CAS: Head, Neck and Spine (Missing stroke) Flashcards
A key part of every clinical examination includes the following steps
Ensuring you have the correct PPE
Washing your hands
Introducing yourself
Confirming the patient’s name and date of birth (biographical information)
Gaining consent from the patient
Ensuring there is adequate exposure and positioning of the patient
Define muscle tone
The amount of tension in a muscle.
Describe the tone of muscles at rest and explain why this occurs
Muscles have a constant tone at rest
This is due to the fact that muscles are in a constant state of partial contraction
How is muscle tone tested?
Passively moving the joints and comparing the resistance to the movements by the muscles on both sides of the body
A muscle without any tone indicates what?
Breach/disruption in the spinal segmental reflex arc and the simple spinal reflexes are not functioning
Hypotonia is indicative of what type of lesion?
Lower Motor Neuron (LMN) lesion
The lower motor neurons of the spinal segmental neurons are influenced by neurones from which 4 brain regions?
Cerebral cortex
Midbrain
Pons
Medulla
N.B. Collectively known as upper motor neurones
What effect does UMN have on LMN?
Inhibitory effect
What effect does an UMN lesion have on muscle tone?
Leads to hypertonia (exaggerated muscle tone/stiffness)
N.B. Sometimes may also have spasticity which is shown in image below.
What scale can be used to measure the power (strength) of muscles?
Medical Research Council (MRC) Muscle Power scale
According to the muscle power scale, what criteria must be met to give scores 0-5?
Define reflex
Involuntary resposne to stimuli
A reflex pathway consists of which 2 types of neurones?
Afferent (sensory) neurones conveying impulses from sensory receptors in the muscle spindle to the spinal cord (CNS)
Efferent (motor) neurones running from the anterior grey columns of the spinal cord (CNS) to the effector organ which is the limb muscle.
What are the 2 types of reflex arcs and which is most comon for myotatic reflex arcs?
The reflex arc may be monosynaptic or multi synaptic
Most of the myotatic reflex arcs are monosynaptic.
Testing for reflexes in a normal patient, you notice that you cannot elicit a reflex response. What is the next course of action?
May have to apply “reinforcement”
Ask the patient either clench the teeth or squeeze an object in the contralateral (other) hand while you directly test the reflex on the limb to be tested
Should a neurological deficit be concluded on the findings of abnormal absence/exageration of reflexes?
Must not jump into conclusion and instead findings should be used to support other clinical findings
Name the law which is used to explain how body posture works and antagonistic pairing between muscles
Law of reciprocal innervation
Explain the law of reciprocal innervation
In the same limb the flexor and extensor muscles cannot contract simultaneously.
The afferent nerves responsible for flexor reflex muscle action must have branches to synapse with the extensor motor neurons of the same limb to inhibit the extensor muscle contraction.
Abnormally exaggerated myotatic reflexes is indicative of which type of motor lesion?
Upper motor lesion
Complete absence (areflexia) of reflexes is indicative of which type of lesion?
Lower motor neurone lesion
Define dermatome
An area of skin supplied by a single spinal nerve root or spinal cord segment
Explain why loss of a single spinal nerve root may not produce any detectable sensory loss in that dermatome
On the skin, the adjacent dermatomes (for example C4, C5, C6) overlap considerably
In order to detect a significant sensory loss at least how many adjacent dermatomes must be affected?
At least 3
There is however no overlap of dermatomes in which regions of the body?
no overlap (for example C4 and T2 or C5 and T1) across the axial lines of the limb.
Damage to which type of nerves may affect large areas of skin and muscle?
Peripheral nerves
Damage to a peripheral nerve may result in?
Wide ranging effects on more than one dermatomal area or myotomes as peripheral nerves carry nerve components from several spinal segments (or roots) to muscles and skin areas.
Memorise dermatome map
C4 dermatome is located in which region?
Shoulder
C5 dermatome is located in which region?
Lateral side of arm
C6 dermatome is located in which region?
Lateral side of forearm and thumb
C7 dermatome is located in which region?
Middle and ring finger
C8 dermatome is located in which region?
Medial side of hand, little finger and forearm
T1 dermatome is located in which region?
Medial side of forearm and arm
T2 dermatome is located in which region?
Axilla
What peripheral nerve is responsible for supplying the C5,C6 and C7 dermatome segments?
Musculocutaneous nerve
What peripheral nerve is responsible for supplying the C6-C8 and T1 dermatome segments?
Median nerve
What peripheral nerve is responsible for supplying the C5-C8 and T1 dermatome segments?
Radial nerve
What peripheral nerve is responsible for supplying the C7, C8 and T1 dermatome segments?
Ulnar nerve
Memorise dermatomal map of lower limb
Where would you asses L1
Area over inguinal ligament
Where would you assess L2 dermatome?
Lateral side of thigh
Where would you assess L3 dermatome?
Medial side of thigh
Where would you assess L4 dermatome?
Medial side of leg, medial side of foot and big toe
Where would you assess L5 dermatome?
Lateral side of legt, mid dorsum of foot and middle three toes
Where would you assess S1 dermatome?
Little toe
Lateral side of foot
Sole of foot
Where would you assess S2 dermatome?
Back of upper leg and whole thigh
Where would you assess S3 dermatome?
Area over gluteal fold
The posterior rami (over the buttock region) supplies which dermatome segments?
L1-L3 and S1-S3
The obturator nerve supplies which dermatome segments?
L2, L3, L4
The femoral nerve supplies which dermatome segments?
L2, L3, L4 (Same as obturator)
The common fibular nerve (part of sciatic nerve) supplies which dermatome segments?
L4-S2
The tibial nerve (part of sciatic) supplies which dermatome segments?
L4-S3
