Week 2 - The Brachial Plexus Flashcards
What are the cords named in relation to?
The axillary artery
Give the order of branching of the brachial plexus
"Read Those Damn Cadaver Books" - Roots - C5, C6, C7, C8, T1 Trunks - superior, middle and inferior Divisions - anterior and posterior Cords - lateral, posterior and medial Branches - musculocutaneous, axillary, radial, median and ulnar
What is the name given to an upper brachial plexus injury?
Erb’s palsy
Which nerve roots do Erb’s palsy affect?
C5 and C6
Which nerves do an upper brachial plexus injury affect?
Musculocutaneous
Axillary
Suprascapular
Nerve to subclavius
Which muscles are paralysed in Erb’s palsy?
"BBCDISST" Biceps brachii Brachialis Coracobrachialis Deltoid Infraspinatus Supraspinatus Subclavius Teres minor
Where would sensory loss be in an upper brachial plexus injury?
The lateral portion of the arm
What movements would be affected by Erb’s palsy?
Supination of the forearm
Lateral rotation of the arm
Flexion at the shoulder
Abduction at the shoulder
How might an upper brachial plexus injury be sustained?
Caused by anything that increases the angle between the neck the shoulder.
Fairly common in babies during difficult births.
What is the classic sign of Erb’s palsy?
What does this look like and why does this occur?
The “waiter’s tip” sign
The limb is medially rotated due to unopposed action of pectoralis major
The forearm is pronated due to biceps brachii being paralysed
The limb is fully extended and hangs limply.
What is the name given to a lower brachial plexus injury?
Klumpke palsy
How does a lower brachial plexus injury usually occur?
Result of excessive abduction of the arm, e.g. from catching a branch whilst falling out of a tree.
(Think clumsy monkey - Klumpke)
Which nerve root(s) is/are affected by Klumpke palsy?
T1 only
Which nerves are affected by a lower brachial plexus injury?
The median and ulnar nerves
Which muscles are paralysed by a lower brachial plexus injury?
The intrinsic muscles of the hand
NB - Although the flexors in the anterior compartment of the forearm are supplied by the median and ulnar nerves, they are supplied by nerve roots other than TI, so remain intact.
