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
To Zanzibar By Motor Car
What are the muscles of facial expression?
- Occipitofrontalis
- Orbicularis oris
- Buccinator
- Orbicularis oculi
- Risorius
- Platysma
- Zygomaticus (major and minor)
What are the attachments, actions and nerve supply to the occipitofrontalis?
- Elevates eyebrows, wrinkles the forehead.
- Originates from the epicranial aponeurosis
- inserts into the skin of the eyebrow and forehead.
- Temporal branch of facial nerve
What are the attachments, actions and nerve supply to the buccinator?
- Compresses cheeks against teeth during mastication.
- Originates from mandible and maxilla
- inserts into angle and later upper and lower lips.
- Buccual branch of the facial nerve.
What are the attachments, actions and nerve supply to the risorius?
- Pulls corner of the mouth laterally
- Originates from fascia of lateral cheek and inserts into angle of mouth.
- Buccal branch of facial nerve
What are the attachments, actions and nerve supply to the major and minor zygomaticus?
- Draw angle of the mouth laterally and superiorly.
- Originate from the lateral and anterior zygomatic bone and insert into skin of angle of mouth and lateral upper lip.
- Buccal branch of facial nerve.
What are the attachments, actions and nerve supply to the orbicularis oris?
- Compression and protrusion of lips/ brings lips together/ purses lips
- Originates from anterior medial surface of maxilla and mandible and inserts into skin/fascia of lips.
- Zygomatic branch of facial nerve.
What are the attachments, actions and nerve supply to the orbicularis oculi?
- Orbital part squeezes eye shut forcibly, palpebral part closes eye e.g. gentle blinking.
- Temporal and zygomatic branches.
What are the attachments, actions and nerve supply to the platysma?
- Depresses angles of the mouth and tenses skin of the neck.
- Arises from skin/fascia of lower face and mandible, inserts into fascia covering anterior chest wall.
- Cervical branch of the facial nerve
What will Injury or pathology affecting the facial nerve result in?
weakness of the muscles of facial expression on the ipsilateral side, causing that half of the face to ‘droop’
What is the most common non-traumatic cause of facial paralysis?
inflammation of the facial nerve (Bell’s palsy). Inflammation of the nerve, likely viral in aetiology, causes oedema and compression of the nerve as it runs through the bones of the skull.
What is Weakness of the facial muscles on one side in association with an ipsilateral parotid enlargement highly likely to be?
parotid cancer - until proven otherwise
How can parotid cancer lead to Weakness of the facial muscles?
The cancerous cells invade and damage the facial nerve during its course through the gland. It is rare for benign, infective or inflammatory conditions of the parotid gland e.g. as can occur in mumps, to cause damage to the facial nerve and thus these conditions are not typically associated with facial muscle weakness.
Describe how dilators and sphincters work?
dilators - stretch or open out structures around orifices
sphincters - contraction of the muscles lead to closure of orifices
why might injury to facial nerve lead to redness and swelling of eye?
paralysis of sphincter muscles (orbicularis oculi) so unable to close eye/ blink as well so eyes dry out
What are the muscles of mastication and what do they act on?
All act to move the mandible at the temporomandibular joint (TMJ):
Temporalis, massester, medial and lateral pterygoids
Which nerve innervates the muscles of mastication?
Mandibular division of trigeminal nerve(cranial nerve v)
What is the main sensory nerve of the face and what are its branches?
Trigeminal: ophthalmic, maxillary and mandibular
Which of the branches of the trigeminal nerve is motor?
ophthalmic- sensory
maxillary - sensory
mandibular - sensory + motor
What are the attachments, actions and nerve supply to the temporalis?
- Anterior fibres elevate the mandible, posterior fibres retract the jaw.
- Arises from temporal fossa and fascia, inserts into ramus and coronoid process of mandible.
- Mandibular branch of trigeminal nerve?
What are the attachments, actions and nerve supply to the masseter?
- Main elevator of mandible.
- arises from zygomatic arch and inserts into angle and ramus of mandible.
- Mandibular branch of trigeminal nerve?
What are the attachments, actions and nerve supply to the medial pterygoid?
- Elevation and protrusion of the mandible
* mandibular branch of trigeminal nerve?
What are the attachments, actions and nerve supply to the lateral pterygoid?
- Depression and protrusion of the mandible
* Mandibular branch of the trigeminal nerve?
Which muscles are mainly involved in depression of the mandile? give and example.
Suprahyoids e.g Digastric muscles (anterior and posterior bellies)
- assisted by gravity and lateral pterygoid
(The action of the lateral pterygoid, in assisting opening of the mouth can be helpful remembered by how you pronounce lateral. Saying ‘Laaaaaaa’teral requires you to open your mouth!
What are the borders of the anterior triangle of the neck?
superior border: inferior margin of mandible
medial border:
Midline of the neck
lateral border: anterior margin of SCM.
What are the borders of the Posterior triangle?
Anterior border: posterior border of SCM
posterior border: anterior border of trapezius
inferior border: clavicle
roof: platysma
What are the borders of the carotid triangle?
medial border: Superior belly of omohyoid
lateral border: SCM
superior border: posterior belly of digastric
What structures are found within the posterior triangle?
- subclavian artery and vein
- trunks of brachial plexus
- scalene muscles
- omohyoid
- external jugular vein
What is the difference between structures coursing through the anterior and posterior triangles?
anterior triangle: associated with structures coursing between head and thorax
posterior triangle: associated with structures coursing between neck and upper limb
Describe the omohyoid muscles
- infra hyoid muscle
* two bellies
How does the scalene muscle relate to neck triangles?
Forms floor of the posterior triangle.
Which structures run close to the scalene muscles?
The trunks of the brachial plexus and subclavian artery pass between the anterior and middle scalenes, as they head towards the upper limb. The phrenic nerve, which arises from within the neck (C3,4,5) descends along the surface of the anterior scalene before entering into the thorax
Which artery supplies the face?
Facial artery, branch on external carotid.
The cranium is split into what two parts?
Neurocranium + viscerocranium
What is the function of neurocranium? What is it made up of?
The neurocranium encases + PROTECTS the brain. Made up of :
CALVARIA (skull cap)
CRANIAL FLOOR
CRANIAL CAVITY
Are the branches of the facial (cranial VII) nerve sensory or motor?
All MOTOR branches
The thyroid gland is found below the level of the cricoid cartilage - true or false?
True
What 3 (bony) structures can you palpate in the neck?
Hyoid Bone Thyroid cartilage (NOT BONE) Cricoid cartilage (NOT BONE)
What do the common carotid arteries bifurcate into in the neck?
internal and external carotid artery
What can you use as a landmark to find the carotid sinus and body?
The bifurcation of the common carotid arteries (at 4th cervical vertebrae level) into the external + internal carotid arteries
What is the clinical importance of the carotid triangle?
Contains bifurcation of common carotid (in+ext) which is landmark for CAROTID SINUS. This can be massaged to stimulate baroreceptors to decrease hr (bcs of supraventricular tachycardia).
Also palpate pulse at carotid sheath (bcs contains common carotid artery)
Which, artery, a branch from the common carotid artery, gives no branches while running in the neck?
Internal carotid artery - doesn’t branch and runs up through the skull, through the carotid canal. Only external carotid branches into 8
The union of which two veins forms the brachiocephalic vein on both the right and left side of the body?
Subclavian and internal jugular vein
Where does the internal jugular vein lie in relation to the carotid artery?
lies lateral to the internal carotid artery
What are the 3 main branches of the arch of the aorta?
- brachiocephalic trunk(which divides into right common carotid artery and the right subclavian artery)
- left common carotid artery
- left subclavian vein
Where does the facial vein drain into?
internal jugular vein
Where does the brachiocephalic vein drain into?
vena cava
What are the important muscles of the neck?
– Platysma – Trapezius – Sternocleidomastoid – Scalene muscles – Supra- and infra-hyoids
Describe the Supra- and infra-hyoids
- Located above and below the hyoid bone
- Supra-hyoids supplied by cranial nerves
- Infra-hyoids supplied by cervical nerves (C1-3)
Where does the SCM originate and insert?
Sternal head originates from sternum
Clavicle head originates from clavicle
both heads insert into mastoid process
What are the actions of the SCM?
rotates head to contralateral side and laterally flexes neck
What are the actions of trapezius?
upper fibres elevate shoulder
also rotate scapula when elevating shoulder above 90
What nerve innervates the SCM?
cranial nerve - accessory nerve
What nerve innervates the trapezius?
cranial nerve - accessory nerve
What are the structures found in the carotid triangle?
- internal carotid artery
- external carotid artery
- internal jugular vein
- vagus nerve
Actions of suprahyoid muscles?
Elevate hyoid Depress mandible (open jaw)
Actions of infrahyoid muscles/strap like muscles?
Depress + stabilise hyoid
