THE AXILLA AND BRACHIAL PLEXUS Flashcards
what are the lymph nodes of the upper limbs?
apical lateral central, posterior and pectoral
what are the roots of the brachial plexus?
anterior rami of C5-T1
there are 7 cevrical vertebrae so why in the brachial plexus do we have C8?
because we name cervical nerves by the vertebrae that lies beneath them so C8 would lie above T1
how do we name thoracic nerves?
using the vertebrae above the nerve root
what are the 5 segments of the brachial plexus?
roots trunks divisions cords branches
what are the trunks of the brachial plexus?
superior middle and infeiror
what are the divisions of the brachial plexus?
the 3 anterior divisions, one from each trunk
the 3 posterior divisions, one from each trunk
what are the cords of the brachial plexus?
lateral, posterior and medial
what are the branches of the brachial plexus?
musculocutaneous axillary radial median ulnar
what branches does the lateral cord give rise to?
the musculocutaneous nerve and, along with the medial cord, the median nerve
which branches does the posterior cord give rise to?
axillary and radial nerves
what branches does the medial cord give rise to?
ulnar nerve and, along with the lateral cord, the median nerve
how do we exclusively test nerve function for the media nerve?
tip of the index or middle finger
how do we test for the ulnar nerve exclusively?
tip of the little finger
how do we test for the radial nerve exclusively?
in the webbing between thumb and index finger
what are the signs of radial nerve injury?
loss of sesnation over dorsal web between thumb/index finger
weakness of extensors = wrist drop
what would damage to T1 do?
causes paralysis of the forearm flexor and the intrinsic muscles of the hand
what is Erb’s palsy?
an upper brahcial plexus injury -injury to C5 and C6
This causes muscles around the shoulder to be paralysed so the arms hang limply by the side with loss of sensation.
what is Klumpke’s paralysis (aka horner syndrome)?
injury to T1 - loss of sesnaton of medial side of forearm and loss of motor function in small muscles of the hand
may result due to a difficult delivery
describe the course of the radial nerve through the arm?
exits axilla inferiorly , descends fown the arm within the radial grrove wrapping around the humerus laterally. It travels anteror to the lateral epicondyle of the hymerys and through the cubital fossa to enter the forearm
describe the course of the musculocutaneous nerve?
it leaves the exilla nd puerces the coracobrachialis muscle and then passes down the arm, superficialt to brachialis but deep to biceps brachii. it pierces the deep fascia lateral to biceps brachii to emerge lateral to biceps tendon. it continues into the forearm as the lateral cutaneous nerve
outline the course of the medial nerve?
it descends down the arm lateral to the brachial artery. halfway down the arm it corsses over the brachial artery and is situated medially. it enters the anterior compartment of the forearm via the cubital fossa. in the forarm it travels between the flexor digitorum profundus and flexor digitorum superficialis muscles
describe the course of the ulnar nerve?
it descends down the medial aspect of the arm with the brachial artery located lateral. at the midpoint of the arm, the ulnar nerve penetrates the medial fascial septum to enter the posterior compartment of the arm. in the forearm the ulnar nerve pierces the 2 heads of the flexor capri ulnaris and travels deep to the muscle alongisde the ulna.
what nerve does root C5 give off?
the dorsal scapular nerve
what nerve do roots C5,6,7 give off?
the long thoracic nerve
what nerve do roots C5 and 6 give off?
the nerve to subclavius
what nerve do the lateral and medial cords give off?
the lateral and medial pectoral nerves which come together
what nerves does the posterior cord give off?
radial nerve axillary nerve lower subscapular nerve thoracodorsal nerve upper subscapular nerve
what is the function of the dorsal scapular nerve?
motor: rhomboid muscle and levator scapulae muscles
what is the function of the suprascapular nerve?
motor: supraspinatus and infraspinatus muscles
what is the function of the nerve to subclavian?
motor: innvrtaion to subclavius muscle
what is the functuon of the lateral and medial pectoral nerve?
motor: pectoralis major and minor muscles respectively
what is the function of the medial cutaneous nerve of the forearm and arm?
sensory: medial skin of forearm and arm respectively
what is the function of the lower subscapularis nerve?
motor: subscapularis and teres major
what is the function of the thoracodorsal nerve?
motor: latissimus dorsi muscle
what is the function of the upper subscapular nerve?
motor: subscapularis
what does the musculocutaneous nerve innervate?
motor: muscles of anterior arm
sensory: lateral side of forarm
what does the axillary nerve innervate?
motor: teres minor and deltoid
sensory: glenohumeral joint and skin covering inferuor portion of deltoid (sergeants patch)
what does the radial nerve innervate?
motor: all muscles of posterior arm and forearm
sensory: skin of posterior arm + forearm, lateral edge of thumb on palmar side, lateral hand and proximal 3.5 fingers on dorsal hand
what is the function of the median nerve?
motor: muscles of anterior forearm except flexor capri ulnaris and the ulnar half of flexor digitorum profundus. thenar muscles and lateral lumbricals in hand
sensory: lateral 3.5 digits on adjacent palm on palmar side and distal asoects of lateral 3.5 digits on dorsal side
what is the function of the ulnar nerve?
motor: flexor carpi ulnaris and ulnar half of flexor digitorum profundus, most intrinsic muscles of the hanf
sensory: medial 1.5 digits and adjacent palm
