NECK
Neck
Neck – transition
between the base
of the Cranium
superiorly and the
clavicles inferiorly
Joins the head to
the trunk and
limbs – major
conduit for
structures passing
between them
Important organs
– larynx, thyroids
and parathyroids
Region of
vulnerability
Main arterial
blood flow –
Carotids
Brachial plexus –
originates in the
neck
Bones of the Neck
• Cervical vertebrae
• C1 through C7
• Atlas, Axis, C3 – 6 have bifid posterior spinous process, transverse process
foramina; C7 – long spinous process
• Hyoid bone
• Mobile bone – lies in the anterior neck – suspended by muscles at the level of
the 3rd cervical vertebra.
• Consist of a body, greater horn and lesser horn
Clinical Box
• Cervical Pain
• Causes include inflamed lymph nodes, muscle strain, protruding disc
• Enlarged nodes – malignant tumor in the head
• Also primary cancer may be in the thorax or abdomen
• Most chronic pain is caused by bony abnormalities or trauma
• Cervical pain is usually affected by movement of the head and neck
• Can also be exaggerated during coughing or sneezing
Fascia of the Neck
• Structures in the neck are surrounded by a layer of subcutaneous
tissue (Superficial fascia) – compartmentalized by layers of deep
cervical fascia.
• It is these fascial planes that determine the direction an infection may
spread.
• Cervical Subcutaneous tissue:
• Layer of fatty connective tissue – lies between the dermis of the skin and the
investing layer of the deep cervical fascia; Thinner esp. Anteriorly; Cutaneous
nerves, blood and lymphatic vessels, superficial nodes.
Platysma
• A broad but thin sheet of muscle in the subcutaneous tissue of he neck;
develops from the 2nd pharyngeal arch
• Nerve innervation – branches of the facial Nerve (CN VII)
• External Jugular vein (EJV) descends from the angle of the mandible to the
middle of the clavicle
• Bones of the Neck: Cervical vertebrae – 7; Bifid posterior spinous process;
transverse process foramina
• Hyoid Bone – Isolated from the rest of the skeleton; U shaped and
suspended between the body of the mandible superiorly and the
manubrium of the sternum inferiorly. Movable base for the Tongue;
• Maintains the patency of the pharynx ( Required for swallowing and
respiration)
• Prevertebral Layer of Deep Fascia
• Carotid Sheath – Common and ICA; Internal Jugular vein; Vagus nerve (CN X);
• Retropharyngeal Space – loose connective tissue; potential space
• Pretracheal Layer of Deep Cervical Fascia
• Thin; limited to the anterior neck; Inferiorly from the Hyoid bone – into the
Thorax
Clinical Box
• CERVICAL FASCIA
• Paralysis of Platysma – usually due to an injury to the cervical branch
of the facial nerve – skin falls away from the neck in slack folds;
Cervical branch of the facial nerve can be damaged during neck
dissections; Most suture the skin and edges of the platysma – skin will
be distracted by the contracting fibers of the platysma.
Clinical Box
• Spread of Infections in the Neck
• Investing layer of deep cervical fascia helps to prevent the spread of
abscesses; however, if the infection occurs between the investing
layer of the deep cervical fascia and the muscular part – pretracheal
fascia – the infection will usually not spread beyond the superior edge
of the manubrium of the sternum.
• Retropharyngeal abscess – posterior to the SCM – pus may perforate
the prevertebral layer of the deep cervical fascia and enter the
retropharyngeal space – Can cause dysphagia and dysarthria
Superficial Structures
of the Neck
• Neck is divided into 4 major
regions
• Anterior Cervical Region
• Posterior Cervical Region
• Sternocleidomastoid Region
• Lateral Cervical Region
Sternocleidomastoid Region
• SCM muscle is a key landmark
• SCM divides each side of the neck into the Anterior and Lateral
cervical region
• Muscles: SCM; Platysma; Trapezius
Posterior Cervical Region
• Region posterior to the anterior borders of the trapezius
• Suboccipital region is deep to the superior part of this region
• Trapezius covers the posterolateral aspect of the neck and thorax
Lateral Cervical Region
• Known as the Posterior Triangle
• Bounded anteriorly by the posterior border of SCM; Posteriorly by the
anterior border of the Trapezius; Inferiorly by the middle third of the
clavicle between the trapezius and the SCM
Arteries in the Lateral Cervical region
• Thyrocervical trunk
• Subclavian artery ( 3rd part)
• Occipital artery (part)
Veins in the Lateral Cervical Region
• External Jugular (EJV) – begins near the angle of the mandible –
crosses the EJV obliquely and deep to the platysma
• Subclavian Vein
• Brachiocephalic vein
ANTERIOR CERVICAL REGION
• Anterior boundary – Median line of he neck
• Posterior boundary – Anterior border of the SCM
• Superior boundary – Inferior border of the mandible
• Submental triangle
• Submandibular triangle
• Carotid triangle
• Muscular triangle
Muscles of the Anterior Cervical Region
• Suprahyoid Muscles
• Mylohyoid
• Geniohyoid
• Stylohyoid
• Digastric
• Infrahyoid Muscles
Sternohyoid
Omohyoid
Sternothyroid
Thyrohyoid
Vessels of the Anterior Cervical Region
• Carotid system of arteries
• Common Carotid with its
terminal branches; Internal and
External carotid arteries; IJV and
its tributaries and the anterior
jugular veins.
• Veins
• Internal Jugular vein (Carotid
Sheath)
• External Jugular vein
• Major branches include: Facial
vein; Common facial, Lingual vein;
• Brachiocephalic and subclavian
Nerves of the Anterior Cervical Region
• Transverse Cervical Nerve – C2 –C3 – supplies Skin covering the
Anterior Cervical region
• Hypoglossal Nerve – CN XII – Motor to the tongue (posterior belly of
Digastric) and 5 extrinsic muscles of the tongue
• Branches of the Glossopharyngeal – CN IX and Vagus (CN X) – tongue
and pharynx
Cervical Torticollis
• A contraction or shortening of the cervical muscles that produces
twisting of the neck and slanting of the head
• Most common type is Wry neck – fibrous tissue tumor that develops
in the SCM before and shortly after birth. Normally unilateral SCM
contraction
• Can result from a difficult birth or hematoma
Spasmodic Torticollis
• Cervical dystonia – abnormal tonicity of the cervical muscles
• Usually begins in adulthood
• May involve bilateral combination of lateral neck muscles ( esp., SCM
and Trapezius)
Carotid Endarterectomy
• Removal of atherosclerotic thickening of the intima of the ICA
• Obstructed blood flow – bruit, TIA, stroke like symptoms; Diagnosed
with Doppler color flow. Risk of cranial nerve injury (CN IX, X, or
branch to superior laryngeal nerve), CN XI or CN XII.
Glands of Neck
• Thyroid Gland – anteriorly in the neck – C5 –T1 vertebrae; Left and
Right lobes with an isthmus
• Blood supply is the Superior and Inferior thyroid arteries; 10% of
people have a small unpaired thyroid ima artery – from the arch of
the aorta.
• Veins – thyroid plexus – superior, middle, and inferior thyroid veins –
superior and middle drain into the IJV; Inferior drain into the
brachiocephalic
Glands of the Neck
• Parathyroid glands – usually 4 small pea sized – posterior surface of
the thyroid gland – sometimes may be embedded. 5% of people have
more and some have 2; Calcium metabolism
• Thymus – lower neck or just posterior to the sternum