Head & Neck S1 Flashcards
Describe the buccinators
The keep the face taut and aid during chewing
Can be tested by asking patient to puff their cheeks full of air, then pushing on their cheeks to see if air leaks
Supplied by the facial nerve
What are the major groups of muscles in the head?
Muscles of facial expression
Cheek muscles (buccinators)
Occipitofrontalis
The muscles of mastication
Describe the muscles of mastication
For chewing
Supplied by the mandibular division of the trigeminal nerve
Describe occipitofrontalis
Involved in the raising of eyebrows
Supplied by the facial nerve
What does the facial nerve supply?
Platysma, muscles of facial expression and the ear and occipitofrontalis
Describe Bell’s palsy
Inflammation of the facial nerve as it exits the cranium via the stylomastoid foramen
This causes oedema and inflammation of the facial nerve in the intracranial facial canal
This causes structural and functional disorders and is the most common non traumatic cause of facial paralysis
What is the clinical relevance of the superficial location of the branches of the facial nerve?
They are easily damaged in childbirth, surgery, etc
What is the clinical significance of the facial nerve passing through the parotid gland?
The nerve is vulnerable to damage during surgery on the gland or infection.
What are the layers of fascia in the neck?
Superficial layer
Investing layer of deep cervical fascia
Pretracheal layer of the deep cervical fascia
Prevertebral layer of deep cervical fascia
If an infection occurs between the investing fascia and the muscular component of the pretracheal fascia, where is it likely to spread?
It’s unlikely to spread further than the manubrium
If an infection occurs between the investing fascia and the pretracheal layer, where can it spread?
It can spread into the thoracic cavity anterior to the pericardium
If there is an infection posterior to the prevertebral fascia, where is it likely to spread?
It may extend laterally in the neck
If it perforates the fascia, it can enter the retro pharyngeal space, which can cause dysphagia and dysphonia by putting pressure on the pharynx. It’s also a route for the infection to spread to the thorax.
What is the calvaria?
The vault of the skull and the base of the cranium
It consists of two layers of compact bone with a layer of marrow between them, known as the diploe
What are the names of the sutures connecting the bones of the calvaria?
Lambdoid, coronal and saggital
What is the pterion?
The thinnest part of the calvaria
Located on the lateral part of the skull
Vulnerable to fractures
What does trauma to the vault of the skull usually result in?
Radiating linear fractures (where the fractures spread in two or more directions away from the point of impact)
Describe a depressed fracture
Where the fragments of bone from the fracture have been pushed into the tissue beneath, causing pressure
May be the result of a severe, localised blow to the head
If a patient has received a sharp blow to the side of the head, what would you be worried about?
Fracture of the pterion
If so, the middle meningial artery may have been damaged, so an epidural haematoma could form between the periosteal layer of the dura mater and exert pressure on the cerebral cortex beneath it
What is a counter coup fracture?
When there has been trauma to one side of the head but the fracture is on opposite side of the skull
Discuss fractures to the base of the skull
The bone here is strong but is fractured reasonably regularly because it is the point of contact between the head and the body, so a lot of force can travel to it up the spine.
If a patient has an infection in their scalp, what would you be worried about and why?
Osteomyelitis of the bone beneath, because the superficial veins of the scalp are connected to the diploic veins and the intracranial venous sinuses by emissary veins, which are valveless so can be a route for infection to spread.
Discuss common facial fractures
Facial fractures are usually caused by fist fights, falls and RTIs
Nasal bone involvement in fractures is common due to the prominence of the nose on the face
Maxillofacial fractures are associated with massive trauma
A hard blow to the jaw can cause fracture of the neck of the mandible along with dislocation of the TMJ
Why might a fracture of the lower mandible cause numbness of the lower lip?
The inferior alveolar nerve runs through the mandible so is easily damaged in fractures and its branches supply the lower lip.
What usually causes a black eye?
Bruising around the orbit causes accumulation of tissue fluid and blood in the surrounding connective tissue
Describe malar flush
Red rash across the zygomatic processes, associated with mitral valve stenosis
Aka mitral facies
Why are cervical vertebrae prone to dislocation?
They are stacked atop one another almost horizontally so require less force to be dislocated
How is the dens most commonly fractured?
A fall on the head
Displacement can result in quadriplegia or damage to the medulla, causing death
Why is neck pain more common as patients age?
The intervertebral foramina narrow with age, causing compression of nerves and so neck pain
What injuries are associated with hyper flexion of the cervical spine (whiplash)?
Rupture of the lower cervical intervertebral disks, resulting in compression of C6 & C7 spinal nerve roots and so upper limb pain
Tearing of anterior and posterior longitudinal ligaments
Damage to neck muscles and blood vessels may also occur