brachial plexus
key landmarks to identify the brachial plexus
'•M' shape •Musculocutaneous pierces coracobrachialis •Median nerve travels with brachial artery •Radial nerve = major branch posterior cord
what is a plexus
A branching network of intersecting nerves and they innervate large areas of the body eg lumbosacral plexus Nerve fibres from several spinal nerves are sorted/recombined, meaning terminal nerves contain fibres from more than one spinal nerve.
label from A-E
A-dorsal root-contains sensory/afferent fibres B-spinal nerve-mixed-sensory and motor C-ventral root-contains motor/efferent fibres D-posterior (dorsal) rami -innervates the skin/muscles of the back E-anterior (ventral) rami -innervates everything else, including plexues
what roots contribute to the axillary nerve
C5 C6
what roots contribute to the median nerve
C5 C6 C7 C8 T1
what roots contribute to the radial nerve
C5 C6 C7 C8 T1
What roots contribute to the musculocutaneous nerve?
C5, C6, C7
what roots contribute to the ulnar nerve
C8 T1
what does the brachial plexus lie close to
In the axilla Lies in close relation to the axillary artery
additional branches of the brachial plexus
Medial brachial cutaneous AKA medial cutaneous nerve of arm Medial antebrachial cutaneous AKA medial cutaneous nerve of forearm
what are the 5 terminal branches of the brachial plexus
Musculo-cutaneous nerve Axillary nerve Radial nerve Median nerve Ulnar nerve
what parts does the brachial plexus split into
Rugby Teams Drink Cold Beverages The roots are from anterior rami C5 - T1 The roots merge to form 3 trunks Each trunk separates into different divisions The divisions unite to form cords The terminal branches arise from the cords
why is the cervical vertebra an exception
The cervical vertebra is the only place where there is an extra spinal nerve-C8. 8 spinal nerves with 7 cervical vertebrae.
when is the plexus prone to damage
The plexus is quite superficial and prone to damage when it cross rib 1 into the axilla.
what rami are involved in plexuses
Whenever talking about plexuses, we are always talking about the anterior rami of spinal nerves!!
where do cervical spines arise
•Cervical spinal nerves arise above their corresponding vertebra •C8 arises between vertebra C7 and T1
what does the musculocutaneous nerve pierce
•Musculocutaneous pierces coracobrachialis
what do the brachial plexus roots emerge in between?
•The roots emerge in the neck between the anterior and middle scalenes Starts in neck, crosses rib 1 to enter axilla
what forms the brachial plexus
•anterior rami of C5 - C8 (T1) •7 cervical vertebra •8 cervical spinal nerves • These are the roots of the brachial plexus
