Download Submandibular gland

Viscera of neck
By
Dr. Adel Sahib Al-Mayaly
‫جبتلكم معي‬
Submandibular gland
Submandibular gland
O Is one of three paired salivary glands:O parotid, submandibular & sublingual.
O Each gland is walnut in appearance.
O About 10 - 20 gms in weight.
O It is a mixed gland with predominantly serous in type.
O It lies beneath the lower border of the body of the mandible
(submandibular fossa)
Major Salivary Glands
submandibular fossa
O is an impression on the medial side of the
body of the mandible below the mylohyoid
line. It is the location for the submandibular
gland.
Submandibular Gland
structure
Each gland is divided into superficial and
deep lobes separated by mylohyoid muscle.
O 1- Superficial lobe comprises most of the
gland .
O 2- Deep lobe is the smaller part.
O Secretions are delivered into the Wharton
duct (submandibular duct ) from the
anterior end of the deep lobe
O
Superficial lobe
O It presents two ends:-
O 1-two ends:- anterior & posterior
O Anterior end extends to the anterior belly of digastric muscle.
O Posterior end:- extends to the stylomandibular ligament.
O This end presents a groove for the lodgment of the cervical
loop of facial artery.
Superficial lobe
O 3 surfaces:- inferior, lateral and medial.
O Among the three surfaces:O the investing layer of deep cervical fascia
splits into two layers to cover the inferior and
medial surfaces of the gland
3 surfaces
O 1-Lateral surface:O It lies against the submandibular fossa of the
mandible.
O 2-The inferior or superficial surface:O is covered by skin, platysma and the investing fascia
O crossed by the facial vein and the cervical branch of
the facial nerve.
O
surfaces
O The medial surface:O It lies against the mylohyoid, and behind it
on the hyoglossus , lingual nerve,
hypoglossal nerve and its accompanying
veins.
The deep part
O It extends forwards for a variable distance,
between mylohyoid and hyoglossus, below
the lingual nerve and above the hypoglossal
nerve.
O
Submandibular duct
(Wharton duct(
O Excretory duct that is about 5 cm. long.
O begins from the medial surface of the
superficial part little behind the posterior
border of the mylohyoid
O It passes at first; between the mylohyoid
and hyoglossus
O Thereafter; between the sublingual gland
and genioglossus.
Wharton duct
O Finally opens in the floor of mouth on a
sublingual papilla on each side of frenulum
linguae.
O The duct shows intimate relation to lingual
nerve
O first the nerve lies above the duct, then
crosses its lateral side and finally ascends
medially winding round the lower border of
the duct.
Blood supply
O From the facial artery, with veins draining
into the facial vein.
O Lymph drainage
O To the submandibular lymph nodes.
Nerve supply
O Secretomotor fibres to the gland have their
cell bodies in the submandibular ganglion.
O which hangs suspended from the lingual
nerve on the surface of hyoglossus.
O Sympathetic (vasoconstrictor) fibres come
from the plexus around the facial artery.
Excretory salivary unit
Thyroid Gland
Thyroid gland.
Location and Description
O The thyroid gland is situated low down at the
front of the neck
O It consists of right and left lobes connected by a
narrow isthmus.
O The lobes lie on either side of the larynx and
trachea, extending from the oblique line of the
thyroid cartilage to the sixth tracheal ring.
O Its weight is 25 gram
O
Thyroid Gland
Each Lateral lobe
O is pyramidal - shaped structure.
O Each lobe has narrow apex & broad base
O Its base lies below at the level of the 4th-5th
tracheal ring.
Each lobe
O has:- superficial(lateral), medial & posterior
surfaces.
O Lateral surface is under cover of sternothyroid
and sternohyoid muscles.
O The posterior surface overlaps the carotid
sheath
O The parathyroid glands usually lie in contact with
this surface, between it and the fascial sheath.
O
The medial surface
O is related to
O 1- larynx & trachea.
O 2- pharynx & esophagus.
O 3- cricothyroid & inferior constrictor muscle
of pharynx.
O 4- superior laryngeal & recurrent laryngeal
nerves.
O
The isthmus
O Extends across the midline in front of the
second , third, and fourth tracheal rings
O A pyramidal lobe is often present, and it
projects upward from the isthmus, usually to
the left of the midline.
O A fibrous or muscular band frequently
connects the pyramidal lobe to the hyoid
bone.
O If it is a muscular is called levator glandulae
thyroideae.
Thyroid gland
The relation of the recurrent
laryngeal nerves to the thyroid
lobes
O they approach the medial surface of the gland from
O
O
O
O
O
O
below.
The left nerve:- recurves around the arch of the aorta
in the superior mediastinum.
entered the groove and lies posterior to inf. Thyroid
artery.
Right nerve:- recurves around the right subclavian
artery at the root of the neck may be more lateral to
the trachea, .
passing anterior or posterior to the inferior thyroid
artery or in between its branches
(accessory thyroid glands)
O are not uncommonly found near the hyoid
bone, in the tongue, superior mediastinum ,
or anywhere along the path of descent of
the thyroglossal duct,
Blood supply
O The superior thyroid artery:O the first branch from the anterior aspect of the
external carotid.
O pierces the pretracheal fascia as a single vessel
to reach the summit of the upper pole.
O The external laryngeal nerve is immediately
behind the artery.
The inferior thyroid artery,
O from the thyrocervical trunk.
O arches upwards and medially behind the carotid sheath.
O then loops downwards to the lower pole
O
O
Relation of RLN to inferior
thyroid A
Venous drainage
O 1-Superior thyroid vein:- follows the superior
O
O
O
O
thyroid artery and enters either the internal
jugular.
2- Middle thyroid vein:Crosses anterior to the common carotid
artery to drain into the internal jugular vein.
The inferior thyroid vein:Drain into brachiocephalic vein.