The Brachial plexus

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The Brachial plexus
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The Brachial plexus
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The Brachial plexus

• The brachial plexus is formed by the union of the
  anterior rami of C5-C8 T1 (the roots of the
  BP).
• The roots pass laterally between the anterior and
  middle scalene muscles with the subclavian
  artery.
• Sympathetic fibers from the middle and inferior
  cervical ganglia join the roots as they pass
  between the scalenes.

• Fig 6.29 p 775

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• Fig 6.28 p 774

• In the supraclavicular area the roots unite to
  form trunks
• Superior trunk C5 C6
• Middle trunk C7 continues
• Inferior trunk C8 T1

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• Fig 6.28 p 774

• As the trunks pass lateral to the 1st rib each
  trunk splits into anterior and posterior
  divisions as they pass beneath the clavicle and
  enter the cervicoaxillary canal
• Anterior divisions innervate the muscles of the
  anterior compartment in the arm and forearm.
• Posterior divisions innervate muscles of the
  posterior compartment of the arm and forearm

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• Fig 2.08 p 21 Grants Dissector 13th Ed., Patrick
  Tank

• Divisions form cords in the area superior to the
  pectoral minor
• Superior middle anterior divisions unite the
  from the lateral cord
• Inferior division of the inferior trunk forms
  the medial cord
• Posterior divisions unite to form the posterior
  cord.

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• Fig 6.28 p 774

• To simplify understanding and remembering the BP
  in can be divided into supraclavicular
  infraclavicular segments by the clavicle

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Supraclavicular branches

• There are four, they arise from roots, a trunk
  and a division
• Root branches
• Dorasl scapular nervepierces middle scalene and
  passes inferiorly to the rhomboids
• Long thoracic nerve from C5,6,7 roots passes
  inferiorly on to the surface of the Serratus
  anterior
• Trunk branch
• Nerve to subclavius passes directly to the
  inferior surface of clavicle gives branch to
  sternoclavicular joint
• Division branch
• Suprascapular nerve runs parallel to the
  suprascapular artery to the suprascapular notch
  (beneath the suprascapular ligament) supplies the
  supraspinatus m. around the greater scapular
  notch to the infraspinatus m.
• Small braches arise from all roots to supply the
  scalene and longus coli muscles.
• C5 gives a root to the Phrenic nerve (C3-5)

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Supraclavicular branches

• Fig 6.29 p 775

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• Fig 6.28 p 774

• Infraclavicular Branches - -arise from the cords
  and can be divided into branches and little
  branches (very unscientific).

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Infraclavicular Branches

• ? The lateral medial braches join to form the
  Median nerve

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• Fig 6.31 p 785

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Fig 2.09 p 21, Grants Dissector 13th Ed.,
Patrick Tank
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Fig. 6.31, p 785
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Brachial Plexus Root Injuries

• Upper brachial plexus injury
• Erb-Duchenne Palsy
• C5C6 root injury, caused by stretch between the
  head and shoulder, shoulder stops head/neck
  dont.
• Waiters tip deformity- arm adducted, medially
  rotated and pronated. Why?
• Sensory loss where?
• Major cause is obstetric injury ()

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Brachial Plexus Injuries

• Lower brachial plexus injury
• Klumpke palsy
• C7,C8T1 injury
• Arm abduction injury
• Paralysis of the muscles of the distal forearm
  and hand (all ulnar innervated) plus distal
  radial median innervated muscles.
• Horner's syndrome (ptosis,meiosis, anhydrosis) if
  T1 sympathetics involved.

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Brachial Plexus Variations

• Brachial Plexus Variations in Human Fetuses.
  ANATOMIC REPORTS
• Neurosurgery. 53(3)676-684, September
  2003.Uysal, Ismihan Ilknur M.D. Seker, Muzaffer
  Ph.D. Karabulut, Ahmet Kagan M.D., Ph.D.
  Buyukmumcu, Mustafa Ph.D. Ziylan, Taner Ph.D.
• This study was performed with 200 BPs from
  spontaneously aborted fetuses without detectable
  malformations. The BPs were composed mostly of
  the C5, C6, C7, and C8 nerves and the T1 nerve
  (71.5). A prefixed plexus was observed in 25.5
  of cases, and a postfixed plexus was observed in
  2.5 of cases.
• Another study BPs noted phrenic nerve formation
  by C5,67 in 20 of specimens

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BP Anomalies
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Brachial Plexus

• Really cool procedure, do the same in lab!

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End