Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4450_Библиотеки_им_академика_М_И_Перельмана
.pdf
1.3Nasal Development and Growth
1.3.1The Phases
Two phases should be distinguished in nasal ontogenesis:
the developmental phase, and the growth phase.
Developmental or Morphogenetic Phase
The developmental phase is the period of embryonic life
during which the nose and related structures are formed.
This phase lasts roughly from the third week to the third
month after conception. At the third week, the maxillary
and mandibular processes begin to develop, and the nasal
olfactory placode becomes visible. At about the third
month, formation of the nose, maxilla, and mandible is
completed.
Growth Phase
In the subsequent growth phase, the dimensions of the
nose and related structures increase. Simultaneously,
changes in the anatomical relationships of the various nasal
structures occur, while several cartilaginous structures
become partially or completely ossified. The nose grows
rapidly in the first few years of life but growth gradually
slows down. A second period of growth occurs during
puberty. The growth phase may be divided into the
following more or less arbitrary periods: prenatal, neonatal,
childhood, and pubertal.
1.3.2Developmental Phase
The nose and midface are formed by the two maxillary and
mandibular processes and the frontonasal prominence
between the fourth and eighth week of postovulatory age.
Age 4 Weeks (Length 3–5 mm)
The olfactory placode (or nasal placode) becomes visible as
a convex thickening of the surface ectoderm. It transforms
into the fovea nasalis and then forms the nasal sac. From
then on, a frontonasal prominence starts to develop in a
caudal direction. Simultaneously, the two maxillary and
mandibular processes grow from lateral to medial (see ▶
Fig. 1.108).
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
Fig. 1.108The human face at 5 to 6 weeks of embryonic life (length 5 to 6 mm). 1 =
lateral nasal process; 2 = medial nasal process; 3 = primary nasal cavity; 4 = maxillary
process; 5 = mandibular process. (After [52].)
Age 5 to 6 Weeks (Length 5–6 mm)
The frontonasal prominence divides into a medial and a
lateral nasal process. The maxillary processes first fuse
with the lateral nasal folds and then extend and fuse with
the medial folds. The two mandibular processes also fuse at
this stage. The openings between the maxillary and
mandibular processes form the primitive mouth (▶ Fig.
1.108). If the fusion between the maxillary process and the
nasal processes is incomplete, a cleft will remain. The
result will be a cleft lip and/or palate.
Age 6 to 7 Weeks (Length 12–18 mm)
The anterior nares are formed and the grooves between the
various processes gradually disappear. The primitive nasal
cavity is formed as well as a transverse furrow between the
frontonasal prominence and forehead. The nasal pyramid
becomes recognizable.
Age 7 to 8 Weeks (Length 22 mm)
The nasal capsule is formed, consisting of a median septal
part and two lateral parts. The septum starts to develop in
a caudal direction. Three transverse prominences appear
on the lateral wall of the nasal cavity to become the three
main turbinates (▶ Fig. 1.109).
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
Fig. 1.109Coronal section at 7 weeks (length 22 mm). 1 = septum; 2 = tongue; 3 =
palatine process; 4 = buds of superior, middle and inferior turbinates. (After [7].)
Age 2 to 2.5 Months (Length 3–4 cm)
Ossification of the maxillary and palatine processes starts.
Age 3 to 3.5 Months (Length 10–12 cm)
The nasal capsule and turbinates are still cartilaginous (▶
Fig. 1.110).
Fig. 1.110Coronal section at 3.5 months (length 18 cm). 1 = septum; 2 = vomeral
alae; 3 = beginning of ossification of turbinates; 4 = ossification of maxilla. (After [7].)
Age 4 to 4.5 Months (Length 15–18 cm)
Ossification of the nasal capsule and of the lateral part of
the inferior turbinate begins (▶ Fig. 1.111).
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
Fig. 1.111Coronal section at about 4 months (length 18 cm). 1 = nasal bones with
underlap of upper margin of triangular cartilages; 2 = septolateral cartilage; 3 = septal
cartilage with processus lateralis ventralis and paraseptal or vomeronasal cartilage.
(After [183].)
1.3.3Growth Phase
Face and Nose
At birth, the facial part of the skull is smaller than its
cranial part. By adulthood they are about the same size.
The neurocranium reaches 90% of its adult dimensions by
the age of 6 years. The viscerocranium, on the other hand,
continues to grow until 18 to 20 years of age. The external
nasal pyramid becomes more prominent, higher, and
longer. The maxilla and the mandible grow in a ventral
direction.
Nasal growth rate is high in embryonic life and during the
first months after birth. It then gradually decreases until
the onset of sexual maturation, when it strongly
accelerates. This pubertal growth spurt continues until age
16 to 17 years in girls and 16 to 18 years in boys, then
rapidly declines. Nasal growth rate generally follows the
same pattern as the growth velocity of the skeleton as a
whole as measured by body length (▶ Fig. 1.112). During
adult life, the nose continues to grow slowly, in contrast to
body length.
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
Fig. 1.112Growth rate of body length in relation to age in boys and girls. (After data
from [300].)
Septum
The septum develops from the medial wall of the nasal
capsule between the seventh to eighth week and the
second to third month of embryonic life. In the beginning, it
is completely cartilaginous; later, some parts start to ossify.
At birth, the vomer, maxillary crest, and palatine crest are
bony. After birth, the posterior part of the septum gradually
ossifies from cranial to caudal and from caudal to cranial
directions. The septum, in particular its anterior part,
demonstrates rapid growth in neonatal life and in early
childhood. Its growth then gradually slows down.
The septum plays a decisive role in the ventral growth of
the nasal pyramid, the nasal cavity, and the midface. This
has been shown clearly by the work of Scott (1950) and
[276], and by the elaborate experiments on rabbits by
Verwoerd and collaborators in the 1980s and 1990s. While
the growth of the more caudal part of the septal cartilage
influences the outgrowth of the midface, the growth of its
anterior and ventral part determines the prominence and
length of the nasal pyramid. This has also been
demonstrated in patients who have suffered a septal injury
in early childhood ([140]; [249], [245]; [91]).
Cartilaginous Septum
The cartilaginous septum grows rapidly in the first 2 years
of life. Its growth then slows down and almost stops after
the age of 3 years (▶ Fig. 1.113 and ▶ Fig. 1.114). At that
point, the cranial and posterior part of the cartilaginous
septum starts to ossify by enchondral ossification in an
anterior and caudal direction, thereby forming the
perpendicular plate. This process continues in adult life,
though at a slower pace. The basal margin of the septal
cartilage is fitted into a groove formed by the two fusing
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
Соседние файлы в папке Библиотека им академика М.И. Перельмана