Oblique ventrolateral views of the tympanic cavity and skull
Figure 3A. Obliqued ventrolateral view of important structures within rostrodorsal compartment of the tympanic cavity. The arch-shaped maleus is located in the rostrodorsal aspect of the cavity, referred to as the epitympanic recess. In the most rostral aspect of the cavity is the opening of the auditory tube, an area often lined with ingrown secretory epithelium from the external ear canal. This epithelium must be completely excised during the LBO. Note the promontory and cochlear window which house the inner ear structures. A portion of the large fundic compartment of the tympanic cavity is well exposed caudally.
Figure 3B. Obliqued ventrolateral view of the skull after the lateral wall of the tympanic bulla is removed. The internal carotid artery, a major blood supply to the brain, is illustrated. The internal carotid artery enters the caudal carotid foramen in the in the petro-occipital fissure and traverses in the carotid canal. The medial wall of the tympanic bulla forms the lateral wall of the carotid canal.