the neck

Anterior triangle of neck

By
Dr. Adel Sahib Al-Mayaly




سنة مباركة عليكم وندعو الله ان تكون سنة خير وامن وامان على بلدنا واهلنا انه سميع الدعاء

It emerges from the base of skull via the jugular foramen.

It lies behind the ICA at the base of skull
It receives the inferior petrosal vein.
It descends lateral to the ICA & CCA then anterolateral to the carotid artery during its descent in the neck .
At the root of neck;
it joins the subclavian vein to form the brachiocephalic vein .
Internal jugular vein

Surface anatomy of neck veins

Internal jugular vein

Vagus nerve

It leaves the cranial cavity through the jugular foramen with cranial root of accessory n.
In the foramen the nerve is swollen to form the superior ganglion.
A short distance below the foramen it bears the larger inferior ganglion.


Course of vagus nerve

Superior ganglion:- carries the cutaneous neurons which travel through the auricular nerve (Arnold nerve).
Inferior ganglion:- contains the taste & visceral sensory neurons.
Below the inferior ganglion; is joined by cranial root of accessory n.
Vagus nerve

Vagus n. descends vertically down within the carotid sheath first between ICA & IJV then between the IJV & CCA.
In the root of neck;
•The right vagus nerve passes anterior to the subclavian artery and posterior to the sternoclavicular joint, entering the thorax.

Vagus nerve

•The left vagus nerve passes inferiorly between the left common carotid and left subclavian arteries, posterior to the sternoclavicular joint, entering the thorax.

Vagus nerve

1- superior ganglion:-
A- meningeal branch:- to dura of post. Cranial cavity.
B- auricular branch:- cutaneous n.
To external auditory canal
Branches of vagus nerve

2- inferior ganglion:-

A- pharyngeal branch:- it joins the pharyngeal branch of GPN to form the pharyngeal plexus.
Pharyngeal plexus:- motor fibres from the cranial root of accessory nerve to the muscles of pharynx & soft palate.

branches

2- superior laryngeal nerve:-
It descends on the side of pharynx deep to ICA
It divides
1-Internal laryngeal nerve:- it pierces the thyrohyoid membrane to supply mucosa of larynx above vocal cords.
2-External laryngeal nerve:- motor to inferior constrictor & cricothyroid m.
branches

+3- Minute branches to the carotid body.

4- Recurrent laryngeal nerve:-
Right side:- neck by hooking around R subclavian a.
It ascends in the neck in the groove between the trachea & esophagus.
Left side:- stems from the vagus in front of arch of aorta
It ascends in the neck to reach side of trachea
Branches


Upon reaching the lower pole of thyroid lobe the n. Is closely related to the inferior thyroid artery.
The n. usually passes behind but infrequently between or in front the recurrent laryngeal nerve.
Recurrent laryngeal nerve

Superior & Inferior cardiac branches:- they supply the parasympathetic of the heart

They join CARDIAC PLEXUS. They convey parasympathetic fibres to the heart.
1- Mylohyoid muscle
2- Hyoglossus muscle
3- Genniohyoid muscle
4- Digastric muscle
5- Stylohyoid muscle.
of branches

Muscular triangle

Roof:- investing layer.
Floor:- Infrahyoid muscle.
Superior;-superior belly of omohyoid muscle.
Inferior;- anterior border of SCM
Anterior;- midline of neck.


Boundaries

1- superior belly of omohyoid.

2- sternohyoid muscle.
3- thyrohyoid muscle.
4- sternothyroid muscle.

They are supplied by ansa cervicalis nerve except thyrohyoid which supplied by C1via hypoglossal n.
Infrahyoid muscle

Innervation

Insertion
Origin
Muscle

Ansa cervicalis

Medial part of lower border of hyoid bone
Posterior surface of manubrium sterni
sternohyoid muscle
Ansa cervicalis

Oblique line of thyroid cartilage

Posterior surface of manubrium sterni
Sternothyroid
Cervical spinal nerve 1 via the hypoglossal nerve
Lower border of the body and the greater cornu of the hyoid bone
Oblique line of thyroid cartilage
Thyrohyoid
Superior root of ansa cervicalis (C1)
Hyoid bone
Intermediate tendon
Omohyoid (superior belly)
Ansa cervicalis (C1-C3)
Intermediate tendon
Superior border of scapula
Omohyoid (inferior belly
Infrahyoid muscles


Ansa cervicalis

Suprahyoid muscles

Suprahyoid muscles

Suprahyoid muscles

Innervation
Insertion
Origin
Muscle
Mylohyoid nerve - branch of CN V3 (Mandibular division of Trigeminal nerve
Intermediate Tendon
Digastric fossa of Mandible
Digastric (anterior belly)

Digastric ( posterior belly)

4 muscles
1- sternohyoid muscle.
2- omohyoid muscle.
3- sternothyroid muscle.
4- thyrohyoid muscle.

Infrahyoid muscles

Muscles of anterior triangle