Mastoid Cells

The mastoid cells are continuous with the antrum and permeate the mastoid process down to its tip. The cells come so close to the surface that suppuration within them often bursts through and discharges behind the ear. The upper, inner, and lower portions of the bone are also sometimes perforated, which will be referred to later.

Middle-Ear Disease

Suppuration from middle-ear disease is caused by an infective inflammation travelling up the Eustachian tube from the pharynx and nasal cavities. It may pass to the attic above and thence to the mastoid antrum and mastoid cells. Pus usually finds an exit by perforating the tympanic membrane and discharging through the external auditory meatus. As already stated, it may pass down the Eustachian tube to be blown out of the anterior nares. It has been known to pass down the canal for the tensor tympani muscle, and form a retropharyngeal abscess. As the pus reaches the pharynx behind the prevertebral fascia, it may extend laterally and appear externally behind the sternomastoid muscle. Having thus reached the base of the skull, the infection may involve the meninges and brain through the crevices in the bone. It is rare for it to perforate the bone below and anteriorly, and thus implicate the jugular vein and internal carotid artery. It may eat into the posterior wall and involve the facial nerve, which is covered by only a thin shell of bone, and produce facial paralysis, attack the internal ear through the fenestra ovalis and rotunda and pass through the internal meatus to the brain. If it extends upward and involves the attic and antrum, it may perforate the roof, or tegmen, and form a subdural abscess in the back part of the middle cerebral fossa, whence it travels a distance of about a centimetre to the lateral sinus, causing a thrombus to form, or it may produce an abscess of the temporosphenoidal lobe of the brain. The antrum and mastoid cells being continuous, the posterior and inner walls may be perforated, the pus thereby reaching the posterior cerebral fossa,' again involving the lateral sinus, or producing a cerebellar abscess. If it perforates the mastoid process on its inner wall at the groove for the digastric muscle, the pus gains access to the back of the neck, forming what is known as Bezo/d's abscess.

Fig. 105.   Tenotomy of the tensor tympani tendon and separation of the incus from the stapes.

Fig. 105. - Tenotomy of the tensor tympani tendon and separation of the incus from the stapes.

Fig. 106.   Removal of the incus by means of Ludwig's hook.

Fig. 106. - Removal of the incus by means of Ludwig's hook.