Wraetorius
Other names:
Writing muscle
Origin:
Cerebral cortex
Insertion:
Metacarpals
Proximal phalanges
Innervation:
Minor segment of vagus nerve branching off heart
Optic nerve
Olfactory nerve
Cranial nerve vii (auditory)
(Galen postulated autonomic innervation--doubted by post-modern anatomists; some older authorities attribute hormonal influences.)
Movement:
Choreographed movements of fingers, allowing for graphical representations of thought
Occasional quickening of heart rate (may reflect retrograde nerve impulse from vagus root)
Comments:
This muscle, atrophied in much of the population, has been known to be overly developed in patients with psychotic and bipolar tendencies; may also be larger than usual in people with alcohol dependency. Irish scientists report hypertrophy among Celtic populations, but this may reflect the usual medical hyperbole we see from that island.
This muscle has been known to increase in size with exercise and is worshipped by some cults (see Everythingians).
Occasionally this muscle goes into tetany, becoming totally useless for variable lengths of time (see writer's block).
Inspired by a conversation with my wife who, after hearing my lengthy and not terribly informative explanation of E2, said it sounded like a good way to exercise one's writing muscle.