Question

A patient severely injures their spinal cord between spinal nerves C7 and C8. Give an example of an upper limb muscle that would be paralyzed, a muscle that could be weakened, and a muscle that would be unaffected by this injury

Answer 1

this question is based on the brachial plexus, the nerves arise from it and the muscles which are supplied by these nerves and the root vale of the nerve.

if the damage is between C7 and C8

the muscle which will be completely paralyzed will have root value below C8 (examples- all flexor muscles in the forearm except flexor digitorum profundus and flexor carpi ulnaris - supplied by the medial root of median nerve having root value of C8 and T1)

the muscle which is weakened will be supplied by a nerve with root value C7 or above and C8 and below. (examples are muscles supplied by the ulnar nerve and radial nerve - flexor carpi ulnaris )

muscle unaffected will have root value C7 and above ( deltoid muscle which is supplied by axillary nerve with root vale of C5, C6)