Oesophagus
Tony Tiemesmann
Diagnostic Radiology
Bloemfontein Hospital Complex
Key points 1
• The adult human esophagus is an 18- to 25-cm long
muscular tube that has cervical, thoracic, and abdominal
parts.
• The esophagus wall is composed of striated muscle in the
upper part, smooth muscle in the lower part, and a mixture
of the two in the middle.
Key points 2
• Esophagus develops from foregut and by week 10 is lined by
ciliated epithelial cells.
• Beginning at 4 months, the ciliated epithelium starts to be
replaced by squamous epithelium. At either end of the
esophagus the ciliated epithelium gives rise to esophageal
glands.
• The upper esophagus is derived from branchial arches 4, 5,
and 6.
• Esophageal peristalsis appears in the first trimester, and
gastroesophageal reflux can be documented in the second
trimester.
Introduction
• From mouth to stomach, the food conduit consists of the
oral cavity, pharynx, and esophagus.
• Dynamic tube, pushing food toward the stomach, where
digestion and absorption can take place.
• Mucus produced by the esophageal mucosa provides
lubrication and eases the passage of food.
• Active peristaltic contractions propel residual material from
the esophagus into the stomach.
• During vomiting and reflux, the esophagus also serves as a
passageway for gastrointestinal contents traveling
retrograde from the stomach or small intestine.
Embryology 1
• In the 4th developmental week, a small diverticulum
appears at the ventral wall of the foregut - the respiratory
(tracheobronchial) diverticulum.
• It becomes gradually separated from the foregut by the
esophagotracheal septum.
• The proliferation of esophageal epithelium almost
obliterates the lumen, but the recanalization of the
esophagus occurs by the end of the 8th week.
Embryology 2
Anatomy 1
• Flattened muscular tube of 18 to 26 cm from the upper
sphincter to the lower sphincter.
• Between swallows the esophagus is collapsed,
canndistend to approximately 2 cm in the anterior-posterior
dimension & up to 3 cm laterally.
• Connects the pharynx to the stomach - beginning in the
neck, at the pharyngoesophageal junction, descends
anteriorly to the vertebral column through the superior and
posterior mediastinum.
• Traverse diaphragm at the diaphragmatic hiatus extends
through the gastroesophageal junction to end at the orifice
of the cardia of the stomach.
Anatomy 2
• Cervical esophagus: pharyngoesophageal junction to the
suprasternal notch.
• Thoracic esophagus: suprasternal notch to the
diaphragmatic hiatus.
• Abdominal esophagus: diaphragmatic hiatus to the orifice
of the cardia of the stomach.
Anatomy 3
• Two high-pressure zones prevent the backflow of food: the
upper and lower esophageal sphincter. These functional
zones are located at the upper and lower ends of the
esophagus but there is not a clear anatomic demarcation of
the limits of the sphincters.
• Structurally, the esophageal wall is composed of four
layers: innermost mucosa, submucosa, muscularis propria,
and adventitia. Unlike the remainder of the GIT, the
esophagus has no serosa.
Blood supply 1
• Rich arterial supply is segmental.
• The branches of the inferior thyroid artery provide arterial
blood supply to the upper esophageal sphincter and
cervical esophagus.
• The paired aortic esophageal arteries or terminal branches
of bronchial arteries supply the thoracic esophagus.
• The left gastric artery and a branch of the left phrenic artery
supply the LES and the most distal segment of the
esophagus.
• The arteries end in an extensive, dense network in the
submucosa; rarity of the esophageal infarction.
Blood supply 2
Venous drainage 1
• The venous supply is also segmental.
• From the dense submucosal plexus the venous blood
drains into the superior vena cava.
• The veins of the proximal and distal esophagus drain into
the azygous system.
• Collaterals of the left gastric vein receive venous drainage
from the mid-esophagus.
• The submucosal connections between the portal and
systemic venous systems in the distal esophagus form
esophageal varices in portal hypertension.
Venous drainage 1
Innervation 1
• The esophagus receives parasympathetic and sympathetic
innervation that regulates glandular secretion, blood vessel
caliber, and the activity of striated and smooth muscle.
• The thin nerve fibers and numerous ganglia of the
intramural myenteric (Auerbach) and the submucosal plexi
Meissner) provide the intrinsic innervation of the
esophagus.
Innervation 2
• The spinal afferents have their cell bodies in the dorsal root
ganglia and terminate in the spinal column and in the
nucleus gracilis and cuneatus in the brainstem. From there,
they project, through the thalamus, to primary sensory and
insular cortical areas.
• The spinal afferents merging from nerve endings in the
muscle layer and serosa act as nociceptors for perception
of discomfort and pain and are mechanosensitive.
Innervation 3
Lymphatics 1
• The lymphatics from the proximal third of the esophagus
drain into the deep cervical lymph nodes, and subsequently
into the thoracic duct.
• The lymphatics from the middle third of esophagus drain
into the superior and posterior mediastinal nodes.
• Lymphatics of the distal third of the esophageal follow the
left gastric artery to the gastric and celiac lymph nodes.
• There are considerable interconnections among these
three drainage regions; bidirectional lymph flow in this
region is responsible for the spread of malignancy from the
lower esophagus to the upper esophagus.
Lymphatics 2
Musculature 1
• The muscular coat consists of an external layer of
longitudinal fibers and an internal layer of circular fibers.
• The longitudinal fibers descend in the esophagus and
combine to form a uniform layer that covers the outer
surface of the esophagus.
• The circular muscle layer provides the sequential peristaltic
contraction that propels food toward the stomach.
• The internal muscular layer is thicker than the external
muscular layer. Below the diaphragm, the internal circular
muscle layer thickens and the fibers become semicircular
and interconnected, constituting the intrinsic component of
the LES.
Musculature 2
Upper oesophageal sphincter 1
• The upper esophageal sphincter is a high-pressure zone
situated between the pharynx and the cervical esophagus.
• The UES is a musculocartilaginous structure composed of
the posterior surface of the thyroid and cricoid cartilage, the
hyoid bone, and three muscles: cricopharyngeus,
thyropharyngeus, and cranial cervical esophagus.
Upper oesophageal
sphincter 2
Lower oesophageal sphincter 1
• The lower esophageal sphincter is a high-pressure zone
located where the esophagus merges with the stomach.
• The LES is a functional unit composed of an intrinsic and
an extrinsic component: intrinsic structure is under
neurohormonal influence; extrinsic component consists of
the diaphragm muscle.
Lower oesophageal
sphincter 2
Lower oesophageal sphincter 3
Imaging
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Endoscopy
Rigid
Soft
PillCam
Fluoroscopy
Contrast swallow (BaSO4, Iodinated)
Nuclear medicine
Ba-swallow 1
Ba-swallow 2
Ba-swallow 3
References
• Embryo.chronolab.com
• Kuo B, Uma D. Oesophagus: Anatomy & development. GI
Motility (2006) doi:10.1038/gimo6. 16 May 2006.
• Radiologyassistant.nl
• Netter FH. Atlas of human anatomy 2nd ed. Hoechstetter.
1999.