Nerves + Vessels LL

Question 1

Which Spinal nerves make out the Lumbo-sacral pexus?

Answer 1

(L1)L2-S3

Question 2

How many pairs of spinal nerves are there?

How are they classified?

Answer 2

„There are 31 pairs of spinal nerves

• 8 Cervical
• 12 Thoracic
• 5 Lumbar
• 5 Sacral
• 1 Coccygeal

“

Question 3

Where do autonomic fibres fom the spinal chord emerge?

Answer 3

They emerge from cranial nerves (PNS)+

• T1-L2 (SNS)
• S2-S4 (PNS)

Question 4

Which spinal nerve generally supply the lower limb?

Answer 4

L2-S2

Question 5

Which spinal nerves generally supply the perineum?

Answer 5

S2-C1

Question 6

Which spinal nerves generally supply the upper limb?

Answer 6

C5-T1

Question 7

Explain the involvement of the anterior and posterior rami in the lumbo-sacral plexus

Answer 7

The anterior rami of the spinal nerves merge and give rise to the lumbar plexus

The posterior rami (much smaller) normally cutaneous innervation

Question 8

Explain the formation and route of the femoral nerve

Answer 8

L2-L4

• leaves the pelvis under the inguinal ligaments
• runs in the femoral triangle, in anteriomedial part of the thigh
• gives rise to many brances, one of them is the saphenous nerve (green in picture)

Question 9

What is the motor and sensory function of the femoral nerve?

Which spinal nerves are involved?

Answer 9

Motor

It supplies all muscles in the anterior compartment of the thigh

• also gives branches to iliacus, psoas and pectineus
• –> extention of the knee

Sensory

• skin on anterior thigh+ medial side of leg and foot (though saphenous nerve)

Question 10

Explain the route of the obturator nerve

Which spinal nerves are involved in its formation?

Answer 10

L2-L4

• descends along posterior abdominal wall
• passes through the obturator canal/foramen

Question 11

Explain the motor and sensory innervation of the obturator nerve

Answer 11

L2-4

Motor

• medial compartment of the thigh (except pectineus)
• obturator externus

Sensory

• sin upper medial aspect of thigh

Question 12

Explain the route of the sciatic nerve from the hip to the thigh

Whhich spinal route are inoveled in its formation?

Answer 12

L4-S3

• leaves pelvis through greater sciatic foramen, around piriformis,
• passes through gluteal region (inferior)
• runs down posterior side of thigh
• gives rise to posterior cutaneous nerve of thigh

Question 13

Explain the route of the sciatic nerve in the polpiteal fossa

Answer 13

It devides into

1. Tibial nerve (runs
2. Common peroneal nerve

Question 14

Explain the route of the tibial nerve

Answer 14

• emerges from the sciatic nerve in the polpiteal fossa
• runs down posterior leg
• travels behind medial malleolus and enters foot

Question 15

What does the sciativ nerve supply?

Where does it get its spinal nerves from?

Answer 15

L3-S3

• supplies
  
  • posterior compartment of tigh
  • leg and foot via tibial and fibular nerve

Question 16

What does the tibial nerve supply?

Which spinal nerves are involved?

Answer 16

Branch of the sciatic nerv L3-S3

• supplies posterior compartment of leg
• intrinsic muscles of the foot

Question 17

Explain the route of the common fibular nerve in the leg

What does it supply?

Answer 17

Branch of the sciatic nerve, runs laterally along the fibula where it is suspectible to damage!

Is soon subdevides into

1. superficial peroneal nerve (L4-S1)
   
   • runs down laterally and supplies the lateral compartment of the leg
2. deep fibular nerve (L5-S2)
   
   • runs down anteriorly and supplies anterior compartment of leg

Question 18

Explain the function and route of the superior gluteal nerve

Which spinal nerve contribute to its formation?

Answer 18

L4-S1

• supplies gluteal medius and minimus and tensor faccia lata

Question 19

Explain the function and route of the inferior gluteal nerve

Which spinal nerve contribute to its formation?

Answer 19

L5-S2

• supplies gluteus maximus

Question 20

Explain the use of the words anteriro and posterior devisions of the lumbar plexus in the lower limb

Answer 20

Anterior devisions–> supply posterior LL (e.g. sciatic nerve)

Posterior devisions –> supply anteiror LL (e.g. femoral nerve)

• due to permanent pronation during development

Question 21

Explain the segmental motor supply in the (lower) limb

What are its kex characteristics?

Answer 21

• Muscles are supplied by two adjacent segments
• Same action on joint = same nerve supply
• Opposing muscles 1-2 segments above or below
• More distal in limb = more caudal in spine

Question 22

What is the segmental motor supply to the hip?

Answer 22

• Flexion= L2-3
• Extension= L4-5

Question 23

What is the segmental motor supply to the knee?

Answer 23

Extension= L3,4

Flexion= L5,S1

Question 24

Explain the segmental motor supply to the ankle

Answer 24

1. Dorsiflexion = L4,5
2. Plantarflexion= S1,2

• inversion= L4
• Eversion= L5,1

1. toe flexion= L5,S1
2. toe extension= S1,2

Question 25

Explain the Main dermatomes in the LL

Answer 25

Anterior: 1. "L3 to the knee, L4 to the floor" --\> work you other way around it Posterior: * Medial= S2 * Lateral= S1, seperated by axial line

Question 26

What is an autonomous sensory zone?

Answer 26

Normally: spinal neres largely overla when it comes to cutaneous sensory supply (e.g dermatomes) But ther are some zones where overlap is minimal, called **autonomous sensory zones**

Question 27

Which factors would you test to access nerve funciton?

Answer 27

1. •Motor Function 2. •Sensory Function 3. •Reflex Function 4. •Autonomic Function

Question 28

Name an example nerve function testing with a prolapsed disk at L5/S1

Answer 28

* Motor – loss of eversion * Sensory – loss of sensation outer border of foot * Reflex – loss of ankle jerk (S1) * Autonomic – minimal

Question 29

What would a lesion of the common fibular nerve at the neck of the fubular cause?

Answer 29

* Motor – foot drop * Sensory – dorsum of foot at least * Reflex – none * Autonomic – minimal

Question 30

Explain the difference between a dermatome and cutaneous sensory innervation

Answer 30

Dermatomes describe regions that are supplied by a single spinal nerve route Cutaneous sensory innervation is carries out by peripheral nerves, that carry information from several spinal nerves

Question 31

Name some of the clinically significant sensory autonomous zones of the LL

Answer 31

„L3 – front of the thigh (“L3 to the knee”) L4 – front of the leg (“L4 to the floor”) L5 – dorsum of the great toe S1 – lateral aspect of the foot S2-4 – perineum and perianal region“

Question 32

Which spinal nerves supplies the knee-jerk reflex?

Answer 32

L3

Question 33

Which spinal nerve supplies the ankle jerk reflex?

Answer 33

S1

Question 34

When is the femoral nerve suspectible to damage?

Answer 34

Mainly by doctors * during hip replacements * during reparirng of inguinal hernias * cannulation of femoral artery/vein

Question 35

Explaint the route of the lateral cutaneous branch of the thigh and its result in compression

Answer 35

* passes superficially 2cm medial to the anterior superior iliac spine at the level of the inguinal ligament. * It can be compressed at this level causing **meralgia paraesthetica.“**

Question 36

Explain the possible situations in which the superior gluteal nerve is damaged and its consequences

Answer 36

* Might be damaged in hip replacements, * leading to trendelberg gait

Question 37

What is the saphenous nerve? What happens in damage?

Answer 37

Branch of the femoral nerve suppying cutaneous sensory innervation in the medial leg and foot * might be damaged at the medial malleolus * or at knee (both: often linkes to medical procedures)

Question 38

Explaint the route of Arteries from the aorta into the LL

Answer 38

1. Aorta into 2. Common iliac artery 3. into 1. interal iliac artery 1. obturator artery 2. external iliac artery 1. becomes femoral artery at the inguinal ligament

Question 39

Explain the route of the femoral artery in the thigh

Answer 39

* passes inguinal ligament at mid-inguinal point * just below the inguinal ligament it gives rise to the * the superficial circumflex iliac artery * the superficial epigastric artery * the superficial external pudendal artery * the deep external pudendal artery * Below that it gives of big branch the **profunda femoris artery** * ​perforating artery * medial+ lateral circumflex artery * Superficial femoral artery passes through adducturo hiatus and becomes the polpiteal artery

Question 40

Explain the route of the polpiteal artery

Answer 40

* runs in polpiteal fossa * bifurcates into * anterior tibial artery * passes anterior in leg, becomes dorsalis pedis at foot (anterior) * posterior tibial artery * gives off peroneal artery that runs laterally * rest: runs posteriorly in leg and entery foot **posterior to medial malleolus** *

Question 41

What are the main arteries of the foot? Where do they originate from?

Answer 41

1. Anterior tibial artery gives rise to dorsalis pedia 2. posterior tibial artery gives rise to medial plantar artery

Question 42

What are the main superficial veins of the LL Explain their route

Answer 42

1. Great saphenous vein * forms dorsal venous arch * runs anterior to medial malleolus * runs medially, in the leg, goes slightly posterior in knee,runs up mediall in thigh and * joins femoral vein at the saphenous-femoral junction 2. Short saphenous vein * forms from dorsal venous arch * runs posterior to lateral malleolus * runs up the leg posteriorly and * joins the polpiteal vein in the polpiteal fossa

Question 43

Explain the organisation of deep veins in the LL

Answer 43

* most of them as venae comitantes along the arteries * some can be named e.g. * anterior and posterior tibial veins * polpiteal vein (where SSV joins) * femoral vein (where LSV joins) * profunda femoris vein * external iliac vein

Question 44

What are the characteristics of venae comitatnes?

Answer 44

* •Multiple veins form a network of smaller veins with arteries which they accompany * often they are inter-connected

Question 45

Explain the venous blood flow in the lower limb and how this might lead to problems

Answer 45

Generally * Venous blood flow is suppoerted by muscular pump+ arterial pump * Blood flow is from superficial to deep veins, regulated by valves * in valve damage: blood flows from deep to superficial leading to varicose veins

Question 46

What are varicouse veins? What are the main complications?

Answer 46

in valve damage: blood flows from deep to superficial leading to varicose veins May lead to * •Lipodermatosclerosis (skin thickening) (chronic inflammatory cause? * Venous ulcers

Question 47

What is compartment syndrome? What is its cause?

Answer 47

Neuromuscular compartments in limbs are enclosed by fibrous sheaths--\> Ischaemia caused by trauma-induced increased pressure in a confined limb compartment * •Normal pressure = 25mmHg; only need 50-60 to collapse vessels, so pulse still present (systolic 120mmHg but still causes ischaemia) •Commonly the anterior, posterior and lateral compartments of the leg

Question 48

What is the difference between acute and chronic compartment syndrome?

Answer 48

* Acute compartment syndrome (trauma associated) * Chronic compartment syndrome (exercise-induced)