Nerves MD3 Flashcards
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
- C5-T1
- 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
- C5-C6
- elbow flexion & chief supinator
- gives rise to lateral cutaneous nerve of forearm
Median nn
branch off lateral & medial cords of brachial plexus
- C5-T1
- 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
(2)
-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
(3)
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
(4)
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
(5)
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
Femoral
-quadriceps femoris, iliopsoas, pectineus, sartorius
Obturator
-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
-anterior
Sciatic nn-> common peroneal (superficial & deep peroneal) & tibial (lateral & medial plantar)
-posterior
Lower extremity dermatomes
