Brachial Plexus 2018 PDF

The Brachial Plexus The Brachial Plexus 1. The brachial plexus is formed by the union of the anterior rami of C5-C8 & T1 (the roots of the BP). 2. The roots pass laterally between the anterior and middle scalene muscles with the subclavian artery. 3. Sympathetic fibers from the middle and inferior c...

The Brachial Plexus The Brachial Plexus 1. The brachial plexus is formed by the union of the anterior rami of C5-C8 & T1 (the roots of the BP). 2. The roots pass laterally between the anterior and middle scalene muscles with the subclavian artery. 3. Sympathetic fibers from the middle and inferior cervical ganglia join the roots as they pass between the scalene muscles. In the supraclavicular area the roots unite to form trunks: 1. 2. 3. Superior trunk – C5& C6 Middle trunk – C7 Inferior trunk – C8 & T1 As the trunks pass lateral to the 1st rib each trunk splits into anterior and posterior divisions as they pass beneath the clavicle and enter the cervicoaxillary canal: – Anterior divisions innervate the muscles of the anterior compartment in the arm and forearm. – Posterior divisions innervate muscles of the posterior compartment of the arm and forearm Divisions form cords in the area superior to the pectoral minor: – Superior & middle anterior divisions unite the from the lateral cord – Anterior division of the inferior trunk forms the medial cord – Posterior divisions unite to form the posterior cord. To simplify understanding and remembering the BP it can be divided into supraclavicular & infraclavicular segments by the clavicle Supraclavicular Branches Nerve Origin Course Distribution Dorsal scapular Anterior ramus of C5 with a frequent contribution from C4 Pierces middle scalene, descends deep to levator scapulae, and enters deep surface of rhomboids Innervates rhomboids and occasionally supplies levator scapulae Long thoracic Anterior rami of C5-C7 Descends posterior to C8 and T1 rami and passes distally on external surface of serratus anterior Innervates serratus anterior Nerve to subclavius Superior trunk receiving fibers from C5 and C6 and often C4 Descends posterior to clavicle and anterior to brachial plexus and subclavian artery Innervates subclavius and sternoclavicular joint Suprascapular Superior trunk receiving fibers from C5 and C6 and often C4 Passes laterally across posterior triangle of neck, through scapular notch under superior transverse scapular ligament Innervates supraspinatus, infraspinatus, and glenohumeral (shoulder) joint Supraclavicular Branches There are four, they arise from roots, a trunk and a division* Root branches Dorsal scapular nerve:pierces middle scalene and passes inferiorly to the rhomboids Long thoracic nerve: from C5,6,7 roots passes inferiorly on to the surface of the Serratus anterior Trunk branch Nerve to subclavius: passes directly to the inferior surface of clavicle gives branch to sternoclavicular joint Suprascapular nerve: runs parallel to the suprascapular artery to the suprascapular notch (beneath the suprascapular ligament) supplies the supraspinatus m. around the greater scapular notch to the infraspinatus m. Infraclavicular Branches Infraclavicular Branches - -arise from the cords and can be divided into big and smaller branches (not scientific). Infraclavicular Branches Cords Big Branches Smaller Branches Lateral Musculocutaneous Lateral* Lateral pectoral Posterior Axillary Radial Upper subscapular Lower subscapular Thoracodorsal Medial Ulnar Medial* Medial pectoral Medial cutaneous nerve of arm Medial cutaneous nerve of forearm *Medial and lateral branches unites to form median nerve. Branches from Lateral Cord Cords Lateral Big Branches Smaller Branches Musculocutaneous Lateral pectoral Lateral branch Branches from Lateral Cord Nerve Origin Course Lateral pectoral Lateral cord receiving fibers from C5-C7 Pierces clavipectoral fascia to reach deep surface of pectoral muscles Musculocutaneous Median Distribution Primarily supplies pectoralis major but sends a loop to medial pectoral nerve that innervates pectoralis minor Lateral cord receiving Enters deep surface of Innervates fibers from C5-C7 coracobrachialis and coracobrachialis, biceps descends between brachii and brachialis; biceps brachii and continues as lateral brachialis cutaneous nerve of forearm Lateral root is a Lateral root joins medial Innervates flexor continuation of lateral root to form median muscles in forearm cord, receiving fibers nerve lateral to axillary (except flexor carpi from C6 and C7; medial artery ulnaris, ulnar half of root is a continuation of flexor digitorum medial cord receiving profundus ) and five fibers from C8 and T1 hand muscles Branches from Posterior Cord Cords Big Branches Smaller branches Posterior Axillary Radial Upper subscapular Lower subscapular Thoracodorsal Branches from Posterior Cord Nerve Origin Course Distribution Upper subscapular Branch of posterior cord receiving fibers from C5 and C6 Passes posteriorly and enters subscapularis Innervates superior portion of subscapularis Thoracodorsal Branch of posterior cord receiving fibers from C6, C7 and C8 Arises between upper and lower subscapular nerves and runs inferolaterally to latissimus dorsi Innervates latissimus dorsi Lower subscapular Branch of posterior cord receiving fibers from C5 and C6 Passes inferolaterally, deep to subscapular artery and vein to subscapularis and teres major Innervates inferior portion of subscapularis and teres major Axillary Terminal branch of posterior cord receiving fibers from C5 and C6 Innervates teres minor and deltoid, glenohumeral joint and skin over inferior part of deltoid Radial Terminal branch of posterior cord receiving fibers from C5-C8 and T1 Passes to posterior aspect arm through quadrangular space in company with posterior circumflex humeral artery and then winds around surgical neck of humerus; gives rise to lateral cutaneous nerve of arm Descends posterior to axillary artery; enters radial groove with deep brachial artery to pass between long and medial heads of triceps Innervates triceps brachii, anconeus, brachioradialis and extensor muscles of forearm; supplies skin on posterior aspect of arm and forearm via posterior cutaneous nerves of arm and forearm Branches from Medial Cord Cords Big branches Little branches Medial Ulnar Medial branch Medial pectoral Medial brachial cutaneous Medial antebrachial cutaneous Branches from Medial Cord Nerve Origin Course Distribution Medial pectoral Medial cord receiving fibers from C8 and T1 Passes between axillary artery and vein and enters deep surface of pectoralis minor Innervates the pectoralis minor and part of pectoralis major Medial cutaneous nerve of arm Medial cord receiving fibers from C8 and T1 Runs along the medial side of axillary vein and communicates with intercostobrachial nerve Supplies skin on medial side of arm Medial cutaneous nerve of forearm Medial cord receiving fibers from C8 and T1 Runs between axillary artery and vein Supplies skin over medial side of forearm Ulnar A terminal branch of medial cord receiving fibers from C8 and T1 and often C7 Passes down medial aspect of arm and runs posterior to medial epicondyle to enter forearm Innervates 1 and 1/2 half flexor muscles in forearm, most small muscles in hand and skin of hand medial to a line bisecting 4th digit CUTANEOUS INNERVATION OF HAND( ANTERIORLY) LATREAL 3 &1/2 FINGERS AND LATERAL PALM – MEDIAN NERVE MEDIAL 1 &1/2 FINGERS AND MEDIAL PALM- ULNAR NERVE CUTANEOUS NERVE SUPPLY HAND (POSTERIORLY) MEDIAL 1 &1/2 FINGERS AND HANDULNAR NERVE TIPS OF FINGERS LATERAL 3 &1/2 FINGERS- MEDIAN NERVE REST OF LATERAL 3& 1/2 FINGERS AND HAND - RADIAL NERVE MEDIAN NERVE FORMED FROM BOTH MEDIAL AND LATERAL CORDA) SUPPLIES ALL THE FLEXORS OF THE FOREARM (EXCEPT FLEXOR CARPI ULNARIS AND MEDIAL HALF OF FDP) B) INTRINSIC MUSCLES IN THE LATERAL PALM INCLUDING THENAR EMINENCE) *INJURY TO MEDIAN NERVE-” APE HAND” Median Nerve Supplies no muscles of the arm Damage can cause – Hand of benediction – Ape Hand – Carpal Tunnel Syndrome Patient trying to make a fist 46 Pope's Hand (Hand of Benediction) The pope's hand is seen with median nerve dysfunction when asking the patient to make a fist due to inability to flex 1st & 2nd fingers at PIP. The median nerve controls the 1st & 2nd lumbricals, three thenar muscles (abductor pollicis brevis, flexor pollicis brevis, and via a distal branch the opponens pollicis).Additionally there may be thenar atrophy MEDIAN NERVE: Ape Hand This is the nerve that gets cut when people try to slit their wrists. The arteries are so small in the wrist; people rarely die from this type of suicide attempt. However, they live with a lot of tissue damage. They are not able to move the thumb towards the little finger, so it is hard to pick up small objects. This is called “ape hand”. 48 Carpel Tunnel Syndrome The median nerve travels under the transverse carpal ligament. The nerve is pinched in carpal tunnel syndrome. 49 Carpel Tunnel Syndrome 50 Patient Case Hakan has been a computer technician for 20 years. He has numbness in his right hand on the thumb, index finger, and middle finger. Tapping on the carpal tunnel causes parathesias (tingling) in the median nerve distribution (positive Tinel’s sign). Placing his wrist in sustain flexion for one minute also causes the parathesias 51 (positive Phalen’s test). Patient Case Treatment began with splinting the wrist in neutral position and patient education for proper ergonomics (use a wrist pad while typing). 52 ULNAR NERVE A) SUPPLIES THE MEDIAL HALF OF FDP AND THE FLEXOR CARPI ULNARIS B) SUPPLIES MOST OF THE INTRINSIC MUSCLES OF THE HAND INCLUDING THE HYPOTHENAR EMINENCE, AND SKIN ON THE MEDIAL SIDE OF THE HAND INJURY TO ULNAR NERVE-” CLAW HAND” Ulnar Nerve Damage can cause claw hand; cannot adduct or abduct fingers 55 MUSCULOCUTANEOUS NERVE A) SUPPLIES THE BICEPS, CORACOBRACHIALIS AND BRACHIALIS AXILLARY NERVE - SUPPLIES THE DELTOID AND TERES MINOR MUSCLE SUPPLIES THE SHOULDER JOINT RADIAL NERVE - SUPPLIES THE TRICEPS SUPPLIES THE BRACHIORADIALIS SUPPLIES MOST OF THE EXTENSORS OF THE FOREARM * INJURY RESULTS IN “ WRIST DROP” Carpel Tunnel Syndrome Ape Hand 65 Upper Brachial Plexus Injury: Erb-Duchenne Palsy C5&C6 root injury, caused by stretch between the head and shoulder. The most commonly involved nerves are the suprascapular nerve, musculocutaneous nerve, and the axillary nerve. Waiter’s tip deformity- arm adducted, medially rotated and pronated. Appearance: Waiter’s tip deformity- arm adducted, medially rotated and pronated. Loss of innervation to abductors, flexors,& medial rotators of shoulder and flexors & supinators of elbow Loss of sensation to lateral aspect of upper extremity Lower brachial plexus injury:Klumpke palsy C7,C8&T1 injury Arm abduction injury Major motor deficits in the muscles working the hand: “claw hand” Paralysis of the muscles of the distal forearm and hand (all ulnar innervated) plus distal radial & median innervated muscles Loss of sensation to medial aspect of upper extremity Horner's syndrome (ptosis,meiosis, anhydrosis) if T1 sympathetics involved. Injury to long thoracic nerve-winging of scapula Brachial Plexus