triangles of the neck sanjaya adikari department of anatomy
TRANSCRIPT
Triangles of the
Neck
Sanjaya AdikariDepartment of Anatomy
Boundaries of the neck
Spinous process of C7
Acromian
Compartments of the neck
Neck has 4 major compartments
• Vertebral compartment
– Cervical vertebrae and associated muscles
• Visceral compartment
– Parts of respiratory and digestive tracts, important glands (thyroid, parathyroid and thymus)
• Two vascular compartments
– Contains major blood vessels and vagus nerve
Compartments of the neck
Cervical fascia
SuperficialContains platysma muscle, cutaneous nerves, superficial veins and superficial LNs
Deep
Deep cervical fascia
Consists of 4 parts
• Investing layer
– Encircles the neck completely
• Pretrachial fascia
– Encircles the visceral compartment
• Prevertebral fascia
– Encircles the vertebral compartment
• Carotid sheaths
– Enclose the two vascular compartments
Clavicle
Manubrium
Acromian & spine
L. nuchae
E.O. protuberance & s. nuchal line
Investing layer• Splits to
enclose the
parotid gl.
• Superficial
layer forms
parotid
fascia &
attached to
zygomatic
arch
MandibleMastoid p.
Clavicle
Manubrium
Acromian & spine
L. nuchae
E.O. protuberance & s. nuchal line
Investing layer
MandibleMastoid p.
Stylomandibular ligament
• Deep layer forms stylomandibular ligament between styloid process & angle of mandible
Prevertebral fascia
• Lies in front of prevertebral muscles
• Extends from skull base to T4 body getting attached to anterior longitudinal ligament
• Extends around the subclavian artery and brachial plexus and becomes axillary sheath
• Phrenic nerve lies behind
• Sympathetic trunk lies in front
• Cutaneus branches of Cx plexus pierce it
Pretrachial fascia
Carotid sheath
Anterior
Vagus nerve
Triangles of the neck
Posterior triangle - contents• External jugular
vein after piercing the investing layer.
• Accessory nerve
• Branches of Cx plexus– Lesser occipital
– Great auricular
– Transverse cervical
– Supraclavicular
Floor of the posterior triangle
• Prevertebral
fascia lying on
the muscles
• Semispinalis
capitis
• Splenius
capitis
• Levator
scapulae
• Scalenus
medius
• Scalenus
anterior
Anterior triangles of the neck
Anterior triangle of the neck
• Suprahyoid muscles
– Digastric: poterior belly by facial N. & anterior
belly by nerve to mylohyoid
– Stylohyoid: by facial nerve
– Mylohyoid: by nerve to mylohyoid, a branch of
inferior alveolar nerve (mandibular division)
– Geniohyoid: by C1 through hypoglossal nerve
Anterior triangle….
• Infrahyoid muscles
– Sternohyoid
– Omohyoid
– Thyrohyoid
– Sternothyroid
These are depressors of the larynx. Supplied by
ansa cervicalis (C1-C3)
Carotid triangle
• Tip of the greater horn of hyoid is an important reference point
• Note the relationships of hypoglossal nerve
Root of the neck
• All structures
that pass
between the
head and
thorax or upper
limb and thorax
must pass
through the
root of the neck
Subclavian Artery
• 1st part of subclavian artery– Vetebral A– Internal thoracic
A– Thyrocervical
trunk• 2nd part of
subclavian artery– Costocervical
trunk• 3rd part of
subclavian artery– Dorsal scapular
A
Thoracic duct in the neck
• Join the
junction
between the
left
subclavian
and internal
jugular veins