symposium Flashcards
what is the different parts of the brachial plexus?
roots, trunk, divisions, cords, terminal nerves
what is the roots of the brachial plexus?
anterior rami of C5,6,7,8 and T1
what is the trunks of the brachial plexus and what roots are they formed from?
superior –> C5,C6
middle –> C7
inferior –> C8 and T1
how many posterior and anterior divisions are there?
3 posterior and 2 anterior
what are each cord made up of?
the lateral is made up of 2 anterior divisions
the medial is made up of 1 anterior division
the posterior is made up of all 3 divisions
what is the terminal nerves, what roots do that originate from and what cords they formed from?
musculocutaneous –> C5,6,7 –> lateral cord
radial nerve –> C5-T1 –> posterior cord
ulna nerve –> C7/C8-T1 –> anterior cord
median nerve –> from lateral and medial –> C6-T1
what nerve branches from the root division?
long thoracic nerve –> C5,6,7
dorsal scapula nerve –> C5
what nerve branches from the trunk division?
superior trunk –> suprascapular nerve –> C5 and C6
superior trunk –> subclavius –> C5 and C6
what nerve branches from the lateral cord ?
lateral pectoral nerve
what nerves branch from the medial cord?
middle pectoral nerve
middle cutaneous nerve of arm and forearm
what nerves branch from the posterior cord?
inferior and superior subscapularis
thoracodorsal nerve
axillary nerve –> C5 and C6
what structures are innervated by radial nerve?
the posterior compartment of the arm –> tricep brachii and brachioradalis
the extensor muscles of the forearm
what structures are innerated by the musculocutaneous nerve?
muscles of the anterior compartment of the arm
what structures are innervated by the mediannerve?
innervates most of the muscles of the forearm and the thenar muscles, and lumbricales 2 and 3
what structures are innervated by the ulnar nerve?
the muscles of the hand except for the thenar muscle and 2 and 3 lumbrical muscles, the flexor carpi ulnaris and medial half of flexor digitorium profundus
where is the trunks of the brachial plexus formed?
in the neck
where is the divisions of the brachial plexus formed?
under the clavicle
where is the cords and terminal nerves of the brachial plexus formed?
in the axillia
what nerves suppy the mytomes of the glenohumeral joint that do flexion, abduction and lateral rotation?
C5
what nerves suppy the mytomes of the glenohumeral joint that do extension, adduction and medial rotation?
C6,C7,C8
what myotomes are involved in extension and flexion of elbow joint?
extension of the joint involves C6 and C7
flexion –> C5 and C6
what is the myotomes involved in extension and flexion at the wrist joint?
extenson –> C6 mainly and C7
flexion –> C6 and mainly C7
what is the myotomes invovled in abduction and adduction of the digits?
T1
what myotomes are involved in pronation and supinatin at the radioulnar joint?
pronation –> C7 and C8
supination –> C6
what myotomes are involved in digital flexion and extension?
flexion –> C7 and mainly C8
Extension –> mainly C7 and C8
what occurs in ebr’s palsy?
when there is excessive stretching of the neck of the child during child birth either by hands or forcep –> causes the damage to the upper nerve roots –> C5 and C6 nerve root
what is the sensory deficit of ebr’s palsy?
sensory deficit around the elbow –> between dermatome C5 and 6 –> worse place affected as there is no sensory innervation at all
what is the clinical signs of a baby with ebr’s palsy?
waiters tip shoulder adducted arm pronated hand medial rotation extension of the elbow
what functions are lost in erb’s palsy?
lost of abduction –> deltoid ( axillary nerve C5 and C6) and supraspinatour ( suprascaular nerve C5,C6)
loss of lateral rotation –> teres minor and infraspinatous
loss of supination and flexion of bicep brachii –> musculocutaneous get majority of its innervation by C5 and C6
same for the loss of flexion for brachialis
how can a adult get erb’s palsy?
fall from a high level –> for example from a horse onto the head/neck region –> stretch the head and neck apart which leads to damage the brachial plexus
how can you investigate if a adult has erb’s palsy?
MRI scan that shows the damaged nerve roots
how is prognosis of erb’s palsy measured?
the extend of the damage affects the prognosis –> if only a small damage and the nerve parts have only been seperated a little bit then within few months should get some function back.
However if you have a big damage and there is large then the nerve will not be able to heal
why is prognosis of nerve healing is poor when there is large damage?
nerves are poor at finding each other when there is a large gap –> take a bad root and therefore won’t heal and recover
how is erb’s palsy treated if there is a large damage?
By a nerve transplant
In large damage the nerves will produce neuroma –> scaring–> connective tissue and nerves
so remove the neuroma and then replace it with sensory nerves harvested from somewehre else such as the calf or neck.
The movement of that limb be weaker than off the one taht is unaffected
how does klumpke’s occur?
during child hood –> baby is pulled out by excessive pulling of the upper limb –> damage to the lower trunks of the brachial plexus –> C8 T1 –> ulnar nerve
what is more common erb’s palsy or klumpke’s palsy?
eber’s palsy
what muscles are paralysed in klumpker’s palsy?
most of the intrinsic muscles of the hand
what can imbalance of intrinsic and extrinsic muscles due to klumpke’s cause?
deformity of the hand
what does klumpker’s palsy cause?
ulnar claw
what occurs in ulnar claw?
the paralysis of the lumbricals 3 and 4 –> hyperextension of the metacarpophalongeal joint and flexion of the interphalangeal joints –> do to no opposition of the lumbricals –> spontaneous so all the time
how can a adult get klumpker’s palsy?
if the upper limb is suddenly pulled superiorly –> falling and grasp onto something
how can you assess the prognosis of klumpker’s palsy?
like erb’s palsy you use a MRI scan to detect the nerve root damage and the prognosis again depends on how badly it has been damaged –> can take few months to heal or won’t heal at all.
how common is the cubital tunnel syndrome?
it is the 2nd most common entrapment syndrome
what is the cubital tunnel?
tendinous arch between the humeral and ulnar head of the flexor carpi ulnaris –> between the olecranon process and the medial epicondyle.
what nerve is damaged in the cubital tunnel?
ulnar nerve
what is the cause of the cubital tunnel syndrome?
constricting facial bands
occupational activities such as repetitive extension and flexion of the elbow
direct compression of the area
what is the treatment and symptoms of cubital tunnel syndrome?
symptoms same as the klumpker’s palsy but also elbow pain –> inflammation and sensitive to touch
treatment –> anti inflammatory and not resolved then surgery is required
what palsy can cuae horners syndrome and why?
klumpker’s palsy because of the damage it does to T1 which supplies the sympathetic neurones to the face and also can be caused by traction
what are the symtpoms of horners syndrome?
ptosis
miosis –> excessive constriction of the pupil
anhidrosis –> not able to produce sweat
vasodilation –> flushing
what is radial nerve palsy? possible cause?
damage to the radial nerve in the spiral groove of humerus can cause wrist drop –> mid humeral shaft fracture
what happens in radial nerve palsy?
the inability to extend the wrist or the metacarpalphalangeal joints due to paralysis of the extensor muscles of the forearm
why is tricep weakend not paralysed by damage to the radial nerve at the radial groove?
it gives a branch to each head of the tricep. The branch to the long head is before the spiral groove so there is still some innervation to the triceps
how is the median nerve damaged at the elbow?
by supracondylar fracture of pronator teres syndrome –> compression of median nerve in pronator teres
what is the outcome of damage to median nerve?
hand of benidiction
what muscles are affected by the syndrome of hand of benediction?
cannot flex digits 1 to 3
Thenar eminence, flexor pollicis longus, lumbricals 1 and 2, FDS and FDP
when does hand of benediction occur?
when you ask the patient to make a fist
what happens to digit 4 and 5 in hand of benediction?
can still flex but is weekend. It is supplied by the ulna nerve
