4 Peripheral Nervous System

4 Peripheral nervous system

Checklist / P / MP / F /
HELP:
H: ‘Hello’ (introduction and gains consent)
E: Exposure and explains he or she wants to examine the nerves of the arms
L: Lighting
P: Have the patient in a position that they find comfortable and in which the examination can easily be undertaken
Washes hands
Inspects from end of bed:
• Relevant paraphernalia: walking stick, crutches, foot supports, wheelchair, special glasses, hearing aid
Inspects patient’s arms:
• Asymmetry
• Scars
• Skin changes
• Deformities
• Claw hand
• Wrist drop
• Fasciculations
• Wasting of small muscles of hands
• Scars
• Contractures
• Signs of denervation, such as:
• Injuries
• Neuropathic ulcers/Charcot joints
Inspects patient’s back:
• Spinal scars (back or side of neck)
• Kyphosis
Abnormal movements:
• Abnormal movements
• Tremor
• Dyskinesia
• Chorea
Scars and skin changes  signs of denervation:
• Injuries
• Neuropathic ulcers
• Charcot joints
Inspects patient’s neck:
• Spinal scars – these can be at the back or on the side of the neck
• Kyphosis
Motor examination
Screening test: Asks patient to raise both arms forwards when in a supine position
Pronator drift: Asks patient to sit up and close their eyes. Ask them to stretch their arms out with the palms up at the level of their shoulders. Looks for drift into pronation
Tone: Checks at each joint in flexion, extension, pronation and supination
Power:
• Shoulder abduction: C5
• Shoulder adduction: C6, C7, C8
• Elbow flexion: C5, C6
• Elbow extension: C7
• Wrist flexion: C8
• Wrist extension: C7
• Fingers: T1
Fingers: flexion, extension, abduction, adduction, opposition, grip strength
Thumb: abduction, adduction, extension
Reflexes:
• Reinforces if absent (clench teeth or apply Jendrassik* manoeuvre)
• Biceps: C5/C6
• Triceps: C6/C7
• Supinator: C5/C6
Hoffman’s sign:
• Flexes and then suddenly releases distal phalanx of middle finger
• Looks for abnormal flexion of other fingers
• This indicates an upper motor neuron lesion
Coordination:
• Finger–nose testing bilaterally
• Dysdiadochokinesis bilaterally
• Looks for intention tremor and past-pointing
• Tests for rebound by pushing down on the outstretched arms and looking for rebound past the original position
Sensory examination
Explains examination to patient and checks their sensation on a part of the body known to have normal sensation (such as forehead or sternum)
Examines the following modalities on all dermatomes:
• Dermatomes of the upper limbs:
• C3: lateral neck
• C4: lateral shoulder
• C5: lateral upper arm
• C6: thumb
• C7: middle finger
• C8: little finger
• T1: medial lower arm
• T2: medial upper arm
• T3: axilla
• Dermatomes of the lower limbs:
• L1: just below groin
• L2: medial aspect of mid-thigh
• L3: knee
• L4: medial lower leg
• L5: big toe
• S1: little toe
• S2: medial aspect of back of knee
Pin-prick (spinothalamic tract): uses a Neurotip
Vibration(dorsal column): uses a 128 Hz tuning fork on most distal phalanx, and only proceeds proximally if a deficit is identified
Joint proprioception(dorsal column):
• Only proceeds proximally if a deficit is identified
• Holds terminal phalanx of thumb. Shows patient that ‘up’ means extension and ‘down’ means flexion. Asks them to close their eyes. Moves phalanx and ask them to say if it is ‘up’ or ‘down’. Only proceeds proximally to the wrists and elbows if a deficit is identified. Offers to perform two-point discrimination using calipers
Light touch (dorsal column): uses a wisp of cotton wool
Temperature (spinothalamic tract): offers to use syringes of hot and cold water
Identifies pattern of sensory loss:
• Identifies if the pattern is dermatomal or ‘glove and stocking’
• Identifies level if it is dermatomal
Special tests: performs these based on the likely diagnosis from the examination. Common ones to know are Phalen’s, Tinel’s and Froment’s
Thanks patient
Offers to help patient get dressed
Washes hands
Presents findings
Offers appropriate differential diagnosis
Suggests appropriate further investigations and management
OVERALL IMPRESSION:

*If the reflexes are difficult to elicit, reinforce them by asking the patient to interlock their fingers and pull them in opposite directions (Jendrassik manoeuvre).

Checklist / P / MP / F /
HELP:
H: ‘Hello’ (introduction and gains consent)
E: Exposure (shorts or underwear)  explains he or she wants to examine the nerves of the legs
L: Lighting
P: Have the patient in a position that they find comfortable and in which the examination can easily be undertaken. Ensure privacy and dignity
Washes hands
Inspects from the end of the bed for paraphernalia: walking stick, crutches, foot supports, wheelchair, special glasses, hearing aid
Inspects patient’s legs:
• Fasciculations
• Wasting of proximal and distal lower limb muscles
• Scars
• Skin changes
• Signs of denervation (injuries, neuropathic ulcers, Charcot joints)
• Contractures
• Pes cavus
• Foot drop
• Deformities
• Abnormal movements
Inspects patient’s back:
• Spinal scars
• Kyphosis, scoliosis
MOTOR EXAMINATION
Gait: Asks patient to walk and turn, and observes gait carefully and any walking aids the patient uses. Assesses heel–toe gait and patient’s ability to stand on tiptoes
Romberg’s test:
• Asks patient to stand with both feet together and their arms to their sides, first with their eyes open and then with their eyes closed
• Positive if patient appears to be falling (indicates dorsal column or sensory nerve pathology) – ensure that patient does not fall!
Tone:
1) Lifts the knees quickly off the ground
2) ‘Rolls’ both hips gently
3) Checks for clonus (using ankle dorsiflexion)
Power:
Hip flexion: L1, L2
Hip extension: L5, S1
Knee flexion: L5, S1
Knee extension: L3, L4
Ankle dorsiflexion: L4, L5
Ankle plantarflexion: S1, S2
Foot inversion: L4, L5
Foot eversion: L5, S1
Toe movements: L5, S1
Reflexes:
Reinforces if absent (clench teeth or Jendrassik* manoeuvre)
Knee: L3/4
Ankle: L5/S1
Plantar: Up (upper motor neurone lesion) or down (lower motor neurone lesion/normal)
Coordination: Heel–shin testing bilaterally, gait
SENSORY EXAMINATION
Explains examination to patient and checks their sensation on a part of the body known to have normal sensation (such as forehead or sternum)
Examines following modalities on all dermatomes:
• Pin-prick (spinothalamic tract):uses a Neurotip
• Vibration (dorsal column):uses a 128 Hz tuning fork on most distal phalanx, and only proceeds proximally if a deficit is identified
• Joint proprioception (dorsal column):
• Holds great toe and shows patient that ‘up’ means extension and ‘down’ means flexion. Then asks them to close their eyes, and moves the toe, asking patient to say if it is moving ‘up’ or ‘down’
• Only proceeds proximally if a deficit is identified
• Offers to perform two-point discrimination using calipers
• Light touch (dorsal column):uses a wisp of cotton wool
• Temperature (spinothalamic tract):offers to use syringes of hot and cold water
• Identifies pattern of sensory loss:
• Identifies if the pattern is dermatomal or ‘glove and stocking’
• Identifies level if it is dermatomal
Thanks patient
Offers to help patient get dressed
Washes hands
Presents findings
Offers appropriate differential diagnosis
Suggests appropriate further investigations and management
OVERALL IMPRESSION:

*If the reflexes are difficult to elicit, reinforce them by asking the patient to interlock their fingers and pull them in opposite directions (Jendrassik manoeuvre).

OSCEs for Medical Finals, First Edition. Hamed Khan, Iqbal Khan, Akhil Gupta, Nazmul Hussain, and Sathiji Nageshwaran.