Brachial Plexus and Axilla PDF

Brachial Plexus and Axilla Madison Barber, MS [email protected]  Learning Objectives Describe the borders and general contents (axillary vessels, brachial plexus, lymphatics) of the axilla. Describe the course and principal branches...

Brachial Plexus and Axilla Madison Barber, MS [email protected]  Learning Objectives Describe the borders and general contents (axillary vessels, brachial plexus, lymphatics) of the axilla. Describe the course and principal branches of the axillary artery (thoracoacromial, lateral thoracic, anterior and posterior circumflex humeral, subscapular, thoracodorsal, circumflex scapular). Describe the structure of the brachial plexus including its roots, trunks, divisions, cords and major branches Describe the relationship of the roots, trunks and cords of the brachial plexus relative to the scalene muscles, first rib, and axillary artery, respectively. List the regions of the body drained by lymphatics that converge at the axillary lymph nodes. Identify the axillary artery and its major branches on angiograms of the upper extremity.  Axilla Borders Apex – Cervico-axillary canal, the passageway between neck and axilla Base – Thoracic wall and medial aspect of humerus Posterior wall – scapula and subscapularis on its anterior surface and inferiorly by teres major and latissimus dorsi Anterior wall – pectoralis major and minor Lateral wall – intertubercular sulcus on the humerus Medial wall – formed by the thoracic wall (1st – 4th ribs)  Axilla Contents Brachial Plexus  Network of nerve roots that join to form large peripheral Axillary Vein nerves  Axillary vein is removed  Terminal branches innervate here, but is a continuation the upper limb of the subclavian artery.  Cephalic vein drains into axillary vein Axillary Artery Lymphatics  Begins at the lateral border of the first rib as a continuation of subclavian artery  At the lateral border of teres major m., it continues as the brachial artery  Apical Nodes  Receive lymph from all other groups of Axillary Lymph Nodes axillary nodes as well as from lymphatics accompanying the cephalic Right lymphatic duct vein Central Nodes  Receive the lymph from the humeral, subscapular, and pectoral nodes Humeral Nodes  Receive lymph from almost all of upper limb except those carried by cephalic vein Subscapular Nodes  Axillary lymph nodes are arranged in 5  Receive lymph from posterior aspect principal groups: pectoral, subscapular, of thoracic wall and scapular region humeral, central and apical  Groups are arranged in a manner that reflects the pyramidal shape of axilla Pectoral nodes  Receives lymph mainly from ant. Thoracic wall, including most of breast  Axillary Artery Subclavian artery Lateral thoracic artery 1 Posterior circumflex 2 Superior thoracic a. humeral a. 3 Anterior circumflex humeral a. Thoraco-acromial trunk Subscapular artery Brachial artery Circumflex scapular a. Thoracodorsal a. Angiogram  “Run To Drink Cold Beverages” Brachial Plexus!!  Roots  Anterior rami from last four cervical nerves and the first thoracic nerve (C5-T1)  Trunks  Roots unite to form three trunks:  Superior trunk  Middle trunk  Inferior trunk  Divisions  Each trunk gives off an anterior and posterior division  Cords  Divisions unite to form 3 cords name in reference to the axillary artery  Lateral  Medial  Posterior  Branches  Each cord continues as a peripheral nerves that innervates muscles of the upper limb  Roots Trunks Divisions Cords Branches C5 Superior Lateral Musculocutaneous n. A C6 A P Middle Posterior C7 P Axillary Artery P Median n. C8 Inferior Medial Ulnar n. A T1  Brachial Plexus Sup. Trunk C5 Posterior Cord C6 Axillary n. Lateral Cord C7 Musculocutaneous n. Middle Trunk Median n. Inf. Trunk Medial Cord Radial n. Ulnar n. Let’s break it down: Musculocutaneous Nerve  Musculocutaneous Nerve Terminal branch of lateral cord, receiving fibers from C5, C6, C7  Exits axilla by piercing coracobrachialis  Continues into the forearm as the lateral cutaneous nerve of the forearm  Motor Innervation to muscles of the anterior compartment of the arm Cutaneous innervation of the lateral forearm **Allows for flexion of forearm at the elbow ** Median Nerve  Median Nerve Lateral and medial cord give a contribution to form the median nerve receiving fibers from C6, C7, C8, and T1  Descends through the arm lateral to the axillary artery and continues into the forearm  Motor innervation to the muscles of the anterior compartment of the forearm as well as 5 muscles of the palmar hand Cutaneous innervation to the tips of the first 3 digits as well as radial half of 4th digit and palm of hand **Allows for flexion at the wrist and fingers. As well as pronation of the forearm** Ulnar Nerve  Ulnar Nerve Larger terminal branch of medial cord, receiving fibers from C8, T1, and often C7  Descends along medial arm and forearm into the hand Motor innervation to 2 muscles in the forearm and most intrinsic muscles of the hand Cutaneous innervation to the ulnar half of the the 4th digit as well as all of the 5th digit **Allows for some flexion at the wrist and most of the flexion of the hand** Axillary Nerve  Axillary Nerve Terminal branch of posterior cord, receiving fibers from C5 and C6  Passes posteriorly to the surgical neck of humerus Motor innervation to 2 muscles of the shoulder  Cutaneous innervation to the glenohumeral joint, as well as the superior lateral shoulder **Allows for some external rotation, flexion, abduction, and extension at the shoulder** Radial Nerve  Radial Nerve Larger terminal branch of posterior cord, receiving fibers from C5-T1  Exits axillary fossa posterior to axillary artery; passes posterior to humerus in radial groove, passes between heads of triceps  Then descends into the forearm Innervates the entire posterior compartment of the arm and forearm  Cutaneous innervation to the posterior and inferolateral arm, posterior forearm and dorsum of hand **Allows for extension at the shoulder, elbow, wrist and fingers**  Main actions Nerve Root Contributions Cord Muscles Innervated performed Motor to anterior Flexion at the elbow Musculocutaneous C5-C7 Lateral Cord compartment muscles and some flexion at the of arm and shoulder Contributions from Muscles of anterior Flexion at the wrist, Median C6-T1 medial and lateral cord forearm, 5 intrinsic digits, and pronation of hand muscles forearm Flexor carpi ulnaris and Some flexion of the Ulnar C8, T1, and sometimes Medial Cord ulnar half of flexor wrist and digits, and C7 digitorum profundus abduction of wrist Teres minor, and Lateral rotation, Axillary C5, C6 Posterior Cord deltoid abduction, flexion and extension at the shoulder All muscles of posterior Extension of the Radial C5 – T1 Posterior Cord arm and forearm shoulder, elbow, wrist, and digits  Suprascapular n. C6 C8 C5 C7 T1  Dorsal scapular n. Suprascapular n. Lateral pectoral n. Medial pectoral n. Medial cutaneous n. of arm Long Thoracic n. Thoracodorsal n. Medial cutaneous n. of forearm  Main actions Nerve Root Contributions Cord/Trunk Muscles Innervated performed Long thoracic n. C5, C6, C7 N/A Serratus anterior Holds scapula against thoracic wall Subclavian n. C5, C6, and often C4 Superior Trunk Subclavius Depression of clavicle Suprascapular n. C5, C6, and often C4 Superior Trunk Supraspinatus, infraspinatus First 15 degrees abd. & lateral mm. rotation Lateral pectoral n. C5, C6, C7 Lateral Cord Pectoralis Major Flexion, abd., internal rotation Upper subscapular n. C5 Posterior cord Sup. portion of subscapularis Medial rotation Lower subscapular n. C6 Posterior Cord Inf. Portion of subscapularis Medial rotation as wall as and teres major abduction Thoracodorsal n. C6, C7, C8 Posterior Cord Latissimus dorsi Extension, adduction, medial rotation Medial pectoral n. C8, T1 Medial Cord Pectoralis minor and pectoralis Flexion, abduction, internal major rotation, depression of scapula Medial cutaneous n. of arm C8, T1 Medial Cord N/A N/A Medial cutaneous n. of C8, T1 Medial Cord N/A N/A forearm  Dermatomes Sensory of Upper Limb #Dermatomes “segmented cutaneous innervation” unilateral strip of skin innervated by fibers of… single spinal nerve proximal to plexus overlap between adjacent spinal nerves clinically important because they indicate where injury/deficit is originating  Anterior Posterior Cutaneous Inn. Supraclavicular nerves (C3,C4) Supraclavicular nerves (C3,C4) Axillary nerve (C5, C6) Axillary nerve (C5, C6) Medial brachial cutaneous n. (T1) Medial brachial cutaneous n. (T1) Radial nerve (C5, C6) Radial nerve (C5, C6) Medial antebrachial Medial antebrachial cutaneous n. (C8, T1) cutaneous n. (C8, T1) Terminal part of Terminal part of musculocutanous n. (C5, 6, 7) musculocutanous n. (C5, 6, 7) Radial nerve (C5, C6) Ulnar nerve (C8, T1) Median Nerve (C6, 7, 8) Median Nerve (C6, 7, 8) Ulnar nerve (C8, T1)  Erb’s Palsy Damage to C5 and C6 spinal roots Excessive increase in the angle between the neck and shoulder Thrown from bike/motorcycle Neck stretched during childbirth Affected limb is adducted, medially rotated with extended, pronated forearm and flexed wrist “Waiter’s tip” Treatment is typically physical therapy  Erb’s Palsy Paralysis Deltoid, infraspinatus, teres Unable to laterally rotate, abduct, flex and Damage to C5 and C6 affect minor and supraspinatus extend arm at the shoulder the nerves: Long thoracic, suprascapular, subclavian, lateral pectoral, axillary, and Paresis Serratus anterior, biceps Weakened flexion of forearm at the musculocutaneous brachii and brachialis elbow, weakened protraction of scapula  Klumpke Palsy Damage to C8 and T1 Occurs when the upper limb is suddenly pulled superiorly When a person is falling and grasps something to break the fall Can occur during childbirth if the arm is pulled excessively Affected lime will have a claw hand Treatment is typically physical therapy  Klumpke’s Palsy Inability to flex the Paralysis Flexor carpi ulnaris, pectoralis metacarpophalangeal joints of 4th Damage to C8 and T1 affect minor, 3rd and 4th lumbricals and 5th digits the nerves: medial pectoral nerve, medial cutaneous Weakened flexion of distal nerve of the arm & forearm, Ulnar half of flexor digitorum interphalangeal joints of 4th and 5th ulnar nerve as well as parts of Paresis profundus, muscles of anterior digits, weakened flexion of forearm radial and median forearm, posterior compartment at wrist, weakened extension of arm of arm and forearm and forearm  Arm Learning Objectives Describe the major features of the scapula, humerus, radius & ulna. Describe the anatomy of the elbow joint including the surrounding bursae & movements. Name the muscles of the arm within two fascial compartments & describe their general attachments, actions, & innervations. Describe the course of the musculocutaneous, radial, median, & ulnar nerve in the arm. Describe the course & principal branches of the brachial vessels. Describe the borders of the cubital fossa & its major contents. Synthesize anatomical relationships through the various clinical correlates. AAA Gross Anatomy Learning Objectives for Competency-based Undergraduate Medical Education  Arm ArmOverview Overview Extends from shoulder to elbow Flexion, extension, supination Anterior compartment (flexion/supination Posterior compartment (extension) Most movement happens at elbow joint but some will involve the glenohumeral joint Anterior Posterior  Anterior Anterior Osteology Posterior Deltoid tuberosity Radial Groove Lateral Epicondyle Supracondylar ridge Coronoid fossa Radial Groove Medial Epicondyle Capitulum Trochlea Trochlea Lateral Medial  Anterior Elbow Joint Hinge Joint – flexion & extension only Joint capsule Fat pad Joint capsule – outer fibrous layer and inner synovial membrane Synovial membrane Olecranon bursae Articular cartilage Posterior Radial Head Coronoid Process Olecranon Radius Ulna  Anterior Compartment What is this nerve? Biceps Brachii Coracobrachialis Long Head Short head Brachialis  Biceps Brachii Short head O: Tip of coracoid process I: radial tuberosity via bicipital aponeurosis A: Resists shoulder dislocation and flexes forearm Long head O: supraglenoid tubercle of scapula I: Radial Tuberosity and via bicipital aponeurosis A: Flexes and supinates the forearm and elbow *Innervated by the musculocutaneous nerve  Clinical Correlates Biceps tendinitis Repetitive microtrauma can cause inflammation of biceps tendon within bicipital groove Causes friction when biceps tendon moves back and forth within the groove Bicep tendon rupture (Long Head) Prolonged biceps tendinitis causes rupture of tendon Torn from attachment to supraglenoid tubercle Snap or pop is typically heard and the muscle balls up in middle of arm “Popeye Deformity”  Coracobrachialis Coracobrachialis O: Tip of coracoid process of scapula I: Middle third of medial surface of humerus A: Helps flex and adduct arm at the shoulder Stabilizes the glenohumeral joint Resists downward dislocation of head of humerus *Pierced and innervated by the musculocutaneous nerve  Brachialis Brachialis O: Distal half of anterior humerus I: Coronoid process and tuberosity of ulna A: flexes forearm at the elbow  Posterior Compartment What is this nerve and artery and what space is it passing through? What about this one? Triceps Brachii Long head Lateral head Medial head Anconeus  Triceps Brachii All three muscle heads insert onto the proximal end of the olecranon of the ulna and forearm fascia Long head O: Infraglenoid tubercle of scapula A: Resists humerus dislocation; extends and adducts arm at the shoulder Lateral head O: Posterior surface of humerus, superior to radial groove A: Extension of forearm against resistance Medial Head O: Posterior surface of humerus, inferior to radial groove A: Main extensor of the forearm at the elbow *Innervated by the radial nerve  Anconeus Anconeus O: Lateral epicondyle of humerus I: Lateral surface of olecranon and superior part of posterior surface of ulna A: Assists triceps in extending forearm, stabilizes elbow joint, may abduct ulna during pronation  Arterial Supply Anterior circumflex humeral Posterior circumflex humeral Axillary a. Brachial a. Radial collateral a. Profunda brachii Radial recurrent a. Superior ulnar collateral a. Radial a. Inferior ulnar collateral a. Anterior & posterior ulnar recurrent aa. Ulnar a.  Humeral Fractures Proximal – surgical neck of humerus Axillary n. and posterior humeral Axillary nerve circumflex Deltoid paralysis and teres minor paresis Cutaneous sensation over the shoulder CR: Dr. Fickert  Humeral Fractures Midshaft Radial groove of humerus Radial nerve and profunda brachii Triceps brachii spared Radial nerve innervates triceps proximal to midshaft humeral fracture Forearm wrist extensors paralysis Wrist drop – unopposed flexion of the wrist Cutaneous sensation loss to dorsal hand and proximal lateral three-digits CR: Dr. Fickert  Humeral Fractures Distal end Supracondylar regions of humerus Median n. and brachial a. Inability to flex digits 2 and 3 at the metacarpal-phalangeal joint “hand of benediction” Loss of sensation on the palmar side of digits 1-3 and tips of digits 1-3 on the dorsal side Anterior Posterior CR: Dr. Fickert  Humeral Fractures Distal end Medial epicondyle of humerus Ulnar nerve and brachial artery Paresis of wrist flexion, decreased grip strength, and hyperextension of the 4-5th metacarpal-phalangeal joints Ulnar claw Loss of cutaneous sensation to the 4th and 5th digits of the hand Anterior Posterior CR: Dr. Fickert  Venous & Lymph Drainage Cephalic Vein Axillary nodes Cubital nodes Medial Cubital Vein Cephalic Vein Basilic Vein  Cubital Fossa Borders: Superior: the line between medial and lateral Median humeral epicondyles Brachial Radial Lateral: brachioradialis Medial–pronator teres Floor – brachialis and supinator Brachioradialis Contents: Biceps Tendon Biceps tendon Median Cubital Median nerve Bicipital Brachial artery Aponeurosis Median cubital vein CR: Dr. Fickert  Clinical Correlates Cubital fossa is a common site of blood draws, transfusion, intravenous injections, and coronary angiography Median cubital vein *Be aware of bicipital aponeurosis and variations of vasculature  Blood pressure Temporarily blocked blood flow through the brachial artery and slow release of pressure cuff to resume blood flow is the basis of BP measurement Stethoscope is placed in the cubital fossa 1st sound is systolic ~ 120mmHg 2nd sound diastolic ~ 80mmHg Quiz Time!  Thank you for listening! Please email with any questions! [email protected]