Inner Ear Development and Abnormalities

12 Questions

7 weeks

A bony structure that surrounds the inner ear

Cephalic mesoderm

10 weeks

Displaced vertical segment of facial nerve

Fused malleus-incus

A structure that develops from six ectodermal hillocks

A structure that develops from the first pharyngeal pouch

Neural crest mesenchyme

A structure that innervates six areas of neuro-epithelial ectoderm

A space that forms by means of resorption of precartilage

A condition where the ear canal is absent or underdeveloped at birth

Study Notes

The inner ear development is completed in the 24th week.
The otic capsule development is a part of the inner ear development.
The precartilaginous precursor of the otic capsule appears at 7 weeks.
It originates from the cephalic mesoderm.
The development of the otic capsule begins at 7 weeks.
The development of the inner ear begins earlier than the otic capsule.
The inner ear is an important part of the auditory system.
The otic capsule is a bony structure that surrounds the inner ear.
The development of the otic capsule is crucial for the proper functioning of the inner ear.
The development of the inner ear and otic capsule is a complex process.

The auricle develops from six ectodermal hillocks arising from the first and second branchial arches.
The tympanic cavity develops from the first pharyngeal pouch and remains a slit-like structure until the fifth month.
The ossicles develop from the neural crest mesenchyme of the first and second branchial arches.
The facial nerve only comes to lie in its adult position late in fetal life.
The membranous labyrinth develops from the otic placode and achieves adult form at 10 weeks and adult size at 20 weeks of gestation.
The organ of Corti becomes functional in its basal turn at approximately 20 to 24 weeks.
The vestibulocochlear ganglia are derived from the otic placode and innervate six areas of neuro-epithelial ectoderm.
The perilymphatic space forms by means of resorption of precartilage from week 8 to week 24.
Congenital inner ear abnormalities are divided into those affecting the membranous labyrinth alone and those affecting both the bony and membranous labyrinths.
Molecular-genetic techniques have helped to elucidate the development of the ear.

The most common facial nerve abnormality in congenital aural atresia is the vertical segment of facial nerve displaced anteriorly/laterally.
The most common ossicular abnormality in congenital aural atresia is fused malleus-incus.
The first and second branchial arches contribute to the development of the auricle.
There is an obtuse angle of facial nerve at second genu in some cases.
Dehiscent vertical segment of facial nerve is a possible abnormality.
Enlarged geniculate ganglion is a possible abnormality.
Congenital aural atresia is a condition where the ear canal is absent or underdeveloped at birth.
It can lead to hearing loss and other complications.
Treatment options include surgery to reconstruct the ear canal and hearing aids.
Early diagnosis and intervention can improve outcomes for individuals with congenital aural atresia.