Lumbosacral Plexus

Question 1

lower limbs

function

Answer 1

support body weight
locomotion
maintain balance

extend from the trunk

Question 2

gluteal region

Answer 2

transition b/t trunk and free lower limb

buttocks + hip region

Question 3

leg region

aka crus

Answer 3

b/t knee and ankle

‘leg’ NOT THE SAME as lower limb

Question 4

hip major movements

Answer 4

ball and socket joint

-flex/extend
-adduct/abduct
-medial/lateral rotate
-circumduct (just a combo of other moves)

Question 5

knee movements

Answer 5

hinge joint
flex/extend

Question 6

ankle movements

Answer 6

hinge joint
-plantarflex (point foot)
-dorsiflex (flex foot)

Question 7

if muscle crosses joint

then what

Answer 7

it will move that joint BC
by definition crossing means it will have an origin proximal and insertion distal

werning rule

Question 8

fascile direction

Werning rule

Answer 8

muscle will shorten/contract in direction of long axis fascicles

insertion is pulled TOWARD origin = move joint so action

if fascicles go 1+ direction then more than 1 action

Question 9

origin/insertion in limb muscles

Werning rule

Answer 9

origin will be more medial than the insertion

except it limb-trunk muscle and spine/neck muscles then origin inferior to insertion

Question 10

naming

Werning rule

Answer 10

if named for origin and insertion then origin is ALWAYS first

otherwise named for shape or action

Question 11

how to injure a joint

Answer 11

1. move in wrong direction
2. move too far in right direction
3. disconnect the bones via torn ligaments or break bones

Question 12

how to injure muscle that moves joint

Answer 12

1. trauma so injure muscle tissue directly
2. disconnect muscle from bones via torn ligaments or break bones
3. cut off blood supply
4. paralyze via injure nerve supply

Question 13

parts of lumbosacral plexus

Answer 13

1. lumbar (T12-S4) deep to psoas
2. sacral (L4-S4) superficial to piriformis
3. coccygeal (S4-Co1)

overlap at L4 of lumbosacral trunk

Question 14

LSP function

Answer 14

1. provide motor and cutaneous innervatino to lower limb
2. carry postganglionic symp fibers that regulate vasoactivity of lower limb vessels

Question 15

blood supply of LSP

Answer 15

from internal iliac and it’s branches
-lateral sacral, iliolumbar, superior gluteal

makes lumbar plexus resistant to ischemia bc roots run through psoas major so very well vascularized

Question 16

anterior divisons actions

Answer 16

flexion and abduction

Question 17

posterior division actions

Answer 17

extension and adduction

Question 18

roots of LSP

Answer 18

ventral primary rami of T12-S4

ignoring coccygeal

Question 19

divisions of LSP

Answer 19

T12-L1 no divisions
L2-S4 each have anterior and posterior

Question 20

pre-torsion embryology

Answer 20

dorsal mass inn by posterior divisions > extensor and abductor muscles

ventral mass inn by anterior divisions > flexor and adduction muscles

Question 21

post-torsion divisions

Answer 21

posterior divisions + extensor muscles are ANTERIOR

anterior divisions + flexor muscles on POSTERIOR side of adult free lower limb

Question 22

big 4 motor nerves

Answer 22

1.femoral (post divs of L24)
2.obturator (ant divs of L2-4)
————–
3.common fibular/peroneal (post divs L4-S2)
4.tibial (ant divs L4-S3)
*will run together in gluteal and posterior thigh regions as sciatic N

Question 23

superficial thigh inn

superior to F/O N

Answer 23

lateral femoral cutaneous N
(post divs L2-L3)

up one from F/O

Question 24

inguinal region inn

superior to F/O N

Answer 24

1. iliolinguinal L1
2. genitofemoral (L1-L2)

up two from F/O

no divisions

Question 25

body wall inn | superior to F/O N

Answer 25

1. subcostal T12 2. iliohypogastric L1 up 3 from F/O

Question 26

between F/O and T/CF

Answer 26

gluteal nerves 1. superior gluteal (post divs L4-S1) 2. inferior gluteal (post divs L5-S2)

Question 27

superficial thigh inn | inferior to T/CF

Answer 27

1. posterior femoral cutaneous (ant and post divs of S1-3)

Question 28

perineum inn | inferior to T/CF

Answer 28

pudendal (ant divs of S2-4)

Question 29

pelvis inn | inferior to T/CF

Answer 29

nerves of coccygeal plexus

Question 30

LSP symmetry pattern

Answer 30

1. nerve to perineum 2. a femoral cutaneous N 3. 2 big motor nerves (both sides post + ant) 4. a gluteal N (both sides post) repeat 4-1 inferiorly

Question 31

smaller branches of LSP

Answer 31

1. direct to psoas major (L1-3 ventral rami) 2. N to quadratus femoris (ant div L4-S1) 3. N to obturator internus (ant div L5-S2) 4. N to piriformis (post div S1-2)

Question 32

pelvic outlet route

Answer 32

for digestive, urinary, most reprod organs

Question 33

over pelvic rim/inguinal lig route

Answer 33

for few LSP nerves and spermatic cord

Question 34

spaces route

Answer 34

for arteries, veins, lymphatics, most LSP nerves aka obturator foramen/canal, sciatic foramina, and retroinguinal spaces

Question 35

paired sacral foramina route

Answer 35

for dorsal rami of sacral spinal nerves and branches of lateral sacral A

Question 36

superior to pelvic rim/inguinal ligament | nerves

Answer 36

1. subcostal T12 2. iliohypogastric L1 lateral and anterior body wall

Question 37

inguinal canal | nerves

Answer 37

1. ilioinguinal L1 2. genital branch genitofemoral L1-2 anterior body wall and perineum

Question 38

retroinguinal space | nerves

Answer 38

superior space:lateral and anterior thigh 1. lateral femoral cut. L2-3 2. femoral N L2-4 inferior space: anterior thigh 1. femoral of genitofemoral L1-2

Question 39

obturator canal | nerves

Answer 39

1. obturator N L2-4 medial thigh

Question 40

greater sciatic foramen- above piriformis | nerves

Answer 40

1. superior gluteal L4-S1 gluteal region

Question 41

greater sciatic foramen below piriformis | nerves

Answer 41

1. inferior gluteal L5-S2 gluteal region 2. sciatic N with common fibular (L4-S2) + tibial (L4-S3) posterior thigh + leg + foot 3. posterior femoral cut. S1-S3 posterior thigh 4. pudendal S2-4 as exits pelvis

Question 42

lesser sciatic foramen | nerves

Answer 42

1. pudendal S2-4 as enter the perineum

Question 43

obturator N

Answer 43

ANT DIV-exits pelvis anteromedially hip adductors -og on pubis medial compartment thigh

Question 44

femoral N

Answer 44

POST DIV-exit pelvis anterolateral hip flexors and knee extensors -og from ant surfaces of ilium or femur anterior compartment thigh

Question 45

tibial N

Answer 45

ANT DIV-exit pelvis posteromedial knee flexors and lateral hip rotators -og from ischium -posterior thigh compartment or deep gluteal OR knee flexor, ankle plantarflexor, foot everters, toe flexor -posterior and lateral leg and plantar foot compartments

Question 46

common fibular and gluteal N

Answer 46

POST DIV- exit posterolateral hip extensors, hip abductors, hip medial rotators -og from posterior and lateral surfaces of ilium -superficial gluteal region and lateral hip OR ankle dorsiflexors, foot inverters, toe extensors -anterior leg and dorsal foot regions

Question 47

upper root plexopathies

Answer 47

reflect femoral and obturator N symptoms

Question 48

lower root plexopathies

Answer 48

reflect common fibular/gluteal and tibial/lateral rotator symptoms