Brachial plexus

Brachial plexus

1. What are plexus

   • The innervation of limbs is via plexuses (a branching network of nerves). Plexus take your spinal nerves and mix them up so by the time you reach
     • The major nerve plexus are:
       • Brachial
         • For the upper limb
       • Lumbosacral
         • For the lower limb

2. Arises from the

   • Ventral rami (anterior division of the spinal nerve) of spines arising from C5-T1

3. Parts of the plexus (in order starting from their exit from spinal cord)

   • 1. Roots
     • Emerge from
       • Scalenus anterior and scalenus medius
         • = muscles running down sides of neck
   • 2. Trunks
     • Form the anterior and posterior divisions
     • Location:
       • Lie in the lower part of the posterior traingle of the neck (roots and trunks form the supraclavicular part of the plexus)
   • 3. Divisions
     • Anterior division supplies the
       • Flexor compartment
     • Posterior compartment supplies the
       • Extensor compartment
     • Location:
       • Lie behind the clavicle
   • 4. Cords
     • Named with respect to their spatial relationship with the axillary artery: medial, lateral and posterior
     • Location:
       • Formed at the outer border of the first rib and enter the aoex of the axilla together with the axillary artery and vein (cords and their branches for the infraclavicular part of the plexus)
   • 5. Terminal branches
     • What are the names of the terminal nerves and where do they arise from
       • Ulnar and medial head of the medial nerve from the medial cord
       • Musculotaneous and lateral head of the median nerve from the lateral cord
       • Axillary and radial from the posterior cord
     • Where do they go/what are they
       • Mixed sensory and motor nerves supplying the skin and muscles of the upper limb. Other motor or sensory branches from the roots, trunks and cord of the plexus also supply specific muscles of the lumb girld or skin (look at pop up)
         • Note: -dermatome = area of skin supplied by a particular spinal nerve. may be supplied by several cutaneous nerves, the distribution of which may nto be confined to that dermatome -[arastejesoa and pain my indicate specfic dermatome/spinal involvement

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