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_4407_Библиотеки_им_академика_М_И_Перельмана
.pdf
316
https://t.me/med1917
SECTION IV — Diseases of Pharynx
TABLE 55.4 SUMMARY OF MANAGEMENT OF OSA
Nonsurgical Surgical
• Weightreduction
• Avoidanceofalcohol,sedativesandsmoking
• Positionaltherapy
• Intraoraldevices
• Mandibular advancement device
• Tongue retention device
• CPAPorBiPAPorAPAP
• Tonsilandadenoidsurgery(children)
• Nasalsurgery:septoplasty,turbinatereduction,polypectomy
• Palatesurgery
• Uvulopalatoplasty (UPP)
• Uvulopalatopharyngoplasty (UPPP)
• Advancementpharyngoplasty
• Tonguebasesurgery:lingualtonsillectomy,lasermidlineglossectomy
• Tonguebaseradiofrequencyreduction
• Mandibularosteotomywithgenioglossusadvancement
• Hyoidmyotomyandsuspension
• Hyoid bone suspended to lower border of mandible
• Hyoid bone suspended to upper border of thyroid cartilage
• Maxillomandibularosteotomyandadvancement
• Tracheostomy—thegoldstandard
Procedure involves resection of a rectangular portion
of the mandible including genial tubercles and the attached genioglossi muscles, its rotation by 90° and fixation by plates. It helps to pull the base of tongue anteriorly. Along with this procedure, the hyoid bone is freed
from its inferior musculature and suspended from lower
border of mandible by wires. This also helps to pull the
base of tongue anteriorly.
5. Tongue base radiofrequency. Radiofrequency (RF)
is used in five to six sittings to reduce the size of tongue.
RF needle is inserted submucosally. It coagulates tissue
and causes scarring thus reducing the size of tissue.
6. Maxillomandibular advancement osteotomy. Osteotomies are performed on mandibular ramus and maxilla. Osteotomy of the maxilla is like a Le Fort I procedure.
These osteotomies are then fixed in anterior position with
plates and screws. This surgical procedure is effective in
selected cases but has the disadvantage of causing aesthetic facial changes.
See Table 55.4 for summary of management of OSA.
SECTION V
https://t.me/med1917
Diseases of Larynx
and Trachea
S e c t i o n o u t l i n e
56 Anatomy and Physiology of Larynx, 319
57 Laryngotracheal Trauma, 325
58 Acute and Chronic Inflammations of Larynx, 327
59 Congenital Lesions of Larynx and Stridor, 333
60 Laryngeal Paralysis, 337
61 Benign Tumours of Larynx, 343
62 Cancer Larynx, 347
63 Voice and Speech Disorders, 355
64 Tracheostomy and Other Procedures for Airway Management, 359
65 Foreign Bodies of Air Passages, 365
Page left intentionally blank
https://t.me/med1917
Chapter 56
https://t.me/med1917
Anatomy and Physiology of Larynx
ANATOMY OF LARYNX
The larynx lies in front of the hypopharynx opposite the
third to sixth cervical vertebrae. It moves vertically and in
anteroposterior direction during swallowing and phonation. It can also be passively moved from side to side producing a characteristic grating sensation called laryngeal
crepitus. In an adult, the larynx ends at the lower border
of C6 vertebra.
LARYNGEAL CARTILAGES
Larynx has three unpaired and three paired cartilages.
Unpaired: Thyroid, cricoid and epiglottis.
Paired: Arytenoid, corniculate and cuneiform.
1. Thyroid. It is the largest of all (Figure 56.1). Its two
alae meet anteriorly forming an angle of 90° in males
and 120° in females. Vocal cords are attached to the
middle of thyroid angle. Most of laryngeal foreign
bodies are arrested above the vocal cords, i.e. above the
middle of thyroid cartilage and an effective airway can
be provided by piercing the cricothyroid membrane—
a procedure called cricothyrotomy.
2. Cricoid. It is the only cartilage forming a complete
ring. Its posterior part is expanded to form a lamina
while anteriorly it is narrow forming an arch.
3. Epiglottis. It is a leaf-like, yellow, elastic cartilage forming anterior wall of laryngeal inlet. It is attached to the
body of hyoid bone by hyoepiglottic ligament, which
divides it into suprahyoid and infrahyoid epiglottis. A
stalk-like process of epiglottis (petiole) attaches the epiglottis to the thyroid angle just above the attachment
of vocal cords. Anterior surface of epiglottis is separated from thyrohyoid membrane and upper part of
thyroid cartilage by a potential space filled with fat—
the pre-epiglottic space. The space may be invaded in
carcinoma of supraglottic larynx or the base of tongue.
Posterior surface of epiglottis is concavoconvex—
concave above but convex below forming a bulge called
tubercle of epiglottis, which obstructs view of anterior
commissure when examining larynx by indirect laryngoscopy. Epiglottic cartilage shows several pits which
lodge the mucous glands. It may also show perforations
providing direct communication between the laryngeal
surface of epiglottis and pre-epiglottic space. Supraglottic cancers can spread through them to pre-epiglottic
space. Epiglottis is not essential for swallowing and can
be amputated in carcinoma with little aspiration.
4. Arytenoid cartilages. They are paired. Each arytenoid
cartilage is pyramidal in shape. It has a base which
articulates with cricoid cartilage; a muscular process,
directed laterally to give attachment to intrinsic laryngeal muscles; a vocal process directed anteriorly, giving
attachment to vocal cord; and an apex which supports
the corniculate cartilage.
5. Corniculate cartilages (of Santorini) (Corn = horn).
They are paired. Each articulates with the apex of arytenoid cartilage as if forming its horn.
6. Cuneiform cartilages (of Wrisberg). They are rod
shaped. Each is situated in aryepiglottic fold in front
of corniculate cartilage and provides passive supports
to the fold.
Thyroid, cricoid and most of the arytenoid cartilages
are hyaline cartilages whereas epiglottis, corniculate, cuneiform and tip of arytenoid near the corniculate cartilage
are elastic fibrocartilage. Hyaline cartilages can undergo
ossification; it begins at the age of 25 years in thyroid, a
little later in cricoid and arytenoids, and is complete by
65 years of age. Calcification seen in these cartilages can
be confused with foreign bodies of oesophagus or larynx
on X-rays.
LARYNGEAL JOINTS
cricoarytenoid joint. It is a synovial joint surrounded
by capsular ligament. It is formed between the base of arytenoid and a facet on the upper border of cricoid lamina.
Two types of movements occur in this joint: (i) rotatory,
in which arytenoid cartilage moves around a vertical axis,
thus abducting or adducting the vocal cord; (ii) gliding
movement, in which one arytenoid glides towards the other cartilage or away from it, thus closing or opening the
posterior part of glottis.
Figure 56.1. Laryngeal framework.
319
320
https://t.me/med1917
cricothyroid joint. It is also a synovial joint. Each is
formed by the inferior cornua of thyroid cartilage with a
facet on the cricoid cartilage. Cricoid cartilage rotates at
these joints on a transverse axis which passes transversely
through these joints.
SECTION V — Diseases of Larynx and Trachea
LARYNGEAL MEMBRANES
membrane and ligaments oF larynx. The term extrinsic is used when membrane or ligament attaches to
the structures outside the larynx, i.e. to the hyoid bone
or trachea. The term intrinsic is used for membranes joining within the larynx but not extending to hyoid bone
or trachea.
1. Extrinsic membranes and ligaments
(Figure 56.1)
(a) Thyrohyoid membrane. It connects thyroid cartilage to
hyoid bone. It is pierced by superior laryngeal vessels
and internal laryngeal nerve.
(b) Cricotracheal membrane. It connects cricoid cartilage
to the first tracheal ring.
(c) Hyoepiglottic ligament. It attaches epiglottis to hyoid
bone (Figure 56.2).
2. Intrinsic membranes and ligaments
(a) Cricovocal membrane. It is a triangular fibroelastic
membrane. Its upper border is free and stretches between middle of thyroid angle to the vocal process of
arytenoid and forms the vocal ligament (Figure 56.2).
Its lower border attaches to the arch of cricoid cartilage. From its lower attachment the membrane
proceeds upwards and medially and thus, with its
fellow on the opposite side, forms conus elasticus
( Figure 56.3) where subglottic foreign bodies sometimes get impacted.
(b) Quadrangular membrane. It lies deep to mucosa of ar-
yepiglottic folds and is not well-defined. It stretches
between the epiglottic and arytenoid cartilages. Its
lower border forms the vestibular ligament which lies
in the false cord.
Figure 56.3. Coronal section of larynx. Lower free edge of the quadrangular membrane lies in the false cord while upper free edge of
the cricovocal membrane forms the vocal ligament. Note formation of
conus elasticus by the cricovocal membranes of two sides.
(c) Cricothyroid ligament. The anterior part of cricothy-
roid membrane is thickened to form the ligament
and its lateral part forms the cricovocal membrane.
(d) Thyroepiglottic ligament. It attaches epiglottis to thy-
roid cartilage.
MUSCLES OF LARYNX
They are of two types: intrinsic, which attach laryngeal
cartilages to each other and extrinsic, which attach larynx to the surrounding structures.
1. Intrinsic muscles. They may act on vocal cords or
laryngeal inlet.
(a) Acting on vocal cords (Figures 56.4 and 56.5)
• Abductors: Posterior cricoarytenoid
• Adductors: Lateral cricoarytenoid
Interarytenoid (transverse
arytenoid)
Thyroarytenoid (external
part)
• Tensors: Cricothyroid
Vocalis (internal part of
thyroarytenoid)
Figure 56.2. Sagittal section of larynx showing cricovocal and quadrangular membranes and boundaries of the pre-epiglottic space.
Figure 56.4. Laryngeal muscles and their action.
Figure 56.5. Intrinsic muscles of larynx as seen on lateral view.
https://t.me/med1917
Chapter 56 — Anatomy and Physiology of Larynx
321
(b) Acting on laryngeal inlet (Figure 56.5)
• Openers of
laryngeal inlet:
• Closers of
laryngeal inlet:
2. Extrinsic muscles. They connect the larynx to the
neighbouring structures and are divided into elevators
or depressors of larynx.
(a) Elevators. Primary elevators act directly as they are
attached to the thyroid cartilage and include stylopharyngeus, salpingopharyngeus, palatopharyngeus and thyrohyoid.
Secondary elevators act indirectly as they are
attached to the hyoid bone and include mylohyoid (main), digastric, stylohyoid and geniohyoid.
(b) Depressors. They include sternohyoid, sternothy-
roid and omohyoid.
Thyroepiglottic (part
of thyroarytenoid)
Interarytenoid (oblique
part). Aryepiglottic
(posterior oblique part
of interarytenoids)
CAVITY OF THE LARYNX
Laryngeal cavity starts at the laryngeal inlet where it communicates with the pharynx and ends at the lower border
of cricoid cartilage where it is continuous with the lumen
of trachea. Two pairs of folds, vestibular and vocal, divide
the cavity into three parts, namely the vestibule, the ventricle and the subglottic space.
inlet oF larynx. It is an oblique opening bounded
anteriorly by free margin of epiglottis; on the sides, by
aryepiglottic folds and posteriorly by interarytenoid fold
(Figure 56.6).
Vestibule. It extends from laryngeal inlet to vestibular
folds. Its anterior wall is formed by posterior surface of
epiglottis; sides by the aryepiglottic folds and posterior
wall by mucous membrane over the anterior surface of
arytenoids.
Figure 56.6. Laryngeal inlet and intrinsic muscles of larynx as seen
from behind.
Ventricle (sinus oF larynx). It is a deep elliptical
space between vestibular and vocal folds, also extending a short distance above and lateral to vestibular fold.
The saccule is a diverticulum of mucous membrane
which starts from the anterior part of ventricular cavity
and extends upwards between vestibular folds and lamina of thyroid cartilage. When abnormally enlarged and
distended, it may form a laryngocele—an air containing
sac which may present in the neck. There are many mucous glands in the saccule, which help to lubricate the
vocal cords.
subglottic space (inFraglottic larynx). It extends
from vocal cords to lower border of cricoid cartilage.
Vestibular Folds (False Vocal cords). Two in number; each is a fold of mucous membrane extending anteroposteriorly across the laryngeal cavity. It contains vestibular ligament, a few fibres of thyroarytenoideus muscle
and mucous glands.
Vocal Folds (true Vocal cords). They are two pearly
white sharp bands extending from the middle of thyroid
angle to the vocal processes of arytenoids. Each vocal
cord consists of a vocal ligament which is the true upper
edge of cricovocal membrane covered by closely bound
mucous membrane with scanty subepithelial connective
tissue.
glottis (rima glottidis). It is the elongated space
between vocal cords anteriorly, and vocal processes and
base of arytenoids posteriorly (Figure 56.7).
Anteroposteriorly, glottis is about 24 mm in men
and 16 mm in women. It is the narrowest part of laryngeal cavity. Anterior two-thirds of glottis are formed by
membranous cords while posterior one-third by vocal
processes of arytenoids. Size and shape of glottis varies
with the movements of vocal cords. Anterior two-thirds
of glottis is also called phonatory glottis as it is concerned
with phonation but posterior one-third called respiratory
glottis.
322
https://t.me/med1917
SECTION V — Diseases of Larynx and Trachea
Figure 56.7. Rima glottidis. Note anterior two-thirds of vocal cord
is membranous and posterior one-third cartilaginous, and the space
between them is called phonatory glottis and respiratory glottis,
respectively.
MUCOUS MEMBRANE OF THE LARYNX
It lines the larynx and is loosely attached except over the
posterior surface of epiglottis, true vocal cords and corniculate and cuneiform cartilages.
Epithelium of the mucous membrane is ciliated columnar type except over the vocal cords and upper part of the
vestibule where it is stratified squamous type.
Mucous glands are distributed all over the mucous lining and are particularly numerous on the posterior surface of epiglottis, posterior part of the aryepiglottic folds
and in the saccules. There are no mucous glands in the
vocal folds.
Structure of the Vocal Cords
Stratified squamous epithelium lines the vocal cord. It
overlies lamina propria which consists of three layers:
(a) superficial layer (or Reinke’s space),
(b) intermediate layer and
(c) deep layer.
Intermediate and deep layers together form the vocal
ligament (see box).
• Epithelium
• Laminapropria
- Superficial layer
- Intermediate layer
- Deep layer
• Vocalismuscle
Vocal ligament
LYMPHATIC DRAINAGE
Supraglottic larynx above the vocal cords is drained by lymphatics, which pierce the thyrohyoid membrane and go
to upper deep cervical nodes.
Infraglottic larynx below the vocal cords is drained by
lymphatics which pierce cricothyroid membrane and
go to prelaryngeal and pretracheal nodes and thence to
lower deep cervical and mediastinal nodes. Some vessels
pierce through cricotracheal membrane and drain directly into lower deep cervical nodes.
There are practically no lymphatics in vocal cords, hence
carcinoma of this site rarely shows lymphatic metastases.
Figure 56.8. Paraglottic and pre-epiglottic spaces communicate
with each other.
and thyrohyoid membrane in front, hyoepiglottic ligament above and infrahyoid epiglottis and quadrangular
membrane behind. Laterally, it is continuous with paraglottic space. It is filled with fat, areolar tissue and some
lymphatics.
2. paraglottic space. It is bounded by the thyroid cartilage laterally, conus elasticus inferomedially, the ventricle and quadrangular membrane medially, and mucosa
of pyriform fossa posteriorly (Figures 56.3 and 56.8). It
is continuous with pre-epiglottic space. Growths which
invade this space can present in the neck through cricothyroid space.
3. reinke’s space. Under the epithelium of vocal cords
is a potential space with scanty subepithelial connective
tissues. It is bounded above and below by the arcuate
lines, in front by anterior commissure, and behind by
vocal process of arytenoid. Oedema of this space causes
fusiform swelling of the membranous cords (Reinke’s
oedema).
EMBRYOLOGICAL DEVELOPMENT
Laryngeal mucosa develops from the endoderm of the cephalic part of foregut. Laryngeal cartilages and muscles
develop from the mesenchyme. Development of other
structures is as follows:
Epiglottis Hypobranchial
eminence
Upper part of thyroid cartilage 4th arch
Lower part of thyroid cartilage
Cricoid cartilage
Corniculate cartilage
Cuneiform cartilage
Intrinsic muscles of larynx
Upper part of body of hyoid bone
Lesser cornua of hyoid bone
Stylohyoid ligament
Lower part of body of hyoid bone
and greater cornua
6th arch
2nd arch
3rd arch
NERVE SUPPLY (SEE P. 337)
Spaces of the Larynx
1. pre-epiglottic space oF boyer (Figures 56.2
and 56.8). It is bounded by upper part of thyroid cartilage
Superior laryngeal nerve, a branch of vagus, is 4th
arch nerve and supplies cricothyroid and constrictors of
pharynx.
Recurrent laryngeal nerve is 6th arch nerve and supplies all the intrinsic muscles of larynx.
Chapter 56 — Anatomy and Physiology of Larynx
https://t.me/med1917
323
PAEDIATRIC LARYNX
The larynx of an infant differs considerably from that of
an adult and has a great clinical significance.
1. Infant’s larynx is positioned high in the neck level of
glottis being opposite to C3 or C4 at rest and reaches C1
or C2 during swallowing. This high position allows the
epiglottis to meet soft palate and make a nasopharyngeal channel for nasal breathing during suckling. The
milk feed passes separately over the dorsum of tongue
and the sides of epiglottis, thus allowing breathing and
feeding to go on simultaneously.
2. Laryngeal cartilages are soft and collapse easily.
Epiglottis is omega shaped and arytenoids relatively
large covering significant portion of the posterior
glottis.
3. Thyroid cartilage in an infant is flat. It also overlaps
the cricoid cartilage and is in turn overlapped by the
hyoid bone. Thus cricothyroid and thyrohyoid spaces
are narrow and not easily discernible as landmarks
when performing tracheostomy.
4. Infant’s larynx is small and conical. The diameter of cricoid cartilage is smaller than the size of glottis, making
subglottis the narrowest part. It has a bearing in the
selection of paediatric endotracheal tube.
In adults, subglottic-glottic dimensions are approxi-
mately same and larynx is cylindrical.
5. Submucosal tissues of infant’s larynx are comparatively loose and easily undergo oedematous change with
trauma or inflammation leading to obstruction.
Infant’s larynx shows two spurts in growth. In the first
3 years of life, larynx grows in width and length, and
thus obviates the need for any airway surgery in certain
congenital anomalies. The second spurt in growth occurs
during adolescence when the thyroid angle develops.
The length of vocal cords then increases leading to voice
changes associated with puberty (see puberphonia). With
growth of the neck, larynx gradually descends to adult
level; the vocal cords lying opposite C5.
In childhood, vocal cord is 6 mm in females and 8 mm
in males. It increases to 15–19 mm in adult female and
17–23 in adult male.
PHYSIOLOGY OF LARYNX
The larynx performs the following important functions:
1. Protection of lower airways
2. Phonation
3. Respiration
4. Fixation of the chest.
A. PROTECTION OF LOWER AIRWAYS
Phylogenetically, protection of lower airways is the earliest function to develop; voice production is secondary.
The larynx protects the lower passages in three different
ways:
1. Sphincteric closure of laryngeal opening.
2. Cessation of respiration.
3. Cough reflex.
When food is swallowed, its entry into air passage is
prevented by closure of three successive sphincters consisting of (i) laryngeal inlet (aryepiglottic folds, tubercle
of epiglottis and arytenoids, approximate thus closing the
laryngeal inlet completely), (ii) false cords and (iii) true
cords, which close the glottis. Thus, no foreign matter
meant to be swallowed or accidentally vomited can enter
the larynx.
Respiration temporarily ceases through a reflex generated by afferent fibres of ninth nerve, when food comes
in contact with posterior pharyngeal wall or the base of
tongue.
Cough is an important and powerful mechanism to
dislodge and expel a foreign particle when it comes into
contact with respiratory mucosa. Larynx is aptly called
watch-dog of lungs as it immediately “barks” at the entry
of any foreign intruder.
B. PHONATION
Larynx is like a wind instrument. Voice is produced by
the following mechanism (aerodynamic myoelastic theory
of voice production):
1. Vocal cords are kept adducted.
2. Infraglottic air pressure is generated by the exhaled air
from the lungs due to contraction of thoracic and ab-
dominal muscles.
3. The air force open the cords and is released as small
puffs which vibrate the vocal cords and produce sound
which is amplified by mouth, pharynx, nose and chest.
This sound is converted into speech by the modulatory
action of lips, tongue, palate, pharynx and teeth.
Intensity of sound depends on the air pressure produced by the lungs while pitch depends on the frequency
with which the vocal cords vibrate.
C. RESPIRATION
Larynx regulates flow of air into the lungs. Vocal cords
abduct during inspiration and adduct during expiration.
D. FIXATION OF THE CHEST
When larynx is closed, chest wall gets fixed and various
thoracic and abdominal muscles can then act best. This
function is important in digging, pulling and climbing.
Coughing, vomiting, defaecation, micturition and childbirth also require a fixed thoracic cage against a closed
glottis.
Page left intentionally blank
https://t.me/med1917
Chapter 57
https://t.me/med1917
Laryngotracheal Trauma
AETIOLOGY
1. Most common cause is automobile accidents when
neck strikes against the steering wheel or the instrument panel.
2. Blow or kick on the neck.
3. Neck striking against a stretched wire or cable.
4. Strangulation.
5. Penetrating injuries with sharp instruments or gunshot
wounds.
PATHOLOGY
The degree and severity of damage will vary from
slight bruises externally or the tear and laceration of
mucosa internally to a comminuted fracture of the laryngeal framework. The wound may be compounded
externally due to break in the skin or internally by
mucosal tears. Laryngeal fractures are common after
40 years of age because of calcification of the laryngeal
framework. In children, cartilages are more resilient and
escape injury.
Pathological changes that may be seen in laryngeal
trauma are:
1. Haematoma and oedema of supraglottic or subglottic
region.
2. Tears in laryngeal or pharyngeal mucosa leading to
subcutaneous emphysema.
3. Dislocation of cricoarytenoid joints. The arytenoid
cartilage may be displaced anteriorly, dislocated or
avulsed.
4. Dislocation of cricothyroid joint. This may cause recurrent laryngeal nerve paralysis, which traverses just
behind this joint.
5. Fractures of the hyoid bone.
6. Fractures of thyroid cartilage. They may be vertical
or transverse. Fracture of upper part of thyroid cartilage may result in avulsion of epiglottis and one
or both false cords. Fractures of lower part of thyroid cartilage may displace or disrupt the true vocal
cords.
7. Fractures of cricoid cartilage.
8. Fractures of upper tracheal rings.
9. Trachea may separate from the cricoid cartilage and
retract into upper mediastinum. Injury to recurrent
laryngeal nerve is often associated with laryngotracheal separation.
CLINICAL FEATURES
Symptoms of laryngotracheal injury would vary, greatly
depending on the structures damaged and the severity of
damage. They include:
1. Respiratory distress.
2. Change in voice. Hoarseness or aphonia.
3. Painful and difficult swallowing. This is accompanied
by aspiration of food.
4. Local pain in the larynx. More marked on speaking or
swallowing.
5. Haemoptysis, usually the result of tears in laryngeal or
tracheal mucosa.
External signs include:
1. Bruises or abrasions over the skin.
2. Palpation of the laryngeal area is painful.
3. Subcutaneous emphysema due to mucosal tears. It
may increase on coughing.
4. Flattening of thyroid prominence and contour of anterior cervical region. Thyroid notch may not be palpable.
5. Fracture displacements of thyroid or cricoid cartilage
or hyoid bone. Gap may be felt between the fractured
fragments.
6. Bony crepitus between fragments of hyoid bone, thyroid or cricoid cartilages may sometimes be elicited.
7. Separation of cricoid cartilage from larynx or trachea.
DIAGNOSTIC EVALUATION
1. Indirect laryngoscopy or rigid endoscopy of the
larynx. If patient’s condition permits, this is the most
valuable examination. It may reveal location and degree of oedema, haematoma, mucosal lacerations, posterior displacement of epiglottis, exposed fragments of
cartilage, asymmetry of glottis or laryngeal inlet.
2. Flexible laryngoscopy through the nose. It gives
more information than direct laryngoscopy which
may precipitate respiratory disease and need for tracheostomy. Haematoma, mucosal oedema, exposure
of cartilages, arytenoid avulsion or dislocation and vocal chord paralysis can be seen.
3. CT of the larynx. It is very useful in the investigation
of mucosal oedema, fractures of thyroid or cricoid cartilages and dislocation of joints. In addition it gives information about injuries to cervical spine and vascular
structures. 3D CT is proving to be useful in such injuries.
325
Соседние файлы в папке Библиотека им академика М.И. Перельмана