General Organisation of the Head and Neck Flashcards
What are the borders of the neck?
Lower margin of the mandible (jaw) to the suprasternal notch of the manubrium and the upper border of the clavicle
What are the different layers of cervical fascia in the neck called?
Structures in the neck are compartmentalised by layers of cervical fascia
- Superficial cervical fascial
- 3 Deep: Investing, pretrachial, prevertebral
What forms the carotid sheath?
The carotid sheath is a fourth deep cervical fascia layer that is essentially Formed by parts of all 3 layers of deep cervical fascia
What does the superficial fascia mostly contain?
Loose connective tissue mainly containing adipose tissue
What structures are found within the superficial fascia?
Superficial blood vessels e.g. anterior and external jugular veins, cutaneous nerves, superficial lymph nodes and the platysma muscle.
What are the attachments of the investing layer?
- most superficial of the deep cervical fasciae and surrounds the entire neck like a collar.
- Its superior margin is attached on each side to the lower border of the mandible, the mastoid process, the superior nuchal line and the external occipital protuberance in the posterior midline.
- It also attaches to the spinous processes of the vertebrae and ligamentum nuchae posteriorly.
- Inferiorly, attaches to the upper border of the manubrium, the upper surface of the clavicle, acromion and spine of the scapula
What structures does the investing layer split to enclose?
sternocleidomastoid, trapezius, submandibular and parotid salivary glands
Where in the neck is the pretracheal fascia found and what are its attachments?
Anterior and lateral part of the neck. (middle layer)
Superiorly and anteriorly Attaches to hyoid bone and extends inferiorly into thorax and blends with fibrous pericardium.
What are the 2 layers of the pretracheal fascia and what do they enclose?
Muscular layer enclose infra hyoid muscles.
Visceral layer encloses thyroid gland, trachea and oesophagus
What is the posterior part of the pretrachial fascia called and what does it enclose?
when the pretracheal fascia runs behind the oesophagus and and pharynx, it becomes known as the Buccopharyngeal fascia - invests muscles of the pharynx and oesophagus.
The buccopharyngeal fascial layer runs from the base of the skull superiorly, to the diaphragm inferiorly.
Where is the carotid sheath and what does it contain?
Base of the skull through the root of the neck down the thorax to the arch of the aorta.
Contains common carotid artery, internal jugular vein, cranial nerve and vagus nerve
Where is the prevertebral fascia found and what does it contain?
- Extends from the base of the cranium to the 3rd thoracic vertebra and extends laterally as the axillary sheath that surrounds the axillary vessels and the brachial plexus of nerves.
- deepest fascia layer
- Contains the vertebral column and the associated muscles - pre and paravertebral muscles - muscles that surround the cervical vertebrae
list the order of the fascia of the neck from superficial to deep
- superficial cervical fascia
- investing layer
- pretracheal layer
- prevertebral layer
What bone is the pretracheal fascia layer attached to and what is the effect of this?
connected to the hyoid bone which moves when swallowing or speaking so the structures found within the pretracheal layer will also move
What is the superficial cervical fascia also known as?
subcutaneous tissue of the neck
What are 4 common sources of deep neck infections?
Often originates in the teeth, tissues of the pharynx, sinuses or middle ear, and spreads.
What are the functions of the facial compartments?
- Form natural planes
- Ease of movement between structures e.g. when swallowing
- Can restrict but also permit spread of infection
What is the retropharyngeal space and where is it found?
one deep neck space
Between the buccopharyngeal fascia and the prevertebral fascia.
What does the retropharyngeal space allow the pharynx to do?
move freely on the vertebral column and expand during swallowing
Why is an infection in the retropharyngeal space dangerous?
Retropharyngeal space lies between fascial layers that extend the length of the neck, into the mediastinum.
retropharyngeal infections may spread inferiorly into the thorax and mediastinum, risking the development of mediastinitis
What do the deep neck spaces contain?
The fascial compartmentalisation of structures in the neck gives rise to potential spaces between fascial planes.
These deep neck spaces contain a loose connective
tissue, so they are not technically “empty” spaces.
However, infection or an abscess can arise between the fascial planes causing these “spaces” to distend (deep neck space infections).
What are the signs and symptoms of a retropharyngeal abscess?
visible bulge on inspection of the oropharynx, sore throat, difficulty swallowing, stridor, reluctance to move their neck and a high temperature
What is usually found in the retropharyngeal space in children and what problem does it pose?
- Up until the age of 3- 4 years, the superior part of
this space contains lymph nodes, which drain areas of the nose, oral cavity and upper pharynx. - it presents significant problems should infection spread to and collect here.
What commonly results in infection of the retropharyngeal space?
Infection in the retropharyngeal space is usually secondary to an upper respiratory tract infection (e.g. nasal cavity, nasopharynx, oropharynx) and is most commonly seen in children, usually under the age of 5 years due to the involvement of the retropharyngeal lymph nodes. Infection in this space may develop into an abscess.
What may be present in diseases affecting the thyroid gland?
Diseases affecting the thyroid gland can cause enlargement of the gland or discrete lumps to appear.
What can be dome to help localise pathology to the thyroid gland?
- Asking a patient with a swelling or lump in their neck to swallow and observing whether it moves, can help localise pathology to the thyroid gland.
- This is because the thyroid gland is enclosed by pre-tracheal fascia, which is attached to the hyoid bone. The hyoid bone and larynx move up with swallowing,
as such so too will the thyroid gland, and any swelling or lump involving this gland.
Why can an enlarged thyroid gland (goitre) sometimes extend retrosternally?
An enlarged thyroid gland (goitre) can sometimes extend retrosternally (behind the sternum), through the root of the neck because the lower limit of the pre- tracheal fascia extends into the thorax. Retrosternal extension of a goitre can lead to compression of other structures running through the root of the neck (thoracic inlet) such as the trachea and venous blood vessels.
what symptoms can an enlarged thyroid gland (goitre) extended retrosternally present with?
symptoms such as breathlessness and stridor due to tracheal compression, and facial oedema from the compression impeding venous drainage from the head and neck.
What are the two broad divisions of muscles of the head (and face)?
• muscles of facial expression
- (including the muscle of the scalp [occipitofrontalis] and muscle of the cheek [buccinators])
• muscles of mastication
Where are muscles of facial expression found?
- Most of them lie in the subcutaneous tissue, and attach to bone, fascia and often each other.
- Many attach just beneath the skin such that their contraction pulls the skin in particular ways, giving rise to the breadth of facial expressions we possess
Which nerve innervates muscles of facial expression?
Facial nerve (cranial nerve VII)
What is the extracranial path of the facial nerve?
Once the facial nerve exits the skull, Runs superficially within the parotid gland and splits into 5 terminal branches within the gland
What are the two ways in muscles of facial expression act?
muscles will act as either sphincters or dilators around the orifices of the face- the orbits of the eye, the nose or mouth.
What is an exception to the rule that muscles of facial expression act as sphincters or dilators?
buccinators (the muscles of your cheek) which, by keeping the cheek taut, helps ensure food remains within the oral cavity proper when chewing (rather than
‘pooling’ between the cheek and teeth).
What is Bell’s Palsy?
Inflammation or viral infection of the facial nerve that causes one sided weakness/paralysis of the entire face
What are the branches of the facial nerve?
temporal, zygomatic, buccal, marginal mandibular, cervical
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