Week 6 - Brachial plexus Flashcards
Which nerves branch off the lateral cord?
lat pec, musc
Which nerves branch off the posterior cord?
radial, axillary, upper subscap, lower subscap, thoracodorsal
Which nerves branch off the medial cord?
ularn, cut FA, cut arm, med pec
Lat and med pectoral
- C5-T1
- no sensory branches
- injury with clavicle fracture with inferior displacement
Musculocutaneous
- C5-C7
- pierces coracobrachialis and descends laterally between biceps brachii and brachalis
- distal to the elbow, it pierces, deep fascia in cubital fossa, lateral to the biceps tendon
- continues as lat fem cut of FA
- innervates: biceps brachii, brachalis, coracobrachialis
- sensory: lat area of FA
Median
- C6-T1
- lat and med cords
- anterior or lateral to axillary artery
- enters arm lateral to brachial artery
- crosses in front of brachial artery near coracobrachialis insertion and follows artery medially to enter cubital dossa
- in cubital fossa, it sits posterior to bicepital aponeurosis and ant to brachialis
- enters forearm between FDS and FDP
- enters wrist beneath FDS in carpal tunnel
- innervates: pronator teres, prontaor quadratus, palmaris longus, FCR, FLP, FDS, FDP (2nd and 3rd), APL, oppinens pollicis, FPB (sup head), lumbricals (1st and 2nd)
- sensory: radial side of palmar surface of hand and all fingertips on dorsum of hand
- injury: impact to medial arm, cubital fossa, carpal tunnel, honeymoon palsy –> ape hand, Benediction sign
Cubital fossa
Sup border: line between lat and med epicondyles
Lat: brachioradialis
Med: pronator teres
Roof: deep fascia of forearm reinforced by bicipital aponeurosis
Contents: medial nerve, radial nerve, brachial artery, tendon of biceps
Medial cutaneous of the arm
- C8-T1
- sensory: medial upper arm
- no muscular branches
Medial cutaneous of forearm
- C8-T1
- sensory: med forearm
- no muscular branches
Ulnar nerve
- C7-T1
- medial cord of plexus
- descends distally through axilla to axillary artery
- pierces intermuscular septum and passes anterior to medial head of tricpes
- passes post to med epicondyle and enters forearm from behind elbow
- passes through cubital tunnel formed by humeral and ulnar heads of FCU
- descends medially on FDP
- passes beneath flexor retinaculum and through Guyon’s canal
- innervates: FCU, FDP (4th and 5th), palmaris brevis, FDMB, ADM, ODM, adductor pollicis, FPB (deep head), interossei, lumbricals 3-4
- sensory: ulnar side of hand
- injury: impact (ie falling) onto palm of hand –> claw hand
Upper and lower subscapular
- C5-C7
- innervates: subscapularis, teres major
Thoracodorsal
- C6-C8
- innervates: lat dorsi
Axillary
- C5-C6
- posterior cord
- lies lat to radial nerve, post to axillary artery, ant to subscapularis
- passes into axilla at border of subscapularis
- divides into ant (curves around neck of humerus to supply delt) and post (med and post along attachment of lat head of triceps to teres minor
- sensory: delt area
What is Erb’s palsy?
upper trunk injury (delt, brachialis, biceps, loss of lat forearm sensation)
What is Klumpke’s palsy?
lower trunk injury, claw hand
