MSK - Brachial Plexus Flashcards
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What is the Brachial Plexus?
Where does it originate from?
Where does it lead?
What is it made of?
It is a network of nerve fibres
Originates from anterior rami (divisions) of cervical vertebral nerves C5, C6, C7 and C8, and of the first thoracic vertebral nerve, T1
Runs from neck, through axilla and into the arm
The Brachial Plexus can be divided into how many parts?
Name each of these parts
5
Roots
Trunks
Divisions
Cords
Branches
Which rami of which spinal nerves form the root part of the Brachial Plexus?
Anterior Rami of spinal nerves C5, C6, C7, C8 and T1
How many nerve fibres make up the trunks?
3
What nerve fibres combine to give this number of trunks?
Name the three trunks and explain how they get their names
Superior Trunk - C5 and C6 roots combine
Middle Trunk - Just a continuation of C7
Inferior Trunk - Combination of C8 and T1
When are the trunks formed?
Just before they enter the axilla through the apex
How many divisions does each trunk make as it enters the Axilla?
2
What happens to each division?
One travels anteriorly and one travels posteriorly
How are the cords formed?
Recombination of the six Divisions into three nerve fibres
How are the Cords named?
By their position relative to the Brachial Artery
Name the three cords and what divisions they are formed by
Lateral Cord - Formed by:
- Anterior division of superior trunk
- Posterior division of middle trunk
Posterior Cord - Formed by:
- Posterior division of superior trunk
- Posterior division of middle trunk
- Posterior division of inferior trunk
Medial Cord - Formed by:
- Anterior division of inferior trunk
Name the five branches that go on to supply the upper limb
Musculocutaneous
Axillary
Median
Radial
Ulnar
What roots does the Musculocutaneous nerve contain nerve fibres from?
C5, C6, C7
What does the Musculocutaneous nerve innervate?
Brachialis, Biceps brachii and Corocobrachialis muscles
What are the sensory functions of the Musculocutaneous nerve?
Gives off the lateral cutaneous branch of the forearm, which innervates the lateral half of the anterior forearm, and a small lateral portion of the posterior forearm