Download By Dr. harith dahham

‫تشريح‬
‫ثاني اسنان موصل‬
2015 / 12 / 16
SUBMANDIBULAR
REGION I
By
Dr. harith dahham
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DR. Harith Dahham
TOPICS
1. Suprahyoid muscles: origin, insertion,
nerve supply and actions.
2. Tongue muscles.
3. Lingual artery: origin, course, parts and
branches.
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SUPRAHYOID MUSCLES
•
•
•
•
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1- Digastric.
2- Stylohyoid
3- Mylohyoid.
4- Geniohyoid.
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DIGASTRIC MUSCLE
Origin & Insertion:
Posterior belly arises from the
medial surface of the mastoid
process, then it passes downward
and forward crossing 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
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hyoid bone.
DIGASTRIC MUSCLE
•
•
Anterior belly runs forward and
medially and is attached to the
digastric fossa in the lower
border of the body of the
mandible, near the median
plane.
Nerve supply:
– posterior belly: facial nerve(
2nd)
– anterior belly: nerve to the
mylohyoid (branch of the
mandibular division of the
trigeminal nerve)-(1st
pharyngeal arch)
•
Action: elevation of the hyoid bone
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STYLOHYOID MUSCLE
This is a small muscular slip that •
passes along the upper border
of the posterior belly of digastric
muscle.
Origin: from the styloid process. •
Insertion: At the junction of the •
body & the greater cornu of
hyoid.
Near its insertion, it is pierced •
by the intermediate tendon of
the digastric muscle.
Nerve supply: Facial nerve, (2nd) •
Action: elevates the hyoid bone. DR.• Harith Dahham
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DEEP RELATIONS
• Deep to the anterior belly of
the digatric is the mylohyoid.
• Deep to the posterior belly of
the digastric are:
–
–
–
–
–
–
–
–
–
–
Obliques superiorius,
occipital artery,
rectus capitis lateralis,
transverse process of
atlas,
accessory nerve,
internal jugular vein,
hypoglossal nerve,
internal and external
carotid arteries.
facial and lingual
arteries
hyoglossus.
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MYLOHYOID MUSCLE
Flat, triangular muscle
• Origin:
– Mylohyoid line of the
mandible.
• Insertion:
– Posterior fibers into
the body of the hyoid
bone.
– Anterior fibers into the
mylohyoid raphe which
extends from the
symphysis menti to the
body of the hyoid bone.
• Nerve supply:
– mylohyoid branch of
the inferior alveolar
nerve.
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GENIOHYOID MUSCLE
•
•
•
•
The geniohyoid muscle is a slender muscle, superior to the mylohyoid.
Origin: from the inferior mental spine, behind the symphysis menti.
Insertion: anterior surface of the body of the hyoid bone.
Action: elevates the hyoid bone and draws it forward; or it depresses the
mandible.
Nerve supply: first cervical nerve through the hypoglossal nerve.
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MUSCLES OF THE TONGUE
•
•
•
•
•
The muscles of the tongue are divided into two types: intrinsic and extrinsic.
The intrinsic muscles are confined to the tongue and are not attached to bone.
They consist of longitudinal, transverse, and vertical fibers.
Nerve supply: Hypoglossal nerve.
Action: Alter the shape of the tongue.
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Extrinsic Muscles of the Tongue
•
•
The extrinsic muscles are
attached to bones and the
soft palate.
They are:
– the genioglossus,
– the hyoglossus,
– the styloglossus, and
– the palatoglossus.
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GENIOGLOSSUS MUSCLE
The genioglossus muscle is a fan-shaped muscle, extends
backward into the tongue.
• Origin: from the superior mental spine, behind the
symphysis menti of the mandible.
Action: draws the tongue forward and deflects the tip
of the tongue to the opposite side.
Simultaneous contraction of the two muscles
protrude the tongue in the midline.
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Insertion:
– superior fibers - to the tip of the tongue
– middle fibers - to the dorsum of the tongue
– inferior fibers - to the body of the hyoid bone
•
Nerve supply: hypoglossal nerve.
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GENIOGLOSSUS
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STYLOGLOSSUS MUSCLE
The styloglossus muscle is a long, slender muscle.
 Origin: from the styloid process.
• Insertion:
– The fibers run downward and forward on the lateral surface of the superior constrictor muscle.
– On reaching the interval between the superior and the middle constrictor muscles, the styloglossus
passes forward to enter the sides of the tongue.
•
•
Action: draws the tongue upward and backward.
Nerve supply: hypoglossal nerve.
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HYOGLOSSUS MUSCLE
The hyoglossus is a flat, quadrilateral muscle, superficial to the mylohyoid.
• Origin: from upper border of the body and greater cornu of the hyoid bone.
• Insertion: to the side of the tongue.
• Action: depression of tongue. * Nerve supply: hypoglossal nerve.
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STRUCTURES ON THE LATERAL SURFACE OF THE
HYOGLOSSUS MUSCLE
• From above
downwards:
• Lingual nerve.
• Submandibular
ganglion.
• Deep part of the
submandibular salivary
gland.
• Submandibular duct.
• Hypoglossal nerve.
• Suprahyoid artery.
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• Branches
Dorsal lingual branches are two or three in number and ascend to the dorsum
of the tongue.
The sublingual artery supplies the sublingual salivary gland and neighboring
structures.
Suprahyoid artery :from the beginning of the artery and runs superficial to
Hyoglossus
Deep lingual artery: runs on the under surface of the tongue under its mucous
membrane
• It runs forward, forming an upward loop, which is
crossed by the hypoglossal nerve.
• It then proceeds forward deep to the hyoglossus muscle
to supply the tip of the tongue.
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LINGUAL ARTERY
The lingual artery arises from the external carotid artery opposite the tip of the greater
cornu of the hyoid bone.
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SUBMANDIBULAR GANGLION
• It is a small parasympathetic ganglion lying
superficial to hyoglossus & is connected to lingual
nerve by 2 roots (anterior & posterior)
• Origin of fibers: superior salivary nucleus in pons
• Preganglionic fibers:
1. Runs along chorda tympani branch of facial nerve
2. Chorda tympani transmits fibers to lingual nerve
branch of mandibular nerve
3. Lingual nerve transmits fibers to ganglion through
posterior root
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SUBMANDIBULAR GANGLION
• Postganglionic fibers:
1. To submandibular gland: fibers are
distributed directly to the gland
2. To sublingual gland:
• Fibers pass along anterior root to lingual
nerve again
• Lingual nerve transmits fibers to sublingual
gland
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