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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4450_Библиотеки_им_академика_М_И_Перельмана
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turbinate. Because of its location and structure it is to
be considered a (rudimentary) turbinate.
Mucoperichondrium, Mucoperiosteum
The mucoperichondrium and mucoperiosteum consist of
the following structures: (1) the mucous membrane with
ciliated and nonciliated cells, goblet cells, and basal cells;
(2) a basement membrane; (3) a lamina propria with
seromucous glands; and (4) the perichondrium or
periosteum. See also ▶ Fig. 1.75 and ▶ Mucoperichondrium.
Mucous Membrane
The nasal cavity is lined by a membrane that is composed
of four different types of cells: ciliated columnar cells,
nonciliated columnar cells, secretory cells or goblet cells,
and basal cells (▶ Fig. 1.48).
Fig. 1.48Nasal mucosa (TEM) (from [280]).
B = basal cell; BM = basement membrane; C = ciliated columnar cell; M = mucus-
producing goblet cell; NC = nonciliated columnar cell.
The ciliated columnar cells are long slender cells. They are
covered by 300 to 400 microvilli as well as some 100 to 250
cilia that are in constant movement (▶ Fig. 1.49). The cilia
are embedded in a layer of thin fluid and covered by a layer
of thicker mucus. This superficial blanket of mucus is
transported over the thinner fluid layer in a posterior
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direction by the ciliary beat movement, the so-called
mucociliary transport (MCT). This system is one of the most
important defense mechanisms of the upper respiratory
tract (▶ Cilia).
Fig. 1.49Schematic representation of a cilium.
1 = central microtubule; 2 = peripheral doublet of microtubule; 3 = radial spoke; 4 =
outer dynein arm; 5 = inner dynein arm.
The nonciliated columnar cells are similar in size to the
ciliated cells. They are only provided with microvilli that
increase their functional surface area.
The secretory cells or goblet cells are covered by microvilli
and filled with granules. The number of granules in the
cytoplasm gradually increases with time. These granules
distend the cell (hence the name goblet), which finally
leads to a discharge of secretions through its upper surface
(called apocrine secretion). The goblet cells produce the
more viscous component of the mucus.
According to the studies of Tos and collaborators (1982),
the number of goblet cells varies from about 5,700/mm2 on
the septum to 6,000/mm2 in the sinuses, 8,000/mm2 on the
middle turbinate, and 11,000/mm2 on the inferior turbinate.
Their density is higher in children than in adults. In the
nasal cavity, their density slightly increases from anterior
to posterior. In general, the number of goblet cells is higher
in areas where the mucosa is not in contact with air
currents, for example the lateral wall of the inferior
turbinate. (Experimental) breathing obstruction has been
found to cause an increase of goblet cells.
The basal cells are short and rest on the basement
membrane. They do not reach the epithelial surface and are
probably replacement cells.
Basement Membrane
The basement membrane consists of a thin continuous
layer with a thicker layer of collagen fibers underneath.
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This membrane separates the epithelial cells from the
submucosa or lamina propria.
Lamina Propria (Submucosa)
In the submucosa, three layers can be recognized:
A superficial layer of fenestrated capillaries
A layer of mixed tubuloalveolar glands
A zone of venous plexuses of various thickness that
rests on the perichondrium or periosteum and may
develop into a thick mass of cavernous tissue in the
various turbinates
Seromucous Glands
The nasal mucosa is provided with a large number of
glands that produce the more liquid superficial layer of
mucus.
There are two types:
1. The anterior glands (altogether some 20 to 30) with
relatively long ducts that open into the vestibule.
2. The small seromucous glands that are present in the
whole mucosa. Their total number amounts to some
16,000. In contrast to the goblet cells, their density
slightly decreases from anterior to posterior. Their
numbers are somewhat higher on the septum than on
the inferior and middle turbinates ([306]).
Perichondrium, Periosteum
The perichondrium and periosteum consist of several layers
of connective tissue fibers running parallel to the cartilage
or bone. Small blood vessels and nerves run between the
fibers of its outer layers (see ▶ Fig. 1.75).
Mucous Layer
The mucous layer is composed of two sheets:
A lower layer of thin fluid, the periciliary or sol layer,
which surrounds the cilia
An upper gel layer with a higher viscosity
The mucous blanket adds water and warmth to the inspired
air and captures particles in its upper layer (pollutants,
micro-organisms, allergens, etc.). Its thickness varies
between 0.5 and 1.0 mm. The mucus is produced by the
goblet cells and seromucous glands.
Cilia
Phylogenetically, cilia are among the oldest biological
structures. They can even be found on the surface of
protozoa. The length of a respiratory cilium is 5 to 7 mm. It
consists of an axoneme and a surrounding cell membrane.
It has a basal body and a basal root fixed into the
epithelium. The axoneme is made up of two central single
microtubules and nine pairs of peripheral microtubules
with outer and inner dynein arms (▶ Fig. 1.49). These arms
are missing in patients with primary (genetic) ciliary
akinesia.
Vomeronasal Organ (Organ of Jacobson)
The vomeronasal organ is a small canal and pouch lined
with chemosensory cells, located in the deep layers of the
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septal perichondrium at the base of the anterior septum (▶
Fig. 1.50). For details see also ▶ Fig. 1.78, ▶ Fig. 1.79, and ▶
Fig. 1.80; ▶ Vomeronasal Organ. It is considered a vestige of an
earlier phylogenetic accessory olfactory organ. Its
dimensions vary considerably (length: 3 to 12 mm; volume:
2.0 to 34.10−4 mL). It develops from the medial wall of the
olfactory placode and detects chemical signals, especially
odors with a sexual or territorial significance called
pheromones. The vomeronasal organ is found in all
mammals, and recent clinical and cadaveric studies have
shown it to be present in about 80% of human adults. No
differences between males and females have been
observed. In septal surgery, the vomeronasal organ should
be respected. This means that the mucoperichondrium
should be elevated underneath the deepest perichondrial
fibers using a blunt elevator.
Fig. 1.50Vomeronasal organ (organ of Jacobson), consisting of a short duct and a small
pouch lined with high columnar epithelium located in the perichondrium of the base of
the anterior part of the cartilaginous septum.
1.1.4Vasculature of the Nose
The nasal structures receive their blood supply from the
external as well as the internal carotid system (ECS and
ICS; ▶ Fig. 1.51). See ▶ Fig. 10.56 for more details.
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Fig. 1.51The vascular supply of the internal and external nose is derived from both the
internal and the external carotid system.
The anterior septum, the ethmoid bone, and the major part
of the external pyramid receive their blood from the
internal carotid system through branches of the ophthalmic
artery.
The turbinates, inferior part of the septum, palate, the
paranasal area, upper lip, vestibule, columella, and lower
lip are supplied by the external carotid system through two
of its main branches, the maxillary and the facial arteries.
Knowledge of the differences between the basins of the two
systems is of utmost importance in managing nasal blood
loss. Serious recurrent epistaxis from the lower half of the
nasal cavity may be treated by clipping the maxillary artery
or by ligation of the external carotid artery (ECA). Bleeding
from the cranial part of the nasal cavity requires
coagulation or clipping of the anterior and/or posterior
ethmoidal artery. This may be done either endonasally or
through a paranasal, transorbital approach.
Vasculature of the External Nasal Pyramid
The blood supply of the external nasal pyramid is very
variable and usually asymmetric. The nasal pyramid
receives its blood supply mainly from the facial artery
(ECS). In addition, the nasal dorsum is partially supplied by
the ICS through the dorsal nasal artery, a terminal branch
of the ophthalmic artery that leaves the orbit below the
trochlea, and by the external nasal branch of the anterior
ethmoidal artery, which emerges between the nasal bone
and the triangular cartilage (▶ Fig. 1.52).
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