Week 1 Flashcards
- List the major sutures and sutural junctions
Major sutures: Coronal Sagittal Lambdoidal Temporal
Major sutures junctions: Bregma Lambda Asterion Pterion Has ion
List the bones which form the skull. What is the skull also known as?
Also known as the vault or neurocranium
Comprises: 4 single bones - Frontal - Occipital - Sphenoid - Ethmoid
2 paired bones:
- temporal x 2
- parietal x 2
- Why is the pterion of particular clinical significance?
The pterion is of particular significance because a fracture in this area may be life threatening due to it’s relationship to the middle meningeal a.
List the bones which form the face.
Single bones:
Mandible
Ethmoid
Vomer
Pairs of bones: Maxillae Nasal Lacrimal Palatine Zygomatic Inferior Nasal Conchae
- List the attachments of the dura mater to the skull.
Dura has 2 layers:
Outer periosteal layer:
- is formed by the periosteium of the inner calvaria and adheres tightly to the inner aspect of the cranium.
- is most adherent to the sutures and cranial base
Inner meningeal layer:
- continuous with the spinal dura
- List the major infolds of the dura.
Falx cerebri
Falx cerebelli
Tentorium cerebelli
Diaphragm sellae
- What is the nerve supply to the dura?
Above the tent - Trigeminal nerve
Below the tent - spinal ganglia of C2 and C3
- The subdural, subarachnoid and epidural spaces lie between which structures? Which are anatomical and which are pathological spaces?
Epidural: between the skull and the dura
- pathological
Subdural: between the dura and arachnoud mater
- pathological
Subarachnoid: beneath the arachnoid in the subarachnoid space.
- anatomical
- List the major arteries supplying the brain.
Vertebral arteries form the basilar.
The basilar artery enters the Circle of Willis with the Internal carotid arteries. These then anastomose and branch to form the Middle, Anterior and Posterior cerebral arteries.
- How does arterial blood supply enter the skull?
Vertebral arteries enter the skull by traversing the transverse foramina between C6 and C3, then enters the skull via the foramen magnum.
The internal carotid artery enters the skull by entering the carotid canal of the temporal bone, and then exits the temporal bone through the carotid canal
- What are the benefits and limitations of the circle of Willis?
In the case of gradual arterial obstruction, the circle of Willis is an important source of collateral blood supply to the superficial aspect of the cerebrum.
Limitations are that this doesn’t help blockages in the end branches of these arteries
- Which nerves supply the muscles of the face and the muscles of mastication?
Muscles of facial expression - CN VII (facial)
Muscles of mastication - CN V (trigeminal)
- Which nerves give sensory supply to the face and scalp?
Face: Trigeminal nerve (ophthalmic, maxillary, mandibular divisions.
Posterior to the auricles: C2 and C3 spinal cutaneous nerves.
- List the bones that form the orbit.
Roof:
- Frontal
- Sphenoid
Medial:
- Lacrimal
- Ethmoid
- Frontal
- Sphenoid
Floor:
- Maxilla
- Palatine
- Zyoma
Lateral:
- Zygoma
- Sphenoid
- What are the functions of the cornea, lens and retina?
Cornea: the transparent anterior part of the fibrous layer which protects underlying structures and transmits and refracts light.
Retina: The retina has a light sensitive optic part and a supporting non-visual part. The retina sends fibres into the optic nerves and tracts.
- List the extraocular muscles and their nerve supply.
CN III:
- Levator palpebrae superioris (PSNS)
- Medial rectus
- Superior rectus
- Inferior rectus
- Inferior oblique
CN IV:
- Superior oblique
CN VI:
- Lateral rectus
- Review the specific functions of each cranial nerve.
CN I - olfactory CN II - optic CN III - oculomotor CN IV - trochlear CN V - trigeminal CN VI - abducens CN VII - facial CN VIII - vestibulocochlear CN IX - glossopharyngeal CN X - vagus CN XI - accessory CN XII - hypoglossal
- Having had blunt trauma to the skull, is a compressive or ischaemic brain injury more likely?
Compressive, as blunt trauma to the skull can cause a skull fracture which could lead to a epidural haemotoma, which would cause compression of underlying brain substance.
- If Craig had a massive haematoma, what might happen to his brain tissue?
He might get local compression of the brain tissue directly under the haemotoma, causing focal ssx.
He might get false localising symptoms from the compression causing the brain to shift and press against the opposite side of the brain cavity.
He might get herniation of the brain tissue as its pushed across the dural folds.
- What are the signs and symptoms of raised intracranial pressure in an adult?
Headache Generalised Seizures Papilloedema Mental changes Plateau waves Vomiting
- What are the signs and symptoms of raised intracranial pressure in a child?
More likely to have:
- vomiting with preceding nausea
- headache
- What is the most important neurological screening examination you would perform to rule out raised intracranial pressure as a cause of Craig’s headache and neck stiffness?
You would carry out a vitals exam and then a CN exam.
- Vitals examination: as compression of the brainstem can cause increase BP, resp rate and a decrease in heart rate.(?)
- CN exam: Due to the location of CN III and the long pathway of CN IV, these CN’s are most likely to show early ssx of increased intracranial pressure.
- List the pain sensitive structures in the head.
The dura is the structure that sends pain signals, brain tissue is not innervated with nociceptors.
- How might occipitomastoidal compression affect venous drainage of the head?
- How might this cause headache?
The internal jugular vein passes through the jugular foramen which passes through the occipitomastoid suture and drains 85% of venous blood from the head, so compression of this area would lead to a large increase in pressure inside the brain cavity.
This could cause headache by the increase in pressure causing the dura to be stretched by the blood pooling back into the dural venous sinuses.
- How might cervical dysfunction be contributing to his headaches?
The dural areas below the tentorium, as well as the scalp on the posterior head (posterior to the auricles) are supplied by spinal nerves of C2 and C3.
- How could upper thoracic dysfunction cause pain in the head?
Structures in the head and neck derive sympathetic innervation from T1-T4 sympathetic chain ganglia, as does the heart. Dysfunction in this region can lead to increased muscular tone, decreased immune function caused by prolonged SNS hyperactivity causing drying out of mucosa.
