Iii - 46 Esophagus.docx
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ESOPHAGUS
The esophagus = 25 cm long muscular tube, which connects the pharynx with the stomach. The esophagus is kept collapsed anteroposteriorly between the trachea and the vertebral column. It passes downwards in front of the vertebral column behind the trachea, traverses superior and posterior the mediastina of the thorax, passes through the
esophageal opening of the diaphragm and ends at the cardiac orifice of the stomach in the abdomen about 2.5 cm to the left of the median plane. It begins in the neck where it is continuous with the laryngopharynx at the pharyngo-esophageal junction. The esophagus consists of striated (voluntary) muscle in its upper third, smooth (involuntary) muscle in its lower third, and a mixture of striated and smooth muscle in between. When the esophagus is empty, it is a slit-like lumen. When a food bolus descends in it, the lumen expands, eliciting reflex peristalsis in the inferior two thirds of the esophagus. The esophagus is divided into three parts: cervical, thoracic, and abdominal.
N.B. The pharyngoesophageal junction is the narrowest part of the digestive tube except that of the vermiform appendix.
CERVICAL PART OF THE ESOPHAGUS
Its first part, the cervical esophagus, is part of the voluntary upper third. It begins immediately posterior to, and at the level of, the inferior border of the cricoid cartilage in the median plane the level of the C6 vertebra. Externally, the pharyngo-esophageal junction appears as a constriction produced by the cricopharyngeal part of the inferior pharyngeal constrictor muscle (the superior esophageal sphincter) and is the narrowest part of the esophagus. The cervical esophagus inclines slightly to the left as it descends and enters the superior mediastinum via the superior thoracic aperture, where it becomes the thoracic esophagus. The cervical esophagus lies between the trachea and the cervical vertebral column. It is attached to the trachea by loose connective tissue. The recurrent laryngeal n.n. lie in or near the tracheo-esophageal grooves between the trachea and the esophagus. On the right of the esophagus is the right lobe of the thyroid gland and the right
carotid sheath and its contents. The esophagus is in contact with the cervical pleura at the root of the neck. On the left is the left lobe of the thyroid gland and the left carotid sheath. The thoracic duct adheres to the left side of the esophagus and lies between the pleura and the esophagus. Relations of the Cervical Part of the Esophagus
Anteriorly, it is related to: (a) trachea and (b) recurrent laryngeal nerve.
Posteriorly, it is related to: (a) prevertebral fascia, (b) longus colli muscles, and (c) vertebral column. N.B. The prevertebral layer of deep cervical fascia forms a movable base on which the trachea and esophagus move up and down during swallowing and phonation.
On each side, it is related to: (a) lobe of the thyroid gland, (b) common carotid artery, and (c) thoracic duct on the left side. INNERVATION OF THE CERVICAL ESOPHAGUS
The nerve supply to the esophagus is somatic motor and sensory to the upper half and parasympathetic (vagal), sympathetic, and visceral sensory to the lower half. The cervical esophagus receives somatic fibres via branches from the recurrent laryngeal n.n. and vasomotor fibres from the cervical sympathetic trunks through the plexus around the inferior thyroid artery
BLOOD SUPPLY AND LYMPHATIC DRAINAGE
The cervical part of the esophagus is supplied by the inferior thyroid arteries. The veins from this part drain into the inferior thyroid veins & the left brachiocephalic vein. The lymph vessels from the cervical part of esophagus drain into the pretracheal & the deep cervical lymph nodes. CLINICAL SIGNIFICANCE
• The left margin of the esophagus projects laterally from behind the trachea in the region of the neck. • Therefore, the cervical part of the esophagus can be mobilized and exposed surgically more easily from the left side. • The interior of the esophagus can be examined in vivo by an esophagoscope. This procedure helps to obtain tissue biopsy or removal of swallowed foreign body.
The esophagus = 25 cm long muscular tube, which connects the pharynx with the stomach. The esophagus is kept collapsed anteroposteriorly between the trachea and the vertebral column. It passes downwards in front of the vertebral column behind the trachea, traverses superior and posterior the mediastina of the thorax, passes through the
esophageal opening of the diaphragm and ends at the cardiac orifice of the stomach in the abdomen about 2.5 cm to the left of the median plane. It begins in the neck where it is continuous with the laryngopharynx at the pharyngo-esophageal junction. The esophagus consists of striated (voluntary) muscle in its upper third, smooth (involuntary) muscle in its lower third, and a mixture of striated and smooth muscle in between. When the esophagus is empty, it is a slit-like lumen. When a food bolus descends in it, the lumen expands, eliciting reflex peristalsis in the inferior two thirds of the esophagus. The esophagus is divided into three parts: cervical, thoracic, and abdominal.
N.B. The pharyngoesophageal junction is the narrowest part of the digestive tube except that of the vermiform appendix.
CERVICAL PART OF THE ESOPHAGUS
Its first part, the cervical esophagus, is part of the voluntary upper third. It begins immediately posterior to, and at the level of, the inferior border of the cricoid cartilage in the median plane the level of the C6 vertebra. Externally, the pharyngo-esophageal junction appears as a constriction produced by the cricopharyngeal part of the inferior pharyngeal constrictor muscle (the superior esophageal sphincter) and is the narrowest part of the esophagus. The cervical esophagus inclines slightly to the left as it descends and enters the superior mediastinum via the superior thoracic aperture, where it becomes the thoracic esophagus. The cervical esophagus lies between the trachea and the cervical vertebral column. It is attached to the trachea by loose connective tissue. The recurrent laryngeal n.n. lie in or near the tracheo-esophageal grooves between the trachea and the esophagus. On the right of the esophagus is the right lobe of the thyroid gland and the right
carotid sheath and its contents. The esophagus is in contact with the cervical pleura at the root of the neck. On the left is the left lobe of the thyroid gland and the left carotid sheath. The thoracic duct adheres to the left side of the esophagus and lies between the pleura and the esophagus. Relations of the Cervical Part of the Esophagus
Anteriorly, it is related to: (a) trachea and (b) recurrent laryngeal nerve.
Posteriorly, it is related to: (a) prevertebral fascia, (b) longus colli muscles, and (c) vertebral column. N.B. The prevertebral layer of deep cervical fascia forms a movable base on which the trachea and esophagus move up and down during swallowing and phonation.
On each side, it is related to: (a) lobe of the thyroid gland, (b) common carotid artery, and (c) thoracic duct on the left side. INNERVATION OF THE CERVICAL ESOPHAGUS
The nerve supply to the esophagus is somatic motor and sensory to the upper half and parasympathetic (vagal), sympathetic, and visceral sensory to the lower half. The cervical esophagus receives somatic fibres via branches from the recurrent laryngeal n.n. and vasomotor fibres from the cervical sympathetic trunks through the plexus around the inferior thyroid artery
BLOOD SUPPLY AND LYMPHATIC DRAINAGE
The cervical part of the esophagus is supplied by the inferior thyroid arteries. The veins from this part drain into the inferior thyroid veins & the left brachiocephalic vein. The lymph vessels from the cervical part of esophagus drain into the pretracheal & the deep cervical lymph nodes. CLINICAL SIGNIFICANCE
• The left margin of the esophagus projects laterally from behind the trachea in the region of the neck. • Therefore, the cervical part of the esophagus can be mobilized and exposed surgically more easily from the left side. • The interior of the esophagus can be examined in vivo by an esophagoscope. This procedure helps to obtain tissue biopsy or removal of swallowed foreign body.
