ANTERIOR TRIANGLE OF THE NECK II

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ANTERIOR TRIANGLE OF THE NECK II
Dr. Ahmed Fathalla Ibrahim
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CAROTID TRIANGLE

• BOUNDARIES
• Superiorly posterior belly of digastric
• Inferiorly superior belly of omohyoid
• Posteriorly sternomastoid
• FLOOR
• Anteriorly hyoglossus thyrohoid muscles
• Posteriorly middle inferior constrictors of
  pharynx

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CAROTID TRIANGLE
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CAROTID TRIANGLE
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CAROTID TRIANGLE
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CONTENTS OF CAROTID TRIANGLE

• CAROTID SHEATH
• A condensation of deep fascia that contains
• Common internal carotid arteries (medially)
• Internal jugular vein (laterally)
• Vagus nerve between a little posterior to
  arteries vein

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CONTENTS OF CAROTID TRIANGLE

• ARTERIES
• Termination of common carotid at level of disc
  between C3 C4 (level of upper border of thyroid
  cartilage)
• Proximal part of external carotid
• Proximal part of internal carotid
• Five branches of external carotid superior
  thyroid, ascending pharyngeal, lingual, facial
  occipital

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CONTENTS OF CAROTID TRIANGLE

• VEINS
• Internal jugular vein
• Five tributaries to internal jugular veins
  common facial, lingual, superior thyroid, middle
  thyroid, pharyngeal veins

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CONTENTS OF CAROTID TRIANGLE

• FIVE NERVES
• TWO NERVES RELATED TO CAROTID SHEATH
• Ansa cervicalis (anterior rami of C1,2,3)
  embedded in the anterior wall of sheath
• Sympathetic trunk embedded in the posterior wall
  of sheath

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CONTENTS OF CAROTID TRIANGLE

• THREE NERVES BETWEEN INTERNAL JUGULAR VEIN
  INTERNAL CAROTID ARTERY
• Vagus (10th cranial) nerve descends between
  internal jugular vein common carotid artery
• Spinal part of accessory (11th cranial) nerve
  crosses internal jugular vein, passes deep to
  sternomastoid to reach posterior triangle
• Hypoglossal (12th cranial) nerve crosses
  internal external carotid arteries, passes deep
  to posterior belly of digastric to reach
  digastric triangle

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CONTENTS OF CAROTID TRIANGLE

• DEEP CERVICAL LYMPH NODES embedded in the
  anterior wall of sheath, along the internal
  jugular vein

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MUSCULAR TRIANGLE

• BOUNDARIES
• Anteriorly midline of neck
• Superiorly superior belly of omohyoid
• Inferiorly sternomastoid

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MUSCULAR TRIANGLE

• CONTENTS
• THE INFRAHYOID MUSCLES
• Superficial layer
• Sternohyoid medially
• Omohyoid laterally
• Deep layer
• Thyrohyoid above
• Sternothyroid below

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MUSCULAR TRIANGLE
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MUSCULAR TRIANGLE
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MUSCULAR TRIANGLE

• FLOOR
• PRETRACHEAL FASCIA
• STRUCTURES IN THE INFRAHYOID PART OF MEDIAN
  REGION OF FRONT OF NECK
• Thyrohyoid membrane
• Thyroid cartilage
• Cricothyroid ligament muscle
• Cricoid cartilage
• Cricotracheal ligament
• Trachea
• Structures in front of trachea jugular arch,
  inferior thyroid vein, isthmus of thyroid gland

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INFRAHYOID MUSCLES(SUPERFICIAL LAYER)

• Sternohyoid
• Origin back of manubrium sterni
• Insertion hyoid bone
• Action depression of hyoid bone
• Omohyoid
• Superior belly hyoid bone
• Inferior belly upper border of scapula
• Insertion intermediate tendon (deep to
  sternomastoid) attached to clavicle
• Action depression of hyoid bone

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INFRAHYOID MUSCLES(DEEP LAYER)

• Thyrohyoid
• Origin oblique line of thryroid cartilage
• Insertion hyoid bone
• Action depression of hyoid bone, elevation of
  larynx
• Sternothyroid
• Origin back of manubrium sterni
• Insertion oblique line of thryroid cartilage
• Action depression of larynx

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INFRAHYOID MUSCLES

• NERVE SUPPLY
• All muscles are supplied by ansa cervicalis
  (anterior rami of C1,2,3) EXCEPT thyrohyoid (by
  anterior ramus of C1)