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Flashcards in Nerves MD3 Deck (40):

Brachial Plexus

-Real Texans Drink Cold Beer

-Roots: C5 & C6, C7, C8 & T1

-Trunks: Superior, Middle, Inferior

-Divisions: Anterior (flexors), Posterior (extensors)

-Cords: Lateral, Posterior, Medial

-Branches: Musculocutaneous (lat), Median (lat & med), Ulnar (med), Axillary (post), Radial (post)

-also medial cutaneous nerve of arm & forearm (med)


Axillary nn

-branch off posterior cord of brachial plexus

-C5 & C6

-shoulder abduction & shoulder sensation

-traverses quadrangular space


Radial nn

-branches off of posterior cord of brachial plexus

-runs under brachioradialis


-extension (elbow, wrist, fingers)

sensation to back of hand (radial/lateral aspect of fingers 1-4)


Musculocutaneous nn

branch off lateral cord of brachial plexus


-elbow flexion & chief supinator

-gives rise to lateral cutaneous nerve of forearm


Median nn

branch off lateral & medial cords of brachial plexus


-wrist & digit flexion, chief pronator, hand sensation (primarily)

-motor of hand (LOAF): lumbricals 1&2, opponens pollicis, abductor pollicis brevis, flexor pollicis brevis



Ulnar nn

branch off of medial cord of brachial plexus

-C8 & T1

-hand intrinsics



Long Thoracic nn

-C5-C7 (mainly 6 & 7) roots of brachial plexus

-supplies serratus anterior


Suprascapular nn

-C5, C6 (5 mainly), branches off from superior trunk of brachial plexus

-supplies supra & infraspinatus

-passes through scapular notch under the transverse scapular ligament


Thoracodorsal nn

C6-C8 (mainly 6 & 7), branch off from posterior cord of brachial plexus

-supplies latissimus dorsi


Upper & Lower Subscapular nn

C5 & C6 (6 mainly)

-upper supplies only subscapularis

-lower supplies subscapularis & teres major



Medial cutaneous nerve of the forearm

-C8 & T1, branches off from medial cord of brachial plexus (axilla)

-supplies anteromedial skin of forearm up to wrist


Lateral Cutaneous Nerve of Forearm

from: musculocutaneous (C5, C6)

supplies skin of dorsolateral forearm


Recurrent Median nn

from: median nn

supplies the thenar muscles


Common Palmar Digital nn

from median nn (x 3) and ulnar nn (x 1)

supply lumbricals on adjacent sides of digits 2-4



Proper Digital nn

branches off of common palmar digital nn,

runs on both sides of phalanges, supplies skin of distal phalanges?


Dorsal Digital nn

from radial nn, and some ulnar nn

supplies skin on dorsal surface of proximal & middle phalanges


Superficial & Deep Ulnar nn

from ulnar nn

deep supplies hypothenar, all interossei, lumbricals 4 & 5

superficial supplies palmaris brevis, skin on ulnar side of hand


Interosseus nn

anterior (median nn) innervates deep muscles of anterior forearm (FDP, PQ, FPL)

posterior (radial nn ) innervates all muscles of posterior forearm


Superficial branch of radial nn

supplies skin on the dorsolateral hand up to the proximal digits and proximolateral 4th digit


Superficial Cluneal/Gluteal nn.

Superior & Middle: off of lateral branches of posterior rami (L1-S3)

Inferior: off of posterior cutaneous nn of thigh

-all innervate skin of buttocks (superior = superior buttock, middle = sacrum, inferior = inferior buttock)


Superior Gluteal nn. (7)

branch off of sacral plexus

runs b/w glute medius & minimus, w/ superior gluteal aa.

superior branch supplies glute med, inferior branch supplies glute med, min, & TFL


Inferior Gluteal nn.

branch off of sacral plexus

-superficial to sciatic nn., deep to glute max

-supplies glute max

-travels w/ inferior gluteal aa & vv.


Sciatic nn.

off of sacral plexus

-has own arterial supply (branch off inferior gluteal aa)

-supplies all muscles of posterior thigh via tibial branch, except short head of biceps femoris (common peroneal branch)

-supplies all muscles of leg & foot, most skin of leg & foot, joints of lower limb

-splits into tibial & common peroneal nn.


nn to quadratus femoris

-off of sacral plexus, anterior to sciatic nn & obturator internus, posterior to hip joint

-supplies hip joint, inferior gemellus, quadratus femoris


nn to Obturator Internus

branch off sacral plexus (anterior division of anterior rami), runs parallel course to pudendal nn.

-supplies superior gemellus, obturator internus


Pudendal nn. (2)

-branch off of sacral plexus, exits greater sciatic foramen, wraps around sacrospinous ligament, enters back in via lesser sciatic foramen

-suppies perineum

-most medial structure to pass thru GSF


Posterior Cutaneous nn of Thigh

-supplies skin of inferior buttocks, posterior thigh, popliteal fossa, upper medial thigh, lateral perineum

-branch off sacral plexus, exits GSF deep to glute max & inferior to piriformis, descends posterior thigh beneath fascia lata


Deep Peroneal nn.

-branch off common peroneal, runs anteriorly w/ anterior tibial aa.

-runs through extensor digitorum longus

lesion-> drop foot (no dorsiflexion)


Superficial Peroneal nn.

branch off common peroneal, lateral side of leg, continues to supply skin of dorsal foot


Tibial nn.

larger branch off sciatic nn.

runs b/w heads of gastroc (supplies posterior leg), runs w/ popliteal aa., runs b/w flexor hallucis longus & flexor digitorum longus near ankle

-splits into medial & lateral plantar nn in bottom of foot



Saphenous nn.

largest/longest branch of femoral nn.

passes anterior to medial malleolus

supplies cutaneous innervation to medial lower leg & medial foot


Superficial Peroneal nn.

branch off common peroneal nn.

supplies motor innervation to lateral leg, cutaneous innervation to most of dorsum of foot & anterolateral leg


-ALPs in the DiSTance

anterior compartment of leg: deep peroneal nn

lateral: superficial peroneal nn

posterior: tibial nn


Deep Peroneal nn.

branch off of common peroneal nn.

supplies motor to anterior leg, all extensors

supplies cutaneous innervation to webbing b/w 1st and 2nd toes



Medial Plantar nn.

branch off of tibial nn., larger than lateral, analogous to median nn in hand

supplies motor to Abductor hallucis, FDB, FHB, lumbrical #1

supplies cutaneous innervation to medial 3.5 digits of sole of foot

-more skin, less muscle



Lateral Plantar nn.

branch off of tibial nn.

deep to abductor hallucis, analogous to ulnar nn in hand

more muscle, less skin

supplies motor to all muscles in sole of foot except those by medial plantar nn (1st lumbrical, abductor hallucis, FDB, FHB)

supplies cutaneous innervation to lateral 1.5 digits



Lower extremity myotomes

L2-> S2

(joint movements toward inspector down leg, then back up leg away)

L2: hip flexion

L3: knee extension

L4: dorsiflexion

L5: great toe extension

S1: plantar flexion/eversion

S2: knee flexion


Patellar DTR (L4), Achilles DTR (S1)


Nerves near Hip Joint

Lumbar Plexus


-quadriceps femoris, iliopsoas, pectineus, sartorius


-adductors (magnus, longus, brevis), gracilis, pectineus, obturator externus


Sacral Plexus

nn to quadratus femoris

-inferior gemellus, quadratus femoris

nn to obturator internus

-obturator internus, superior gemellus

superior gluteal

-glute min & medius, tensor fascia latae

inferior gluteal

-glute max


Nerves near knee joint

Sciatic nn from lumbar & sacral plexus

splits into common peroneal & tibial nn @ apex of popliteal fossa

-common peroneal wraps around lateral fibular neck, susceptible to injury (superficial), gives rise to lateral sural cutaneous (skin posterolateral leg)

-splits into superficial (lateral leg: peroneus longus & brevis) & deep peroneal (anterior leg: tom dick & harry, dorsal foot) nn.

-tibial nn supplies muscles of back of leg (popliteus too) & plantar foot


Overview of lower extremity nn

Femoral nn (anterior thigh (quads, pectineus, iliopsoas, sartorius) -> saphenuos nn


Sciatic nn-> common peroneal (superficial & deep peroneal) & tibial (lateral & medial plantar)



Lower extremity dermatomes