Session 1 - General Organisation of the Head and Neck Flashcards
What are the layers of cervical fascia?
1) Superficial cervical fascia
Deep cervical fascia:
2) Investing layer
3) Pre-tracheal layer
4) Pre-vertebral layer
What structures are found within the superficial cervical fascia?
Superficial blood vessels, e.g. External jugular vein
Cutaneous nerves
Superficial lymph nodes
Platysma
The carotid sheath is formed by which layers of cervical fascia?
The 3 deep layers - investing, pretracheal and prevertebral
What structures run through the carotid sheath?
Main structures: Common and internal carotid arteries Internal jugular vein Vagus nerve (CN X)
Also present:
Some deep cervical lymph nodes
Carotid sinus nerve
Sympathetic nerve fibres (carotid peri-arterial plexuses)
What layer of fascia lies directly behind the oesophagus and muscles of the pharynx?
Buccopharyngeal fascia
Where is the retropharyngeal space found?
Between the buccopharyngeal fascia and the pre-vertebral fascia
Why is the retropharyngeal space needed?
To allow the pharynx and oesophagus to expand on swallowing
Retropharyngeal space infections are most commonly seen in people of what age?
Children, usually under the age of 5
What does the retropharyngeal space contain up to the age of 3-4 years?
Lymph nodes
How far could an infection in the retropharyngeal space potentially spread to?
From the neck into the thorax, and potentially as far down as the posterior mediastinum.
This could possibly result in the rare but life-threatening condition mediastinitis.
Infection in the retropharyngeal space is usually secondary to what kind of infection?
Upper respiratory tract infection (e.g. Infection of the nasal cavity, nasopharynx, oropharynx)
A retropharyngeal infection may develop into what?
A retropharyngeal abscess
How would a retropharyngeal abscess present?
A visible bulge on inspection of the oropharynx Sore throat Difficulty swallowing Stridor (high pitched breathing sound) Reluctance to move their neck High temperature
Why does the thyroid gland move upwards on swallowing?
The thyroid gland is enclosed by pre-tracheal fascia, which is attached to the hyoid bone. They hyoid bone and the larynx move up on swallowing, therefore so does the thyroid gland.
Why can goitre sometimes extend retrosternally?
The lower limit of the pre-tracheal fascia extends into the thorax
What complications can a retrosternal extension of goitre lead to?
Compression of other structures running through the root of the neck such as the trachea and venous blood vessels.
This can lead to symptoms such as breathlessness and stridor due to tracheal compression, and facial oedema due to compression of venous drainage from the head and neck.
What is the purpose of the buccinators?
They keep the cheek taut and aid in chewing, ensuring food stays within the oral cavity proper when eating (rather than ‘pooling’ between the cheek and teeth).
What are the four muscles of mastication?
Masseter
Temporalis
Medial pterygoid
Lateral pterygoid
What are the divisions of the trigeminal nerve (CN V)?
Ophthalmic division (Va) Maxillary division (Vb) Mandibular division (Vc)
What nerve supplies the muscles of mastication?
Mandibular division of the trigeminal nerve
What is the action of the muscles of mastication?
They act to move the mandible at the temporomandibular joint (TMJ)
Which muscles are supplied by the facial nerve (CN VII)?
Platysma, muscles of facial expression, buccinators, muscles of the ear, occipitofrontalis
What are the five main terminal branches of the facial nerve?
Temporal Zygomatic Buccal Mandibular Cervical
Facial nerve palsy seen with ipsilateral parotid enlargement is highly likely to be due to what?
Parotid cancer
It is quite rare for benign, infective or inflammatory conditions of the parotid gland to cause a facial nerve palsy.
What is the most common cause of facial paralysis?
Bell’s palsy
What is Bell’s palsy?
A condition that causes temporary weakness or paralysis of the muscles in one side of the face. Inflammation around the facial nerve causes oedema and therefore compression of the nerve as it runs through its bony canal within the petrous part of the temporal bone.
Most arteries supplying structures in the face and neck are branches of what artery?
The external carotid artery
The external carotid artery terminates as what two arteries?
Superficial temporal artery
Maxillary artery
Where do the facial artery and vein run from and to?
From the medial angle of the eye to the inferior border of the mandible
The facial vein drains into what vein?
Internal jugular vein
Which veins drain into the external jugular vein?
Superficial temporal vein
Maxillary vein
The internal and external jugular veins drain into what vein?
Subclavian vein
Why do scalp wounds bleed heavily?
Blood vessels supplying the scalp arise from the internal and external carotid arteries. These anastomoses provide a rich blood supply to the tissues, therefore scalp wounds bleed heavily.
In which fascial layer does the platysma lie?
Superficial cervical fascia
What is the action of the platysma?
Depresses the corners of the mouth
Assists in depression of the jaw
Which nerve innervates the sternocleidomastoid?
Accessory nerve
Where does the sternocleidomastoid originate and insert?
Originates - clavicle and sternum
Inserts - mastoid process
What is the action of the sternocleidomastoid?
Lateral flexion of the neck, tilting the chin up to contralateral side
How do you test the sternocleidomastoid?
Look over shoulder against resistance
What is torticollis?
Twisting of the neck due to involuntary contraction of the sternocleidomastoid.
What is the action of the trapezius muscle?
Elevation of the shoulders
What are the borders of the anterior triangle of the neck?
Midline of the neck
Inferior margin of the mandible
Anterior margin of the sternocleidomastoid
What are the borders of the posterior triangle of the neck?
Posterior margin of sternocleidomastoid
Anterior margin of the trapezius
Clavicle
