Brachial Plexus Flashcards
How do the roots divide as they form the final nerves entering the arm.
Roots, trunks, division, cords then branches (rugby teams drink cold beer).
Other than the final 5 nerves what important derivatives leave the brachial plexus?
Important derivatives: Dorsal scapular nerve (C5), phrenic nerve contribution (C5) and long thoracic nerve (C5, C6 and C7). Suprascapular and subclavius nerves from superior trunk. Lateral pectoral from lateral cord; axillary, inferior and superior subscapular nerve and thoracodorsal nerve from posterior cord and medial pectoral and the median cutaneous of arm and forearm from medial cord.
Which roots does the brachial nerve come from and what path do they take?
Derived from roots C5 to T1, they cross over the first rib and under the clavicle to enter the arm.
Describe the musculocutaneous branch
Musculocutaneous branch – from C5 – C7 passes laterally to innervate coracobrachialis, brachialis and the biceps, terminates as the lateral cutaneous nerve of the forearm.
Describe the Axillary branch
Axillary branch – from C5 and C6 innervates deltoid and sensory information to shoulder passes around the posterior aspect of the humerus.
Describe the Median branch
Median branch – from all roots and innervated anterior forearm and Thenar muscles and provides sensory information to palmer side of the hand.
Describe the Radial branch
Radial branch – from all roots innervates the triceps and posterior forearm and sensory information to the posterior arm and dorsal hand, travels around the humerus in the radial groove.
Describe the Ulna branch
Ulnar branch – from C8 and T1 and innervates intrinsic muscles of the hand except the Thenar muscles. Funny bone nerve passing under the medial epicondyle of the ulna, supplies sensory information to 4th and 5th digit.
What are the Myotomes of the brachial plexus roots
C5 - Abduction an external rotation
C6 - Elbow flexion, wrist extension, supination and internal rotation
C7 - elbow extension, wrist flexio and pronation
C8 - finger flexion, thumb extension
T1 - finger adduction and abduction
Dermatomes and Cutaneous Innervation
See Pictures
Describe Erb’s palsy
Erb’s palsy – injury to C5 and C6 due to forceful pulling of head from shoulder (i.e. increasing the angle between head and shoulder) such as during parturition, motorbike crash. This causes a waiter’s tip presentation.
Describe Klumpke’s palsy
Klumpke’s Palsy – T1 and C8 injury due to increased angle between thorax and arm i.e. excessive abduction. As a result, they can’t make a fist and get a clawed hand.
