General oto esophagus overview Flashcards
The esophagus, an embryologic foregut derivative,
undergoes what important process during week 8
to 10 of life?
Recanalization of the esophageal lumen
Describe the muscular arrangement of the
esophagus.
● Outer longitudinal fibers, inner circular fibers
● Inferior third smooth muscle, middle third mixed,
superior third skeletal
What are three physiologic areas of narrowing
within the esophagus?
● Upper esophageal sphincter (cricopharyngeus muscle,
C6, narrowest segment)
● Crossed by aorta and left main bronchus in mid chest
● Lower esophageal sphincter (passes through diaphragm)
What is the blood supply to the esophagus?
Arterial
● Segmental blood supply, extensive submucosal anasto-
mosis
● Upper esophageal sphincter and cervical esophagus:
Inferior thyroid artery
● Thoracic esophagus: Paired esophageal arteries (terminal
branches of bronchial arteries
● Lower esophageal sphincter: Left gastric artery and left
phrenic artery
Venous
● Neck: Inferior thyroid veins
● Mediastinum: Azygous and hemiazygous veins
● Abdomen: Left gastric vein
What is the innervation of the esophagus?
● Sympathetic innervation from T6-T10 bilaterally
● Greater and often lesser splanchnic nerves
● Branches from the celiac plexus
Note: The vagal nerves form a plexus along the distal
esophagus and then reform two distinct nerves on passage
through the diaphragm.
The upper, mid, and lower third of the esophagus
drain into which nodal basin(s)?
● Upper third = Paratracheal and internal jugular lymph
nodes
● Middle third = Mediastinal nodes
● Lower third = Gastrohepatic and celiac axis lymph nodes
What is the normal epithelial lining of the
esophagus?
Nonkeratinizing stratified squamous epithelium
What are the four layers of the esophageal wall?
Mucosa
Submucosa
Muscularis propria
Adventitia
What key surgical landmarks must be kept in mind
when operating on the esophagus in the neck?
● It lies slightly left of midline.
● Anterior: Trachea, thyroid lobe, and anterolaterally the
recurrent laryngeal nerves bilaterally in the tracheoeso-
phageal groove
● Posterior: Vertebral column and longus colli muscles
● Lateral: Thoracic duct on the left
What key surgical landmarks are relevant when dilating an esophageal stricture in the mediastinum?
● Superior mediastinum: Slightly left of midline
● Posterior: Vertebral column, thoracic duct (not in direct
contact, to left)
● Anterior: Trachea, left mainstem bronchus, aortic arch
● Left lateral: Descending aorta, left parietal pleura (direct
contact)
● Right lateral: Vena azygos
● Inferior mediastinum: Returns to midline
● Posterior: Vertebral column; inferiorly, the aorta moves
posterior to the esophagus and esophagus.
● Anterior: Pericardium
● Left lateral: Parietal pleura (direct contact)
● Right lateral: Parietal pleura (direct contact)
At what thoracic level is the esophageal hiatus?
T10
How many centimeters are the incisor teeth from the cricopharyngeus, aortic arch, left mainstem
bronchus, and lower esophageal sphincter and diaphragm in an average adult?
● 15 cm
● 25 cm
● 40 cm
What two types of peristalsis propel food through
the esophagus?
● Primary peristalsis: Triggered by swallowing
● Secondary peristalsis: Triggered by esophageal dilation
What are the functional muscular components of
the upper esophageal sphincter?
The cricopharyngeus muscle, thyropharyngeus, and the proximal cervical esophagus Note: Many muscles contribute to the function of the upper esophageal sphincter (e.g., movement of the larynx, infrahyoid musculature, etc.).
What is the innervation of the upper esophageal
sphincter?
At rest, the upper esophageal sphincter is contracted, and during oropharyngoesophageal events (swallowing, belching, emesis), the sphincter relaxes. The major tone effect stems from contraction of the cricopharyngeus, which is
modulated by cranial nerve X. Afferent information is primarily transmitted via cranial nerve IX.
What is the innervation of the lower esophageal
sphincter?
At rest, the lower esophageal sphincter is contracting as a result of neurotransmitter and hormonal influences. Swallow-induced relaxation occurs about 1 to 2 seconds after the bolus is swallowed. The vagal efferent motor neurons inhibit neurons within the myenteric plexus, which results in
a decrease in the of the baseline tone.
What anatomical relationship augments the function of the lower esophageal sphincter?
Diaphragmatic crura
What are the four main protective mechanisms
against esophageal reflux?
● Upper esophageal sphincter: Tonically closed
● Lower esophageal sphincter: Tonically closed
● Esophageal acid clearance: Peristalsis, gravity
● Epithelial resistance: Mucous layer, aqueous layer, cell
membrane, and intracellular junctions
When should esophagoscopy be considered after
caustic ingestion?
Within the first 24 hours because the risk for perforation
and complications may be greater at 2 to 3 days after injury
What endoscopic findings suggest an increased
risk of stricture formation after caustic ingestion?
Circumferential erythema with exudate and perforation
Most esophageal foreign-body impactions occur at
what level in the esophagus?
Cervical esophagus, just below the cricopharyngeus muscle
Describe Boerhaave syndrome.
Elevated intraabdominal pressure results in a transmural
tear within the distal esophageal wall after vomiting. This
commonly occurs in the posterolateral wall of the distal
esophagus.
Describe Mallory-Weiss syndrome.
Incomplete tear of the esophageal wall involving the esophageal mucosa and submucosal arteries, often associated with retching
What does the Hamman sign indicate?
● Pneumomediastinum or pneumopericardium, often from
tracheobronchial injury or Boerhaave syndrome
● Demonstrated by a crunching sound that is synchronous
with heartbeat
What type of imaging study should be used In a patient with a suspected esophageal perforation?
Gastrografin swallow study
