Anterior triangle
Boundaries of anterior
triangleAnteriorly- median plane
Posteriorlysternocleidomastoid
muscle
Superiorly-base of the
mandible, line joining
the angle of mandible
to mastoid process.
Apex of the triangle lies
above the manubrium
sterni
Anterior triangle
Landmarks
1. Mandible
2. Hyoid bone
3. Thyroid cartilage
4. Cricoid cartilage
5. Trachea
Anterior triangle
Skin
Free movable
Ant cut nerve of C2,C3
Superficial fascia
1. Platysma
2. Cervical branch of the facial nerve
3. Anterior jugular vein
4. Lymph nodes ( lymph nodes along the AJV,
submental nodes lies below the chin & few of them
lie along the sternocleidomastoid along the EJV)
Anterior triangle
Anterior triangle
Structures in the anterior median region of the neck
Skin- freely movable
Superficial fascia1.
2.
3.
4.
Upper decussating fibres of the platysma
Anterior jugular vein
Submental lymph nodes
Transverse or anterior cutaneous nerve of neck
Deep fasciaAbove the hyoid bone its single layer in the median plane but
splits on each side to enclose the submandibular salivary
gland
Between hyoid bone and cricoid cartilage is single layer
extending the rt & lt sternoclediomastoid muscles
Below the cricoid, fascia splits to enclose the suprasternal
space.
Anterior triangle
Deep structures lying above the hyoid bone
Mylohyoid muscles is overlapped by
1. Ant belly of digastric muscles
2. Superficial part of submandibular salivary gland
3. Mylohyoid nerve & blood vessels
4. Submental branch of the facial artery
5. Anterioinferiorly hyoglossus muscles
6. Intermediate tendon of digastric muscle with its
fibrous pully
7. Bifurcated tendon of the stylohyoid muscle
8. Hypoglossal nerve
9. Subhyoid bursa- between the posterior surface of
hyoid bone and the thyrohyoid membrane
Anterior triangle
Anterior triangle
Anterior triangle
Structures lying below the hyoid bone
Superficial plane ( infrahyoid muscles)1. Sternohyoid
2. Sternothyoid
3. Thyrohyoid
4. Superior belly of omohyoid
Pretracheal fasciaFalse capsule of the thyroid gland and the suspensory ligament. Inferior
thyroid veins lies within the fascia
Deep to pretracheal fascia1. Thyrohyoid membrane deep to thyrohyoid muscle & pierced by internal
laryngeal nerve and superior thyroid vessels
2. Thyroid cartilage
3. Cricothyroid membrane
4. Arch of the cricoid cartilage
5. Cricothyroid muscle
6. Trachea ( covered by isthmus of the thyroid gland from 2to 4th rings)
7. Carotid sheath
8. Lt brachiocephalic vein and brachiocephalic artery
Anterior triangle
Anterior triangle
Clinical anatomy1. Enlargement of submental lymph nodes & sublingual
dermoid in the submental region
2. Thyroglaossal cyst and subhyoid bursitis just below the hyoid
bone
3. Goiter, carcinoma of the larynx and enlarged lymph nodes in
the suprasternal region
4. Tracheostomy-retrothyroid region after retracting the isthmus
of the thyroid gland. Suprathyroid tracheostomy is liable to
stricture & infrathyroid one is difficult due to the depth of the
trachea and is also dangerous because numerous blood
vessels lie to the trachea here
5. “Cut throat”- commonly situated just above or below the
hyoid bone.
Anterior triangle
Subdivision
1. Triangle is enclosed by
suprahyoid musclesdigastric, stylohyoid,
mylohyoid & geniohyoid
2. Infrahyoid musclessternohyoid,
sternothyroid,
thyrohyoid & omohyoid
Anterior triangle
Triangle is subdivided by
the digastric & superior
belly of the omohyoid
muscle into
• Submental
• Digastric
• Carotid
• Muscular
Anterior triangle
Submental triangleBoundariesEach side- ant belly of corresponding digastric muscles
Base- body of hyoid bone
Apex-chin
Floor- rt & lt mylohyoid muscles and median raphe uniting them.
Contents1. 2-4 submental lymph nodes situated in the superficial fascia
between the anterior bellies of the digastric muscles. Drains
lymph from superficial tissues below the chin, central part of
the lower lip, adjoining gum, anterior part of the floor of the
mouth & tip of the tongue
2. Small submental veins to form anterior jugular vein
Anterior triangle
Anterior triangle
Digastric triangleBoundariesAnteroinferiorly- ant belly of digastric
Posteroinferiorly- post belly of digastric & stylohyoid
Superiorly or base- base of the mandible & line joining the angle of the
mandible to the mastoid process
Roof1. Skin
2. Superficial fascia- platysma, cervical branch of the facial nerve &
ascending branch of the transverse or anterior cutaneous nerve of the
neck
3. Deep fascia- splits to enclose the submandibular salivary gland
Floor- mylohyoid anteriorly& hyoglossus posteriorly, small part of middle
constrictor muscle of pharynx appears in the floor
Contents1. Structures superficial to mylohyoid- a)superficial part of the
submandibular salivay gland, facial vein and submandibular lymph
nodes are superficial to it and facial artery is deep to it; b) submental
artery & c) mylohyoid nerve and vessels
Anterior triangle
Anterior triangle
Anterior triangle
Anterior triangle
2. Structures superficial to the hyoglossussubmandiblar salivary gland, intermediate tendon
of the digastric & stylohyoid and hypoglossal
nerve
Anterior triangle
Posterior part of the triangle1. Superficial structures are-lower part of the
parotid gland & ECA
2. Deep structures passing between ECA& ICA
are- styloglossus, stylopharyngeus,
glossopharyngeal nerve,pharyngeal branch of
the vagus nerve,styloid process & a part of the
parotid gland.
3. Deepest structures include- ICA, IJV & vagus
nerve.
Anterior triangle
Anterior triangle
Carotid triangle
BoundariesAnterosuperiorly- post belly of the
digastric muscle & stylohyoid
Anteroinferiorly- superior belly of the
omohyoid
Posteriorly- ant border of the
sternocleidomastoid muscle
Roof- skin, superficial fascia
containing platysma, cervical
branch of the facial nerve &
transverse cutaneous nerve of
the neck
Floor- thyrohoid, hyoglossus, &
middle and inferior constrictors of
the pharynx
Anterior triangle
Anterior triangle
ContentsArteries- CCA with carotid sinus & carotid body, ICA, ECA with
its superior thyroid, lingual, facial, ascending pharyngeal
and occipital branches
Veins- IJV, CFV draining into the IJV, pharyngeal vein, lingual
vein
Nerves- vagus nerve, superior laryngeal branch of vagus
nerve, dividing into external & internal laryngeal nerves,
spinal accessory nerve, hypoglossal nerve & sympathetic
chain
Carotid sheath and its contents
Lymph nodes-deep cervical lymph nodes situated along the
IJV and jugulodigastric node below the digastric and juguloomohyoid nodes above the inferior belly of the omohyoid.
Anterior triangle
Anterior triangle
Anterior triangle
CCARt CCA is branch of brachiocephalic artery. Begins in the neck
behind the rt sternoclavicular jt
Lt CCA is the branch of the Arch of aorta. It begins in the thorax
in front of trachea opposite a point little to the left of the
center of the manbrium. Ascends to back of the lt
sternoclavicular jt & enter the neck.
In the neck both have the same course. It runs upwards within
the carotid sheath, under cover of the anterior border of the
sternocleidomastoid, it lies infront of the lower four cervical
transverse processes.
At the level of upper border of the thyroid cartilage it ends by
dividing into ECA & ICA.
Carotid sinus- baroreceptor or pressure receptor and regulates
the blood pressure
Carotid body-chemoreceptor and responds to the changes in
the oxygen & carbondioxide and the pH content of the blood.
Anterior triangle
Anterior triangle
Anterior triangle
ECA
It lies anterior to the ICA, chief artery which supplies
the front of the neck and the face
Course & relationIt begins in the carotid triangle at the upper border of
the thyroid cartilage opposite the disc betwn the 3rd &
4th cervical vertebra
Runs upwards and slightly backwards and laterally &
terminates behind the neck of the mandible by
dividing into maxillary and superficial temporal
arteries.
Slightly curved course- it is anteromedial to the ICA in
its lower part and anterolateral to ICA in its upper
part.
Anterior triangle
In carotid triangle- superficial & lies under cover of the
sternoclediomastoid. It is crossed superficially by the cervical
branch of the facial nerve, hypoglossal nerve & facial, lingual
and superior thyroid veins. Deep to it are walls of the
pharynx, superior laryngeal nerve which divides into external
and internal laryngeal nerves & ascending pharyngeal artery.
Above to the triangle- lies deep in the substance of the parotid
gland. Within the gland, it is related superficial to the
retromandibular vein and facial nerve. Deep to it is ICA and
betwn the ECA & ICA are- styloglossus, stylopharyngeus, IX
CN, pharyngeal branch of X CN & styloid process and two
structures deep to the ICA namely the superior laryngeal
nerve & superior cervical sympathetic ganglion.
Anterior triangle
Branches
Anterior1. Superior thyroid
2. Lingual
3. Facial
Posterior1. Occipital
2. Posterior auricular
Medial- ascending
pharyngeal
Terminal1. Maxillary
2. Superficial temporal
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