Defects in ear canal development can cause severe hearing loss as sound waves fail to reach the middle ear. Here we reveal new mechanisms that control human canal development and highlight for the first time the complex system of canal closure and reopening. These processes can be perturbed in mutant mice and in explant culture, mimicking the defects associated with canal aplasia. The more superficial part of the canal forms from an open primary canal that closes and then reopens. In contrast, the deeper part of the canal forms from an extending solid meatal plate that opens later. Closure and fusion of the primary canal was linked to loss of periderm, with failure in periderm formation in Grhl3 mutant mice associated with premature closure of the canal. Conversely, inhibition of cell death in the periderm resulted in an arrest of closure. Once closed, re-opening of the canal occurred in a wave, triggered by terminal differentiation of the epithelium. Understanding these complex processes involved in canal development sheds light on the underlying causes of canal aplasia.

The mammalian ear is made up of three parts (the outer, middle, and inner ear), which work together to transmit sound waves into neuronal signals perceived by our auditory cortex as sound. This review focuses on the often-neglected outer ear, specifically the external auditory meatus (EAM), or ear canal. Within our complex hearing pathway, the ear canal is responsible for funneling sound waves toward the tympanic membrane (ear drum) and into the middle ear, and as such is a physical link between the tympanic membrane and the outside world. Unique anatomical adaptations, such as its migrating epithelium and cerumen glands, equip the ear canal for its function as both a conduit and a cul-de-sac. Defects in development, or later blockages in the canal, lead to congenital or acquired conductive hearing loss. Recent studies have built on decades-old knowledge of ear canal development and suggest a novel multi-stage, complex and integrated system of development, helping to explain the mechanisms underlying congenital canal atresia and stenosis. Here we review our current understanding of ear canal development; how this biological lumen is made; what determines its location; and how its structure is maintained throughout life. Together this knowledge allows clinical questions to be approached from a developmental biology perspective.

Reported is the case of a 79-year-old woman initially diagnosed with periorbital abscess on the background of a recent upper respiratory tract infection. Unexpectedly, intraoperative findings were that of a haematoma rather than an abscess. Subperiosteal orbital haematoma (SOH) is an extremely rare complication of rhinosinusitis. In contrast to the more common periorbital abscess, it is seldom listed as a complication of sinusitis. A review of reported cases suggests an older patient demographic are affected by SOH in contrast to periorbital abscess which typically affects paediatric patients. Given current demographic trends toward an older patient population with multiple comorbidities, failure to consider SOH as a differential will have important implications on preoperative workup, perioperative care and final outcome for patients. We present this case as a reminder of a rare but important complication of a common disease.

What is the power of human sensation? How does our ability to hear, salivate and taste affect everyday life? It is typical that patients suffering or surviving head and neck diseases continue to be impaired by disabilities and sensory disorders that are often overlooked by clinicians and patients alike. Not least because our senses of hearing and taste are hidden, by virtue of their anatomy. The theme of ‘hidden disability’ came to the project team in their observations of vulnerable patients, in particular the elderly, those suffering dementia, Sjogren Syndrome and survivors of head and neck cancer. Too readily, aspects affecting the quality of life of these patients are not recognised or even ignored.Hearing and salivation are taken for granted by the public, by patients and even by clinicians. As such the team recognised a need to raise awareness especially amongst clinicians of the hidden nature of hearing loss and dry mouth amongst vulnerable patient groups.A dry and silent world: living with hidden disabilities sought to encourage a three-way dialogue between patients, clinicians and academics mediated and documented through art.A dry and silent world: living with hidden disabilities was a collaboration between King’s College London’s Centre for Craniofacial & Regenerative Biology and Emma Barnard. It was supported by the university’s Culture team.