myelin is produced by Schwann cells.

The brain consists of two cerebral hemispheres, each with

four lobes (frontal, parietal, temporal and occipital), the brainstem

and the cerebellum. The brainstem comprises the midbrain, pons

and medulla. The cerebellum lies in the posterior fossa, with two

hemispheres and a central vermis attached to the brainstem by

three pairs of cerebellar peduncles. Between the brain and the

skull are three membranous layers called the meninges: dura mater

next to the bone, arachnoid and pia mater next to the nervous

tissue. The subarachnoid space between the arachnoid and pia

is filled with cerebrospinal fluid (CSF) produced by the choroid

plexuses. The total volume of CSF is between 140 and 270 mL

and there is a turnover of the entire volume 3–4 times a day;

thus CSF is produced at a rate of approximately 700 mL per day.

The spinal cord contains afferent and efferent fibres arranged

in discrete bundles (pathways running to and from the brain),

which are responsible for the transmission of motor and sensory

information. Peripheral nerves have myelinated and unmyelinated

axons. The sensory cell bodies of peripheral nerves are situated in

the dorsal root ganglia. The motor cell bodies are in the anterior

horns of the spinal cord (Fig. 7.1).

7.1 Clinical characteristics of headache syndromes

Onset Duration/periodicity Pain location Associated features

Primary syndromes

Migraine Evolves over

30–120 mins

Usually last <24 h, recurrent

with weeks/months

symptom-free

Classically unilateral but

may be anywhere

including face/neck

Aura (usually visual), nausea/vomiting,

photophobia and phonophobia

Cluster headache Rapid onset, often

waking patient from

sleep

30–120 mins, 1–4 attacks

within 24 h, clusters usually

last weeks to months, with

months to years of remission

Orbital/retro-orbital;

always same side during

cluster, may switch

sides between clusters

Autonomic features, including

conjunctival injection, tearing, nasal

stuffiness, ptosis, miosis, agitation

Stabbing headache Abrupt, rarely from sleep Very brief, seconds or less Anywhere over head Common in migraineurs

Secondary syndromes

Meningitis Usually evolves over a

day or two, can be

abrupt

Depends on cause and

treatment, usually days to

weeks

Global, including neck

stiffness

Fever, meningism, rash, false localising

signs, signs of raised intracranial

pressure

Subarachnoid

haemorrhage

Abrupt, immediately

maximal, rare from sleep

May be fatal at onset,

usually days to weeks

Anywhere, poor

localising value

20% isolated headache only; nausea/

vomiting, reduced consciousness, false

localising signs, III nerve palsies

Temporal arteritis Gradual onset of temple

pain and scalp

tenderness

Continuous Temple and scalp Usually in those >55 years; unwell, jaw

pain on chewing, visual symptoms, tender

temporal arteries, elevated erythrocyte

sedimentation rate and C-reactive protein

The history • 121

7

Pons

Medulla oblongata

Cerebellum

A

Postcentral gyrus

(sensory area)

Precentral gyrus

(motor area)

Sensory speech area

 (Wernicke's area)

Central sulcus

Occipital lobe

Parietal lobe

Motor speech area

 (Broca's area)

Lateral sulcus (fissure)

Frontal lobe

Temporal lobe

Posterior median septum

Dorsal column

Dorsal root entry zone

Central canal

Ventral grey horn

Rootlets

Mixed spinal nerve

Anterior median

fissure

B

Dorsal

Ventral

Spinal ganglion

Ventral column

Lateral column

Dorsal grey horn

Dorsal intermediate septum

Pia mater

Arachnoid mater

Dura mater

Dural root

sleeve

Position sense

Vibration sense

1/2 touch

Voluntary

movement

Voluntary

movement

Anterior (direct)

corticospinal tract C

Lateral (indirect)

corticospinal tract

Fasciculus gracilis

Fasciculus cuneatus

Anterior spinothalamic tract

Lateral spinothalamic tract

Anterior spinocerebellar tract

Posterior spinocerebellar tract

Areas of

extrapyramidal

tracts

Equilibrium

Pain

Temperature

1/2 touch

Presynaptic

nerve fibres

Nucleus

Dendrites

Cell body

Axon

Myelin

Node of

Ranvier

Spinal

motor neurone

Nerve

terminals

D