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_1120_Библиотеки_им_академика_М_И_Перельмана
.pdf
55
t.me/Dr_Mouayyad_AlbtousH
https://t.me/med1917
FIGURE 1-13 Sequential schematic representations of the
development of the face in frontal and lateral views of the embryo
from approximately the twenty-fourth day of gestation to 14
weeks' gestation. (From Moore KL, and Persaud TVN: Before we are born [7th
ed]. St. Louis: Elsevier, 2008.)
56
t.me/Dr_Mouayyad_AlbtousH
https://t.me/med1917
FIGURE 1-14 Schematic representation of the difference
between merging and fusion in the embryo. (From Patten MB: Normal
development of the facial region. In Pruzansky S [ed]: Congenital anomalies of the face
and associated structures. Springfield, IL: Charles C Thomas, 1961, p. 15.)
The embryonic structures that form the face begin as the branchial
apparatus. This structure is visible on the embryo at the beginning of the
fourth week after conception, and it appears as two rounded ridges on
each side of the future head and neck region. The branchial apparatus
eventually gives rise to the ears, maxilla, mandible, and anterior portion
of the neck. The apparatus consists of paired (one left, one right)
external branchial or pharyngeal arches, branchial grooves between the
arches (the first branchial groove becomes the external auditory canal),
57
t.me/Dr_Mouayyad_AlbtousH
https://t.me/med1917
internal pharyngeal pouches reaching toward those grooves, and
branchial membranes that separate the pouches from the grooves. On
the twenty-second day after conception, the first pair of branchial arches
is separated by a midline depression that will become the primitive
mouth (stomodeum).
By the end of the fourth week of embryonic life, four pairs of arches
are visible: the mandibular arch, consisting of an upper maxillary process
and a lower mandibular process; the hyoid arch; and third and fourth
arches that are designated by number only. Each arch has four
elements: an artery, a cartilaginous bar, a muscle element, and a nerve
growing into it from the brain.
The frontonasal process forms two median nasal processes between the
two nasal pits (visible on the embryo by the thirty-first day of
intrauterine life) and two lateral nasal processes that form the nasal alae.
Together, the two sets of nasal processes form the upper boundary of
the primitive mouth. The lateral boundary is formed by the paired
maxillary processes, and the lower boundary is formed by the paired
mandibular processes. Development of the nose, nasal floor, upper lip,
and palate depends on normal growth and successful joining of the
lateral and medial nasal processes and the maxillary processes.
Formation of the Primary Palate
Fusion of the medial nasal processes, the lateral nasal processes, and the
paired maxillary processes produces the primary palate, which forms
most of the upper lip (roughly the middle two thirds), the
corresponding portion of the maxillary alveolar ridge, and the anterior
portion of the maxilla back to the incisive foramen. As noted earlier,
these portions of the alveolar ridge and hard palate are collectively
called the premaxilla (synonymous with the primary palate); the
associated portion of the lip is called the prolabium. The nasal septum
grows downward and fuses with the palate during the sixth week after
conception.
Formation of the Secondary Palate
The secondary palate is formed by the meeting and fusion of the palatine
processes or palatal shelves, which are medial projections from the left and
right maxillary processes. The shelves are initially in a vertical position
58
t.me/Dr_Mouayyad_AlbtousH
https://t.me/med1917
in the embryo, hanging down on either side of the tongue. They must
elevate over the tongue and reach toward each other as they grow
before they can consolidate. The palatal shelves also fuse with the
primary palate along the left and right premaxillary sutures and with the
nasal septum and vomer bone superiorly. The premaxillary sutures are
the “sides” of the V shape of the primary palate. The rest of the hard
palate and all of the soft palate comprise the secondary palate.
Formation of the secondary palate is complete sometime between the
tenth and twelfth weeks of gestation.
Embryology of Clefts
Clefts of the primary palate appear if the lateral nasal processes, median
nasal processes, and maxillary processes do not grow to sufficient size
at the right time to meet each other or if the fusion between paired
processes and associated structures is impeded. Simonart's band, which
is a very thin bridge of tissue crossing between segments of a cleft of the
primary palate (Fig. 1-15), and congenital fistulas in the secondary
palate are interpreted by many scientists to be evidence of postfusion
rupture in the embryo.
59
t.me/Dr_Mouayyad_AlbtousH
https://t.me/med1917
FIGURE 1-15 Very thin bridge of soft tissue across an
otherwise complete cleft of the lip and palate. This bridge of
tissue is often called a Simonart's band. On close examination,
one can see that this baby actually has an incomplete bilateral
cleft of the primary palate because the child also has a small
defect of the lip on the right side (not easily seen in this picture)
and a more easily seen but small defect of the alveolus. The cleft
of the secondary palate is quite wide. (From Peterson-Falzone SJ, Hardin-
Jones MA, Karnell MP: Cleft palate speech [4th ed]. St. Louis: Elsevier, 2010.)
Fig. 1-2 is a good example of an incomplete cleft of the primary palate
in a patient with an intact secondary palate. Fig. 1-16 shows a baby with
an incomplete cleft of the primary palate but a complete cleft of the
secondary palate.
60
t.me/Dr_Mouayyad_AlbtousH
https://t.me/med1917
FIGURE 1-16 Infant with an incomplete unilateral cleft of the lip
and alveolus on the left, but a complete cleft of the secondary
palate. Notice the straight base of the vomer bone in the
midline. (From Peterson-Falzone SJ, Hardin-Jones MA, Karnell MP: Cleft palate
speech [4th ed]. St. Louis: Elsevier, 2010.)
The fusion of the shelves and the formation of the soft palate take
place in a front-to-back (anterior-to-posterior) order of progression.
Thus the least severe clefts are the minor defects of the uvula, and the
most severe defects are the clefts that affect the entire soft palate and
hard palate. In many infants with very wide clefts the palatal shelves
are still vertical. The normal process of shelf elevation and fusion takes
place approximately 1 week later in girls than in boys (Burdi and Silvey,
1969). This timing difference may help explain why girls are more
susceptible to clefts of the secondary palate alone without cleft lips:
formation of the secondary palate takes more time in girls, thereby
providing more of a time window for adverse effects of environmental
agents.
Marazita and Mooney (2004, p. 134) pointed this out: “In humans and
in animal models for cleft palate wide clefts usually result when shelves
remain in the vertical position, whereas narrow clefts usually indicate
elevated shelves that failed to contact and fuse or that failed to fuse
even if contact was made.” Johnston et al. (1990, p. 2539) spoke to the
same point: “The fact that so many clefts are incomplete (when contact
[between the palatal shelves] is insufficient for complete fusion)
indicates that a large number of embryos are siing squarely on the
threshold.”
61
t.me/Dr_Mouayyad_AlbtousH
https://t.me/med1917
It is worth noting that, within the subgroups of unilateral CL ± P,
bilateral CL ± P, and CPO, the infants with more severe clefts tend to
have more associated anomalies. For example, an infant with a
complete bilateral cleft lip and palate is more likely to have associated
anomalies than an infant with an incomplete bilateral cleft. Babies with
CPO are more likely to have associated anomalies than the other two
groups, and infants with the wider clefts are more likely to have other
defects (or syndromes) than those with smaller clefts.
62
t.me/Dr_Mouayyad_AlbtousH
https://t.me/med1917
A Final Note
In this chapter, we discuss clefts not by classification (many different
classification systems are available) but by description of facial and
intraoral findings. Classification systems are useless if they are not
mutually shared by all professionals caring for the youngster. Some
such systems actually confuse overt clefts with submucous clefts and
even with noncleft VPI.
The assessment and treatment of the speech problems often found in
youngsters with clefts or noncleft VPI can be discussed as nearly one
topic because these children have so many of the same needs. That is
the approach taken in this book. As you will detect many times
throughout the text, we believe that the speech-language pathologist
should be second in command (but only with regard to speech!), right
after the child's parents.
Good care for a child with a cleft or noncleft VPI starts with knowing
what to expect. Very early in the life of that child, his or her caregivers
need to know about the likelihood of associated anomalies such as heart
and kidney defects, immune deficiencies, ear disease, or developmental
problems. That is why it is necessary to document the condition in
detail and similarly to document not only speech development and
problems but every new development or problem as the child grows.
63
t.me/Dr_Mouayyad_AlbtousH
https://t.me/med1917
References
Burdi AR, Silvey RG. Sexual differences in closure of the human
palatal shelves. Cleft Palate J. 1969;6:1–7.
Calzolari F, Pierini A, Astolfi G, et al. Associated anomalies in
multi-malformed infants with cleft lip and palate: an
epidemiologic study of nearly 6 million births in 23 EUROCAT
registries. Am J Med Genet. 2007;143:528–537.
Johnston MC, Bronsky PT. Millicovsky G: Embryogenesis of cleft
lip and palate. McCarthy JG. Plastic surgery. Saunders:
Philadelphia; 1990:2525–2552. Cleft lip and palate and craniofacial
deformities. vol 4.
Jones MC. Etiology of facial clefts: prospective evaluation of 428
patients. Cleft Palate J. 1988;25:16–20.
Jones MC. The genetics of clefting. Presented at the third annual
MUSC craniofacial and cleft anomalies conference. [Charleston,
South Carolina; April 13] 2013.
Marazita ML, Mooney MP. Current concepts in the embryology
and genetics of cleft lip and palate. Clin Plast Surg. 2004;31:125–
140.
Melnick M. Cleft lip (+ cleft palate) etiology: a search for solutions.
J Med Genet. 1992;42:10–14.
Peterson-Falzone SJ, Hardin-Jones MA, Karnell MP. Cleft palate
speech. 4th ed. Elsevier: St. Louis; 2010.
64
https://t.me/med1917
t.me/Dr_Mouayyad_AlbtousH
Соседние файлы в папке Библиотека им академика М.И. Перельмана