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Questions about the neurological examination

Neuro exam questions for doctors, medical student exams, finals, OSCES, MRCP PACES and USMLE

 

Question 1

What are the best ways of examining for fasciculations in the arms?

  • Fasciculations are usually best seen up the deltoid in the upper limb.
  • They may be elicited by gently flicking the muscle if there is a clinical suspicion (e.g. weakness and wasting)

Question 2

What's the difference between spacticity and rigidity?

  • Both spacticity and rigidity are forms of increased tone (increased resistance to stretch)
  • However, spasticity is velocity dependent: the faster the limb is moved the greater the resistance produced
    • Spacticity is often described as “clasp knife” as resistance will change throughout movement.
  • Rigidity has resistance that is constant throughout the stretch
    • Rigidity is an extrapyramidal pathway issue and is knows as “lead pipe” rigidity as it feel as if you are bending a lead pipe.
    • When tremor is superimposed it is described as “cog-wheel” rigidity

Question 3

What is the grading system for testing muscle power?

  • Muscle power is assessed in the clinical exam using MRC grading scale for power.
  • 5: Full Strength (or what is likely normal for the patient – e.g. can be less than your strength if you’re a 6 foot amateur wrestler and your patient is an tiny 80-year old woman)
  • 4 – Movement against partial resistance
  • 3 – Movement against gravity (e.g. can lift heel off bed)
  • 2 – Movement with gravity eliminated (i.e. can move horizontally on the bed)
  • 1 – Feeble contractions (e.g. twitch)
  • 0 – Absent voluntary contraction

Question 4

What muscle groups are tested by each movement in the upper limb exam and what nerves are involved?

Testing power in the upper limbs

ACTION INSTRUCTION ANATOMY (1
Muscle; 2 Nerve Root; 3 Nerve)
Shoulder abduction “Lift your arms into a ‘chicken position’” Test each side together, push arms down at elbow. “Stop me from pushing your arms down”
1: Deltoid
2: C5
3: Axillary Nerve
Arm flexion “Put your arms in front of you in a ‘boxer position’ fist facing in” Place your hand around wrist and steadily pull out. “Stop me from pulling your arm out” 1: Biceps
2: C6
3: Musculocutaneous Nerve
Arm extensionStay in a ‘boxer position’.
Place your hand around wrist and push arm in.
“Push against my hand” 		1: Triceps
2: C7
3: Radial Nerve
Wrist Flexion“Hold your arms straight out, make a fist.” Hold the forearm and your hand under their fist.
“Push my hand down towards the ground” 		1: Flexor Carpi Ulnaris
2: C8
3: Ulnar Nerve
Wrist Extension“Now cock your wrists back.”
Hold the forearm and use your fist to apply force to their hand.
“Stop me from pushing your wrist down”
1: Carpi Ulnaris
2: C7
3: Radial Nerve
Finger Abduction“Spread your fingers”
Use your index and small finger to squeeze their fingers closed.
“Stop me from pushing your fingers together” 		1: Interossei muscles
2: T1
3: Ulnar nerve
Thumb Abduction
“Turn hand palm up, bring thumb towards the ceiling" [to 90 degrees] Use your thumb to push their thumb into their palm.
“Stop me from pushing your thumb down"		1: Abductor pollicus brevis
2: T1
3: Median nerve

Question 5

What is Jendrassik's manoeuvre?

  • Jendrassik’s manoeurve is used to reinforce reflexes.
  • Ask the patient to clench their teeth or grasp hands together and pull apart just as you strike with the tendon hammer.

Question 6

How can you grade or score strength of reflexes?

  • Though there is no universally defined system for grading reflexes, they can be described as absent , hyporeflexic (present with reinforcement), normal or brisk
  • These are often written as: –, +, ++ or +++ respectively

Question 7

What nerves do the upper limb reflexes test?

  • Biceps: C5/6
  • Triceps: C7/8
  • Brachioradialis (supinator): C6

Question 8

What are the three methods of testing lower limb tone?

  • Roll the thigh left and right repeatedly
    • In normal tone the foot will flop in the opposite direction as the way the knee is moved. In increased tone the foot will remain in line with the knee
  • Put your hand under the knee and sharply pull the knee up
    • In a patient with normal tone, the heel will remain on the bed, but with increased tone the foot will leave the bed
  • Ankle clonus
    • The presence of greater than five beats of clonus (or sustained rhythmical contraction while the tendon is stretched) indicates increased tone

Question 9

What is a sequence for testing power in the legs?

Testing power in the lower limbs

ACTION INSTRUCTIONANATOMY
(1 Muscle;
2 Nerve Root;
3 Nerve)
Hip Flexion“Keeping your knee straight, lift your leg off the bed”
Hold their thigh with your hand.
“Stop me from pushing your leg down”		1: Psoas
2: L2
3: Femoral
Hip Extension“Push your leg down” Hold underneath their thigh.
“Push your leg into the bed” 		1: Gluteus Maximus
2: L5/S1
3: Inf. gluteal nerve
Knee Flexion
“Bend your leg at the knee and rest your foot flat on the bed.”
Hold their leg around the back of the calf. “Don’t let me straighten your leg/Pull your heel in towards your bottom” 		1: Hamstrings
2: L5
3: Sciatic
Knee ExtensionHolding their leg on the shin.
“Try to straighten you leg, push against my hand away with your leg” 		1: Quads
2: L3/4
3: Femoral
Dorsiflexion Place leg straight again: point toes toward face. Place your hand on the dorsum of foot.
“Stop me from pulling your foot down” 		1: Tibialis anterior (and others)
2: L4/5
3: Deep Peroneal
Plantar flexion
Place your hand on the sole of the foot. “Push down against my hand” 1: Gastronemeus (and others)
2: S1/2
3: Tibial nerve

Question 10

What are some pathological gait abnormalities?

  • Antalgic gait 
    • A gait due to pain in one area – tends to involve putting one leg down for a shorter time than the other, creating an asymmetrical gait
  • Ataxic or broad-based gait (due to a cerebellar lesion, or alcohol)
    • The patient will also be unable to walk heel-to-toe, a more sensitive test of ataxia
  • Shuffling or festinating gait (“gait apraxia”)
    • Classically seen in extra-pyramidal disease
  • Tilted gait
    • May be indicative of inner ear disorder
  • High-stepping gait
    • Occurs in foot drop, a person will lift their foot far above the ground in order to avoid catching their toes on the ground while walking. The patient will also have difficulty walking on their heels
  • If the gait does not fit any obvious pattern, see if it is distractable or changes over time. This may point more towards a psychologically mediated gait disturbance

Question 11

How do you do Romberg's test and what does it show?

  • Romberg’s test is a method of assessing propioception and can be positive in sensory ataxia (peripheral neuropathy) and in tabes dorsalis (affecting the sensory pathways of the spinal cord)
  • To do Romberg’s:
    • Ask the patient to stand with their feet close together and stretch out their arms. Make sure you position the patient so that if they did fall you can catch them or that they fall onto a bed
    • After giving reassurance that you will catch them if they fall, ask the patient to close their eyes
  • In a positive Romberg’s test the patient will fall with their eyes closed but not with their eyes open, as the visual input that was compensating for the lack of propioceptive input is removed
  • In cerebellar dysfunction the patient will be just as unsteady with their eyes open as closed

Question 12

What are the dermatomes of the upper limbs?

  • Outer shoulder/regimental badge area: axillary nerve C6
  • Outer forearm: lateral cutaneous C5
  • Thumb: median nerve C6
  • Middle finger: median nerve C7
  • Little finger: ulnar nerve C8
  • Back of the hand – radial side: radialnerve C5-T1
  • Medial antecubital fossa: medial cutaneous T1

Question 13

What are the dermatomes of the lower limbs?

  •  Inner thigh: upper L1, mid L2
  • Medial side of knee: L3
  • Medial malleolus: L4
  • Big toe: L5
  • Heel: S1
  • Popliteal fossa: S2
  • Anal sensation/tone: S3 and S4

 

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Perfect revision for medical student exams, OSCES, finals, PACES and USMLE

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