The infantry brigade combat team, as of 2014, contains 4,413 soldiers and is organized around three battalions of infantry. Each type of brigade (light infantry, air assault, or airborne) has the same basic organization.
2.1 Structure and function of the outer and middle ear. Figure 1 is a diagram of the human ear. The outer ear consists of the visible part of the ear or pinna, the external auditory canal (meatus) , and the tympanic membrane (tympanum) or eardrum.The human pinna is formed primarily of cartilage and is attached to the head by muscles and ligaments.igure 1 is a diagram of the human ear. The outer ear consists of the visible part of the ear or pinna, the external auditory canal (meatus) , and the tympanic membrane (tympanum) or eardrum.
Causes. Normal common bacteria resides on the skin of the pinna. A breach of the skin can allow the normal bacteria that resides on the skin of the pinna to infect the skin and the underlying cartilage. Trauma to the pinna and cartilage is the most common cause of pinna infection. If the infection involves the cartilage, it is called perichondritis. Sometimes the infection is severe enough to destroy the cartilage and cause an abscess (pus collection). Infection of the external ear canal may also spread to involve the pinna.