MSK - Lower Limb Flashcards
What is the intertrochanteric line vs intertrochanteric crest of femur? What ligament attaches at the intertrohanteric line?
Intertrochanteric line is anterior
Intertrochanteric crest is at the posterior
Iliofemoral ligament - strong hip ligament
What else is down the posterior of the femur?
Gluteal tuberosity
Linea aspera
What is the artery damages in intracapsular prox femoral fracture? What can happen? What is the clinical presentation of this fracture and why?
Medial femoral circumflex artery
Avascular necrosis of femoral head
Shortened rotated leg
Distal fragment pulled up and rotated laterally
Find out why - put muscles that cause it here
Why does shaft of femur descend in medial direction?
To bring the knees closer to the body’s centre of gravity increasing stability
Do you get avascular necrosis in extra capsular fractures? How do these type of fractures present clinically?
No
Same as intra shortened and rotated
What does the linea aspera on the back of femur widen and become?
Floor of popliteal fossa
Are femoral shaft fractures common? Why? What nerve could be damaged? What usually happens alongside due to mechanism?
No as require a lot of force
Femoral nerve and artery damage
Soft tissue damage due to force required
What is the epiphyseal plate? What can occur in fast growing adolescents?
Growth plate
Hyaline cartilage
Allows long bone growth
Bone can grow faster than muscle - osteochondrosis
Two main functions of patella?
Leg extension
Protection of anterior aspect of knee joint from physical trauma
Where does patella sit? What happens in dislocation?
Is dislocation more commonly lateral or medial? What kind of mechanism can cause dislocation?
Femoropatella groove
Comes out
Lateral more common
High force impact on patella or sudden twisting
How do patella fractures occur? What happens if the patella separates into 2 fragments superior and inferior?
Normall direct trauma to bone
Or sudden contraction of quadriceps muscle
Prox fragment superiorly displaced by quadriceps tendon
Distal fragment inferiorly displaced by patellar ligament
Where does tibia articulate?
Knee and ankle joints
What is a role of the tibial bone?
Weight bearing - second biggest bone in body
What bone is the medial malleolus on?
Tibial
Where does the meniscus and ligaments of knee joint attach?
Intercondylar eminance
How does the femur attach to the tibia?
Via the intercodular tubercles fitting into the intercondyla fossa of the femur
What is a major feature of anterior surface of tibia?
Tibial tuberosity - attaches patellar ligament
What is a major feature of the posterior surface of the tibia?
Soleal line - where part of soleus muscle originates
How do the tibia and fibula bind together?
Via the interosseous membrane on the lateral border of the tibia - interosseous border
At distal end via fibular notch
What are the functions of the widenings at the prox and distal ends of tibia?
Helps with weight bearing
Where on the tibia is most vulnerable to injury?
Prox end - e.g. condylar fractures
What often goes with condylar fractures
Damage to ligaments of the knee
What happens with displacement if the fibular is NOT also fractured
Fibula supports tibia and therefore minimally displaced
How can you get a medial malleolus fracture?
Over inversion
Are tibia fractures common? In who/mechanism?
Usually trauma - middle aged
Common
Does the fibula articulate with the femur at the knee joint?
No
What is its main function
Attachment for muscles
Is it a weight bearer?
No
What are two types of fracture at the lateral malleolus and how do they occur?
Spiral - twisting - forced external rotation
Transverse - eversion - less common
What is the importance of the piriformis muscle?
Sciatic nerve enters the gluteal region directly behind it
Also it divides the superior and inferior parts of gluteal region
Above is super gluteal artery and nerve
Below is inferior gluteal artery and nerve
How can sciatic pain be caused by a muscle?
Some variants of sciatic nerve involve some or all of it going through piriformis muscle - can give sciatic pain if piriformis muscle contracts
Where does obturator arise from? What other nerve arises from here?
L2-L4
Femoral
Whats its course? What does it innervate (5)? What about cutaneous? What if it is damaged?
Runs with common iliac artery
Then goes through obturator foramen
Then supplies adductors, and obturator externus and gracilis
Cutaneous is medial aspect of thigh
Damage is pain paraesthesia in medial aspect and weak adduction or gait/posture problems
Where does the sciatic nerve originate from?
L4-S3
What is its course? What is an anatomical variant of bifurcation?
Arises inferior to piriformis muscle, passes posteriorly to the superior gemellus, obturator internus, inferior gemellus and quadrates femoris muscles
Enters thigh by passing deep to long head of biceps femoris
Bifurcates in popliteal fossa to tibial artery (central) and common peroneal (lateral) - these are technically in a sheath together making up the sciatic nerve so they can bifurcate anywhere up the lower limb
What does the sciatic nerve innervate? What does sensory?
Innervates posterior muscles of thigh - hamstrings
And hamstring portion of adductor magnus
Sensory - not directly but it’s branches do e.g. sural nerve (plus other branches) that comes off the tibial and common peroneal branches does the lateral side of leg and heel, dorsal and plantar surfaces of the foot.
What is piriformis syndrome?
Spasm of piriformis - can affect sciatic nerve esp if variant that goes through piriformis instead of inferior to it - can cause pain and parasthaesia in region of sciatic nerve