Nerve supply of the upper limbs Flashcards
What are the 5 subdivions of the brachial plexus?
Roots Trunk Divisions Cords Branches
(read that damn cadaver book)
What are the roots of the brachial plexus?
C5,6,7,8 and T1-Anterior rami
What are the trunks of the brachial plexus?
Superior trunk-C5 and C6
Middle trunk-continuation of C7
Inferior trunk- combination of the C8 and T1 roots
What are the divisions of the brachial plexus?
Each of the trunks of the trunks of the brachial plexus split into an anterior and posterior branch
What are the cords of the brachial plexus?
Lateral cord- anterior division of superior trunk and anterior division of middle trunk
Posterior cord- posterior division of superior trunk, posterior division of middle trunk, posterior division of the inferior trunk
Medial cord- anterior division of the inferior trunk
What are the branches of the brachial plexus?
Musculocutanous nerve Axillary nerve Median nerve Radial nerve Ulnar nerve
How are these branches related to the cords of the brachial plexus
Musculocutanous- Lateral Axillary-Posterior Radial-posterior Median- Lateral and medial Ulnar- medial
Summarise the Roots, trunks, divisions, cords and branches of the brachial plexus
google images
What is Erb’s palsy
What movements are affected?
Commonly occurs due to an excessive increase in the angle between the neck and shoulder which stretches or tears the C5 and C6 roots.
“Waiters tip” palsy- weak flexion of the wrist, loss of shoulder abduction, lateral rotation of the arm, supination of forearm and shoulder flexion
What are the spinal roots of the axillary nerve?
What are the sensory functions of it?
What are its motor functions?
C5 and C6
Gives rise to upper lateral cutaneous nerve of arm which innervates the skin over the lower deltoid (badge area)
Innervates deltoid and teres minor
Describe the anatomical course of the axillary nerve?
Passes anterior to the subscapularis muscle and exits via the quadrangular space. Terminates in the shoudler where it splits into three branches
What are the nerve roots of the musculocutanous nerve?
What are its sensory functions?
What are its motor functions?
C5-C7
Gives rise to the lateral cutaneous nerve of the forearm, which innervates the lateral aspect of the forearm
Muscles in the anterior compartment of the arm
What is the musculocutanous nerve’s anatomical course
Leaves the axilla and pierces the coracobrachialis near the top of thhe muscle. It then runs straight down the middle of the anterior compartment and terminates at the elbow
What are the nerve roots of the median nerve?
What are its sensory functions?
What are its motor functions?
C6-T1
Lateral aspect of palm, lateral three fingers on palmar surface. tips of thumb, index, middle and ring finger of dorsal surface
anterior forearm compartment and thenar muscles
Describe the anatomical course of the median nerve?
Travels down the lateral aspect of the arm, lateral to the brachial artery. Moving central through the cubital fossa at the elbow and then travelling down to the thumb.Wh
What common neuropathy involves compression of the median nerve
Carpal tunnel syndrome
What are the nerve roots of the radial nerve?
What are its sensory innervations?
What are its motor innervations?
C5-T1
Innervates skin on posterior forearm, dorsal surface of the palm, dorsal surface of lateral three and half digits
triceps brachii and extensor muscles in forearm
Describe the anatomical course of the radial artery
Travels in the posterior arm supplying the triceps and then travelling in the radial groove where it wraps around the humerus. It is accompanied by the deep branch of the brachial artery. Travels through cubital fossa and travels down posterior forearm
What occurs if the radial nerve is damaged in the axilla e.g. by a humeral fracture
loss of innervation to triceps and posterior forearm leading to a wrist drop
What are the roots of the ulnar nerve
What are its sensory functions?
What are its motor functions?
C8-T1
anterior and posterior surfaces of medial one and half areas
Innervates the intrinsic muscles of the hand apart from the thenar muscles and the two lateral lumbricals and the two muscles in the forearm:flexor carpi ulnaris and flexor digitorum profundus
Describe the anatomical course of the ulnar nerve
Travels medially down the arm on the anterior aspect of the arm
How do you test for ulnar nerve palsy?
Ask patient to grip paper between forefinger and thumb and then pull they should be able to hold onto it.
