Lecture 4 -- Pes, Nerves & Blood Supply of the Distal Hindlimb

What structures are part of the Pes region?

Metatarsus and phalanges

Do the pes region has a stopper/carpal pad?

False. The Pes region has NO stopper/carpal pad.

Do cats and dogs have dew claw?

Less common than in forelimb

Always absent in cats

Which muscles are responsible for flexing the hock joint only?

Cranial tibial muscle

Peroneus longus (long fibular) muscles

Peroneus brevis (short fibular) muscle

Peroneus third fibular (Not present in dog and cat)

Where does the cranial tibial muscle originate and insert? Which nerve innervate the cranial tibial muscle?

O: Lateral tibia

I: Metatarsal bones

N: Peroneal/ fibular nerve

Where does the peroneus longus (long fibular) muscle originate and insert?Which nerve innervate the peroneus longus (long fibular) muscle?

O: Lateral tibia and fibula

I: Plantar aspect of tarsus

N: Peroneal = fibular nerve

Where does the peroneus brevis (short fibular) muscle originate and insert? Which nerve innervate the peroneus short fibular muscle?

O: Tibia & fibula

I: 5 th metatarsal bone

N: Peroneal = fibular nerve

Which peroneus muscle is not present in dogs and cats? What is special in horses?

Peroneus tertius (third fibular) muscle

In horses, peroneus third fibular muscle is well developed BUT NO peroneus long and short fibular muscle

Which muscles are responsible for both flexing the hock joint and extending the digits?

Long digital extensor muscle

Lateral digital extensor muscle

What is the origin and insertion of the long digital extensor muscle? Which nerve innervate the lateral digital extensor muscle?

O: Extensor fossa of femur

I: Extensor process of all digits

What is the origin and insertion of the lateral digital extensor muscle? Which nerve innervate the lateral digital extensor muscle?

O: Lateral aspect tibia

I: 4th and 5th digit (Possibly 3rd digits)

Which muscle is responsible for extending the digits only?

Short digital extensor

What is the origin and insertion of the short digital extensor muscle? Which nerve innervate the short digital extensor muscle?

O: Distal row of tarsals and proximal metatarsals

I: Extensor tendons of all digits

N: Fibular nerve

What is another name for the Common calcanean tendon?

Achilles tendon

What is the function of the common calcanean tendon?

Acts as lever for distal limb

Where does common calcanean tendon insert to?

Calcanean tuberosity of calcaneus

What are the 5 musculotendinous components that converge at the common calcanean tendon?

Biceps femoris, Semitendinosus, Gracilis, Gastrocnemius, Superficial digital flexor

Which muscles are responsible for extending the tarsus and flexing the digits?

Superficial digital flexor and deep digital flexor

Where does the superficial digital flexor muscle originate and insert? Which nerve innervates the superficial digital flexor muscle?

O: Popliteal fossa of femur

I: Through calcanean tuberosity via common calcanean tendon to all middle phalanges

Nerve: Tibial Nerve (branch of sciatic)

Apart from extending the tarsal joint and flexing the digits, what is the other function of superficial digital flexor?

Flexing the stifle joint

How many head do deep digital flexor muscle have? Where does the Deep digital flexor muscle originate and insert? Which nerve innervates the deep digital flexor muscle?

2

O: Proximal tibia

• Lateral (Flexor hallicus longus)

  → Tendon runs through sustentaculum tail

  I: All distal phalanges

• Medial (Flexor digitorum longus)

  → Tendon runs through the medial malleolus

  I: All distal phalanges

Nerve: Tibial nerve (Branch of sciatic)

What are the spinal nerves that supply the hindlimb?

L5, L6, L7, S1, S2

What kind of nerve is the Gluteal nerve? Motor, sensory or both?

Motor only

What muscles are supplied by the gluteal nerve?

Gluteal muscle, piriformis, tensor fasica latae

Where is the gluteal nerve located?

On the top of greater sciatic notch = Dorsal surface of the body of ilium

What kind of nerve is the Obturator nerve? Motor, sensory or both?

Motor only

What kind of nerve is the Femoral nerve? Motor, sensory or both?

Mixed

Motor: Cranial thigh muscles (Rectus fermoris/ Sartorius/ Iliopsoas)

Sensory: Proximal thigh, medial aspect of crus and a bit of medial aspect of pet

What does damage to the femoral nerve cause?

1. Cannot extend stifle = cannot weight bear

   NO compensation

2. Loss of patellar reflex

What kind of nerve is the Sciatic nerve? Motor, sensory or both?

Mixed

Motor: Caudal thigh muscle (Biceps femoris/ semitendinosus/ semimembranosus) = Hamstring muscles

What kind of nerve is the tibial nerve? Motor, sensory or both?

Mixed

Motor: Gastrocnemius + Superficial digital flexor + Deep digital flexor

Sensory: Plantar aspect limb

What kind of nerve is the fibular/ peroneal nerve? Motor, sensory or both?

Mixed

Motor: Cranial tibial + Peroneus group + Long digital extensor + Lateral digital extensor

Sensory: Dorsal aspect limb + lateral thigh

What happens if the sciatic nerve damage?

• Motor:

  Lose the supply to to hip extensors (Bicep femoris/ semitendenosus/ semimembranosus) + Hock extensors (Gastrocnemius) + Digital flexors (Superficial digital flexor/ Deep digital flexor) + Hock flexors (Cranial tibial/ Peroneus group) + Digital extensor (Long digital extensor/ lateral digital extensor)

• Sensation:

  Lose the sensation to all BUT NOT medial aspect

What hindlimb can still be able to do if the sciatic nerve damage?

Adduction (Gluteal nerve)

Adduction (Obturator nerve)

Protract/ flex hip via rectus femurs (Fenroral nerve)

Describe the blood supply of hindlimb

Aorta → External iliac artery → Femoral artery (Gives off saphenous artery → Cranial branch of saphenous and caudal branch of saphenous)→ Popliteal artery → Cranial tibial artery → Superficial: Dorsal + Plantar common digital arteries/ Deep: Dorsal metatarsal arteries + Plantar metatarsal arteries

Which part of the body is supplied by saphenous artery?

Superficial supply to paw

Which part of the body is supplied by cranial tibial artery?

Deep supply of paw and dorsal aspect of digits

Where do both the medial and lateral saphenous veins drain into?

Femoral vein

Where is the Popliteal lymph node located?

Caudal to the stifle in between the semitendinosus and semimembranosus muscles

Where is the sciatic nerve located?

Right above the deep gluteal muscle, Below the sacrotuberous ligament

Identify the nerve shown in the picture.

Circle; Gluteal

Arrow: Ischiatic nerve

Locate what types of nerve are involved in this pic.

Left: Obturator nerve

Right: Femoral nerve

Tibial nerve (Shorter)

Fibular nerve (Longer)