Neuroanatomy Flashcards
What is white and black in a T1 vs T2 weighted MRI?
T1: CSF is black, fat is white
T2: Water is white, fat is white
What is the most inferior ventricle?
4th ventricle
Next to cerebellum
What is the space between lateral ventricle and 3rd ventricle called?
Foramen of monro
What is the junction between the occipital and parietal bones called?
Lambdoid suture
What is the junction between the two parietal bones called?
Sagittal suture
What is the junction between the parietal and frontal bones called?
Coronal suture
Where is the cerebral aqueduct?
Between 3rd and 4th ventricles
When do you get an incomplete ptosis?
Horner syndrome
Only smooth muscle impaired, skeletal muscle still in tact
What is the only motor function of the trigeminal nerve?
Mastication
Masseter, temporalis, pterygoids
What muscles are supplied by the radial nerve?
Posterior compartment of arm (triceps)
Posterior compartment of forearm (extensors)
What skin is supplied by the radial nerve?
Posterior arm and forearm
Lateral ⅔ of dorsum of hand
Proximal dorsal aspect of lateral 3½ fingers (thumb, index, middle and half of ring finger)
What happens when radial nerve is injured
Wrist drop
Wasting of triceps (loss of reflex?)
Weak elbow and wrist extension
What muscles are supplied by the median nerve?
Most anterior forearm muscles (flexors, pronator)
Thumb side intrinsic hand muscles
Sensory supply of median nerve
Skin over thenar eminence
Lateral ⅔ palm of hand
Palmar aspect of lateral 3½ fingers
Dorsal fingertips of lateral 3½ fingers (thumb, index, middle and half of ring finger)
Common injury of median nerve
Carpal tunnel
Wrist lacerations
What happens when the median nerve is injured?
Weak forearm pronation, wrist flexion and abduction, and weak finger flexion with preservation of DIPJ flexion at ring and little fingers
Weak thumb opposition
Sensory supply of ulnar nerve
Skin over hypothenar eminence
medial ⅓ palm and dorsum of hand
palmar aspect of lateral 1½ fingers
dorsal aspect of medial 1½ fingers (little finger and half of ring finger)
Motor supply of ulnar nerve
2 anterior forearm muscles
Most intrinsic muscles of hand
What happens when ulnar nerve is injured?
Cannot extend ring finger and little finger (claw hand)
wasting of hypothenar eminence and intrinsic muscles of hand
What does the femoral nerve split into?
Saphenous, tibial and common fibular (peroneal) nerve
Cause of painful 3rd nerve palsy is__
PCA aneurysm until proven otherwise
Difference between UMN and LMN facial nerve palsy
UMN palsy spares upper part of the face (bilateral innervation). LMN is complete paralysis of one side of the face.
Where are the cranial nerve nuclei found?
Floor level of medulla: 10/11/12
Pons: 5,6,7
Midbrain:3/4
CNII is part of CNS, all other CN are PNS
What is seen in cervical artery dissection?
- Fried egg sign on CT/MRI
- Horner’s syndrome/Compression of lower cranial nerves
- Unilateral ipsilateral headache
- Retinal ischaemia/cerebellar ischaemia
- Traumatic or spontaneous, esp in young patients
- Treated with antiplatelets
Where do the parasympathetic fibres run for pupillary constriction?
With CN III
What is the afferent nerve for gag reflex?
IX (glossopharyngeal)
What is the normal plantar reflex? When is abnormal seen?
Normal is downgoing (flexion)
Abnormal is extension of big toes (UMN lesion)
What does the femoral nerve supply?
Sartorius
Quadriceps
What does the sciatic nerve supply?
Hamstrings (semitendinosus/membrinosus, biceps femoris)
Adductor magnus
What does the obturator supply?
Obturator externus
Adductors
Gracilis
What does the tibial nerve supply?
Tibial nerve comes from femoral n.
Supplies posterior calf (gastroncnemius, plantaris)
Tibialis posterior
-> plantar nerve in foot
What does the common fibular nerve supply?
Fibularis muscles
Tibialis anterior
Extensors
Where is dermatome C7?
Middle finger
Where is dermatome C5?
Over deltoid and lateral upper arm
Where is dermatome T2?
Armpit
Where is dermatome S3?
Bum
Where is detmatome S1?
Under foot
Which dermatome is front of knee?
L3
How can intracranial pressure be measured?
Intraparenchymal fibreoptic catheter
Epidural transducer
Subdural catheter
Subdural bolt
Emergency treatment of raised ICP
- Head up: encourage venous return, CSF gets absorbed faster from arachnoid granulations
- Ventriculostomy: ventricular drain to drain CSF
- Mannitol
- Decompressive craniectomy
- Sedate and paralyse them, to decrease the metabolic activity of the brain.
- Cool them down, decrease metabolic activity in the brain.
- Seizure control
- Evacuation of clot
How is an intracranial abscess diagnosed?
DWI shows restriction of diffusion due to presence of a capsule
How quick do nerves grow?
1mm/day
