Nerves and vessels

Question 1

What muscles does the obturator nerve supply?

Answer 1

Gracilis, Adductor, Pectineus (GAP), external obturator

Question 2

What action is compromised if the obturator nerve is injured? What does the leg do?

Answer 2

Adduction of the limb because all muscles of the GAP have been compromised; the leg will slide outwards when bearing weight.

Question 3

What sensation is lost when the obturator nerve is injured?

Answer 3

None, the obturator is only responsible for motor innervation.

Question 4

What muscles does the femoral nerve supply?

Answer 4

Sartorius, iliopsoas, quadriceps (HINT: it’s a SIQ/sick muscle because when damaged the animal is unable to bear weight due to inability to extend stifle)

Question 5

Is any sensory innervation lost when the femoral nerve is injured?

Answer 5

Yes, everything sensory to saphenous nerve (medial thigh, crus, pes)

Question 6

Which muscle does the saphenous nerve supply? If the nerve was damaged, could the animal bear weight?

Answer 6

Sartorius; the animal would be able to bear weight because the action of the sartorius (flex hip, flex/extend stifle) would not be completely compromised

Question 7

Is any sensory innervation supplied by the saphenous nerve?

Answer 7

Yes, sensory to medial thigh, crus, and pes

Question 8

If the pudendal nerve were damage, what clinical signs would you expect to see?

Answer 8

Incontinence (inability to control urination or defecation), no anal tone (a big ol’ mess)

Question 9

What sensory areas do the lateral and caudal cutaneous femoral nerves supply?

Answer 9

The area of proximal cranial thigh and the proximal caudal thigh respectively.

Question 10

True or false: The caudal gluteal nerve supplies the superficial gluteal muscle.

Answer 10

True- the caudal gluteal nerve is the sole innervator of the superficial gluteal muscle.

Question 11

What nerve supplies the middle and deep gluteal muscles?

Answer 11

The cranial gluteal nerve; if damaged, one would expect decreased ability to rotate medially and abduct the limb.

Question 12

What two bony prominences does the sciatic nerve pass between?

Answer 12

The tuber ischii and the greater trochanter; this makes the sciatic nerve prone to damage in the event of a hip luxation.

Question 13

What muscles (there are lots) does the sciatic nerve supply?

Answer 13

Internal obturator
gamelli
quadratus femoris m. 
biceps femoris
semitendinosus 
semimembranosus

Question 14

A hip luxation has inevitably occurred in your german shepherd, what should you expect to see if Randall’s sciatic nerve has been damaged?

Answer 14

Complete anesthesia (lost sensory innervation) below the stifle except on the medial side where the saphenous nerve innervates; weight bearing, but only because the femoral nerve is capable of fixing Randall’s weight, he will not be able to flex his stifle

Question 15

The sciatic nerve branches into two nerves cranially and caudally, what are they?

Answer 15

The Common peroneal nerve (the Cranial branch) and the tibial nerve (the caudal branch)

Question 16

What muscles does the common peronal/fibular nerve supply?

Answer 16

The long digital extensor, the peroneus longus, and the cranial tibial muscles (flex hock, extend digits)

Question 17

True or false: Damage to the common peroneal nerve would not prevent the animal from bearing weight.

Answer 17

False, the animal would possess an over-extended hock and over-flexed digits that would result in “knuckling over” and an inability to bear weight.

Question 18

Sensation to the dorsolateral aspect of the pelvic limb all the way down to the dorsal paw is supplied by which nerve?

Answer 18

The common peroneal nerve

Question 19

True or false: the common peroneal nerve does not have branches.

Answer 19

False, the common peroneal splits into superficial and deep peroneal nerves, each of which supplies cutaneous innervation to the dorsal paw.

…… It also has a lateral cutaneous sural branch that supplies cutaneous inneration to the lateral crus and its dorsal digital nerves (but we really don’t give a crap about those two)

Question 20

This nerve is located between the medial and lateral head of the gastrocnemius.

Answer 20

The tibial nerve

Question 21

What muscles does the tibial nerve supply?

Answer 21

The gastrocnemius, SDF, DDF, popliteus (extend hock, flex digits)

Question 22

What action is compromised if the tibial nerve is damaged at the level of the calcanean tendon? Would the animal be capable of bearing weight?

Answer 22

No, unable to extend hock (i.e. permanently flexed) and the digits would be overextended

Question 23

What sensation would be lost if the tibial nerve were damaged?

Answer 23

All sensation at the plantar surface of the paw would be damaged.

Question 24

Which artery does the deep peroneal nerve run in close association with?

Answer 24

The cranial tibial artery

Question 25

Name the major arterial blood supply to the pelvic limb starting with the external iliac artery down to the pes.

Answer 25

External iliac— Femoral (branch of saphenous)—- Popliteal—- cranial tibial—– dorsal pedal

Question 26

Which vein at the level of the pes is commonly used to find a pulse in the canine pelvic limb?

Answer 26

The dorsal pedal artery (this artery is also used for arterial catheter placement)

Question 27

What artery is the only branch off of the external iliac artery that is still within the abdominal cavity?

Answer 27

The deep femoral artery which then branches into external pudendal and pudendoepigastric trunk.

Question 28

True or false: The medial and lateral circumflex femoral aa. anastamose.

Answer 28

True, they anastamose on the lateral aspect of the thigh.

Question 29

What muscles does the proximal caudal femoral supply? (hint: think obturator nerve)

Answer 29

GAP!
Gracilis
Adductor
Pectineus

Question 30

The medial surface of the stifle is supplied by what artery?

Answer 30

Descending genicular (genuflect= to kneel)

Question 31

The distal caudal femoral supplies a number of important muscles on the caudal aspect of the pelvic limb. What are they?

Answer 31

Biceps femoris, semimembranosus, semitendinosus, gastrocnemius, and digital flexors

Question 32

The cranial tibial artery runs in close association with which nerve?

Answer 32

Deep peroneal nerve