NEET-Basic - NEET - Biology
In the brachial plexus ,
the medial cord gives rise to 3 nerves
1)the medial bracial cutaneous nerve......root value T1
2)the medial antibrachial cutaneous nerve.....root value C8,T1
3)the ulnar nerve.....C8 T1
The posterior cord gives rise to 3 more nerves
1)upper subscapular ...root value-C5,C6
2)lower subscapular....root valueC5,C6
3)thoracodorsal(middle subscapular nerve) ....root valueC7,C8
my doubt is ,
in both the cases the respective nerves arise from a single cord(posterior cord in 1st case/medial cord in 2nd case),then y dont they have same root values?
my teachers are not able to help me ...
so i expect it from topper...
- There are 31 pairs of spinal nerves. C, T, L with appropriate numberings are the abbreviations given to individual nerves as individual root value.
- Brachial plexus is a network of nerves which emerges at five different levels from the spine: C5, C6, C7, C8 and T1. These roots merge to form three trunks.
- C5 and C6 merge to form the upper trunk.
- C7 forms the middle trunk.
- C8 and T1 merge to form the lower trunk.
- Each trunk then splits to form six division which again regroup to become cords.
- Each nerve has different root value.
- For example: Ulnar nerve of the medial cord of the brachial plexus has the root value C8 and T1 which means the nerve fibres arising at C8 (the intervertebral foramen which is present between C7 and T1) and T1 (the intervertebral foramen which is present between T1 and T2)
- Hence, though the nerves are arising from the same cord. their root value depends on the position from where they are emerging as pepripheral nerves.
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