Neurovascular supply to lower limb

Question 1

what kind of joint is the hip joint and what movements can it do?

Answer 1

Hip joint= flexion, extension, abduction, adduction, circumduction movements
* Ball and socket synovial joint - highly mobile
Large volume of load, increased stability needs

Question 2

what are the 3 extracapsular ligaments that support + stabilize the hip joint

Answer 2

• ishchiofemoral ligament= limits internal rotation and hip adduction with flexion
• iliofemoral ligament= is the strongest ligament in the body and attaches the anterior inferior iliac spine (AIIS) to the intertrochanteric crest of the femur= prevents hyperextension

*pubofemoral ligament= arises from the iliopubic ramus, the superior pubic ramus and the obturator crest of the pubic bone= prevents excess abduction + extension

Question 3

what arteries supply vasculature to the head of the femur

Answer 3

The blood supply to the femoral head comes from three main sources, i.e. medial femoral circumflex artery, lateral femoral circumflex artery and small branch of obturator artery through intracapsular terminal branches which run parallel to the neck. Any femoral neck fracture disrupts the terminal blood vessels producing AVN {avascular necrosis }

Question 4

what does the obturator artery branch into + what does it supply

Answer 4

anterior branch of obturator artery follows the inner margin of the inferior pubic ramus to anastomose with the posterior branch of femoral artery and medial circumflex femoral artery. It supplies the obturator externus muscle, hip adductors and the skin over the medial thigh

Question 5

what kind of hip dislocation is more common and why

Answer 5

Posterior hip dislocations are the most common; as anterior has stronger ligament support

femoral head is displaced posteriorly P tears through postero-inferior part of the joint capsule (weakest point)

Question 6

which fracture of neck of femur is more at risk of avascular necrosis

Answer 6

*intracapsular fractures [occur within capsule of hip joint] can damage medial femoral and circumflex artery can cause avascular necrosis (AVN) of femoral head

• extracapsular fractures [occur outside joint capsule] so blood supply to head of femur is intact (AVN is rare complication)

Question 7

the inguinal ligament is a landmark to find which artery?

Answer 7

The femoral artery can only be palpated below the inguinal ligament at the mid-inguinal point. The inguinal ligament is rounded and oblique laterally.

Mid-inguinal point - where external iliac becomes femoral

Question 8

femoral vessels are the most commonly injured vascular structure (almost 70% of injuries), what is located in the femoral triangle?

Answer 8

femoral triangle:
superior border= inguinal ligament
lateral border= sartorius muscle
medial border= adductor longus

this triangle contains (lateral to medial)
-Nerve (femoral nerve
-Artery (femoral artery)
-Vein (femoral vein)
-Lymphatics (inguinal lymph nodes)

Question 9

within what ligament is the artery to the head of the femur

Answer 9

ligamentum teres/ligament to head of femur

ligamentum teres artery descends from the posterior branch of the obturator artery and attaches at the fovea. This artery is commonly disrupted with dislocations. It is the main blood supply to the femoral head in children.

Question 10

What artery + nerve supplies the anterior thigh?

what movement is anterior compartment of thigh responsible for?

Answer 10

femoral artery +femoral nerve (L2-L4)
= ANTERIOR THIGH (aka quadriceps)

anterior compatment;
-extension of knee
-flexion of hip

Question 11

what artery + nerve supplies posterior thigh

what movement is posterior compatment of thigh in charge of?

Answer 11

the muscles of the posterior thigh aka hamstrings

• • inferior gluteal artery, profunda femoris artery, perforating branches of the deep femoral artery

*sciatic nerve (L4-S3)

posterior compatment of thigh is in charge of knee flexion and thigh extension

Question 12

what artery + nerve supplies medial thigh

what movement is medial compartment of thigh responsible for

Answer 12

medial thigh muscles are innervated by the obturator nerve (L2-L4) + obturator artery

Medial compartment = adductors
* **Adduction of hip **

Question 13

the anterior tibial artery is a branch of the popliteal artery and becomes the [] in the foot

Answer 13

the anterior tibial artery is a branch of the popliteal artery and becomes the dorsalis pedis artery in the foot

Question 14

which veins are at highest risk of becoming varicose?

Answer 14

Any vein that is close to the skin’s surface, called superficial, can become varicosed

such as the great + small saphenous vein (both are superficial)

varicose veins= the valves lose integrity and blood pools here, so the vein walls become weakened

Question 15

what is the sensory supply to the lateral leg vs medial leg (dermatome)

Answer 15

lateral leg =L5
medial leg= L4

Question 16

what spinal nerve is responsible for patellar reflex

Answer 16

L2-L4 spinal nerve

The patellar reflex is a deep tendon reflex, mediated by the spinal nerves from the levels L2, L3, and L4 in the spinal cord, predominantly in the root L4

Question 17

The greater and lesser sciatic foramens are separated by the [] ligament

Answer 17

The greater and lesser sciatic foramens are separated by the sacrospinous ligament

Question 18

what movements are lost in a femoral nerve palsy?

Answer 18

paralysis of quadriceps (instability of knee)=
no extension of knee
no flexion of hip

sensory loss of anterior thigh + medial leg

as anterior compartment is innervated by femoral nerve!

causes of femoral nerve palsy;
-compression (treatment for congenital hip dysplasia)
-pelvic fractures
-anterior hip dislocations

Question 19

the sciatic nerve runs inferiorly to which muscle?

Answer 19

sciatic nerve (L4-S3) runs inferiorly to piriformis

Question 20

what artery crosses the medial malleolus

Answer 20

posterior tibial artery crosses the medial malleolus

Question 21

what are some of the causes of a tibial nerve palsy– what kind of paralysis + sensory loss does it cause

Answer 21

causes:
-fracture of tibia
-compression of tarsal tunnel

paralysis of plantar flexors; so no invertion of foot, no toe curling, no foot flexion

sensory loss to back of leg + sole of foot

Question 22

what nerve innervates the lateral compartment of leg

what nerve innervates the anterior compartment of leg

Answer 22

common fibular nerve (responsible for dorsiflexion + eversion) has 2 branches deep + superficial

superficial fibular nerve innervates the lateral compartment of leg

deep fibular nerve innervates anterior compartment of leg

N.B. the common fibular nerve wraps around the neck of the fibular, and so any fractures of the fibular neck can cause nerve palsy. common fibular nerve damage will mean; loss of dorsiflexion + eversion of foot, as well as sensory loss to the dorsum of foot

Question 23

in a sciatic nerve palsy, what kind of sensory loss + paralysis will patient present with + what are some of the causes of sciatic nerve palsy

Answer 23

Sciatic nerve is higher up in gluteal muscle fibres (just under piriformis)

cause of sciatic nerve palsy= posterior hip dislocations

• Foot drop when sat down
• Muscle wasting of:
• Hamstrings
• Calves (gastrocnemius and soleus)
  Dorsiflexors

Patient looses ability to plantarflex and dorsiflex and there is muscle wasting + loss of achilles reflex

Question 24

what are the 3 gluteal muscles and their action

Answer 24

the gluteal muscles are powerful hip extensors!

gluteal muscles; gluteus maximus, gluteus medius, gluteus minimus

Question 25

piriformis is a powerful [] rotator

Answer 25

piriformis is a powerful lateral rotator

Question 26

what does a positive trendelenburg sign indicate?

Answer 26

• +ve Trendelenburg sign indicates weakness in hip abductor muscles - gluteus medius/minimus (innervated by superior gluteal muscle)
• +ve sign - contralateral pelvic drop during single leg stance on affected side
  this indicates its a potential superior/inferior gluteal nerve lesion
• Tested by asking patient to raise left foot - left pelvis want to drop but right gluteus medius/minimus contract to elevate right pelvis - balances out (norm)
• If damaged - patient raises left foot, pelvis on right side moves up and pelvis on left side drops - damage to right superior gluteal muscle

Question 27

where are intramuscular injections carried out + where exactly on the thigh

Answer 27

several possible locations for administering intramuscular injections, including the shoulder, hip, and thigh

Should be done on right upper lateral quadrant (superloateral) aka top side of bum; since it is superior to sciatic nerve

Question 28

damage to which nerve causes foot drop and why is this dangerous?

Answer 28

common cause is damage to COMMON FIBULAR NERVE aka peroneal nerve. Foot drop is an inability to lift the forefoot (no dorsiflexion) due to the weakness of dorsiflexors of the foot. This, in turn, can lead to an unsafe antalgic gait, potentially resulting in falls.

antalgic gait= an abnormal pattern of walking secondary to pain that ultimately causes a limp, whereby the stance phase is shortened relative to the swing phase.