Transcript 16- Thyroid Gland.TRACHEA& ESOPHAGUS.ppt

VISCERA OF THE NECK
 Thyroid
Gland
 Parathyroid
 Trachea
 Esophagus


By
Prof . Saeed Abuel Makarem

The deep cervical
fascia of the neck is
divided into 3 layers:
1- Investing layer.
 2- Pretracheal
layer.
 3- Prevertebral
layer.

Endocrine gland.
 Consists of right & left
lobes.
 The 2 lobes are
connected to each
other by a narrow
isthmus, which overlies
the 2nd 3rd & 4th rings of
the trache.
 It is surrounded by a
sheath derived from the
pretracheal layer of
cervical fascia.

Thyroid gland
Each lobe is pear
shaped, with its apex
reaches up to the
oblique line of the
thyroid cartilage.
 Its base lies at the level
of 4th or 5th tracheal
rings.
 Inside the pretracheal
facial capsule, there is
another capsule.

Each lobe is pear
shaped, with its apex
directed upward as
for as the oblique line
of the thyroid
cartilage; its base is
at the 4th or 5th
tracheal ring.
The isthmus
extends across
the midline in
front of the 2nd
3rd & 4th tracheal
rings.



A small pyramidal lobe is
often present which
projects from the upper
border of the isthmus
usually to left of middle
line.
Pyramidal lobe is
connected to hyoid bone
by a fibrous or muscular
band called levator
glandulae thyroideae.
This represents the
fibrosed & obliterated
thyroglossal duct.














Anterolaterally:
Sternothyroid.
Superior belly of
Omohyoid
Sternohyoid.
Sternomastoid.
Posterolaterally:
Carotid sheath & its
contents.
Medially:
Above:
Larynx & pharynx .
Below:
Trachea & esophagus.
Recurrent laryngeal nerve
in between.
Cricothyroid muscle &
external laryngeal nerve.







Relation of the isthmus
Anteriorly:
sternothyroid,
sternohyoid,
anterior jugular vein,
fascia & skin.
Posteriorly:
2nd,3rd,&4th tracheal
rings.
Terminal branches of
the 2 superior thyroid
arteries which
anastomosis along the
upper border.
The rounded
posterior border is
related to the
superior & inferior
Parathyroid glands.
 It is also related to
the anastomosis
between superior &
inferior thyroid
arteries.


:
Superior thyroid artery



From external carotid artery
It descends to the upper pole
of the lobe, with the external
laryngeal nerve.
It runs along the upper
border of the isthmus to
anastomosis with its fellow.
Thyroidea ima artery


If present, it arises from
aortic arch or from
brachiocephalic artery.
It ascends in front of trachea
to reach isthmus.
Inferior thyroid artery
From thyrocervical trunk
of 1st part of subclavian
artery, ascends behind
the gland to the level of
cricoid cartilage.
Then it turns medially
behind the carotid
sheath.





The it reaches the posterior
border of the gland &
descends downwards.
The recurrent laryngeal
nerve crosses either in
front or behind the artery.
Veins of Thyroid Gland
1- Superior thyroid vein
2- Middle thyroid vein
3- Inferior thyroid vein
Lymph Of the
Thyroid Gland:
Deep cervical &
paratracheal
internal jugular
internal jugular
left brachiocephalic
Goiter
GOITER
A non-neoplastic &
non-inflammatory
enlargement of the
thyroid gland.
ECTOPIC THYROID TISSUE



The thyroid glands
develops high up close
to foramen cecum of
the developing tongue.
Then it descends along
the thyroglossal duct to
reach its final position
by the 7th week.
Descent of the thyroid
could be arrested at any
point, or extends down
to thorax.






Parathyroid glands
Four small ovoid bodies,
about 6mm. Long.
They lie within the facial
capsule of the gland.
2 superior parathyroid has
a constant position at the
middle of posterior border
of the gland.
2 inferior parathyroid
usually at the level of the
inferior pole.
They lie within the thyroid
tissue or sometimes
outside the facial capsule.
PARATHYROID GLAND






They are supplied by superior
& inferior thyroid arteries.
Their veins are drained to
superior, middle and inferior
thyroid veins.
Lymph nodes:
Deep cervical & paratracheal
lymph nodes.
Nerve supply:
Superior & middle cervical
sympathetic ganglia.







10 to 15 cm long mobile
tube.
Formed of cartilage &
membrane.
Its diameter is about 2 cm
in adult male.
It begins at lower border
of cricoid cartilage (C 6).
It descends in the midline
of the neck.
It ends at the level of the
disc between T4 & T5.
.
TRACHEA
The trachea has a fibro elastic wall which is
supported by series of Ushaped bars of hyaline
cartilage that keep the
lumen patent.
18
The posterior free ends of
the cartilage are connected
by smooth muscle, called
the trachealis muscle.
19









Anteriorly:
Skin,
Superficial fascia,
investing cervical fascia
isthmus of thyroid gland,
Inferior thyroid veins
jugular arch,
thyroidea ima artery,
left brachiocephalic
vein,
sternothyroid &
sternohyoid
RELATION













Posteriorly
esophagus,
recurrent laryngeal nerves
(in between trachea and esophagus)
vertebral column.
Laterally:
Lobes of the thyroid gland &
carotid sheath.
Blood supply:
Inferior thyroid artery.
Nerve :
vagi, sympathetic trunk &
recurrent laryngeal
Lymph: Pretracheal & Para
tracheal lymph nodes.
TRACHEA







Muscular tube 25 cm or 10
inches long.
Extends from pharynx to
stomach.
It begins at lower border of
cricoid cartilage (C 6).
It begins in midline, but
inclines to the left.
It descends in superior then
posterior mediastinum of
thorax.
Anteriorly
trachea and recurrent
laryngeal nerves.
ESOPHAGUS













Posteriorly
Prevertebral layer of cervical
fascia,
longus coli muscle &
vertebral column.
Laterally:
Lobe of thyroid gland,
carotid sheath.
Thoracic duct on left side.
Blood:
Inferior thyroid artery.
Lymph:
deep cervical lymph nodes.
Nerves: Recurrent laryngeal
and sympathetic trunk.
ESOPHAGUS