matched fetuses. All malformed fetuses exhibited special features of the levator palpebrae superioris muscle, either its absence, an anomaly of the muscle belly, or an anomalous insertion. In addition, deficient or aberrant muscle bellies of the oblique and rectus muscles were found. In anencephaly, the frontal bone is condensed, forming narrowed orbital cavities with hypotelorism. Frequent disturbance of extraocular muscle development in fetuses with craniofacial malformations is implicated. The presented specimens are examples of extreme variants of cranial and craniofacial malformation syndromes. Thus, similar findings of extraocular muscles might also be regularly found in clinically relevant craniofacial malformations. This would force new considerations about diagnostic and therapeutic approaches to patients with craniofacial malformations.

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

“…The normal muscles do not make a cluster but are distributed at the proper sites in the size of the present specimen (Osanai et al, 2010). The extraocular muscles and bony cranium develop simultaneously (Plock et al, 2007). However, previous references did not refer to the orbital muscle, a smooth muscle that was well developed in the present specimen.…”

“…In contrast, the causes of restricted abnormalities are difficult to determine. Plock et al (2007) described and reviewed anomalies of human extraocular muscles. Abnormal extraocular muscles often appear in combination with common craniofacial anomalies such as Crouzon, Apert, Pfeiffer, and Goldenhar-Gorlin syndromes (in short, these syndromes include anomalies of the mandible, eye, and other parts of the body such as the hand and fingers).…”

Accessory levator muscle slips of the levator palpebrae superioris muscle

“…Variations of the LPS muscle may also cause congenital blepharoptosis. This pathological condition usually occurs as an isolated defect in otherwise healthy children, although it may be associated with craniofacial malformations and ocular mobility disorders 13 . Baldwin and Manners's study centred on distinguishing whether the reason of the disease should be classified as a dystrophy (inherited disease with progressive muscle weakness and wasting) or a dysgenesis (a defect in the development of the muscle) and showed that available histological data appeared to support the classification of congenital blepharoptosis as a dysgenic phenomenon 14…”

A Study on Variations of Levator Palpebrae Superioris Muscle with Its Embryological Basis and Clinical Significance

“…Variations of the LPS may also cause congenital blepharoptosis. This pathological condition usually occurs as an isolated defect in otherwise healthy children, although it may associated with craniofacial malformation and ocular motility disorder (14) .…”

“…Amonoo-Kuofi and Darwish (1998) reported bilateral accessory LPS muscle between superior oblique and LPS that ran from the lessser wing of the sphenoid to the skin of the upper lid, but these muscle were not bipartite (9) . Fetal LPS exhibit a broad aponeurotic insertion on the upper lid and the connective tissue of the lacrimal gland, often with medial and lateral accessory muscular slips or fibrous bands arising from LPS (Plock et al 2005) (10) . Changes during embryogenesis upto 24 months postnatally may result in LPS undergoing adaptation (11) .…”