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 / @xirurgi_2025 / @xirurgi_2025 - 686 - файл
.pdf
CHAPTER 5 The Head, Neck and Spine
Vestibular membrane
Membrana tectoria
cartilage
Frontal process
121
• e function of the semicircular ducts is to convey a
sense of motion in any direction, i.e. they tell you where
you are going.
• e function of the utricle and saccule is to convey a
sense of position in space, i.e. they tell you where you
are.
• Each component of the membranous labyrinth has specialized receptors to achieve their function(s):
• maculae of the utricle and saccule
• ampullary crests of semicircular canals
• spiral organ of Corti in the cochlea.
• e disposition of the semicircular canals in three
planes at right angles to each other renders this part of
the labyrinth well suited to signal changes in position of
the head.
• e organ of Corti is adapted to record sound vibrations transmitted by the stapes at the oval window as
follows:
• sound waves set up vibrations in the tympanic
membrane
• transmission occurs through the ossicles and the
stapes is pushed backwards and forwards in the oval
window, setting up vibrations in the perilymph
• these travel up the scala vestibuli (lled with peri-
lymph) in the cochlea, through the helicotrema and
down through the scala tympani to the secondary
tympanic membrane (Fig. 5.17).
• is sets up vibrations in the basilar membrane, and
these are transformed into nerve impulses.
THE NOSE AND PARANASAL AIR SINUSES
The Nose
e nose comprises:
• external nose
• nasal cavity.
External Nose (Fig. 5.18)
• Bony and cartilaginous framework overlaid by skin and
bro–fatty tissue.
Nasal bone
of maxilla
Cartilage of
septum
Upper nasal
cartilage
Lower nasal
cartilage
Fibro-fatty
tissue
Small alar
Fig. 5.18 The bones and cartilage of the lateral aspect
of the right side of the nose.
Scala vestibuli
Osseous spiral lamina
Spiral ganglion
Fig. 5.17 Section through the cochlea.
Scala
tympani
Stria vascularis
Spiral organ
Basilar
membrane
122
Frontal
nasolacrimal
Cut middle
Opening of sphenoidal
Cut superior
concha
opening
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
SECTION I Anatomy
• Bony margins are the two nasal bones and the frontal
process of maxilla.
• Margins completed by nasal cartilages, supported by
septal cartilage.
• Ala is movable and contains small cartilages, but is composed solely of fatty tissue at its lower free edge.
Nasal Cavity
e nasal cavities are separated from one another by the
septum—open in front by the nostrils, and behind by the
posterior apertures opening into the nasopharynx. Each
cavity possesses:
• roof
• oor
• medial wall
• lateral wall.
Roof
• Highly arched.
• Formed by:
• nasal bones
• nasal spine of frontal bone
• cribriform plate of ethmoid
• undersurface of body of sphenoid
• alae of vomer
• sphenoidal process of palatine bone.
Floor
• Corresponds to roof of mouth.
• Formed by:
• palatine process of maxilla
• horizontal plate of palatine bone.
Medial wall (nasal septum)
• Cartilage of septum.
• Crest of nasal bones.
• Perpendicular plate of ethmoid.
• Vome r.
Lateral wall
• Very irregular due to projections of three conchae.
• Formed by:
• frontal process of maxilla
• lacrimal bone
• ethmoid bone
• nasal surface of maxilla
• perpendicular plate of palatine bone
• medial pterygoid plate of sphenoid.
e features of the lateral wall are shown in Fig. 5.19.
Conchae
• ree conchae project into nasal cavity from its lateral
wall:
• superior concha
• middle concha
• inferior concha.
Meatuses
• Conchae divide lateral wall into four recesses:
• sphenoethmoidal recess above superior concha
• superior recess below superior concha
• middle recess below middle concha
• inferior recess below inferior concha.
Openings
• Sphenoethmoidal recess: sphenoidal sinus.
• Superior meatus: posterior ethmoidal air cells.
• Middle meatus:
• bulla of ethmoid (middle ethmoidal air cells open
onto it)
sinus
Frontal
sinus
opening
Fig. 5.19 The lateral wall of the nasal cavity.
Hiatus
semilunaris
Opening of
duct
concha
Inferior
concha
Anterior ethmoidal
sinus into spheno–
ethmoidal space
Posterior ethmoidal
opening
Sphenoidal sinus
Middle ethmoidal
opening
Bulla ethmoidalis
Opening of auditory
tube (Eustachian)
Maxillary ostium
CHAPTER 5 The Head, Neck and Spine
123
• hiatus semilunaris: receives infundibulum of frontal
sinus and anterior ethmoidal air cells in front and
maxillary ostium behind.
• Inferior meatus: nasolacrimal duct.
Mucous Membrane
• Olfactory:
• superior concha
• upper part of middle concha
• corresponding part of septum
• roof of nose.
• Respiratory:
• lines remainder of nasal cavity.
e epithelium of the various parts of the nose is as
follows:
• olfactory region: columnar epithelium
• respiratory region (and paranasal sinuses): columnar
ciliated epithelium with mucous cells
• vestibule: stratied squamous epithelium.
Olfactory Nerve
• Passes from the olfactory mucosa.
• Passes through holes in the cribriform plate to reach the
olfactory bulb.
Blood Supply
• Upper part of nasal cavity: ethmoidal branches of ophthalmic artery.
• Lower part of nasal cavity: sphenopalatine branch of
maxillary artery.
• Septal branch of facial artery anastomoses with sphenopalatine branch of maxillary artery on the anteroinferior part of septum (Little's area); nosebleeds occur
from this area.
• Venous drainage:
• downwards into facial vein
• backwards to ethmoidal tributaries of ophthalmic
veins, and hence ultimately to cavernous sinus.
PARANASAL AIR SINUSES
Paranasal air sinuses are a complex series of airfilled cavities opening into the nasal cavity on each
side. They are effectively extensions of the nasal cavity. They are lined by columnar ciliated epithelium. The
sinuses are:
• maxillary sinus opening into the middle meatus
• ethmoidal air cells (sinuses), which are variable in
number, in three groups: the anterior, middle and
posterior. e anterior and middle cells open into the
middle meatus; the posterior air cells into the superior
meatus
• the frontal sinus opening into the middle meatus via the
infundibulum
• the sphenoidal sinus opening into the sphenoethmoidal
recess.
Maxillary Sinus
• Largest of the paranasal sinuses.
• e medial wall is composed of thin and delicate bones
on the lateral wall of the nasal cavity. e opening of the
sinus into the hiatus semilunaris lies high on the medial
wall just below the oor of the orbit. As the ostium is
high on the wall, drainage depends on ciliary action and
not gravity.
• e roof of the sinus is the oor of the orbit. e canal
for the infraorbital nerve produces a ridge into the sinus
from the roof.
• e posterior wall faces the pterygopalatine fossa and
infratemporal fossa.
• e anterior wall is comparatively thick and lies between
the infraorbital margin and the premolar teeth.
• e oor is a narrow cle between the posterior and
anterior wall in the alveolar process of the maxilla overlying the second premolar and rst molar teeth. e
canine and all molars may be included in the oor if
the sinus is large. e roots of these teeth may produce
projections into the sinus or occasionally perforate the
bone. A tooth abscess may rupture into the sinus. e
oor of the maxillary sinus is at a more inferior level
than the oor of the nasal cavity.
Clinical Points
• For maxillary sinus washout a cannula is inserted into
the sinus via the inferior meatus of the nasal cavity.
• In the Caldwell–Luc operation for maxillary sinusitis the anterior bony wall of the maxillary sinus is
drainage hole is made into the nose through the inferior meatus.
• Carcinoma of the maxillary sinus may invade the palate
and cause dental problems. It may block the nasolacrimal duct, causing epiphora.
• Spread of the tumour into the orbit causes proptosis.
• Posterior spread may involve the palatine nerves and produce severe pain referred to the teeth of the upper jaw.
Nerve Supply
• e maxillary division of the trigeminal nerve via infraorbital and superior dental nerves. Pain due to sinusitis
may oen manifest itself as toothache.
Lymphatic Drainage
• To the upper deep cervical nodes.
124
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
SECTION I Anatomy
Ethmoidal Air Cells (Sinuses)
• Group of 8–10 air cells within the lateral mass of the
ethmoid.
• Lie between the side walls of the upper nasal cavity and
the orbits.
• Above they lie on each side of the cribriform plate and
are related to the frontal lobes of the brain.
• Anterior and middle air cells open into middle meatus.
Posterior air cells open into the superior meatus.
Frontal Sinus
• Contained in frontal bone.
• Varies greatly in size and shape.
• Absent until end of rst year.
• Separated from one another by bony septum.
• Each sinus drains into the anterior part of the middle
meatus via the infundibulum into the hiatus semilunaris.
Sphenoidal Sinus
• Very small at birth.
• Lies within the body of the sphenoid.
• Pituitary gland lies above it and cavernous sinus laterally.
• Opens into the sphenoethmoidal recess above the superior concha.
THE MUSCLES OF MASTICATION
e muscles of mastication are:
• masseter
• temporalis
• lateral pterygoid
• medial pterygoid.
ey are all developed from the mandibular arch, and
therefore supplied by the mandibular division of the trigeminal nerve.
Masseter
Origin
• Anterior two-thirds of lower border of zygomatic arch,
posterior third of lower border and whole of deep surface of arch.
Insertion
• Outer surface of ramus of mandible from mandibular
notch to angle.
Action
• Closes the jaw.
Temporalis
Origin
• From the temporal fossa.
Insertion
• e coronoid process of the mandible.
Action
• Closes the jaw; the most posterior bres, being horizontal, retract the jaw.
Lateral Pterygoid
Origin
• By two heads: lower head from lateral surface of lateral
pterygoid plate; upper head from the interior surface of
the greater wing of the sphenoid.
Insertion
• Passes horizontally backwards to insert into the anterior
surface of the disc of the temporomandibular joint and
into the neck of the mandible.
Action
• Aids in opening the mouth by sliding the condyle forwards, and also protrudes the jaw. One muscle acting
alone pulls the chin over to the opposite side.
Medial Pterygoid
Origin
• Medial side of lateral pterygoid plate with a small slip
from the tubercle of the maxilla.
Insertion
• Fibres pass downwards, backwards and laterally to the
medial surface of the mandible in the roughened area
near the angle.
Action
• Closes the jaw. One muscle acting alone pulls the chin
over to the opposite side. Medial pterygoids are chewing
muscles for molar teeth grinding.
TEMPOROMANDIBULAR JOINT
• Synovial joint.
• Articular surfaces: head of mandible articulates with
mandibular fossa and articular eminence of temporal
bone.
• Articular surfaces are covered by brocartilage (not
hyaline), and there is also a brocartilaginous articular disc dividing the joint cavity into upper and lower
compartments.
• Capsule: attached to neck of mandible around head;
above it is attached just anterior to the articular eminence in front and to the squamotympanic ssure
behind.
CHAPTER 5 The Head, Neck and Spine
Tongue
Geniohyoid
Mylohyoid
r
125
• Articular disc attached around its periphery to joint
capsule.
• Anteriorly the disc is attached to the lateral pterygoid
muscle, and posteriorly to the temporal bone.
• e posterior attachment of the disc is elastic, allowing
forwards movement of the disc with the mandible by
contraction of lateral pterygoid during opening of the
mouth.
• Capsule of joint is reinforced by the lateral temporomandibular ligament, the sphenomandibular ligament
and the stylomandibular ligament.
• Movements of the joint are:
• depression
• elevation
• protrusion
• retraction
• side-to-side movements of the mandible.
e muscles aecting these movements are:
• elevation: masseter, temporalis, medial pterygoid
• depression: lateral pterygoid together with digastric,
mylohyoid and geniohyoid; gravity also allows the jaw
to open during sleep
• retraction: posterior bres of temporalis
• protraction (protrusion): lateral pterygoid
• side-to-side: lateral and medial pterygoids together, acting alternately on each side.
Clinical Points
• e muscles of mastication and their nerve supply are
tested clinically by asking the patient:
• to clench the teeth; contraction of the masseter and
temporalis can be felt
• to move the chin from side to side, testing the activ-
ity of the pterygoid muscles.
• Dislocation of the mandible occurs in a forwards direction, where the condyloid process of the mandible slides
forwards onto the articular eminence and then into the
infratemporal fossa. is can be reduced by pressing
down the mandible on the molar teeth to stretch the
masseter and temporalis which are in spasm and then
pulling up the chin to lever the condyle back into the
mandibular fossa.
FLOOR OF THE MOUTH AND
TONGUE (Fig. 5.20)
Floor of the Mouth
• Formed by the mylohyoid, which separates the oral cavity from the neck.
• Mylohyoid muscles of both sides meet along a midline
raphe.
• Mylohyoids are reinforced superiorly by geniohyoids.
• Anterior part of tongue rests on mucosa covering the
oor of the mouth.
• In the midline the frenulum of the tongue is seen on the
oor connecting the tongue to the mandible.
• On either side of the frenulum is the sublingual papilla
on which the submandibular gland duct opens.
• Lateral to this is the sublingual fold produced by the
sublingual gland.
• More posteriorly between mylohyoid and tongue lies
the hyoglossus muscle.
• A number of important structures in the oor of
the mouth lie on hyoglossus. ese are, from above
downwards:
• lingual nerve
• deep part of submandibular gland and submandibu-
lar duct
• hypoglossal nerve.
Lingual Nerve
• Branch of mandibular division of trigeminal nerve.
• Runs forwards above mylohyoid.
Genioglossus
Lingual artery
Fig. 5.20 Coronal section of the floor of the mouth.
Hyoglossus
Sublingual
gland
Submandibula
duct and gland
Lingual nerve
Anterior belly
of digastric
126
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
SECTION I Anatomy
• Gives o gingival branch, which supplies the whole of
the lingual gingiva and the mucous membrane of the
oor of the mouth.
• Winds round submandibular duct before being distributed to the mucosa of the anterior two-thirds of the
tongue.
• Submandibular ganglion is suspended from lingual
nerve as it lies on hyoglossus.
• Preganglionic bres in the chorda tympani synapse in
submandibular ganglion.
• Before reaching the oor of the mouth, the lingual
nerve lies against the periosteum of the alveolar process
closely related to the third molar tooth. e nerve can
be damaged here during dental extraction.
Hypoglossal Nerve
• Descends between internal jugular vein and internal
carotid artery.
• Supplies the superior limb of the ansa cervicalis (C1) to
innervate the infrahyoid muscles.
• Reaches the surface of the hyoglossus by passing deep to
the posterior belly of digastric.
• On hyoglossus, breaks up into branches to supply all
muscles of the tongue except palatoglossus.
THE TONGUE
• Buccal and pharyngeal parts separated by V-shaped
groove, sulcus terminalis, at the apex of which is the
foramen caecum.
• Larger vallate papillae lie immediately in front of sulcus
terminalis.
• Median frenulum lies on inferior surface of tongue. e
lingual veins can be seen on either side of the frenulum.
• On either side of the base of the frenulum are the orices of the submandibular ducts.
Structure
• Covered by thick stratied squamous epithelium bearing papillae on the anterior two-thirds. Papillae carry
taste buds.
• Posterior third has no papillae but has numerous lymphoid nodules.
• Tongue is divided by a median septum, on either side
of which are the intrinsic and extrinsic muscles of the
tongue.
• Intrinsic muscles are longitudinal, vertical and transverse; they alter the shape of the tongue.
• Extrinsic muscles move the tongue as a whole:
• genioglossus: protrudes the tongue
• styloglossus: retracts the tongue
• hyoglossus: depresses the tongue.
Blood Supply
• Lingual branch of the external carotid artery.
• Little cross-circulation across the midline, therefore a
relatively avascular plane.
Lymphatic Drainage
• Tip drains to submental nodes.
• Anterior two-thirds drain to submental and submandibular nodes and then to lower deep cervical nodes;
little cross-communication between drainage of two
sides of tongue.
• Posterior third drains to upper deep cervical nodes;
extensive cross-communication, therefore tumours may
spread to contralateral nodes.
Nerve Supply
• Anterior two-thirds: sensory supply from lingual
branch of cranial nerve V. Taste bres pass in lingual
nerve (from chorda tympani of cranial nerve VII).
• Posterior third: sensation and taste (including vallate
papillae) from nerve IX.
• Motor supply from the hypoglossal nerve, except for
palatoglossus.
Clinical Points
• Hypoglossal nerve damage results in wasting of the
tongue on the same side. Deviation to the paralysed side
on protrusion.
• In the unconscious patient, when the tongue has dropped
back, causing laryngeal obstruction, pushing the mandible forwards by pressure on the angle of the jaw on each
side will pull the tongue forwards with the jaw, owing to
attachment of genioglossus to the lower jaw.
SALIVARY GLANDS
Parotid Gland (Serous Gland)
e parotid gland is the largest salivary gland.
Relations
• Anteriorly: mandible and masseter.
• Medially: internal jugular vein, internal carotid artery,
IX, X, XI and XII nerves, and lateral wall of pharynx
separated by styloid process and its muscles.
• Superiorly: external auditory meatus and temporomandibular joint.
• Inferiorly: posterior belly of digastric.
Traversing the gland from supercial to deep are:
• facial nerve
• retromandibular vein
• external carotid artery, dividing into the supercial temporal and maxillary branches.
CHAPTER 5 The Head, Neck and Spine
127
Parotid Duct (Stensen’s Duct)
• Arises from the anterior part of the gland.
• Passes over masseter muscle (can be palpated over the
tensed masseter a nger’s breadth below the zygomatic
arch).
• Pierces buccinator opening opposite the upper second
molar tooth.
• e gland is traversed by the facial nerve, which emerges
from the stylomastoid foramen.
• Nerve divides into two main divisions resulting in ve
branches:
• temporal and zygomatic
• buccal, mandibular and cervical.
• Cross-communications occur between the branches in
the gland, which are not important and can be divided
safely.
• e mandibular division is the longest, thinnest and
therefore most vulnerable branch.
Submandibular Gland (Mixed Serous and
Mucous Gland)
e submandibular gland has a large supercial, and a
small, deep lobe connecting with each other around the
posterior border of mylohyoid.
Relations
• Supercial:
• platysma
• marginal mandibular branch of facial nerve
• cervical branch of facial nerve
• facial vein.
• Deep:
• mylohyoid
• hyoglossus
• lingual nerve
• hypoglossal nerve.
• Separated posteriorly from parotid gland by stylomandibular ligament.
• e facial artery grooves the supercial aspect of a
gland, ascending onto the face.
• e submandibular duct (Wharton’s duct) arises from
the deep part of the gland. It runs forwards and opens at
the side of the frenulum of the tongue. It is crossed from
supercial to deep by the lingual nerve, which passes
from the lateral side of the duct, below and then medial
to it; it ‘double-crosses’ it.
• Submandibular lymph nodes lie between the gland and
mandible. Occasionally they are embedded in the gland.
Clinical Points
• e mandibular branch of the facial nerve descends
below the angle of the mandible before arching upwards
onto the face. To avoid this branch, the incision to
approach the gland should be made more than 2.5 cm
below the angle of the mandible.
• e gland (and a stone in the duct) can be palpated
bimanually in the oor of the mouth.
The Sublingual Gland (Mucous Gland)
• Almond-shaped salivary gland lying immediately below
the mucosa of the oor of the mouth.
• Lies immediately in front of the deep part of the submandibular gland.
• Medially, it is separated from the base of the tongue by
the submandibular duct and the lingual nerve.
• Laterally, it rests against the sublingual groove of the
mandible.
• Opens separately into the oor of mouth by a series of
ducts.
• Part of it also opens into the submandibular duct.
THE NECK
The Fascial Compartments of the Neck
Consist of a ‘cylinder’ around the neck (investing layer) and
a complex system of septae between the neck muscles and
other structures. e fascia of the neck is divided into:
• Supercial fascia.
• Deep fascia, which is divided into a further three layers:
• investing layer (enveloping)
• prevertebral fascia
• pretracheal fascia.
Investing Fascia
• Invests the muscles of the neck.
• Attached to all the bony landmarks at the upper and
lower margins of the neck.
• Above to the mandible, zygomatic arch, mastoid process
and superior nuchal line.
• Below to the manubrium, clavicle, acromion and scapular spine.
• Splits to enclose the trapezius, sternocleidomastoid,
strap muscles and parotid and submandibular glands.
• External jugular vein pierces the investing fascia below
omohyoid, just above the midpoint of the clavicle (if the
vein is divided here, the deep fascia holds it open, air is
drawn into the veins on inspiration and air embolism
occurs).
Prevertebral Fascia
• Passes across the vertebrae and prevertebral muscles.
• Oesophagus, pharynx and great vessels lie in front.
• Forms a base upon which the pharynx, oesophagus and
carotid sheath slide in swallowing and neck movements.
128
Posterior belly of digastric
Posterior triangle
Inferior belly of omohyoid
Muscular triangle
Anterior belly of digastric
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
SECTION I Anatomy
• Laterally, covers the cervical and brachial plexuses and
muscles in the oor of the posterior triangle.
• Brachial plexus and subclavian artery are covered with
a sheath formed from the prevertebral fascia, which
becomes the axillary sheath.
Pretracheal Fascia
• Extends from hyoid bone above to brous pericardium
below.
• Encloses larynx, trachea, pharynx, oesophagus and thyroid gland.
Carotid Sheath
• Separate tube of fascia, strong over carotid arteries and
weak over jugular vein (to allow for expansion of latter).
• Contains:
• carotid artery
• internal jugular vein
• vagus nerve.
THE TRIANGLES OF THE NECK (Fig. 5.21)
• Anterior triangle bounded by:
• in front, the midline of the neck
• above, the ramus of the mandible
• behind, the anterior border of sternocleidomastoid.
• Posterior triangle bounded by:
• in front, the posterior border of the sternocleidomastoid
• below, the middle third of the clavicle
• behind, the anterior margin of trapezius.
Anterior Triangle
e anterior triangle contains, among other structures:
• thyroid and parathyroid glands
• submandibular gland
• carotid sheath
• trachea and larynx
• pharynx and oesophagus
• deep cervical lymph nodes
• suprahyoid and infrahyoid groups of muscles.
e anterior triangle can be further divided into four
smaller triangles:
• submental
• submandibular
• carotid
• mus cul ar.
Muscles Attached to the Hyoid Bone
• ese are in two groups:
• suprahyoid
• infrahyoid.
• e suprahyoids consist of:
• stylohyoid
• mylohyoid
• digastric
• geniohyoid.
• e suprahyoid muscles:
• elevate the hyoid and pull it forwards during
swallowing.
• e infrahyoids are active in opening the mouth against
resistance.
• Infrahyoids consist of:
• sternohyoid
• sternothyroid
• thyrohyoid
• omohyoid.
• e thyroid gland, larynx and trachea lie deep to the
infrahyoids.
Trapezius
Superior belly of omohyoid
Sternocleidomastoid
Fig. 5.21 The triangles of the neck.
Occipital triangle
Supraclavicular triangle
Anterior triangle
Digastric triangle
Carotid triangle
CHAPTER 5 The Head, Neck and Spine
Anterior cerebral artery
Right subclavian artery
129
• e infrahyoids or the strap muscles are supplied by the
ansa cervicalis (C1, 2, 3), which is a nerve loop on the
internal jugular vein.
• e branches enter the muscles in their lower half;
therefore, during exposure of a large goitre, the strap
muscles are cut in their upper half to preserve the nerve
supply from the ansa cervicalis.
Blood Vessels of the Anterior Triangle (Fig. 5.22)
Common carotid artery
• On the right side it is a branch of the brachiocephalic trunk.
• On the le side it arises from the arch of the aorta.
• Bifurcates into external and internal carotid arteries at
the upper border of the thyroid cartilage (level of third
cervical vertebra).
• Enclosed in carotid sheath with the internal jugular vein
lateral to it and the vagus nerve between the artery and
the vein posteriorly.
Internal carotid artery
• Passes vertically upwards as a continuation of common
carotid without giving any branches in the neck.
• Enclosed in carotid sheath.
• Separated from external carotid artery by:
• styloid process
• stylopharyngeus muscle
• glossopharyngeal nerve
• pharyngeal branch of vagus.
• At base of skull, enters the carotid canal.
• Intracranial part supplies the brain and the eye.
External carotid artery
• Extends from point of bifurcation of common carotid to
a point midway between the angle of the mandible and
the mastoid process.
• Upper part of artery enters parotid gland, where it
divides into its two terminal branches, the maxillary
artery and the supercial temporal artery.
• At its commencement it is anteromedial to the internal
carotid artery and can be distinguished from the internal carotid artery by the presence of branches (the internal carotid has no branches in the neck).
• e branches of the external carotid artery are:
• superior thyroid artery
• lingual artery
• facial artery
• occipital artery
• posterior auricular artery
• ascending pharyngeal artery
• maxillary artery
• supercial temporal artery.
Internal jugular vein
• Formed at the jugular foramen as a continuation of the
sigmoid sinus.
• At its commencement, lies behind the internal carotid
ar tery.
Fig. 5.22 MRA showing the blood vessels of the neck and formation of the circle of Willis.
Middle cerebral artery
Right sigmoid sinus
Right internal carotid
artery
Right internal jugular
vein
Right common carotid
artery
Right brachiocephalic
vein
Brachiocephalic trunk
Superior vena cava
Circle of Willis
Basilar artery
Vertebral artery
Left external carotid
artery
Left brachiocephalic
vein
Left subclavian artery
Left common carotid
artery
Aortic arch
130
Strap musclesThyroid isthmus
Prevertebral muscles
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
SECTION I Anatomy
• As it descends, occupies a position lateral to the internal
carotid artery and the common carotid artery.
• Contained within the carotid sheath, which is thinner
over the vein, allowing it to distend.
• e deep cervical chain of lymph nodes is found along
the internal jugular vein.
• In block dissection of the neck, the internal jugular vein
is removed to facilitate removal of the nodes.
• At the root of the neck, the internal jugular vein lies
behind the gap between the sternal and clavicular heads
of sternocleidomastoid.
• e vein terminates by joining the subclavian vein to
form the brachiocephalic vein.
Internal jugular vein cannulation
• Usually carried out on right side as the right vein is in
a straight line with the right brachiocephalic vein and
superior vena cava.
• High approach: vein is palpated lateral to common
carotid artery pulsation deep to anterior border of sternocleidomastoid at the level of C6 vertebra.
• Low approach: the needle is inserted near the apex of
the triangular gap between the sternal and clavicular
heads of the sternocleidomastoid.
THE THYROID GLAND
e thyroid gland is composed of:
• isthmus: overlying second and third tracheal rings
• lateral lobes: extending from lateral aspect of thyroid
cartilage to level of sixth tracheal ring
• inconstant pyramidal lobe extending up from isthmus.
Relations (Fig. 5.23)
• Anteriorly:
• strap muscles
• sternocleidomastoid
• enclosed in pretracheal fascia.
• Posteriorly:
• larynx
• trachea
• pharynx
• oesophagus.
• Laterally:
• carotid sheath.
• Recurrent laryngeal nerve runs in groove between trachea and oesophagus.
• External branch of superior laryngeal nerve lies deep to
upper pole.
Blood Supply
Arterial
• Superior thyroid artery from external carotid passes to
upper pole; closely related to external branch of superior laryngeal nerve.
• Inferior thyroid artery from thyrocervical trunk of rst
part of subclavian; related to the recurrent laryngeal
nerve close to gland.
• yroidea ima, from aortic arch; inconstant.
Venous
• Superior thyroid vein drains upper pole to internal jugular vein.
• Middle thyroid vein drains to internal jugular vein.
• Inferior thyroid vein drains lower pole to brachiocephalic veins.
Clinical Points
• Enlargement of the thyroid gland may compress or displace any of its close relations, e.g. trachea, resulting in
breathing diculties and dicult intubation for anaesthetist; oesophagus, resulting in dysphagia.
• Carcinoma of the thyroid may invade the recurrent
laryngeal nerve, producing hoarseness of voice.
Sternocleidomastoid
Body of seventh
cervical vertebra
Trapezius
Fig. 5.23 CT scan passing through the body of the seventh cervical vertebra showing the thyroid gland and
its relations.
Trachea
Internal jugular vein
Common carotid artery
Lateral lobe of thyroid
Oesophagus
Соседние файлы в папке @xirurgi_2025