12.11.06 Teaching notes

Radiology - Haemorrhage

    • Intra-axial

      • i.e. Parenchymal

    • Extra-axial

      • Extradural

        • Usually from middle meningeal artery

        • Bi-concave

          • Lens shape

        • Never crosses suture lines

        • Strips dura away

        • Check for a fracture!

      • Subdural

        • From bridging veins

        • Crosses sutures

        • Tracks dural reflections - Look for "blood lines" - high intensity lines

          • Falx cerebri

          • Tentorium cerebelli

        • Crescent shape

        • Common in older people

          • Contraction => More subdural space => Longer bridging veins

      • Subarachnoid

        • From arteries

        • Basal cisterns highlighted

        • Sulci, sylvian fissure highlighted

Peripheral neuropathies

    • Mononeuritis multiplex

      • Ssimultaneous or sequential involvement of individual noncontiguous nerve trunks, either partially or completely

      • Evolves over days to years

      • Typically presents with acute or subacute loss of sensory and motor function of individual nerves

      • The pattern of involvement is asymmetric

    • Mononeuropathy

    • Peripheral polyneuropathy

      • Sensory

      • Motor

      • Sensory-motor polyneuropathy

Median nerve

    • Thenar muscles

      • Opponens policis

        • Make a ring between thumb + little finger

      • Abductor policis brevis

        • Lift up + resist

      • Flexor policis brevis

        • Flex over palm + resist

    • Anterior interosseous nerve

      • Supplies terminal flexors of thumb + index finger

        • CRUCIAL for writing etc.

      • Isolate joint, flex + resist

Ulnar nerve

    • 1st dorsal interosseous

      • 1st thing to go => Check muscle bulk!

    • Forearm flexors

    • ALL the interossei

      • Hold piece of paper between fingers (both of you)

      • Pull apart

    • Damage:

      • Leaning on your elbow (protected only by skin)

      • Supracondylar fracture

Radial nerve

    • Extensors

      • HARD-CORE - Should not ever be able to overcome

    • => Posterior interosseous nerve => Finger extensors

Leg stuff

    • Meralgia paresthetica

    • Compression of lateral cutaneous femoral nerve of thigh

        • => numbness or pain in the outer thigh

      • Caused by entrapment or compression where it passes between the ilium and the inguinal ligament near the attachment at the ASIS

      • Causes:

        • Weight gain (belly roll)

        • Pistol

        • Tight underwear

    • Roots

      • L1,2,3 => Femoral

        • Check hip flexion + knee extension

        • c.f. buckling gait

      • L4,5,S1 => Sciatic

        • => Tibial nerve (posterior leg)

        • => Common peroneal nerve

          • => Superficial peroneal nerve (lateral compartment - peroneus longus and peroneus brevis)

          • => Deep peroneal nerve (anterior compartment - tibialis anterior, EHL, EDL, peroneus tertius)

    • Common peroneal nerve wraps round the fibular head => Risk of injury

Falx cerebri / Tentorium cerebelli

Notes

    • Electrophysiology parameters

      • CV - Conduction velocity

      • DML - Distal motor latency

      • SL - Sensory latency

    • Put the muscle in action; Resist the action

    • Susceptibility to neuropathy

      • Diabetes

    • Hereditary neuropathy with liability to pressure palsies

        • Myelin deficiency due to peripheral myelin protein 22 mutation

      • Alcohol

      • Vitamin B12 deficiency

    • Median nerve entrapment in CTS occurs at the DISTAL CREASE OF THE WRIST

    • Femoral nerve runs ABOVE the inguinal ligament in 15% of people => Susceptible to injury

    • Sensory supply to the hand: