The upper (superior) trunk is part of the
brachial plexus
The brachial plexus is a network () of nerves formed by the anterior rami of the lower four cervical nerves and first thoracic nerve ( C5, C6, C7, C8, and T1). This plexus extends from the spinal cord, through the cervicoaxillary canal in th ...
. It is formed by joining of the
ventral rami
The ventral ramus (pl. ''rami'') (Latin for ''branch'') is the anterior division of a spinal nerve. The ventral rami supply the antero-lateral parts of the trunk and the limbs. They are mainly larger than the dorsal rami.
Shortly after a spinal ...
of the fifth (C5) and sixth (C6) cervical nerves. The upper trunk divides into an anterior and posterior division.
The branches of the upper trunk from proximal to distal are:
*
subclavian nerve
The subclavian nerve, also known as the nerve to the subclavius, is small branch of the upper trunk of the brachial plexus. It contains axons from C5 and C6. The subclavian nerve innervates the subclavius muscle.
Structure
The subclavian ner ...
(C5-C6)
*
suprascapular nerve
The suprascapular nerve is a nerve that branches from the upper trunk of the brachial plexus. It is responsible for the innervation of two of the muscles that originate from the scapula, namely the supraspinatus and infraspinatus muscles.
Structur ...
(C5-C6)
*anterior division of upper trunk (C5-C6, forms part of
lateral cord
The lateral cord is the part of the brachial plexus formed by the anterior divisions of the upper (C5-C6) and middle trunks (C7). Its name comes from it being lateral to the axillary artery as it passes through the axilla. The other cords of the br ...
)
*posterior division of upper trunk (C5-C6, forms part of
posterior cord
The posterior cord is a part of the brachial plexus
The brachial plexus is a network () of nerves formed by the anterior rami of the lower four cervical nerves and first thoracic nerve ( C5, C6, C7, C8, and T1). This plexus extends from the ...
)
The
axillary,
radial
Radial is a geometric term of location which may refer to:
Mathematics and Direction
* Vector (geometric), a line
* Radius, adjective form of
* Radial distance, a directional coordinate in a polar coordinate system
* Radial set
* A bearing f ...
,
musculocutaneous
The musculocutaneous nerve arises from the lateral cord of the brachial plexus, opposite the lower border of the pectoralis major, its fibers being derived from C5, C6 and C7.
Structure
The musculocutaneous nerve arises from the lateral cor ...
and
median nerve
The median nerve is a nerve in humans and other animals in the upper limb. It is one of the five main nerves originating from the brachial plexus.
The median nerve originates from the lateral and medial cords of the brachial plexus, and has contr ...
s all contain axons derived from the upper trunk.
Additional images
File:Slide1cord.JPG, Brachial plexus.Deep dissection.
File:Slide1ecc.JPG, Brachial plexus.Deep dissection.Anterolateral view
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Nerves of the upper limb