Brachial Plexus

Brachial Plexus

1. Radial

   • Innervation
     • C5-T1
   • Supplies (All posterior arm & forearm)
     • Forearm
       • Brachioradialis
       • Extensor carpii radalis brevis & Lngus
       • Extensor Digiti Minimi
       • Extensor Carpii Ulnaris
       • Spinator
       • Abductor pollicis Longus
       • Extensor Pollicis Longus & Brevis
       • Extensor Indicis
     • Arm
       • Medial, Lateral & long heads of triceps brachii
       • Anconeus (elbow extensor)
       • Brachioradiais
   • Pathology
     • Axillary nerve: ALL FUNCTION LOST,
       • No elbow extension Wristdrop, No digit extension
       • Sensory loss on dorsolateral forearm & hand
       • Injury: 'Saturday night palsy' limb over back rest, crutches
     • Profunda Brachii
       • Injury in spiral groove (mid shaft #)
       • Elbow extension preserved, Wrist drop, No digit extension
       • Senosry loss: dorsolateral forearm & hand
     • Posterior interosseous nerve (deep branch)
       • Injury: # head of radius
       • No sensory loss (motor nerve)
       • Elbow extension normal, minimal wrist drop (ECR supplied earlier)
     • tumour, upper limb traction
       • Pancoast tumour (mass in the apex of the lung)
       • 1st Rib #
       • Upper limb traction (shoulder distrotia)
       • Trapped between enlarged scalene muscles
       • Tumour
       • Stab wound (post. triangle of neck)

2. Axillary

   • Supplies
     • Teres minor (Lateral Rotation)
     • Deltoids (shoulder abduction)
     • Sensory: regimental band
   • Causes of damage: Shoulder dislocation, Surgical neck of humerus #, Intramuscular injection

3. Musculocutaneous

   • Supplies
     • Anterior forearm
       • Long & short heads of biceps
       • Coracobrachialis (Adduction)
       • Brachialis (elbow Flexor)

4. Median

   • Supply
     • Anterior ForeArm
       • Pronator teres
       • Palmaris Longus
       • Flexor Carpi Radialis
       • Flexor Digitorum Superficials
       • Flexor Pollicis Longus
       • Flexor digitorum Profundus (digits 1,2,3)
       • Pronator Quadratus
     • Innervates all anterior forearm EXCCEPT flexor carpi ulnaris, Flexor digitorum profundus to digit 4& 5
   • Pathology
     • Injury site: Cubital fossa (puncture wound)
     • Forearm
       • No forearm pronation )
     • Wrist
       • Weak wrist flexion that deviates to adduction (FCU = ulnar nerve)
     • Hand
       • Thenar muscle wasting
       • Can't Oppose thumb
       • Thumb laterally rotated
       • adducted Lumbricals 1 & 2
       • Digits 2&3 = No active flexion of IP joints Digits
       • Can’t make fist with digits 2&3 (hand of ‘benediction’)
       • Digit 4&5 = weaker flexion

5. Ulna

   • Pathology
     • Injury: Wrist, superficial to retiinaculum
     • Injury Medial eipcondyle #
       • Wrist abducts on flextion
       • No digits ab/adduction
       • Some clawing
       • Hypothenar & interossei wastingG
     • Ulnar paradox
   • Supply
     • Most o the intrinsic muscles of the hand
       • Hypothenar muscles
       • Interossei
       • EXCEPT: thenar and Lumbricals to digits 2& 3
       • Lumbrcals to digits 4 & 5
     • C8-T1