Overview Introduction Standard: C5, C6, C7, C8, T1 – 77% of patients Prefixed: Prefixed (contributions from C3, C4) – 22% Postfixed (roots caudal to T1) – 1% COMPOSITION: “Robert Turner Drinks Cold Beer” Roots (5): ventral rami of C5-T1, superior and posterior to subclavian dorsal scapular nerve (C5): through levator scapula to supply levator scapula, rhomboid major & minor long thoracic nerve (C5, 6, 7): posterior to plexus onto thoracic wall to supply serratus anterior Trunks (3): emerge from triangle formed by anterior scalene, middle scalene, first rib superior (C5,6 roots) suprascapular nerve (C5, 6): through suprascapular notch to supraspinatus, infraspinatus, AC and glenohumeral joints nerve to subclavius (C5, 6) Erb's palsy tear of upper trunk (C5-C6 roots) that is usually caused by traction during delivery or trauma later in life leads to difficulty with abduction, lateral rotation, and flexion/supination middle (C7) inferior (C8, T1) Divisions (6): 3 anterior, 3 posterior (each trunk gives 1 anterior and 1 posterior division) Cords (3): Posterior Cord: formed from 3 posterior division upper subscapular nerve (C5, 6): subscapularis lower subscapular nerve (C5,6): subscapularis, teres major thoracodorsal nerve (C6, 7, 8): latissmus dorsi Lateral Cord: ant divisions of superior & middle trunks (C5, 6, 7) lateral pectoral nerve (C5, 6, 7): supplies medial aspect of pectoralis major, communication with medial pectoral nerve Medial Cord: anterior division of inferior trunk (C8, T1) medial pectoral nerve (C8, T1): pierces pec minor; supplies pec minor and lateral aspect of pec major medial brachial cutaneous nerve (T1) medial antebrachial cutaneous nerve (C8, T1) Branches (6) – 2 terminal branches from each cord Posterior cord: axillary nerve (C5, 6): through quadrilateral space to teres minor, deltoid, major nerve supply to glenohumeral joint, superior lateral brachial cutaneous nerve radial nerve (C5 – T1): runs with long head of triceps (triangular space) into radial groove on posterior humerus; supplies elbow & forearm extensors, supinator; posterior brachial cutaneous, inferior lateral brachial cutaneous, posterior antebrachial cutaneous, superficial radial (post. radial hand) Lateral cord: lateral cord of median nerve (C5 – C7): joins medial cord anterior to axillary artery then travels with artery: wrist flexors (except FCU, ulnar ½ FDP), pronators, radial two lumbricals, OP, APB, superficial head FPB); sensory distribution in hand musculocutaneous (C5, 6, 7): most superficial branch, pierces coracobrachialis (1.5-9 cm from origin) to supply biceps, coracobrachialis, brachialis, ends as lateral antebrachial cutaneous nerve Medial cord: medial cord of median nerve (C8, T1): see above ulnar nerve (C8, T1) : FCU, ½ FDP, adductor pollicus, deep head FPB, hypothenar, intrinics (except radial 2 lumbricals), sensory to hand
QUESTIONS 1 of 5 1 2 3 4 5 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.AN.14.54) A 56-year-old woman is referred to a plastic surgeon for breast reconstruction approximately 18 months after undergoing right modified radical mastectomy for breast cancer. Physical exam demonstrates atrophy of the lower lateral pectoralis major muscle. Damage to which of the following nerves during mastectomy is the most likely cause of her atrophy? QID: 106360 Type & Select Correct Answer 1 Long thoracic 25% (34/137) 2 Intercostobrachial 7% (9/137) 3 Medial pectoral 23% (31/137) 4 Lateral pectoral 34% (47/137) 5 Lateral intercostal 4% (6/137) M 1 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic (M1.AN.13.39) A 39-year-old male who recently presented with acetaminophen overdose was admitted to the MICU, where several attempts were made at obtaining intravenous access without success. The decision was made to place a right axillary arterial line, which became infected and was removed by the medical student while the patient was still intubated. It was later noticed that he had substantial swelling and bruising of the upper extremity. Given his sedation, a proper neuro exam was not performed at that time. Several days later, after the patient's liver function improved, he was successfully extubated. On exam, he complained of lack of sensation over the palmar and dorsal surface of the small finger and half of the ring finger, as well as weak digit abduction, weak thumb adduction, and weak thumb-index finger pinch of the affected extremity. What is the most likely cause and corresponding location of the injury? QID: 106246 FIGURES: A Type & Select Correct Answer 1 Needle injury to ulnar nerve secondary to blind line placement 34% (58/171) 2 Needle injury to median nerve secondary to blind line placement 8% (13/171) 3 Compression of ulnar nerve secondary to coagulopathy 43% (74/171) 4 Compression of median nerve secondary to coagulopathy 5% (9/171) 5 Stretch injury to ulnar nerve secondary to frequent repositioning 3% (5/171) M 2 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic
All Videos (1) Login to View Community Videos Login to View Community Videos Brachial plexus made easy Luigi Bonini MSK - Brachial Plexus D 2/12/2016 371 views 4.9 (14) MSK | Brachial Plexus MSK - Brachial Plexus Listen Now 16:2 min 4/18/2022 12 plays 0.0 (0)