Brachial plexus:
Ramus definition: (rami)
(Latin for the branch) Ramus is the anterior division of a spinal nerve. The
ventral ramus supplies the anterolateral parts of the trunk and the limbs. It
branches into the dorsal ramus, the ventral ramus, and the ramus communicans.
Each of these three structures carries both sensory and motor information.
Ventral ramus= anterior ramus
Dorsal ramus = posterior ramus
A brachial plexus is a group of nerves that come from the spinal cord in the
neck and travel down the arm. These nerves control the muscles
of the shoulder, elbow,
wrist, and hand, as well as provide feeling in the arm
The brachial plexus originates from the neck. It passes under the clavicle and
over the 1st rib to reach the axilla.
Brachial plexus:
Roots:
Ventral rami from spinal nerves C5 to C8.
And most of the anterior rami of T1.
Trunks:
Superior trunk = C5 + C6
Middle trunk = C7
Inferior trunk = C8 + T1
Divisions:
Each trunk gives rise to the anterior and posterior divisions.
Cords:
Anterior divisions give rise to lateral and medial cord
Posterior divisions give rise to posterior cord
Except for the division part, some small nerves arise from these big nerve
trunks.
To remember these kinds of
stuff, consider a tree, where the trunk of the tree emerges from the roots, and
the trunk gives off its branches that are divisions and each branch has its
sub-branch called cords.
1. Roots and the trunks lie in the posterior triangle of the neck.
2. They run between the anterior and middle scalene muscles.
3. Behind the clavicle, we can see the anterior and posterior divisions of the
trunk.
4. Lateral, posterior, and medial cords lie in the axillary region.
5. These cords lie around the second part of the axillary artery. Shown in the
above image.
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