Brachial Plexus

Report
Glenn M. Fox, Ph.D.
tinyurl.com/foxbrach
anatomy review
evolution
variation
pathology and injury
clinical scenarios
How would you describe your knowledge of
the brachial plexus? (Please choose one)
A. Expert. It is a subject I teach and/or
research
B. Some familiarity
C. I have heard of it
D. I have two of them (I think)
E. No prior knowledge
somatic plexus
ventral rami (not roots!)
upper limb musculature (except trapezius m.)
upper limb cutaneous (except skin near axilla)
typically C5-T1
highly variable
sympathetic outflow
from C8-T2
vasculature, erector pili, & sweat glands
Lateral
Anterior
C5
Superior
C6
Posterior
Middle
C7
C8
Inferior
Medial
T1
Branches (4)
Behave
Cords (8)
Cautiously
Divisions
Don’t
Trunks (2)
Roots (3)
Takers
Risk
dorsal scapular
lateral pectoral
suprascapular
to phrenic
C5
musculocutaneous
subclavian
axillary*
C6
C7
radial
median
C8
ulnar
medial antebrachial cutaneous
medial brachial cutaneous
medial pectoral
T1
long thoracic
Hierarchy:
Risk Takers Don’t Cautiously Behave
Randy Travis Drinks Cold Beer
Terminal branches:
MARMU
C5
Spinal Roots of Terminal Nerves:
C6
3 Musketeers Assassinated 5 Rats,
5 Mice, & 2 Unicorns.
C7
C8
T1
dorsal scapular n. (C5)
levator scapulae m. and
rhomboid major & minor m.
long thoracic (C5-7)
serratus anterior m.
contribution to phrenic nerve (C5)
diaphragm
suprascapular n.
supraspinatus & infraspinatus mm.
subclavian n.
subclavius m.
lateral pectoral n.
pectoralis major m.
medial pectoral n.
pectoralis major & minor mm.
medial brachial cutaneous n.
skin: medial & lateral aspects of
distal arm
medial antebrachial cutaneous n.
skin: medial & lateral aspects of
forearm
lower subscapular n. (C5-C6)
subscapularis & teres major mm.
thoracodorsal n. (C6-C8)
latissimus dorsi m.
upper subscapular n. (C5-C6)
subscapularis m.
axillary n. (C5-C6) *
deltoid & teres major mm.
skin: sf deltoid & superior posterior of
arm
radial n.
triceps brachii, anconeus,
brachioradialis, & extensor muscles in
forearm.
skin: posterior arm, forearm, & hand
Posterior Division Sensory Map
from axillary n.
all others from radial n.
musculocutaneous n. (C5-7)
coracobrachialis, biceps brachii, & brachialis
mm.
median n. (C5-T1)
most flexors in forearm, radial flexor
digitorum profundus, thenar, and lumbricals
I & II mm.
skin: lateral palm
ulnar n. (C8-T1)
flexor carpi ulnaris, ulnar flexor digitorum
profundus, & most intrinsic hand mm.
skin: medial palm
Anterior Division Sensory Map
from musculocutaneous n.
medial antebrachial cutaneous n.
medial brachial cutaneous n.
median n.
ulnar n.
Rate your cognitive mastery of the brachial
plexus, please.
A.
B.
C.
D.
E.
Evaluation and/or Synthesis
Analysis
Application
Comprehension
Knowledge
C4
C3
C4
C4
C4
T1
T1
C4
C4
C4
C6
C8
T1
T2
T2
T2
T1
T2
C4
T1
C5
C4
C8
Prefixed
T2
C5
T1
C5
C5
T2
T2
Typical, with
communication
C6
T2
Postfixed
From Pellerin et al. 2010
From Pellerin et al. 2010
Source
Loukas et al. 2007
Uysal et al. 2003
Senecail et al. 1979
Lee et al. 1992
Kerr 1918
Cunningham 1877
Paterson 1896
Harman 1900
Brunelli & Brunelli
Matejcik 2005
McMinn
Bonnel 1984
Tubbs et al. 2008
n=
214
107
152
175
37
33
12
50
100
60
% Pre
26
25.5
23.8
21.7
62.85
65
48
10
41
15
% Post
4
2.5
23.9
0.66
7.42
72
33
58.33
30
2
10
4
0
From Mizuno 1966 (N.B. these studies address “race”)
From Mizuno 1966 (N.B. these studies address “race”)
diagnosing brachial plexus injury
change of motor innervations
change of dermatomes
brachial plexus anesthesia
cervical disc prolapse diagnosis
nerve compression & thoracic outlet
syndrome
C4 rhizotomy for cervical dystonia
evaluating sympathectomy outcomes
palmar hyperhidrosis
Raynaud’s
Avulsions
Ruptures
Neuropraxia
Neuromas: neoplastic or non-neoplastic
Wilhelm II, the last German Kaiser and King
of Prussia, suffered arrested development
of his left upper limb, with a medially
rotated arm and pronated forearm,
presumably as a result of a difficult breech
birth.
What is the name of this disorder, which
nerves are involved, and how are they
typically damaged?
aka “Waiter’s tip”
root avulsion of C5-C6 ventral rami, sometimes C7
affects:
suprascapular, musculocutaneous and axillary nn.
deltoid, biceps brachii, brachialis, supraspinatus &
infraspinatus mm.
commonly from: shoulder dystocia during birth, or
from a fall
DDx: What are some other possible causes
of abnormal posturing in infants?
A.
B.
C.
D.
E.
Klumpke’s palsy
cerebral palsy
fracture of the clavicle
fracture of the humerus
All of the above
In 1886, Augusta Klumpke was awarded the
Godard Prize by the Academy of Medicine
for her work on a particular type of brachial
plexus radicular palsy named in her
honor.
Which rami are affected in one who suffers
from Klumpke’s palsy, and what are the
associated effects from such damage?
root avulsion of C8-T1 ventral rami (sometimes
C7), inferior trunk or medial cord damage
“claw hand”
affects:
ulnar n.
muscles of the hand
may also produce Horner’s syndrome (miosis &
ptosis)
commonly from brachiating injuries
The incidence of Horner’s syndrome
accompanying Klumpke’s palsy may be
greater in individuals with a brachial plexus
that is:
A.
B.
C.
D.
Prefixed
Typical
Postfixed
None of the above
Benjamin Franklin once wrote of a complaint
against certain Boston distilleries, whose
product gave people “Dry Bellyach, with a Loss
of the Use of their Limbs.” Franklin also
explained how type setters, who would set
their ink to dry by proximity to fire would often
suffer the “Dangles,” a condition marked by
the flaccidity of the wrist joint.
What was the common culprit behind ‘Dry
Bellyach’ and the ‘Dangles,’ and which nerve is
likely damaged in those suffering the
‘Dangles?’
aka wrist drop
honeymoon palsy, Saturday night palsy,
handcuff neuropathy, crutch palsy
affects:
triceps brachii, anconeus, brachioradialis, &
extensor muscles in forearm.
skin: posterior arm, forearm, & hand
commonly from: pressure or compression on
arm or forearm, puncture wounds, lead
poisoning
Assuming the lesion is proximal and that a
patient recovers muscle function, which
muscle(s) innervated by the radial n. will
recover function first
A.
B.
C.
D.
E.
Triceps brachii m.
Anconeus m.
Bracialis m.
Extensor digitorum communis m.
Extensor carpi ulnari m.
Prince Philip, the Duke of Edinburgh,
presented with symptoms of paresthesia
and neuralgia to his left wrist, lateral palm,
and three lateral digits. In June of 2010, His
Royal Highness underwent corrective
outpatient surgery for these issues, and his
discomfort was alleviated.
What nerve was likely being affected, and
what is the name of this common ailment?
aka carpal tunnel syndrome
“ape-hand deformity”
affects:
most flexors in forearm, radial flexor digital
profundus, thenar, and lumbricals I & II mm.
skin: lateral palm & radial digits
commonly from: repetitive occupational injury,
or from deep penetrating wounds to the upper
limb
If the image below is a part of a diagnosis of
a long term lesion on the median nerve,
was the patient instructed to either flex all
digits, or extend all digits?
A. Flex
B. Extend
Michigan Quarterback Denard Robinson
suffered an injury to his right elbow when
tackled in the Michigan-Nebraska game.
Robinson reported having a deficit in grip
strength, and that his medial palm and
digits felt “numb and tingly.”
Which nerve has likely been damaged?
cubital tunnel and Guyon’s canal syndromes
may affect:
flexor carpi ulnaris, ulnar flexor digital profundus, &
most intrinsic hand mm.
skin: medial palm
commonly from: entrapment or blunt force
injury
Which patient’s (pictured below) ulnar nerve
lesion is likely more proximally located?
A. Patient ‘A’
B. Patient ‘B’
C. Not enough information to assess
After a cervical manipulation session with a
chiropractor, a patient experienced right
shoulder pain radiating to the neck and
upper arm. The patient reported difficulty
elevating his arm, and could not abduct his
right scapula. Several months later, the
patient experienced winging of the right
scapula.
Which nerve has likely been damaged? The
scapular winging is the result of the
paralysis of which muscle?
aka scapula alata
affects:
long thoracic n.
serratus anterior m.
commonly from: blunt trauma, repetitive
movements, or any injury to the long thoracic n.
Which direction is scapular winging most
likely?
A.
B.
C.
D.
E.
Medially
Laterally
Superiorly
Inferiorly
A & B are equally likely

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