Brachial plexus Flashcards
Brachial plexus divided in
Roots, Trunks, divisions, cords, branches
ROOTS
Dorsal scapular C5
- levator scapulae
- Rhomboids (retracts scapula)
Long thoracic (C5-C7): -Serratus ant.: protract scapula and ABduction of shoulder
TRUNKS
Suprascapular C5,6:
Supraspinatus: ABdution of arm
Infraspinatus: lat rotation
Subclavious
Lateral Cord
Lateral pectoral C5-7= Pectoralis Major
ADduct, rotates medially rot. cuff
Musculocutaneous C5-7: Biceps, Brachialis, Coracobrachialis
Musculocutaneous (Motor)
Muscles ANT. compartment of arm (flexors)
MC sensory
skin over lateral (radial) side of forearm
*Bicipital tendon reflex
Branches of Medial cord
Medial pectoral (C8,T1): Pectoralis major, minor
Medial cutaneous: skin medial side of arm, forearm
Medial cord
Median n.
Ulnar n.(C7-T1)
Medial cord: ULNAR n.
Motor: innervates Flexor carpi ulnari (FCU), medial 1/2 flexor digitorum profundus
Hand= intrinsic musculature (pinkie side)
Sensory: Medial (ulnar)= 1.5 digits (little finger, 1/2 of ring finger)
Injury of Ulnar n.
at elbow (cubital tunnel) at wrist (Guyon's canal) Ulnar claw hand= lumbricals paralyzed
Medial Cord
Median C5,T1
Motor: forearm flexor muscle and hand musculature (Thumb side)
exception: FCU and medial 1/2 FDP
sensory: skin on central palm, palmar surface of lat. 3 and 1/2 digits and dorsum of digital halves of these digits
Lateral cord/ Medial cord
Median n. that runs along with brachial artery, enters cubital fossa; supply flexor of forearm except those by Ulnar n.
supply: muscles of Thumb, lateral 2 lumbricals
Injury of Median n.
at Forearm and Wrist (laceration and CTS)
CTS
Motor: weakness of Thumb muscles and 1, 2 lumbricals
sensory: pain numbness
Palmar cutaneous n.
branch of Median n.
Posterior cord
Subscapular C5: Subscapularis= ADduction/ medial rot. of arm
Thoracodorsal C6,7,8: Latissimus dorsi= Extension, ADduction, medial rot. of arm
Axillary n. C5, T1
Deltoid
Teres minor
Deltoid
ant. fibers= flex and medial rotation
middle: ABduction arm
post. : extension, lateral rot. of arm
Teres minor
Lateral rotation of arm
Axillary sensory
skin below point of shoulder
Axillary injury
shoulder dislocation, Fx of surgical neck of humerus
Arm abduction is not possible beyond 15-30 dg. and lateral rot. of arm compromised
Posterior Cord
Radial n.
Motor: extensors muscles of elbow, wrist and fingers
Sensory: skin posterior and lower lateral aspect of arm, dorsal aspect of forearm and dorso-radial aspect of hand.
Radial n.
from medial to posterior
supply back arm muscles (Triceps, extensors of wrist)
Posterior intraosseous n.= deep muscles of extensor of forearm
Radial n. injury
Axillary crutch usage
Arm: shaft of humerus Fx
supracondylar Fx and compression
Forearm: entrapment = loss of extension of elbow wrist and fingers, sensory loss
“Wrist drop”
testing radial n.
Triceps tendon reflex C6-C8
Brachioradialis tendon reflex C5,C6
Median n.
in front of cubital fossa; deep to flexor retinaculum
Ulnar n.
behind medial epicondyle, superficial to flexor retinaculum
Radial n.
start medially, then posterior to spinal groove, runs posteriorly in forearm
cutaneous innervation: dorsal 3 and 1/2 finger
Upper brachial plexus injury
Erb’s palsy C5,6
“waiter tip hand”
muscles paralyzed: biceps reflex absent, loss of Rot. cuff muscles
sensory: deficit post. and lat. aspect of arm (axillary n.)
radial side forearm (MC n.)
Thumb (radial n.)
first finger (median n.)
Lateral rotation of shoulder
Infraspinatus (suprascapular n.)
Post. fibers Deltoid (axillary C5, 6)
Teres minor (axillary n.)
Medial rotators
Pectoralis major
Teres major
Latissimus dorsi
coracobrachialis
Klumpke’s palsy
Lower trunk (C8,T1)
-excessive Abduction of arm
claw hand 4 fingers
