The outer surface of the eye is composed of parts of two spheres with different radii. The anterior segment, part of the smaller sphere, is formed by the transparent cornea and accounts for approximately 7% of the ocular surface. The…
Bony Orbit The bony orbits are skeletal cavities located on either side of the root of the nose that serve as sockets for the eyes and associated tissues. The walls of each orbit protect the eye from injury, provide points…
The inner ear contains the organ of hearing and the organs of balance. All are located within the labyrinth, a series of interlinked cavities in the petrous temporal bone containing interconnected membranous sacs and ducts. All spaces within the labyrinth…
By convention, the ear is subdivided into three parts: the external, middle and inner ear. It is largely, but not entirely, contained within the temporal bone. The ears not only receive, modulate, conduct, amplify and discriminately analyse the complex pressure…
The larynx is an air passage, a sphincter and an organ of phonation, and extends from the tongue to the trachea. It projects ventrally between the great vessels of the neck and is covered anteriorly by skin, fasciae and the…
The pharynx is a 12–14 cm long musculomembranous tube shaped like an inverted cone. It extends from the cranial base to the lower border of the cricoid cartilage (the level of the sixth or seventh cervical vertebrae), where it becomes…
Box 39.1 and Table 39.1 set out the different anatomical and clinical terms that are applied to some of the structures described in this chapter. Box 39.1 A note on terminology ‘The advent of endoscopic sinus surgery led to a…
Infratemporal Fossa The infratemporal fossa lies deep to the ramus of the mandible. It communicates with the temporal fossa superiorly deep to the zygomatic arch; the orbit anteriorly through the inferior orbital fissure; the pterygopalatine fossa medially through the pterygomaxillary…
The mouth extends from the lips and cheeks externally to the anterior pillars of the fauces internally, where it continues into the oropharynx. The mouth can be subdivided into the vestibule external to the teeth and the oral cavity proper…
Skin The scalp and buccolabial tissues are described here. The structure of the eyelids is discussed in Chapter 44 . Scalp The scalp extends from the top of the forehead anteriorly to the superior nuchal line posteriorly. Laterally, it projects…