Brachial Plexus + Injuries Flashcards
Which spinal nerves are involved in the Brachial Plexus?
Where does it start and terminate?
Which 2 muscles do the ‘Roots” pass between?
Anterior rami of C5-T1
Starts in neck, terminates in axilla
Anterior and middle scalene muscles (Enter at posterior triangle of neck)
What are the 5 parts of the Brachial Plexus
Real Teenagers Drink Cold Beer
Roots Trunks Divisions Cords Branches
Where do the brachial plexus roots converge to form the Trunks?
What are the trunks, and what roots are they a combination of?
At base of neck
Superior- C5 and C6
Middle- Direct continuation of C7
Inferior- C8 and T1
How many Divisions are there in the Brachial Plexus
Where do they pass into?
6
(Anterior, posterior from Superior/ Middle/ Inferior Trunks)
Leave posterior triangle of neck, pass into axilla
What do the Divisions do once they enter Axilla?
These new structures are named by their position relative to what structure?
Combine to form Lateral, Posterior, Medial Cords relative to Axillary Artery
Which divisions make up each of the Cords in Brachial Plexus
Lateral Cord;
- Anterior division of Superior Trunk
- Anterior division of Middle Trunk
Posterior Cord;
- Posterior division of Superior Trunk
- Posterior division of Middle Trunk
- Posterior division of Inferior Trunk
Medial Cord;
- Anterior division of Inferior Trunk
What are the terminal branches of the Posterior Cord?
Which components of upper limb do they supply?
Axillary and Radial
Supply the Extensor components of upper limb
What are the terminal branches of the Lateral, Medial Cords?
Which components of upper limb do they supply?
Musculocutaenous
Median
Ulnar
Supply the Flexor components of upper limb
What are the 5 Major branches of the brachial plexus?
What spinal nerve roots contribute to each
3 Musketeers: Musculocutaenous- C5, C6, C7 Assassinated: Axillary- C5, C6 4 Mice: Median- C6, C7, C8, T1 5 Rats: Radial- C5, C6, C7, C8, T1 2 Unicorns: Ulnar- C8, T1
What spinal nerve roots make up the;
Long Thoracic Nerve
Medial Pectoral Nerve
Lateral Pectoral Nerve
Long Thoracic: C5, C6, C7
Medial Pectoral: C8, T1
Lateral Pectoral: C5, C6, C7
Each muscle takes nerve supply from how many spinal cord segments?
For this to happen, what must occur in the fibres and in what part of the brachial plexus?
From more than one segment
Convergence of fibres at Trunks
Each spinal cord segment supplies both flexors and extensors
For this to happen, what must occur in the fibres and in what part of the brachial plexus?
Divergence at Divisions
Where does Re-assortment of fibres occur
( In what part of brachial plexus?)
Why?
Cords of brachial plexus
To distribute to limb compartments
The more inferior cord segments in brachial plexus supply what muscles?
Describe the topography of the 5 Major branches of the brachial plexus
The more distal muscles
- MSC nerve runs laterally into anterior arm
- Axillary+radial nerves run posteriorly to supply extensors
- Median nerve runs down centre of limb
- Ulnar nerve runs medially down upper limb
When dissecting the Brachial Plexus, we look for an M shape, lying superficial to Axillary artery
What nerves make this shape
Musculocutaeneous
Median
Ulnar
