Triangles Of The Neck Flashcards
Borders of the quadrilateral outline of the neck
Superior: body of mandible and imaginary line drawn from the angle of mandible to mastoid process
Inferior: upper border of clavicle
Anterior: anterior midline of the neck
Posterior: anterior border of the trapezius muscle
What divides the quadrilateral into anterior (medial) and posterior (lateral triangle)
Sternocleidomastoid muscles
Origin of SCM muscle
Origin: medial third of the clavicle and manubrium of sternum
Insertion: mastoid process of temporal bone
Innervation: spinal accesory nerve and anterior rami of C2,C3 (for proprioception)
Action: rotates the head to opposite side, extends head and flexes vertebrae column
Borders of the anterior or medial triangle
body of the mandible
SC
Median line of the neck from the chin to the manubrium of sternum
Anterior triangle is divided into 4 triangles by ———
which are
Anterior and posterior belly of digastric muscles
Superior belly of omohyoid bone
Submandibular or digastric triangle
Submental
Carotid
Muscular
Submental triangle is formed by
Anterior midline of the neck
Anterior belly of digastric muscle
Hyoid bone
Submnadibular or digastric triangle
Anterior belly of digastric muscle
Posterior belly of digastric muscle
Inferior border of mandible
Carotid triangle
Anterior border of SCM
Posterior belly of digastric
Superior belly of omohyoid
Muscular triangle
Anterior border of SCM
Superior belly of omohyoid
Anterior midlife of the neck
Contents of the anterior triangle
Vessels: Common carotid system (CCA, ICA, ECA)
Injmternal jugular vein
Nerves: CN 7,9,10,11,12
Cervical plexus
Muscles:
Suprahyoid ( geniihyoid, myohoid, digastric, stylohyoid
Infrahyoid: sternohyoid, thryrohyoid, omohyoid, sternothyroid.
Borders of the posterior triangle
Anteriorly - Posterior border of SCM
Posteriorly - Anterior border of the trapezius
Inferiorly - middle third of clavicle
Apex: occipital bone (the junction of the trapezius and SCM). It’s blunt and directed upwards.
The roof of the posterior triangle is formed by
Skin
Superficial fascia
Platysma muscle
Investing layer of the deep cervical fascia
Muscles that form the floor of the posterior triangle from above to below
Splenius capitis
Lavatory scapulae
Posterior scalene
Middle scalene
Anterior Scalene
(Look at the diagram)
Subdivision the posterior triangle
Occipital
Subclavian or supraclavicular
Boundaries of the occipital triangle
SCM
Trapezius
Inferior belly of omohyoid muscle
Boundaries of the subclavian or supraclavicular
SCM
Superior border of the clavicle
Inferior belly of omohyoid muscle
Nerves in the posterior triangle
Spinal accesory nerve
Branches of cervical plexus (lesser occipital nerve, greater auricular, transverse cervical, dorsal scapula, nerve to the levator scapula)
Roots and trunk of brachial plexus
Muscles in the posterior triangle
Inferior belly of the omohyoid muscle
Splenius capitis, levator scapulae, scalenes medius and posterior.
Vessels in the posterior triangle
Subclavian artery and vein
Transverse cervical artery
Suprascapular artery
Occipital artery
External jugular vein (terminal part)
Lymph nodes in the posterior triangle
Occipital
Supraclavicular or subclavian
Jugular trunk
Thoracic duct
Deep cervical lymph nodes
Clinical correlation of the posterior triangle
> The external jugular vein is present in a superficial location therefore vulnerable to injury
> Accessory nerve may be damaged when taking lymph nodes biopsy
> Nerve block for surgical procedures
Carotid stenosis
Subclavian syndrome
> Thoracic outlet syndrome: check picture on phone for explanation
Subclavian syndrome (subclavian steal syndrome): check picture on phone for explanation
Horner’s syndrome: cervical sympathetic pathway injury
Contents of the subclavian triangle
3rd Subclavian artery, subclavian vein
Suprascapular artery, vein, lymph nodes
Supraclavicular part of brachial plexus
Nerve to the subclavius
Contents of the occipital triangle
Accessory nerve
Occipital artery
Part of branches of brachial plexus
Transverse cervical vessels and lymph nodes
