Anatomy of the esophagus

Question 1

Describe the esophagus?

Answer 1

• It is the narrowest part of the digestive tube
• It extends from the pharynx to the stomach

Question 2

What are the parts of the esophagus?

Answer 2

• It begins at the upper esophageal sphincter at C6 and ends at the gastroesophageal junction, as it exits the diaphragm at T10

1) Cervical part (4cm)

2) Thoracic part (20cm)

3) Abdominal part (1.25 cm)

Question 3

What is the longest part of the esophagus?

Answer 3

The thoracic part (20cm)

Question 4

What is the shortest part of the esophagus?

Answer 4

the abdominal part (1.25 cm)

Question 5

Describe the course of the esophagus

Answer 5

• It begins at the lower border of the cricoid cartilage at C6
• Pierces the diaphragm at T10
• Ends at the gastroesophageal junction

Question 6

What are the crus of the diaphragm?

Answer 6

1) Right crus: acts like a sling for the esophagus, pulling the duodenum in place and providing support, it turns around the esophagus

2) Left crus: It is on the left side of the aorta, and it does not cross the esophagus

• Ligament of treitz/suspensory ligament of the duodenum is a thin muscle that extends from the right crus to the duodenojejunal junction

Question 7

What are the constrictions of the esophagus?

Answer 7

• There are four constrictions from above downwards, which are caused by the structures overlying it

1) 1st constriction is at the pharyngeo-esophegeal junction

• 15cm from the incisor teeth

2) 2nd constriction is at the level of the aortic arch

• 22cm from the incisor teeth

3) 3rd constriction is when the bronchus crosses the esophagus

• 27cm from the incisor teeth

4) 4th constriction is when the esophagus pierces the diaphragm

• 40cm from the incisor teeth

Question 8

What are the most common areas for foreign bodies in the esophagus to become entrapped?

Answer 8

1) Cricopharyngeal sling (70%)

2) Mid-esophegeal-aortic arch (15%)

3) At the lower esophageal sphincter (gastro-esophegeal junction) (15%)

Question 9

what is the most commonest site for esophegeal objects to be entrapped?

Answer 9

The first constriction is the most common site, exactly at the cricopharyngeal sling (where 70% of objects gets entrapped)

Question 10

In which crus is the esophageal hiatus (the abdominal esophagus) located?

Answer 10

In the right crus of the diaphragm

Question 11

Describe the course of the abdominal esophagus

Answer 11

Enters through the right crus via the abdomino-esophageal hiatus of the diaphragm, on the left of the midline, it becomes continuous with the stomach at the cardiac orifice

• The right border of the esophagus is continuous with the lesser curvature of the stomach
• The left border of the esophagus is seperated from the fundus of the stomach via the cardiac notch

Question 12

What is the abdominal esophagus related to?

Answer 12

1) Anteriorly: Left lobe of the liver and the anterior vagal trunk (left vagus)

• Anteriorly the abdominal esophagus is covered with the peritoneum of the greater sac

2) Posteriorly: Left crus of the diaphragm and the posterior vagal trunk (right vagus)

• Posteriorly the abdominal esophagus is covered with the peritoneum of the omental bursa (lesser sac, behind the liver and stomach)

Question 13

What is the covering of the stomach?

Answer 13

The lesser omentum, this covering continues as the greater omentum and covers the intestine and folds on itself, it then goes up and attaches to the transverse mesocolon

Question 14

What ligament connects the stomach to the spleen?

Answer 14

The gastrosplenic ligament

Question 15

Which ligament connects the stomach to the diaphragm?

Answer 15

Gastrophrenic ligament

Question 16

What is the hepatogastric ligament?

Answer 16

It is the lesser omentum

Question 17

What is the hepatoduodenal ligament?

Answer 17

It is the smaller part of the lesser omentum associated with the duodenum, it contains the portal vein, hepatic artery, and the common bile duct

Question 18

What is the gastrocolic ligament?

Answer 18

It is the greater omentum

Question 19

At which vertebral segment does the esophagus pierce the diaphragm?

Answer 19

at T10

Question 20

At which vertebral segment is the inferior esophageal sphincter?

Answer 20

At T11

Question 21

What is the Z-line?

Answer 21

• AKA: Ora serrata
• It is a jagged line where the mucosa abruptly changes from esophageal to gastric mucosa (stratified squamous non-ciliated epithelium to simple columnar “in the stomach”), the Z-line appears as the transition is not smooth

Question 22

What is the function of the inferior esophageal sphincter (cardiac sphincter)?

Answer 22

It is a physiological sphincter (not anatomical) that prevents the reflux of gastric contents into the esophagus

Question 23

What type of epithelium lines the esophagus?

Answer 23

Stratified squamous non-ciliated epithelium

Question 24

What type of epithelium lines the stomach?

Answer 24

Simple columnar

Question 25

What are the factors that maintains the cardiac sphincter?

Answer 25

1) Valvular effect of the esophago-gastric angle 2) The rosette-like folds of the gastric mucosa membrane at the cardia 3) The presence of a length of intra-abdominal esophagus 4) The clamp like action of the right crus of the diaphragm

Question 26

What is the gastroesophageal reflux disorders?

Answer 26

- It occurs in association with many different esophageal conditions, including most of the motility disturbances (reflux is a symptom of abnormalities at the diaphragmatic hiatus)

Question 27

What are the types of hiatus hernia?

Answer 27

1) Sliding 2) Paraesophegeal/rolling

Question 28

What is meant by sliding (hiatus hernia)?

Answer 28

When the fundus of the stomach and the abdominal esophagus ascends into the thorax through or lax or enlarged diaphragmatic opening - The normally acute esophage-gastric angle is reduced so that reflux is common even though the intrinsic lower sphincter is normal

Question 29

What is the paraesophageal/rolling hiatus hernia?

Answer 29

When the cardia remains in its normal position and the fundus extends through the esophageal hiatus, usually no regurgitation of gastric contents occurs

Question 30

What is meant by fundoplication?

Answer 30

- Used to treat gastroesophageal reflux disease - When the crura of the diaphragm are approximated and sutured, and the fundus is rolled around the esophagus and sutured in front

Question 31

What is the blood supply of the cervical part of the esophagus?

Answer 31

Inferior thyroid artery

Question 32

What is the blood supply of the thoracic part of the esophagus?

Answer 32

The descending aorta

Question 33

What is the blood supply of the abdominal part of the esophagus?

Answer 33

1) Left gastric artery 2) Left inferior phrenic artery

Question 34

What drains the esophagus?

Answer 34

1) Intra-esophegeal drainage 2) Extra-eophageal drainage

Question 35

What is the intra-oesophageal drainage?

Answer 35

- Longitudinal, arranged in submucosa (submucosal venous plexus), they extend from the cervical to the abdominal part, but drains different levels depending on the part

Question 36

What is the extra-esophageal drainage?

Answer 36

- They drain into the locally corresponding veins 1) The inferior thyroid drains the cervical part of the esophagus 2) The azygos and hemiazygos drains the thoracic part of the esophagus 3) The left gastric, inferior vena cava and the hemiazygos veins drains the abdominal part of the esophagus

Question 37

What will happen to the venous drainage in case of liver cirrhosis?

Answer 37

The road gets blocked and the blood will backup into the esophagus

Question 38

What is the major source of hemorrhage in cirrhosis?

Answer 38

The submucosal connections between the portal and systemic venous systems in the distal esophagus (they can form esophageal varices in portal hypertension)

Question 39

What is the lymphatic drainage of the cervical part of the esophagus?

Answer 39

The jugolo-omohyoid lymph nodes

Question 40

What is the lymphatic drainage of the thoracic part of the esophagus?

Answer 40

1) Paratracheal 2) Tracheobronchial 3) Posterior mediastinal lymph nodes

Question 41

What is the lymphatic drainage of the abdominal part of the esophagus?

Answer 41

The celiac group of the lymph nodes (around the celiac artery) - important to know

Question 42

What is the parasympathetic innervation of the esophagus?

Answer 42

- From both the vagus and the recurrent laryngeal nerves

Question 43

What is the parasympathetic innervation of the cervical part of the esophagus?

Answer 43

The recurrent laryngeal branch of the vagus nerve

Question 44

What is the parasympathetic innervation of the thoracic esophagus?

Answer 44

The mesh-like network of neurons (esophageal plexus) which is formed by the sympathetic and parasympathetic fibers - The parasympathetic fibers will then form the left and right vagus nerve

Question 45

What are the functions of the parasympathetic innervation of the esophagus?

Answer 45

- Rest and digest 1) Induces peristalsis 2) Stimulates the glands to secrete 3) Motor branch to the smooth muscles of the wall of the abdominal viscera

Question 46

What is the sympathetic innervation of the esophagus?

Answer 46

1) The cervical esophagus is innervated from the cervical and T1 region of the sympathetic trunk - Lateral horn cells give rise to the preganglionic cells, they ascend up to the cervical ganglions which then give rise to post ganglionic cells to relay to organs there 2) The lower thoracic esophagus is also innervated from T2-T5/6 ganglia of the sympathetic trunk - Lateral horn cells of T2-T5/T6 and they relay in the same level of ganglia (SAME SEGMENT OF sympathetic chain) Lateral horn 🡪 Preganglionic fibers 🡪 ganglia--> postganglionic fiber

Question 47

What is the function of the sympathetic trunk?

Answer 47

1) Vasoconstriction 2) Inhibition of peristalsis

Question 48

How is visceral pain reffered?

Answer 48

Afferent visceral pain fibers travels via the sympathetic fibers to the T1-T4/5 segments of the thoracic spinal cord, so pain can be referred to these dermatomes (Pain in T10🡪 referred to the area of the skin supplied by T10 (dermatome))

Question 49

What is meant by Achalasia?

Answer 49

A disorder where the myenteric plexus (plexus between the outer longitudinal and the inner circular smooth muscle layers of the intestine) and other vagal elements degenerate/destroyed in addition to the fact that the lower esophageal sphincter is unable to relax, leading to the distention of the esophagus (Birds beak deformity) with food and fluid, then once the person sleep the upper sphincter relaxes and the contents of the esophagus may overflow into the pharynx and lungs leading to aspiration pneumonia

Question 50

What is meant by bird's beak deformity?

Answer 50

When the Lower esophageal sphincter fails to relax resulting in the dilation of the esophagus proximal to the area of obstruction

Question 51

FYI

Answer 51

Parasympathetic has a Craniosacral Outflow Sympathetic Has a Thoracolumbar Outflow As a general Rule for Parasympathetic Innervation: The GIT System is mostly supplied by the Vagus nerve, except for the lower part which is supplied by the pelvic nerve, and its responsible for REST And DIGEST (Stimulate the digestion process) As A general Rule for Sympathetic Innervation: Its supplied by the Sympathetic trunk, Celiac Trunk What is the innervation of Esophagus? Sympathetic: Sympathetic Trunk on the sides of the vertebral column. Parasympathetic: Right and Left Vagus Nerves and the Upper part by the Recurrent Laryngeal Nerve (Since the Preganglionic fibers of the PS Nerves are long and Postganglionic are Shorter, the Nerve cells in the muscular layer of the esophagus (Myenteric and coloured black) and In the Submucosal plexus in the Submucosa (Meissner and Coloured Blue) They are considered the PG Neurons for the PS Nerves) What if these nerves are absent? There will be loss of peristalsis Sympathetic Has a Thoracolumbar Outflow This means the lateral horn (Responsible for the sympathetic action) is absent in The Cervical Region and Lower Lumbar and Sacral, But the sympathetic ganglion is present everywhere, Cervical, Lumbar, Thoracic, Sacral and they are connected. For that reason, the Fibers coming out from the Thoracic and Upper Lumbar region have the lateral horn as their origin as well as a continuation when they reach the Sympathetic ganglion, but for the areas absent, the Sympathetic ganglion is their origin.