The outer ear consists of the pinna, ear canal, and eardrum. The pinna catches the sound and sends it to ear eardrum via the ear canal. The ear canal has a protective lining of hairs and glands that produce wax, which traps dust and stops small objects. The eardrum is a thin membrane that separates the middle ear from the ear canal. When sound travels down the ear canal, the eardrum vibrates and passes it to the middle ear. The middle ear is an air-filled cavity that contains three small bones or ossicles. The ossicles are called the malleus, incus, and stapes. Vibration of ear eardrum is amplified by the ossicles and then passed to the inner ear.

The middle ear is connected to the nose by the Eustachian tube and to another air-filled cavity behind the ear called the mastoid. The Eustachian tube maintains pressure outside and inside the drum whilst opening during yawning and swallowing. The inner ear is delicate and complex. It contains the cochlea, which changes sound vibrations into a nerve signal, and the vestibule with semicircular canals, which maintain our sense of balance and position. Hearing loss arises when any part of the ear, starting from the outer ear to the cochlea, is diseased. Balance is a complex process and requires information from semicircular canals, the eyes, and special sensors in major joints, particularly in the neck. This information is sent to a part of the brain called the cerebellum. Even a small problem with any one of these information sources can make one feel dizzy. Deafness (including glue ear), a total inability to hear, is fortunately very rare.

Occasionally, children are born with a profound or complete hearing loss, sometimes in adulthood, one acquires hearing loss, usually only in one ear, but there are many causes of partial hearing loss, or commonly, there is a gradually progressive loss as seen in old age. Hearing loss is described as conductive when there is an inability of the sound waves in the air to reach the nerves of hearing (the cochlea). This type of hearing may be treated with an operation. The other type of deafness is sensorial neural hearing loss, where there is a failure of the nerves or part of the brain. This is not usually treated by surgery (except a cochlear implant in selected cases). It may be treated with a hearing aid.

The nose is an air passage that runs from the nostrils, over the roof of the mouth, to the top of the throat. The nose is divided into two compartments by a partition called the nasal septum. The nasal septum is formed by a piece of cartilage and thin bones. It is often bent to one side in normal people without a problem. The nostrils open into the nasal cavity, which is formed by bones at the base of the skull and the palate. On each side of the cavity are three or four bony projections called the turbinate. Turbinate increases the surface area available for moistening air. The nerve cells that detect smell are in the roof of the nasal cavity in the area called the olfactory bulb.

The sinuses are air-filled cavities that lie within the bones surrounding the nose and are connected to the nose by narrow holes and passages. There are four sinuses: maxillary, ethmoid, sphenoid, and frontal. Their function is not completely known, but they work for moistening the air and keeping the skull’s weight light. Sinuses do have mucous secretions and a specific pathway for their drainage into the cavity. Whenever this pathway is blocked for some reason, sinusitis develops.

In front of the larynx is the thyroid gland, which produces hormones that determine how quickly or slowly many body systems function. Below the jaw bone (mandible) on each side lies the submandibular gland, and in front of the pinna lie on each side parotid glands. These glands, along with multiple small glands in the buccal mucosa and other parts of the mouth, secrete saliva and keep our oral cavity moist. There are multiple small nodes on both sides of the neck known as lymph nodes. They are interlinked with thin tubes known as lymphatics and make lymphatic system. The lymphatic system works to drain debris from our bodies. Lymph nodes are not palpable until they get enlarged.

Tonsils and adenoids are part of your lymphatic system. Tonsils are in the back of your throat, and your adenoids are higher up, behind your nose. They help protect you from infection by trapping germs coming in through your mouth and nose. Sometimes your tonsils and adenoids become infected themselves. Tonsillitis makes your tonsils sore and swollen. Enlarged adenoids can be sore, make it hard to breathe, and cause ear problems.