Fascial layers of the neck Flashcards
what is the fascia?
a layer of fibrous tissue that surrounds muscles, vessels and nerves
what do the fascia layers in the neck act to do?
support and compartmentalise the structures present
where does the superficial cervical fascia lie?
between the dermis and deep cervical fascia
what does the superficial cervical fascia contain?
neurovascular supply to the skin superficial veins (e.g. external jugular vein) superficial lymph nodes fat platysma muscle
how is double chin created in obese individuals?
extra fat is deposited in the superficial fascia
where is the platysma muscle situated?
on anterior aspect of neck
origin of platysma?
has 2 heads (L + R)
originate from fascia of pectorlis major and deltoid
where do the 2 heads of the platsyma muscle meet?
fibres from the 2 heads cross the clavicle
meet in the midline, fusing with muscles of the face
what is the motor innervation to the platysma muscle via?
cervical branch of the facial nerve
what is the layers of the deep fascia? (superficial to deep)
investing
pre-tracheal
pre-vertebral
describe the investing layer (location)?
surrounds all the structures in the neck
where it meets the trapezius + SCM muscles, splits into 2, completely surrounding them
what are the attachments of the investing fascia?
thought of like a tube: has superior, anterior, inferior and posterior attachments
what is the superior attachment of the investing fascia?
attaches to the external occipital protuberance (back of skull) and superior nuchal line (line across external occipital protuberance
what is the anterior attachment of the investing fascia?
hyoid bone
what is the inferior attachment of the investing fascia?
attaches to the spine and acromion of the scapula, clavicle and manubrium of the sternum
what is the posterior attachment of the investing fascia?
along ligamentum nuchae (continuation of supraspinous ligament)
where is the pretracheal layer of fascia situated?
anteriorly in the neck
where does the pretracheal fascia span?
between the hyoid bone and the thorax - where it fuses with the pericardium
what does the pretracheal fascia enclose?
trachea
oesophagus
thyroid gland
infrahyoid muscles
how can the pretracheal fascia be divided anatomically?
into 2 parts:
muscular
visceral
what does the muscular part of the pretracheal fascia enclose?
the infrahyoid muscles
muscular part encloses muscles
what does the visceral part of the pretracheal fascia enclose?
thyroid gland, trachea, oesophagus
visceral around structures
what is the posterior aspect of the visceral fascia formed by?
contributions from the buccopharyngeal fascia
what is the buccopharyngeal fascia?
fascial covering of the pharynx
what does the prevertebral fascia surround?
the vertebral column and its associated muscles (scalene, prevertebral and deep muscles of the back)
what are the attachments of the prevertebral fascia?
antero/posterior
superio/inferior axes
what is the superior attachment of the prevertebral fascia?
base of skull
what is the anterior attachment of the prevertebral fascia?
transverse processes and vertebral bodies of the vertebral column
what is the posterior attachment of the prevertebral fascia?
attaches along the ligamentum nuchae (continuation of supraspinous ligament)
what is the inferior attachment of the prevertebral fascia?
fuses with endothoracic fascia of ribcage
what forms the floor of the posterior triangle of the neck?
anterolateral portion of prevertebral fascia
what does the prevertebral fascia also surround?
brachial plexus and subclavian artery as they leave the neck
forms the axillary sheath
what are the carotid sheaths?
paired structures which enclose important vessels and nerves
what forms the carotid sheaths?
contributions from all 3 deep cervical fascias (investing, pretracheal, prevertebral)
what are the contents of the carotid sheath?
common carotid artery
internal jugular vein
vagus nerve
cervical lymph nodes
what happens to the common carotid artery within the carotid sheath?
bifurcates into internal and external carotid arteries
clinical: how is the carotid fascia organised? where does it travel?
organised into a column
runs from base of skull to thoracic mediastinum
(spread of infection)
clinical: how does neck fascia affect spread of infection?
compartmentalise structures within the neck
layers of tough fascia define where infection can spread
e.g. superficial skin abscess is prevented from spreading further into the neck by investing fascia
clinical: where do infections posterior to the prevertebral fascia spread?
can erode through the prevertebral fascia, and drain into the retropharyngeal space
what is the retropharyngeal space?
a space bewteen the pretracheal and prevertebral fascial layers
clinical: where does the retropharyngeal space extend? what does this mean?
into the thorax, infection can spread to mediastinal contents
clinical: where do infections between the investing fascia and visceral part of pretracheal fascia spread? causing?
spread inferiorly into the chest, causing infection of anterior mediastinum
