Anatomy clinical correlates: Ear

The ear has many roles, from hearing and maintaining balance, to showing off jewelry and piercings. But just like the rest of our body, there are a variety of conditions that can affect them, so understanding the anatomy of the ear can help us better understand the clinical conditions that affect it!

Let’s start with the auricular hematoma, also known as a cauliflower or boxer’s ear. You may have guessed from its name - this condition is most common in professional boxers and wrestlers. Boxer’s ear is a deformity caused by blunt trauma to the auricle, in which blood accumulates between the perichondrium and auricular cartilage, resulting in a hematoma. If left undrained, fibrosis can develop in the overlying skin which causes deformity of the auricle. This results in the auricular deformity known as the cauliflower or boxer’s ear.

Next up, let's look at ear pain. The ear receives cutaneous innervation from multiple nerves of the head and neck which makes it prone to referred pain. This is called secondary otalgia, which means that the ear perceives pain when the primary issue is in another anatomical site.

Now, the majority of the external auditory canal innervation comes from the auriculotemporal nerve, which is a branch of the trigeminal nerve. It provides sensory innervation to the anterior portion of the preauricular skin, anterior auricle, and the anterior portions of the external auditory canal. Conditions such as dental infections, maxillary sinusitis, as well as temporomandibular joint disease can cause referred pain in these parts of the ear.

Along with the auriculotemporal nerve innervating the ear, a small auricular branch of the vagus nerve and parts of the glossopharyngeal nerve go on to innervate a small portion of the posterior external auditory canal and tympanic membrane. As these two nerves also innervate portions of the pharynx and larynx, pathologies irritating these areas can be referred to the ear. Examples include hypopharyngeal and laryngeal cancer, as well as oropharyngeal infections, which can all cause otalgia.