Brachial Plexus And Nerve Injuries Flashcards
What are the 5 sections of the brachial plexus?
Roots Trunks Divisions Cords Branches
What are the 3 anterior motor compartments of the arm and what does each do?
Musculocutaneous - arm & elbow flexion, supination.
Median - wrist flexion, thumb.
Ulnar - hand.
What are the 2 posterior motor compartments of the arm and what does each do?
Auxillary - shoulder abduction.
Radical - extension.
What are the 5 nerves the brachial plexus gives rise to, in order?
Musculocutaneous Axillary Median Radial Ulnar
How would you test the C5 myotome?
Elbow flexion
How would you test the C6 myotome?
Wrist extension
How would you test the C7 myotome?
Elbow extension
How would you test the C8 myotome?
Grip
How would you test the T1 myotome?
Finger abduction
In what direction do the dermatomes go around the anterior arm from C5 to T2?
Anti-clockwise - Lateral to medial.
Which dermatome is the middle finger?
C7
Where do you test axillary nerve sensation?
Regimental badge
Where do you test musculocutaneous nerve sensation?
Lateral epichondyle
Where do you test radial nerve sensation?
Anatomical snuff box
Where do you test median nerve sensation?
Tip of thumb
Where do you test ulnar nerve sensation?
Tip of 5th digit
Injury to what nerve causes winging of the scapula?
Long thoracic nerve
What clinical features are seen in musculocutaneous nerve injury? WHich area would sensation be lost from?
Motor - loss of supination, arm and elbow flexion, paralysis BBC (upper anterior arm).
Sensation - lateral forearm.
What nerve is most likely to be damaged following shoulder dislocation or fracture of the humeral surgical neck? Why?
Axillary nerve.
Runs posterior to the humeral head.
What sensory and motor loss would damage to the axillary nerve lead to?
Motor - posterior shoulder. Loss of shoulder abduction (deltoid) and external rotation (Teres major).
Sensory - regimental badge.
What does Erb’s palsy present as? What causes this?
Waiters tip.
Upper trunk injury - shoulder forced down and head pushed to opposite side causing damage to C5 and C6, so musculocutaneous and axillary nerve damage.
How does hand of benediction appear? What is affected sensory?
Completely flexed 4th and 5th digits, slightly flexed distal phalanges of 2nd and 3rd digits.
Sensory - lateral digits 1-3.5. Anterior hand, posterior fingertips.
Injury to what nerve causes hand of benediction? What causes the damage?
Median nerve. Supracondylar fractures (runs through cubical fossa, presents with additional weakened wrist flexion), wrist lacerations, carpal tunnel.
How does ulnar claw present?
Flexed digits 4 & 5, full extension of digits 1-3.
