L11 Upper Limb Nerve Injuries Flashcards
How do you approach a neurological problem?
Anatomically localise the lesion - whether UMN/ LMN lesion
Consider pathophysiology
Differential diagnosis
Where do the lower motor neurons arise from?
The anterior horn cell of the spinal cord
What type of nerves are cranial nerves and spinal nerves?
LMN
UMN lesions of the upper limb result in:
aka pyramidal insufficiency
Held in flexed posture if chronic
Increased tone
Pyramidal weakness (muscle weakness) because flexor muscles are stronger than extensors
Brisk reflexes
Decreased control of active movement, slowness
Sensory level
LMN lesions lead to what in the upper limb
Wasting/ fasciculations
Flaccid tone (decreased muscle tone)
Weakness in either a myotomal distribution or a peripheral nerve distribution
Dermatomal/ peripheral nerve distribution of sensory loss
What are the 3 anatomical regions for localising the region?
Roots
Brachial plexus
Peripheral nerve
What is a myotome?
The relationship between a spinal nerve and the muscle via the ventral rami
What is a dermatome?
The relationship between a spinal nerve and the skin via the dorsal rami
A dermatome is an area of the skin supplied by nerve fibres originating from a single dorsal nerve root
Coordination problems would localise towards the?
Cerebellum
What landmark corresponds to the C7 dermatome?
The middle finger
What landmark corresponds to the C6 dermatome?
The index finger & thumb
Which muscle does the C5 root innervate and what is the resulting muscle action?
Deltoid
Shoulder abduction
Which muscle does the C6 root innervate and what is the resulting muscle action?
Biceps, brachialis, brachioradialis
Elbow flexion
Which muscles does the C7 root innervate and what is the resulting muscle action?
Triceps, superficial extensors of the forearm, flexors of the forearm
Elbow extension
Wrist flexion & extension
Which muscles does the C8 root innervate and what is the resulting muscle action?
Forearm extensors, deep forearm flexors
Finger flexion & extension
Which muscles does the T1 root innervate and what is the resulting muscle action?
Intrinsic muscles of the hand
Finger abduction