Triangles of the Neck
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Transcript of Triangles of the Neck
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Triangles of the
Neck
Sanjaya AdikariDepartment of Anatomy
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Boundaries of the neck
Spinous process of C7
Acromian
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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
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Compartments of the neck
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Cervical fascia
SuperficialContains platysma muscle, cutaneous nerves, superficial veins and superficial LNs
Deep
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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
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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.
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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
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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
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Pretrachial fascia
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Carotid sheath
Anterior
Vagus nerve
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Triangles of the neck
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Posterior triangle - contents• External jugular
vein after piercing the investing layer.
• Accessory nerve
• Branches of Cx plexus– Lesser occipital
– Great auricular
– Transverse cervical
– Supraclavicular
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Floor of the posterior triangle
• Prevertebral
fascia lying on
the muscles
• Semispinalis
capitis
• Splenius
capitis
• Levator
scapulae
• Scalenus
medius
• Scalenus
anterior
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Anterior triangles of the neck
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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
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Anterior triangle….
• Infrahyoid muscles
– Sternohyoid
– Omohyoid
– Thyrohyoid
– Sternothyroid
These are depressors of the larynx. Supplied by
ansa cervicalis (C1-C3)
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Carotid triangle
• Tip of the greater horn of hyoid is an important reference point
• Note the relationships of hypoglossal nerve
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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
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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
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Thoracic duct in the neck
• Join the
junction
between the
left
subclavian
and internal
jugular veins