Final answer:
Congenital abnormalities associated with atresia of the external ear canal include conditions like microtia, Treacher Collins syndrome, and Goldenhar syndrome, which lead to conductive hearing loss due to abnormal ear canal development.
Step-by-step explanation:
Congenital abnormalities that can feature atresia of the external ear canal involve conditions such as microtia and associated syndromes like Treacher Collins syndrome and Goldenhar syndrome. Atresia refers to the absence or closure of the external auditory canal, a vital component for sound conduction.
Conditions such as microtia, where the external ear is underdeveloped, can be accompanied by atresia, leading to various degrees of conductive hearing loss. Treacher Collins syndrome, a genetic disorder characterized by craniofacial deformities, can also present with atresia of the external ear canal along with abnormalities of the eye, cheekbones, and jaw. Goldenhar syndrome, sometimes presenting with a benign growth of the eye (epibulbar dermoid), can also include ear and spinal abnormalities. All these conditions have the potential to disrupt normal hearing due to compromised ear canal development.
Hearing involves not just the presence of the external ear structures, but also their functional integrity, as they pass the sound waves through to the middle ear and then to the inner ear structures. Any abnormality in this pathway, such as atresia, can impede the sound transmission, necessitating comprehensive diagnosis and management tailored to the individual's specific needs.