Download Triangles and Root of the Neck

Triangles and Root of the Neck
Human Musculoskeletal System
Kittikun Viwatpinyo, Ph.D.
Neck : Introduction
• Neck (Cervical region)
▫ Area in between base of
skull to T1 vertebra, clavicle
and acromion
• Transitional area between
head, thorax and upper
limb
(Drake, Wayne & Mitchell, 2005)
Neck : Surface anatomy
Superficial structures of neck
• Skin
• Superficial fascia
• Platysma muscle
(Tank, 2005)
Superficial structures of neck
• Cutaneous nerves
(Tank, 2005)
(Moore, Dalley & Agur, 2010)
Superficial structures of neck
• Superficial veins :
(Moore, Dalley & Agur, 2010)
Deep cervical fascia
• Investing layer
• Prevertebral layer
• Pretracheal layer
• Carotid sheath
(Moore, Dalley & Agur, 2010)
Fascial spaces
• “Potential spaces”
• Pretracheal space
• Retropharyngeal
space
• Prevertebral space
(Moore, Dalley & Agur, 2010)
Fascial spaces
(Drake, Wayne & Mitchell, 2005)
Anterior triangle of neck
• Area anterior to sternocleidomastoid muscle
• Sub-triangles :
▫
▫
▫
▫
Submental
Submandibular
Carotid
Muscular
(Moore, Dalley & Agur, 2010)
Skeletal landmarks
• Hyoid bone
• Thyroid cartilage
▫ Thyroid prominence
▫ Oblique line
▫ Thyrohyoid membrane
• Cricoid cartilage
(Drake, Wayne & Mitchell, 2005)
Muscles of anterior triangle
• Suprahyoid muscles
▫ Digastric m.
▫ Stylohyoid m.
▫ Mylohyoid m.
(Moore, Dalley & Agur, 2010)
(Drake, Wayne & Mitchell, 2005)
Muscles of anterior triangle
• Infrahyoid muscles
▫
▫
▫
▫
Sternohyoid m.
Omohyoid m.
Sternothyroid m.
Thyrohyoid m.
(Moore, Dalley & Agur, 2010)
Nerves of anterior triangle
• Vagus nerve (CN. X)
▫ Located within carotid sheath
posterior to vessels
▫ Major branch : Superior
laryngeal n.  Internal and
External laryngeal nerves
(Drake, Wayne & Mitchell, 2005)
Nerves of anterior triangle
• Hypoglossal nerve (CN. XII)
▫ Located anterior to carotid arteries and medial to digastric
and stylohyoid muscles
▫ In submandibular triangle : located lateral to hyoglossus
muscle
(Moore, Dalley & Agur, 2010)
Nerves of anterior triangle
• Transverse cervical nerve (C2, C3)
▫ Receives sensation from skin of
anterior triangle
(Tank, 2005)
(Drake, Wayne & Mitchell, 2005)
Nerves of anterior triangle
• Ansa cervicalis
▫ Loop of motor branches of
cervical plexus (C1-C3)
▫ Located anterior to carotid
sheath
▫ Superior and inferior roots
▫ Supplies infrahyoid muscles
(except thyrohyoid m.)
(Tank, 2005)
Carotid arterial system
• Common carotid artery
▫ Bifurcates at level of upper
border of thyroid cartilage
• Internal carotid artery
▫ Directs into skull
▫ No branches in neck
• External carotid artery
▫ Gives many branches to neck
and facial structures
(Moore, Dalley & Agur, 2010)
External carotid artery : branches
• Superior thyroid artery
Superior laryngeal a. : pierces thyrohyoid membrane to
supply larynx
Glandular branches : supply thyroid gland
(Drake, Wayne & Mitchell, 2005)
External carotid artery : branches
• Lingual artery
▫ Passes anteriorly and deep to hyoglossus muscle to supply
tongue
(Drake, Wayne & Mitchell, 2005)
External carotid artery : branches
• Facial artery
▫ Passes anteriorly and medial to posterior belly of digastric
muscle and travels along inf border of mandible
▫ Supplies submandibular salivary gland, submental region and
face
(Drake, Wayne & Mitchell, 2005)
External carotid artery : branches
• Occipital artery
▫ Passes posteriorly and medial to posterior belly of digastric
muscle
▫ Supplies sternocleidomastoid muscle and posterior part of
scalp
(Drake, Wayne & Mitchell, 2005)
Carotid pulse
(Drake, Wayne & Mitchell, 2005)
Internal jugular vein
• IJV : located lateral to
common carotid a.
• Joins subclavian vein at
venous angle
• Major tributaries
▫ Facial vein
▫ Lingual vein
▫ Superior and middle
thyroid veins
▫ Occipital vein
(Moore, Dalley & Agur, 2010)
Lymphatics of the neck
• Superficial lymph nodes
▫ Occipital nodes
▫ Mastoid nodes
▫ Parotid nodes
▫ Submental nodes
▫ Submandibular nodes
▫ Superficial cervical nodes
(Drake, Wayne & Mitchell, 2005)
Lymphatics of the neck
• Deep cervical lymph nodes
▫ Superior deep cervical nodes
▫ Inferior deep cervical nodes
▫ Pretracheal and Paratrachel
nodes
(Moore, Dalley & Agur, 2010)
Posterior triangle of neck
• Area posterior to sternocleidomastoid muscle
• Sub-triangles :
▫ Occipital
▫ Omoclavicular
(Moore, Dalley & Agur, 2010)
Muscles of posterior triangle
• Sternocleidomastoid
muscle (SCM)
▫ Origin : Mastoid process
and lateral ½ of sup nuchal
line
▫ Insertion : medial 1/3 of
clavicle and upper
manubrium
▫ Nerve : Spinal accessory
nerve (CN. XI)
(Drake, Wayne & Mitchell, 2005)
Muscles of posterior triangle
• Sternocleidomastoid muscle : Actions
▫ Extends neck (when in anatomical position)
▫ Flexes neck (when neck is initially flexes)
▫ Rotates neck to opposite side (unilateral)
(Moore, Dalley & Agur, 2010)
Muscles of posterior triangle
• Scalene muscles
▫ Scalenus anterior
▫ Scalenus medius
▫ Scalenus posterior
• Main action : Flex neck
and elevate ribs 1-2
(Drake, Wayne & Mitchell, 2005)
Nerves of posterior triangle
• Accessory nerve (CN. XI)
▫ Passes downward and
posteriorly to supplies SCM
and Trapezius muscles
▫ Just beneath investing fascia
 frequently injured
▫ “Careful region of the posterior
triangle”
(Tank, 2005)
Nerves of posterior triangle
• Cervical plexus : from ventral rami of C1-C4
▫ Muscular branches : Ansa cervicalis and Phrenic n.
▫ Cutaneous branches
Nerves of posterior triangle
• Supraclavicular part of brachial plexus (root + trunk level)
▫ Passes between scalenus anterior and medius muscles
(Drake, Wayne & Mitchell, 2005)
Nerves of posterior triangle
• Terminal branches
▫
▫
▫
▫
Dorsal scapular n. (C5)
Long thoracic n.(C5 – C7)
Suprascapular n. (C5, C6)
Nerve to subclavius (C5, C6)
(Drake, Wayne & Mitchell, 2005)
Arteries of posterior triangle
• Branches from Subclavian artery
▫ Suprascapular artery
▫ Transverse cervical artery
(Drake, Wayne & Mitchell, 2005)
Root of the neck
• Deep part of neck that connects with thorax (via superior
thoracic aperture)
(Drake, Wayne & Mitchell, 2005)
Root of the neck
• Major contents : Subclavian vessels, Nerves, Lymph
trunks, Visceral structures
(Moore, Dalley & Agur, 2010)
Subclavian artery
• From Brachiocephalic trunk
(right) and aortic arch (left)
▫ Curves laterally in between
Scalenus anterior and medius
muscles
▫ Continues as Axillary artery
▫ Three parts (related with
scalenus anterior muscle)
(Tank, 2005)
Subclavian artery : branches
• First part : Vertebral a.,
Internal thoracic a. &
Thyrocervical trunk
• Vertebral artery
▫ Passes upward and medial to
scalenus anterior m.
▫ Penetrates foramen
transversarium (mostly C6)
(Drake, Wayne & Mitchell, 2005)
Subclavian artery : branches
• Internal thoracic artery
▫ Pass downward to supply anterior
thoracic wall
• Thyrocervical trunk
▫ Suprascapular a.
▫ Transverse cervical a. gives
superficial and deep branches
▫ Inferior thyroid a.
(Moore, Dalley & Agur, 2010)
Subclavian artery : branches
• Second part : Costocervical trunk
▫ Give rises to Deep cervical artery and Superior thoracic
artery
Subclavian artery : branches
• Third part :
▫ In 1/3 give rises to Dorsal scapular artery (replace deep
branch of transverse cervical artery)
Subclavian vein
• Subclavian vein
▫ Continues from Axillary vein
▫ Passes anterior to scalenus
anterior muscle and join IJV at
venous angle
▫ Drained into Brachiocephalic
vein
(Drake, Wayne & Mitchell, 2005)
Lymph trunks and nodes
• At venous angle, lymph trunks join
venous system:
▫ Left side : Thoracic duct
▫ Right side : Rt lymphatic duct
• Supraclavicular lymph nodes can
be found along subclavian vein
(Moore, Dalley & Agur, 2010)
Nerves of root of the neck
• Vagus nerve
▫ Recurrent laryngeal nerve : passes in tracheo-esophageal
groove to supply internal laryngeal muscles
(Drake, Wayne & Mitchell, 2005)
Nerves of root of the neck
• Phrenic nerve (C3-C5)
▫ Passes anterior to scalenus anterior muscle and descends into
thorax to supplies diaphragm
(Drake, Wayne & Mitchell, 2005)
Nerves of root of the neck
• Cervical part of sympathetic
trunk
▫ A bundle of sympathetic fibers
posterior to carotid sheath
▫ Three ganglions (location of
postganglionic sympathetic
neurons)
• Lesion : Horner’s syndrome
▫  loss of sympathetic control in
head
(Drake, Wayne & Mitchell, 2005)
Nerves of root of the neck
• Cervical sympathetic ganglions
▫ Superior cervical ganglion :
 sends symp fibers into head and
neck along internal carotid artery
▫ Middle & Inferior cervical ganglions
 sends symp fibers to heart
(Drake, Wayne & Mitchell, 2005)