Download 15-SUBMANDIBULAR REGION I

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SUBMANDIBULAR
REGION I
By
Prof. Saeed Makarem
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TOPICS
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1.
2.
3.
Suprahyoid muscles: origin, insertion,
nerve supply and actions.
Tongue muscles.
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
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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
DIGASTRIC
MUSCLE
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
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)
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Action: elevation of the hyoid bone
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STYLOHYOID MUSCLE
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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.
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SUPERFICIAL RELATIONS OF THE DIGASTRIC
5 muscles, 2 glands,
one vein & one
bone
1. Platysma.
2. Sternomastoid.
3. Splenius capitis.
4. Longissimus capitis.
5. Parotid gland.
6. Submandibular
gland.
7. Stylohyoid.
8. Retromandibular
vein.
9. Mastoid process.
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DEEP RELATIONS
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Deep to the anterior belly of
the digatric is the mylohyoid.
Deep to the posterior belly of
the digastric are:






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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.


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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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
Action: the two mylohyoid muscles form a muscular sheet that
supports the tongue and the floor of the mouth.
 When the mandible is fixed, they elevate the floor of the
mouth and the hyoid bone during the first stage of swallowing.
 When the hyoid bone is fixed, it assists the depression of the
mandible and the opening of the mouth.
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GENIOHYOID MUSCLE
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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
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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
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
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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The genioglossus muscle is a fan-shaped muscle,
extends backward into the tongue.
Insertion:

GENIOGLOSSUS
MUSCLE
– superior fibers
to the tip
of the tongue
Origin: from the superior mental spine, behind the symphysis
menti-of
mandible.
– middle fibers - to the dorsum of the tongue
– inferior fibers - to the body of the hyoid bone
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Nerve supply: hypoglossal nerve.
Action: draws the tongue forward and deflectsProf.
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tip of the tongue to the15
opposite side.
Simultaneous contraction of the two muscles protrude the tongue in the midline.
GENIOGLOSSUS
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
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STYLOGLOSSUS MUSCLE
Insertion:
– The fibers run downward and forward on the lateral surface of the superior constrictor muscle.
The–styloglossus
muscle is a long, slender muscle.
On reaching the interval between the superior and the middle constrictor muscles, the
passes forward
Origin:styloglossus
from the styloid
process.to enter the sides of the tongue.
Action: draws the tongue upward and backward.
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Nerve supply: hypoglossal nerve.
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The hyoglossus is a flat, quadrilateral muscle, superficial to the mylohyoid.
HYOGLOSSUS
MUSCLE
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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
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
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From above downwards:
Lingual nerve.
Submandibular
ganglion.
Deep part of the
submandibular salivary
gland.
Submandibular duct.
Hypoglossal nerve.
Suprahyoid artery.
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•
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Branches
Dorsal
lingualforming
branchesanare
two or three
number
and ascend
to the
dorsum of the
tongue.
It runs
forward,
upward
loop, inwhich
is crossed
by the
hypoglossal
nerve.
The sublingual
artery supplies
sublingual
salivary
glandtoand
neighboring
It then
proceeds forward
deep the
to the
hyoglossus
muscle
supply
the tip structures.
of the tongue.
LINGUAL ARTERY
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
The lingual artery arises from the external carotid artery opposite the tip of the greater cornu
of the hyoid bone.
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