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1. ANATOMY
OF
ESOPHAGUS

2. INTRODUCTION:
 Esophagus is a 25 cm long soft muscular tube that allows
food to pass from pharynx to the stomach
 It is Collapsed at rest
 Flat in upper 2/3 & rounded in lower 1/3
 Commences from the lower border of the cricoid
cartilage(C6). Then it descends along the front of the
spine, through the posterior mediastinum, passes
through the Diaphragm, and, enters into the abdomen,
terminates at the cardiac orifice of the stomach, opposite
to T11 vertebra.

3. NATURAL CONSTRICTIONS:
Site Vertebral
Level
Distance from
upper central
incisor
Cricopharynx C 6 15 cm
Aortic arch T 4 22 cm
Lt main
bronchus
T 5 25 cm
Oesophageal
hiatus
T 10 40 cm

4. THESE AREAS ARE WHERE MOST OESOPHAGEAL
FOREIGN BODIES BECOME ENTRAPPED.
 The most common site of oesophageal
impaction is at the thoracic inlet
 The cricopharyngeus sling at C6 is also at this
level and may "catch" a foreign body.
 About 70% of blunt foreign bodies that lodge
in the oesophagus do so at this location.
 Another 15% become lodged at the mid
oesophagus, in the region where the aortic
arch and carina overlap the oesophagus on
chest radiograph.
 The remaining 15% become lodged at the
lower oesophageal sphincter (LES) at the
gastroesophageal junction.

5. DIVISIONS:
 Topographically, there
are three distinct regions:
cervical, thoracic, and
abdominal.
 1.CERVICAL
OESOPHAGUS:
 extends from the
pharyngoesophageal
junction to the
suprasternal notch.
 about 4 to 5 cm long.

6. 2.THORACIC
OESOPHAGUS:
 Extends from the
suprasternal
notchdiaphragmatic
hiatus.
 Passes posterior to the
trachea, the tracheal
bifurcation, and the left
main stem bronchus.

7.  The esophagus lies
posterior and to the right
of the aortic arch at the T4
vertebral level.
 the esophagus lies
anteriorly to the aorta
from the level of T8 until
the diaphragmatic hiatus

8. 3.ABDOMINAL
OESOPHAGUS:
 Extends from the
diaphragmatic
hiatusorifice of the
cardia of the stomach.
 Forms a truncated cone,
about 1 cm long.

9.  Two high-pressure zones
prevent the backflow of food:
 The upper and
 The lower esophageal
sphincter.

10. UPPER OESOPHAGEAL SPHINCTER
 Between pharynx and the
cervical oesophagus.
 Located at C5-C6 level.
 The UES is a
musculocartilaginous structure.
 This is formed by fibers of
cricopharyngeus, part of the
inferior constrictor, which
encircles the oesophageal
entrance

11.  The cricopharyngeus muscle
is a striated muscle.
 produces maximum tension in
the A.P direction and less
tension in lateral direction.
 composed of a mixture of fast-
and slow-twitch fibres.
 This muscle forms the main
component of UES.

12. LOWER OESOPHAGEAL SPHINCTER
 The lower esophageal sphincter is a high-pressure zone
located where the esophagus merges with the stomach.
 Mean pressure here is approx. 8mm Hg.

13.  The LES is a functional unit
composed of an intrinsic and
an extrinsic component.
INTRINSICoesophagel
muscle fibers and is under
neurohormonal influence
EXTRINSICdiaphragm
muscle.

14. HISTOLOGY
Four coats from outside inwards:
1. Fibrous layer (adventitia)
2. Muscular layer (muscularis
propria)
3. Submucosa
4. Mucosa

15. 1.FIBROUS COAT (ADVENTITIA)
 Layer of loose, supportive fibrous tissue
 Conducts major vessels & nerves longitudinally
 A serosa formed by visceral peritoneum replaces
adventitia of intra-abdominal segment of
oesophagus

16. 2.MUSCULARIS PROPRIA
 External longitudinal muscle
 Internal circular muscle : which at lower end gets
thickened and form cardiac sphincter
 Parasympathetic ganglia forming Auerbach's nerve
plexus lies b/w them
 Upper 1/3: striated muscle
 Middle 1/3: striated & smooth
 Lower 1/3: smooth muscle

17. 3.SUBMUCOUS COAT
Loose supporting areolar tissue contains:
 Serous and mucous glands
 Blood vessels
 Lymphatic channels
 Parasympathetic ganglia forming Meissner's
nerve plexus

18. 4.MUCOUS COAT
1. Epithelium: non-keratinizing stratified sqamous
epithelium
2. Lamina propria: loose areolar tissue with
lymphoid aggregates
3. Muscularis mucosae: produces local
movement of mucosa & helps in
drainage of gland secretions

19. BLOOD SUPPLY
 The rich arterial supply of the
esophagus is segmental .
 Branches of the inferior thyroid
arteryUES and cervical
esophagus.
 Paired aortic esophageal arteries
or terminal branches of bronchial
arteriesthoracic esophagus.
 The left gastric artery and a
branch of the left phrenic
arteryLES and the most distal
segment of the esophagus.

20. VENOUS DRAINAGE
 The venous supply is also
segmental.
 From the dense submucosal
plexus the venous blood drains
into the superior vena cava.
 veins of proximal and distal
esophagus azygous system.
 Veins of mid
oesophaguscollaterals of left
gastric vein.

21. LYMPHATICS
 The lymphatics from the proximal
1/3rd
drain into the deep cervical LNs
subsequently into the thoracic duct.
 Middle 1/3rd
 into superior and
posterior mediastinal nodes.
 Distal 1/3rd
gastric and celiac lymph
nodes.
Surgical Importance:
 Submucosal lymphatics explain why
tumours may extend long distance before
obstructing lumen
 May also explain high recurrence rates
 Bidirectional lymph flow may explain
retrograde tumour seeding if flow is
blocked

22. NERVE SUPPLY
 Parasympathetic nerve
supply:
(SENSORY,MOTOR,SECRET
OMOTOR)
 Upper ½rec.laryngeal
nerve.
 Lower ½oesophageal
plexus formed by the 2 vagus
plexus.
 The sympathetic nerve
supply(VASOMOTOR)
 Upper ½by fibres from mid
cervical ganglion.
 Lower ½directly from
upper four thoracic ganglia.

23.  The ganglia that lie between
the longitudinal and the
circular layersmyenteric or
Auerbach's plexus.
 That lie in the submucosa
form the submucous or
Meissner's plexus.
 Auerbach's
plexusregulates
contraction of the outer
muscle layers.
 Meissner's plexusregulates
secretion and the peristaltic
contractions of the
muscularis mucosae.

24. PHYSIOLOGY OF DEGLUTITION
Deglutition is the act of swallowing, through which a food or
liquid bolus is transported from the mouth through the pharynx
and esophagus into the stomach.
Normal deglutition is a smooth coordinated process that involves
a complex series of voluntary and involuntary neuromuscular
contractions and typically is divided into three distinct phases:
 Oral
 Pharyngeal
 Esophageal

25. ORAL PHASE
1. ORAL PREPARATORY PHASE
2. ORAL PHASE PROPER

26. ORAL PREPARATORY PHASE
 This phase is where the food is readied for swallowing
by reducing & mixing it with saliva, by the muscles of
jaw and oral cavity.
 Jaw is closed by jaw elevator muscles ( temporalis,
masseter & medial pterygoid).
 Lips maintain a seal under the action of Orbicularis
oris.
 Food is returned from the vestibule by contraction of
buccinators.

27.  Through out this phase, the soft palate is lowered &
Ant and Post pillars approx. under the action of
palatoglossus & palato pharyngeus muscles.
 Thus, the oral cavity is sealed posteriorly & the
airway remains open.
 Bolus is progressively accumulated on the posterior
surface of the tongue, by several cycles of upward and
downward movement on the tongue surface.

28.  When the bolus consistency ( sensed by mechano-receptors in
the oral cavity) is suitable for swallowing, the oral phase
proper begins.

30. ORAL PHASE PROPER
 The first event is mandibular elevation
 Mandibular elevation assists the suprahyoid
muscles in raising the hyoid bone
 Next, the tip of the tongue is elevated towards
the hard palate by the action of genioglossus
muscle

31.  Blade of the tongue then moves up due to contraction
of intrinsic muscles.
 These movements are accompanied by lifting the floor
of the mouth under the action of stylohyoid.
 As the bolus reaches the back of the tongue ,the soft
palate is elevated by tensor and levator veli palatini to
protect the nasopharynx.

33. PHARYNGEAL PHASE
 As the bolus enters the oropharynx, it makes
contact with faucial pillars or with the mucosa
overlying the posterior pharynx, the region which
is sensory innervated by glossopharyngeal nerve.
 Hereafter swallowing becomes reflexive
 Pharyngeal phase consists of a sequence of events
that ensures that the airway is protected during
bolus transport.

34.  Soft palate is elevated to ensure closure of the
nasopharynx.
 Vocal cords start to close to protect the airway, either
do the vestibular folds.
 The larynx is closed by the contraction of muscles of
laryngeal inlet(AEF, interarytenoid and thyro
epiglottic).

36.  The larynx is closed under the contraction of
suprahyoid muscles, in order to narrow the laryngeal
inlet and moving it towards the pharyngeal surface of
epiglottis.
 As the bolus moves in to oropharynx, the epiglottis
moves downwards.
 This downward movement occurs in 2 distinct stages.
1.movement from vertical to horizontal position
2.movement from horizontal to below horizontal in
order to cover the narrow laryngeal inlet.

37.  The bolus enters the pharynx which is widened.
Widening is partly due to relaxation of constrictor
muscles and partly due to anterior movement of the
pharynx under the action of suprahyoid muscles.
 As the food passes over the post. Part of the epiglottis,
it is diverted into the pyriform fossae. Solids tend to
go straight over the epiglottis, whereas liquids are
diverted laterally.

38. OESOPHAGEAL PHASE
 After food enters esophagus, the cricopharyngeal
sphincter closes and the peristaltic movements of
esophagus take the bolus down the stomach.
 Gastro esophageal sphincter at the lower end of
esophagus relaxes well before peristaltic wave
reaches and permits fluids to pass.
 Bolus of food passes by contraction of peristaltic
waves and then the sphincter closes.

40.  Regurgitation of food back from stomach into
esophagus is prevented by:
 Tone of GE sphincter
 Negative intrathoracic pressure
 Pinch cock effect of diaphragm
 Mucosal folds
 Esophago-gastric angle