Canine Lumbosacral Plexus And Pelvic Limb Nerves

Question 1

What three nerves innervate the abdominal wall?

Answer 1

Costoabdominal n, cranial iliohypogastric n, caudal iliohypogastric n

Question 2

What two components make up the lumbosacral plexus and what are their corresponding vertebra?

Answer 2

Lumbar component L3-L6
Sacral component S1-S3

Question 3

What are intercostal nerves?

Answer 3

Intercostal nerves are the ventral branches of thoracic spinal nerves 1-12

Question 4

What structures do intercostal nerves provide motor function for?

Answer 4

External and internal intercostal mm, transversus thoracis m, and rectus abdominis m

Question 5

What provides the cutaneous sensory innervation from intercostal n?

Answer 5

Lateral cutaneous branch and ventral cutaneous branch

Question 6

True or False: the nerves that innervate the abdominal wall all provide sensory and motor function.

Answer 6

True

Question 7

What makes up the lumbosacral plexus?

Answer 7

Ventral branches of lumbar and sacral spinal nerves

Question 8

The genitofemoral nerve is motor to what structure?

Answer 8

Cremaster muscle

Question 9

The genitofemoral nerve is sensory for what?

Answer 9

From skin in inguinal region (inguinal mammary gland, prepuce) and proximal medial thigh

Question 10

The genitofemoral nerve is formed by ventral branches of which vertebra spinal nerves?

Answer 10

L3 and L4

Question 11

True or False: the genitofemoral nerves supplies motor function only in males.

Answer 11

True

Question 12

The obturator nerve innervates adductors of pelvic limb, which includes what structures?

Answer 12

External obturator muscle, pectineus muscle, gracilis muscle, adductor muscle

Question 13

The obturator nerve arises from which spinal nerves?

Answer 13

L4, L5, L6

Question 14

The obturator nerves supplies what function?

Answer 14

Motor

Question 15

The femoral nerve arises from which spinal nerves?

Answer 15

L4, L5, L6

Question 16

The femoral nerve emerges from what structure?

Answer 16

Iliopsoas muscle

Question 17

What structures does the femoral nerve innervate and provide motor function?

Answer 17

Iliopsoas muscle, quadriceps femoris muscle, sartorius muscle

Question 18

The femoral nerve gives rise to what other nerve and what is its function?

Answer 18

Saphenous nerve
Cutaneous innervation to skin of medial femoral, genual, tibial and pes regions

Question 19

Describe the afferent input, central connection, and efferent output of the patellar reflex.

Answer 19

Afferent input: the sensory receptor in the quadriceps muscle sends a signal along the afferent neuron to the spinal cord
Central connection: the signal synapses at the level of L3 and L4 in the spinal cord
Efferent output: an alpha motor neuron conducts efferent impulse back to the quadriceps femoris muscle, triggering contraction. Contraction causes the leg to kick.

Question 20

The caudal cutaneous femoral nerve arises from which spinal nerves?

Answer 20

S1, S2, S3

Question 21

The caudal cutaneous femoral nerve terminates where?

Answer 21

In skin on proximal caudal half of thigh

Question 22

The caudal cutaneous femoral nerve follows the caudal gluteal artery to the level of what?

Answer 22

Ischiatic tuberosity

Question 23

The lumbosacral trunk gives rise to what nerves?

Answer 23

Caudal gluteal nerve, cranial gluteal nerve, sciatic nerve (ischiatic nerve)

Question 24

The lumbosacral trunk is formed by the ventral branches of?

Answer 24

L6, L7, S1, S2

Question 25

The caudal gluteal nerve provides motor function to what structure?

Answer 25

Superficial gluteal muscle

Question 26

The cranial gluteal nerve provides motor function to what structures?

Answer 26

Middle gluteal muscle, piriformis muscle, deep gluteal muscle, tensor fasciae latae muscle

Question 27

The efferent sciatic nerve innervates what structures within the pelvis?

Answer 27

Internal obturator muscle, gemelli muscle, quadratus femoris muscle

Question 28

The efferent sciatic nerve innervates what structures caudal to the hip?

Answer 28

Biceps femoris muscle, semimembranosus muscle, semitendinosus muscle

Question 29

Describe the path of the sciatic nerve.

Answer 29

Courses over greater ischiatic notch, dorsal and caudal to the coxal joint

Question 30

What nerves arise from the fibular and tibial components of sciatic nerve to supply cutaneous innervation to lateral and caudal surfaces of crus?

Answer 30

Lateral and caudal cutaneous sural nerves

Question 31

Proximal to the stifle, the sciatic nerve divides into?

Answer 31

Common fibular (peroneal) nerve and tibial nerve

Question 32

The common fibular (peroneal) nerve innervates?

Answer 32

Flexors of the tarsal joint and extensors of the digit

Question 33

The tibial nerve innervates?

Answer 33

Extensors of the tarsal joint and flexors of the digit

Question 34

The common fibular nerve divides into?

Answer 34

Deep and superficial peroneal (fibular) nerves

Question 35

The deep fibular nerve innervates?

Answer 35

Cranial tibial muscle, long digital extensor muscle, peroneus longus muscle

Question 36

The deep fibular nerve courses distally with what vessel?

Answer 36

Cranial tibial artery

Question 37

The superficial fibular nerve innervates?

Answer 37

Lateral digital extensor muscle and peroneus brevis muscle

Question 38

The tibial nerve arises from what spinal nerves?

Answer 38

L7, S1

Question 39

The tibial nerve innervates?

Answer 39

Gastrocnemius muscle, superficial digital flexor muscle, deep digital flexor muscle, popliteus muscle

Question 40

The tibial nerve divides into what sensory nerves?

Answer 40

Medial and lateral plantar nerves

Question 41

The medial and lateral plantar nerves are sensory to?

Answer 41

Plantar surface of pes

Question 42

What is/are the most probable muscle(s) affected (paralysis) in a total laceration of the tibial nerve at the level of the popliteal fossa?

Answer 42

Gastrocnemius, plantaris, popliteus, and soleus in cats

Question 43

What is the cutaneous region with hypoesthesia or numbness, in a dog with the common fibular nerve sectioned?

Answer 43

Digit 2, 3, 4, and 5 then up the dorsal side of the tarsocrural joint

Question 44

What are clunial nerves in the lumbar component of the lumbosacral plexus?

Answer 44

Dorsal cutaneous branches from the last four lumbar nerves that innervate the skin in the gluteal area

Question 45

What are clunial nerves in the sacral component of the lumbosacral plexus?

Answer 45

Dorsal cutaneous branches from the sacral nerves that innervate the skin in the gluteal and dorsal areas of the pelvis

Question 46

The pudendal nerve includes what nerve branches?

Answer 46

Dorsal rectal nerve, perineal nerve, dorsal nerve of the penis/nerve of the clitoris

Question 47

Where is the most caudal end of the conus medullaris located in dogs and cats?

Answer 47

Located at the level of the caudal half of the L6 vertebra and the cranial part of the L7 vertebra Can also be found at L7-S1 in cats depending on the individual

Question 48

The pelvic nerve is from what spinal nerves?

Answer 48

S1, S2

Question 49

The pelvic nerve fibers run into what structures before getting distributed to its target organs?

Answer 49

Pelvic plexus

Question 50

The pelvic plexus lives lateral to what?

Answer 50

Rectum