Imaging findings of the developing temporal bone in fetal specimens

• Published in: American journal of neuroradiology : AJNR Vol. 17; no. 8; pp. 1467 - 1477
• Main Authors: Nemzek, WR, Brodie, HA, Chong, BW, Babcook, CJ, Hecht, ST, Salamat, S, Ellis, WG, Seibert, JA
• Format: Journal Article
• Language: English
• Published: Oak Brook, IL Am Soc Neuroradiology 01-09-1996; American Society of Neuroradiology
• Subjects: Biological and medical sciences; Cartilage - embryology; Cochlea - embryology; Ear Canal - embryology; Ear Canal - growth & development; Ear, Inner - embryology; Ear, Middle - embryology; Fetus; Fundamental and applied biological sciences. Psychology; Gestational Age; Humans; Labyrinth Diseases - congenital; Magnetic Resonance Imaging; Mammography; Mastoid - embryology; Mastoid - growth & development; Osteogenesis; Petrous Bone - embryology; Petrous Bone - growth & development; Semicircular Canals - embryology; Skeleton and joints; Temporal Bone - embryology; Tomography, X-Ray Computed; Vertebrates: osteoarticular system, musculoskeletal system; Vestibular Aqueduct - embryology; Vestibular Aqueduct - growth & development; Vestibule, Labyrinth - embryology; Radiography; Embryonic development; Temporal bone; Radiodiagnosis; Exploration; Fetus; Computerized axial tomography; Nuclear magnetic resonance imaging
• ISSN: 0195-6108; 1936-959X

To trace the development of the normal fetal temporal bone by means of plain radiography, MR, and CT.
Eighteen formalin-fixed fetal specimens, 13.5 to 24.4 weeks' gestational age, were examined with a mammographic plain film technique, CT, and MR imaging at 1.5 T. Temporal bone development and ossification were assessed.
The membranous labyrinth grows with amazing rapidity and attains adult size by the middle of the gestation period. The cochlea, vestibule, and semicircular canals are very prominent and easily recognized on MR images. The otic capsule develops from a cartilage model. Ossification of the otic capsule proceeds rapidly between 18 and 24 weeks from multiple ossification centers that replace the cartilaginous framework. The mastoid, internal auditory canal, vestibular aqueduct, and external auditory canal continue to grow after birth.
The study of fetal developmental anatomy may lead to a better understanding of congenital disorders of the ear. Faster MR scanning techniques may provide a method for in utero evaluation of the fetal temporal bone.