Brachial Plexus & Lumbosacral Plexus Flashcards
Brachial plexus is formed in the
Posterior triangle of the neck
Brachial plexus is the union of the
Anterior rami of the
5,6,7,8th cervical spinal nerves
1st thoracic spinal nerves
Upper trunk Union of the roots ___
C5 & C6
Middle trunk continuation of the roots ___
C7
Lower trunk Union of the roots ___
C8 & T1
From the 3 posterior divisions of the 3 trunks
Posterior cord
From the anterior divisions of the upper and middle trunks
Lateral cord
the continuation of the anterior division of the lower trunk
Medial cord
C5,C6,C7 branches
Long thoracic nerve
C5 branches
Dorsal scapular nerve
Upper trunk branch
Suprascapular nerve
Supplies supraspinatus & infraspinatus
Suprascapular nerve (upper trunk branch)
Upper trunk gives of the nerve to
Subclavius
Lateral cord gives rise to
Lateral Pectoral nerve
Lateral root of median nerve
Musculocutanous nerve
Posterior cord gives rise to
Upper subscapular nerve
Lower subscapular nerve
Thoracodorsal nerve
Radial nerve
Axillary nerve
Brachial plexus injury (upper trunk)
Erb-Duchenne palsy “waiter’s tip position”
Brachial plexus injury (lower trunk)
Klumpke palsy
Lumbar plexus formation
By ventral rami of L1,2,3 and most of L4
Lumbar plexus site
In the substance of posas major
Lumbar plexus main branches to anterior abdominal wall
iliohypogastric & ilioingyinal
Lumbar plexus main branches to median compartment of thigh
Obturator
Lumbar plexus main branches to anterior compartment of thigh
Femoral
Femoral nerve origin
Branch of lumbar plexus (L2,3,4)
Descends lateral to psoas major & enters the thigh behind the inguinal ligament
Femoral nerve
Passes lateral to femoral artery & divides into terminal branches
Femoral nerve
Femoral nerve injury (motor effect)
Wasting of quadriceps femoris
Loss of extension of knee
Sacral plexus formation
By ventral rami of a part of L4 & whole L5 (lumbosacral trunk) + S1, 2, 3 and most of the S4
Sacral plexus site
In front of piriformis muscle
Sacral plexus main branches (parasympathetic to pelvic viscera & hindgut)
Pelvic splanchnic nerve
Pudendalnerve (from sacral plexus) branches to
perineum
Sciatic nerve (from Lumbosacralplexus: L4&5+S1,2,3) branches to
lower limb
Sciatic nerve origin
From sacral plexus
Leaves the pelvis through greater sciatic foramen, then to posterior of thigh compartment
Sciatic nerve
Divides into tibial & common peroneal (fibular) nerves
Sciatic nerve
Descends through popliteal fossa to posterior compartment of leg, accompanied with posterior tibial vessels
Tibial nerve
Leaves popliteal fossa & turns around the lateral aspect of neck of fibula
Common peroneal (fibular) nerve
Common peroneal (fibular) nerve Leaves popliteal fossa & turns around the lateral aspect of neck of fibula. Then divides into :
Superficial peroneal: descends into lateral compartment of leg
Deep peroneal : descends into anterior compartment of leg