Transcript 10-Anterior triangle

By
Prof. Saeed Abuel Makarem
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TRIANGLES OF THE NECK
The neck is divided into
anterior and
posterior triangles by
the sternocleidomastoid
muscle;
• the anterior triangle
lies in front of the
muscle
• and the posterior
triangle lies behind it.
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Boundaries:
Anteriorly:
Median plane.
Posteriorly:
Anterior border of
sternomastoid.
Superiorly:
Base of mandible.
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Subdivisions of the anterior triangle
Subdivisions:
It is divided into 4
triangles: by digastric
muscle & superior belly
of omohyoid.
1- Submental triangle.
2- Submandibular
3- Carotid triangle.
4- Muscular triangle.
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Boundaries:
Apex: Symphysis menti
Base: Hyoid bone.
On each side: anterior belly
of digastric.
Submental triangle
• Floor: Mylohyoid muscle
( diaphragma oris)
Contents:
1- Submental lymph nodes.
2- Submental artery (from
facial artery.
3- Submental veins which
form anterior jugular vein.
4- Nerve to Mylohyoid.
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Digastric Triangle
• Boundaries:
Above:
Base of mandible.
Anteriorly:
Anterior belly of digastric.
Posteriorly:
Posterior belly of digastric
and stylohoid.
Floor:
Mylohyoid anteriorly &
Hyoglossus muscles
posteriorly.
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• Submandibular salivary
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gland.
Submandibular lymph
nodes
Part of facial artery.
Part of facial vein.
Part f Hypoglossal nerve.
Submental artery.
Mylohyoid N & Vessels.
Part of Parotid gland.
Part of external carotid a
Part of carotid sheath &
its contents.
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Contents of
Submandibular
triangle:
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DIGASTRIC MUSCLE
• Origin and insertion:
• the posterior belly arises from
the medial surface of the
mastoid process passes
downward and forward across
the carotid sheath, and ends
in the intermediate tendon.
The intermediate tendon pierces the stylohyoid insertion and is held in position by a
loop of deep fascia, which binds the tendon down to the junction of the body and the
greater cornu of the hyoid bone.
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DIGASTRIC MUSCLE
• The anterior belly runs
•
forward and medially and is
attached to the lower border
of the body of the mandible,
near the median plane.
Nerve supply:
– posterior belly: facial
nerve
– anterior belly: nerve to
the mylohyoid (branch of
the mandibular division
of the trigeminal nerve)
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Action: elevation of the hyoid bone
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