![]() ![]() ![]() Its embryologic origin has long been debated and recently got attention in a newly proposed theory of a dual embryologic origin. Single origin of the epithelium of the human middle ear "The epithelium lining the human middle ear and adjacent temporal bone cavity shows a varying morphological appearance throughout these cavities.The most common malformation, Type IV, was isolated footplate fixation observed in 33% of cases." The footplate, and thereby oval window is present and without fixation. Twenty-seven percent were of Type III with a dysmorphic or monopodal capitulum and or crura. Eleven percent expressed a Type II malformation with dysmorphic or monopodal capitulum and crura and a fixed footplate. The crura and capitulum may be absent, monopodal or dysmorphic. Twenty-seven percent of stapes malformations had a Type I morphology characterized by a hypoplastic or absent inner footplate and hypoplastic to absent mesoderm footplate or oval window. Each case of stapes malformation could be classified into one of four malformation types based on our current understanding of the embryologic origin of the subunits of the stapes and timing of development. Serial sections stained with hematoxylin and eosin were examined by light microscopy and the morphology of the stapes was compared to age-matched controls. Developmental Disruptions of the Human Stapes "Twenty-five temporal bone specimens from 18 patients with congenital stapes malformations were identified in the Mass Eye and Ear temporal bone collection.Historic Embryology: 1880 Platypus cochlea | 1892 Vertebrate Ear | 1902 Development of Hearing | 1906 Membranous Labyrinth | 1910 Auditory Nerve | 1913 Tectorial Membrane | 1918 Human Embryo Otic Capsule | 1918 Cochlea | 1918 Grays Anatomy | 1922 Human Auricle | 1922 Otic Primordia | 1931 Internal Ear Scalae | 1932 Otic Capsule 1 | 1933 Otic Capsule 2 | 1936 Otic Capsule 3 | 1933 Endolymphatic Sac | 1934 Otic Vesicle | 1934 Membranous Labyrinth | 1934 External Ear | 1938 Stapes - 7 to 21 weeks | 1938 Stapes - Term to Adult | 1940 Stapes | 1942 Stapes - Embryo 6.7 to 50 mm | 1943 Stapes - Fetus 75 to 150 mm | 1946 Aquaductus cochleae and periotic (perilymphatic) duct | 1946 aquaeductus cochleae | 1948 Fissula ante fenestram | 1948 Stapes - Fetus 160 mm to term | 1959 Auditory Ossicles | 1963 Human Otocyst | Historic Disclaimer ![]() Hearing Links: Introduction | inner ear | middle ear | outer ear | balance | placode | hearing neural | Science Lecture | Lecture Movie | Medicine Lecture | Stage 22 | hearing abnormalities | hearing test | sensory | Student projectĬategories: Hearing | Outer Ear | Middle Ear | Inner Ear | Balance Note that in other species, such as the guinea pig, the malleus and incus are normally found as a single complex. In addition there are two muscles (tensor tympani and stapedius) formed from arch mesenchyme. The space in which these bones sit (tympanic cavity) is derived from the first pharyngeal pouch and is connected directly to the oral cavity by a hollow tube (auditory tube). The middle ear bones (ossicles) are derived from separate origins in the first and second arch mesenchyme. The tympanic membrane separates the outer ear from the middle ear and is formed initially from the first pharyngeal arch membrane. The embryology of the middle ear requires many separate components from different embryonic origins. ![]()
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