Lumbosacral Plexus

Front 1

Which spinal nerves make up the Lumbosacral Plexus?

Back 1

Ventral Branches of L1-S3

Front 2

Ventral branch of L4 Serves a a common trunk for (4):

Back 2

-Lateral Cutaneous Femoral n.
-Genitofemoral n.
-Femoral n.
-Obturator n.

Front 3

Ventral branch of L5 Serves as a common trunk for (2):

Back 3

-Femoral n.
-Obturator n.

Front 4

Ventral branch of L6 Serves as a common trunk for (3):

Back 4

-Femoral n.
-Obturator n.
-Sciatic n.

Front 5

Ventral branch of L7 Serves as a common trunk for (3):

Back 5

-Caudal Gluteal n.
-Cranial Gluteal n.
-Sciatic n.

Front 6

Ventral branches of S1-S3 serve as a common trunk for:

Back 6

-Pudendal n.
(-Sciatic n., S1-S2)

Front 7

LUMBOSACRAL PLEXUS
-Major Nerves (7):

Back 7

-Obturator n.
-Femoral n.
-Pudendal n.
-Caudal Cutaneous Femoral n.
Lumbosacral Trunk:
-Caudal Gluteal n.
-Cranial Gluteal n.
-Sciatic n.

Front 8

OBTURATOR N.
-Origin:
-Course:

Back 8

-L4, L5,L6
-Leaves Iliopsoas m. dorsomedially, runs caudoventrally along Ilium, penetrates the medial side of Levator ani m., and leaves the penis by passing thru the obturator foramen.

Front 9

OBTURATOR N.
-Muscle Group Innervated:
-Damage:

Back 9

-Medial Thigh mm.
(Adductors of Pelvic Limb)
-Inability to adduct Limb

Front 10

OBTURATOR N.
-Where to Find it:
-Arborizes with:

Back 10

-Emerges ventrally from the obturator foramen and arborizes in the adductor mm. with the branches of Medial Circumflex femoral a.

Front 11

FEMORAL N.
-Origin:
-Course:
-Branches:

Back 11

-L5, L5, L6
-With Lateral Circumflex Femoral a.
-Saphenous n. branches Cranially within Iliopsoas m.

Front 12

FEMORAL N.
-Muscle Group Innervated:
-Damage:

Back 12

-Cranial Thigh Muscles
(Extensors of stifle joint)
-i. Inability to extend stifle joint
-ii. Decreased ability to flex hip joint
-iii. Can NOT bear weight!

Front 13

SAPHENOUS N.
-Origin:
-Innervates:

Back 13

-Femoral n.
-Sartorius m.
Skin on MEDIAL side of:
-Thigh
-Stifle
-Leg
-Tarsus
-Remainter of pes

Front 14

PUDENDAL N.
-Origin:
-Course:

Back 14

-S1, S2, S3
-passes caudolaterally, lies lateral to Levator ani& Coccygeus mm, Medial to Superficial Gluteal m. & Dorsal to Internal Pudendal vessels.
-It appears superficially in the ischiorectal fossa after emerging from the medial side of the superficial gluteal m. and courses caudomedially toward the pelvic symphysis at the ischial arch.

Front 15

PUDENDAL N.
-Branches (3):

Back 15

i. Caudal Rectal n.
ii. Perenial nn.
iii. Dorsal n. of Penis

Front 16

CAUDAL RECTAL N.
-Origin:
-Innervates:

Back 16

-Pudendal n. at caudal border of Levator ani m.
-External Anal Sphincter

Front 17

PERINEAL NN.
-Origin:
-Innervates:

Back 17

-Dorsal surface of Pudendal n.
-Skin of:
-Anus
-Perineum
-Scrotum/Labium
-mm. of Penis/Vestibule & Vulva

Front 18

DORSAL N. OF PENIS/CLITORIS
-Origin:
-Innervates:

Back 18

-Pudendal n.
-Glans penis/Clitoris

Front 19

CAUDAL CUTANEOUS FEMORAL N.
-Origin:
-Innervates

Back 19

-Sacral Plexus united to Pudendal n.
-Skin of proximal caudal half of thigh

Front 20

LUMBOSACRAL TRUNK
-Origin:
-Branches:

Back 20

-L6, L7, S1, S2 adjacent to greater ischiatic notch
-i. Caudal Gluteal n.
-ii. Cranial Gluteal n.
-iii. Sciatic n.

Front 21

CAUDAL GLUTEAL N.
-Origin:
-Course:
-Innervates:
-Damage:

Back 21

-L7, S1, S2
-Over ischiatic notch medial to middle gluteal m. enters medial surface and is sole innervation to Superficial Gluteal m.
-None seen clinically

Front 22

CRANIAL GLUTEAL N.
-Origin:
-Course:
-Innervates:
-Damage:

Back 22

-L6, L7, S1, S2
-Passes over greater ischiatic notch, crosses lateral surface of ilium at orgin of deep gluteal m.
-Middle & Deep Gluteal mm. & TFL m.
-i. Sig. atrophy of rump mm.
-ii. Decreased ability to extend hip joint

Front 23

SCIATIC N.
-Origin:
-Innervates:
-Branches:

Back 23

-L6, L7, T1, T2
-i. Caudal Thigh mm. Prior to branching
-ii. Craniolateral mm. of Crus
-Common Peroneal n.
-iii. Caudal mm. of Crus
-Tibial n.

Front 24

SCIATIC N.
-Damage:
i. At Level of Hip Joint

Back 24

i.
1.Reduced ability to extend hip joint
2. Inability to flex stifle jt.
3. Inability to flex or extend tarsal and digital jts
4. Animal can NOT bear weight

Front 25

SCIATIC N.
-Damage:
ii. Prior to branching but after innervation to caudal thigh:

Back 25

ii.
1. Inability to flex or extend tarsal and digital joints

Front 26

SCIATIC N.
-Damage:
iii. to just Common Peroneal nerve:

Back 26

iii.
1. Inability to flex tarsal jts
2. Inability to extend digital jts

Front 27

SCIATIC N.
-Damage:
iv. to just Tibial n.:

Back 27

iv.
1.Inability to extend tarsal jts
2. Inability to flex digital jts
3. walks more plantargrade

Front 28

FEMORAL N.
-Autonomous zone:

Back 28

(via Saphenous n.)
a. Medial limb, from mid-thigh to mid-pes

Front 29

SCIATIC N.
-Autonomous zone:

Back 29

a. Caudolateral Crus & Caudolateral Distal Thigh
b. Craniolateral Distal Crus & Dorsal Pes ->via Common Peroneal n.
c. Plantar Pes-> via Tibial n.

Front 30

GENITOFEMORAL N.
-Autonomous zone:

Back 30

a. Inguinal region
(medial mid-thigh to ventral midline)

Front 31

CAUDAL CUTANEOUS FEMORAL N.
-Autonomous zone:

Back 31

-Caudolateral Proximal Thigh

Front 32

PUDENDAL N.
-Autonomous zone:

Back 32

-Perineal region