Neuralgic Amyotrophy: idiopathic and hereditary ... - UMC St Radboud

What is Neuralgic Amyotrophy?
Name
The condition that you have is officially termed: ‘neuralgic amyotrophy’.This is also
abbreviated as ‘NA’. The Latin term literally means: ‘lack of muscle growth accompanied
by neuralgia.’ There are two forms of this condition: the hereditary (‘’hereditary
neuralgic amyotrophy’ or HNA) and the non-hereditary forms (´idiopathic
neuralgic amyotrophy’ or INA). The latter condition is also called the Parsonage-
Turner syndrome or amyotrophic neuralgia of the shoulder.
Neuralgic amyotrophy is a descriptive term: this tells us what the problem is, but
not why or how it is caused. The term also does not specify where in the body the
condition occurs. Because, with NA, it is generally the muscles of the shoulder,
arm and hand that are affected, the condition used to be termed (and still is by
some doctors) differently. For example, ‘brachial plexus neuritis’ or ‘brachial
plexus neuropathy’. ‘Brachial plexus’ refers to the interweaving of the nerves
located in the neck at the level of the shoulder blade (see also the picture on the
front page of this folder). These nerves are responsible for the ‘innervation’ of the
muscles and the feeling in the shoulders, arms and hands.
Nerve
cell
Axon
Figure 1. Motor nerve with axon and myelin sheath
Myelin sheath
Muscle
fibers
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