The head is the superior part of the body that is connected to the trunk via the neck. It houses and protects important structures like the brain, and therefore regarded as the control and communication center of the body. It is the site of an individual’s consciousness. A place where ideas, creativity, imagination, responses, decision making and memories formulate. The head contains all the receptor systems linked with the special senses: the orbits associated with vision; the nasal cavities with smell; the ears with hearing and balance; and the oral cavity with taste. It also contains the upper parts of both the respiratory and digestive systems (nose and mouth), which serve as portals for oxygen and food intake.
The head can be grouped into a series of compartments, formed by bones and soft tissue.
There’s the cranial cavity, the largest of all head compartments. It houses the brain and its associated cranial meninges.
The second compartment is the ear apparatus on each side. Its internal part is contained within the floor of the cranial cavity, while its external part extends laterally from the same region.
The third compartment is that of the two orbits. They are cone-shaped chambers present immediately inferior to the anterior aspect of the cranial cavity. They contain the eyes. The walls of the orbit are comprised of bones, whereas the base of each conical chamber is covered by the eyelids.
The fourth compartment are the nasal cavities. They are located between the orbits, and form the upper portion of the respiratory tract. Bones and cartilages comprise the walls, floors, and roofs of the nasal cavities. The nares (or nostrils) form their anterior openings.
The last compartment is the oral cavity. It is located inferior to the nasal cavities, and separated from them by the hard and soft palates. Its floor is formed entirely by soft tissues. And the oral fissure (mouth) forms its anterior opening. In addition to these compartments, the infratemporal and pterygopalatine fossae are two anatomically defined regions on either side of the head. They serve as areas of transition from one compartment of the head to another.
Face and scalp
The face and scalp are also anatomically defined regions related to the external surface of the head. The face forms its anterior aspect. It is comprised of an unique group of muscles that control facial expression, and act as sphincters and dilators for the orifices of the face. These muscles originate from the second pharyngeal arch and are innervated by the facial nerve (CN VII). The face also provides the distinguishing features of an individual, from hair and eye color, to nose, eye, mouth shape and wrinkles.
The scalp is a multilayered structure formed by the skin, connective tissue, aponeurotic layer, loose connective tissue, and the pericranium (S.C.A.L.P). The first three layers form a single unit called the scalp proper, which is the tissue affected in scalp injuries. The scalp encloses the superior, posterior and lateral regions of the head. It extends from the superciliary arches anterior to the external occipital protuberance, and superior nuchal lines posteriorly. Laterally, it extends inferiorly to the zygomatic arch.