Flashcards in MSK Session 11 Deck (108):
What do all of the superficial posterior leg muscles attach to distally?
What innervates the muscles in the posterior compartment of the leg?
What common function do all muscles in the superficial layer of the posterior compartment of the leg share?
What functions does gastrocnemius have in addition to plantarflexion of the ankle?
Raises heel while walking
What function additional to plantarflexion of the ankle does soleus have?
Steadies leg on foot
Which muscles are in the deep layer of the posterior leg compartment?
Flexor hallucis longus
Flexor digitorum longus
What is the main action of popliteus?
Weakly flex knee
Unlock knee by rotating femur
Medially rotate unplanted limb
What is the main action of flexor hallucis longus?
Flex all great toe joints
Support medial longitudinal arch of foot
What is the main action of flexor digitorum longus?
Flex lateral 4 digits
Support longitudinal arches of foot
What is the main action of tibialis posterior?
From which nerve does the tibial nerve originate?
Where can the tibial nerve be located at the ankle?
B/w tendons of FHL and FDL
How does the tibial nerve enter the posterior compartment of the leg?
Passes b/w heads of gastrocnemius
What happens to the tibial nerve at the ankle?
Divides into medial and lateral plantar nerves
What is the sensory distribution of the tibial nerve?
Lateral and posterior part of inferior 1/3 of leg
Lateral foot and heel
Which branch of the popliteal artery supplies the posterior leg and foot?
What accompanies the posterior tibial artery in the leg?
Tibial nerve and veins
Describe the path of the posterior tibial artery as it moves through the posterior compartment of the leg.
Posterior to medial malleolus
Runs b/w tendons of FHL and FDL
Divides into medial and lateral plantar arteries deep to flexor retinaculum
What is the largest tibial artery branch called?
Describe the passage of the fibular artery in the posterior compartment of the leg.
Inferior to popliteus and tendinous soleus arch
Moves medially w/in FHL
What does the fibular artery give rise to?
Nutrient artery of fibula
What have their origin from the anterior and posterior tibial arteries?
Cx fibular artery
Nutrient artery of tibia
What branches off from the anterior and posterior tibial arteries and anastomoses around the knee?
Cx fibular artery
Which is the largest nutrient artery of the body?
How are the veins of the posterior leg usually arranged?
As venae comitantes
What is present in all veins of the posterior leg to prevent back flow of blood?
What do veins in the posterior leg accompany?
All major arteries (so have same names)
Describe the veins through which blood in the posterior compartment of the leg drains.
Superficial --> perforating --> deep
How does calf muscle contraction aid venous return?
Propels blood to heart
Closes lower valve therefore preventing bloodflow away from heart
How is the passage of the great saphenous vein described?
How is the passage of the small saphenous vein described?
Which muscles make up the superficial layer of the posterior compartment of the leg?
What is the WHO definition of old age?
> 65 y.o.
Why will 40% of all women >50 y.o. have a fracture?
At what rate does bone mineral content decline after the age of 30?
~1% per year
What accelerates bone mineral loss?
Decreased reproductive hormone levels
Poor vitamin D
What causes a decrease in bone strength as both a material and a structure?
Loss of bone mineral
Changes in architectural structure
What is sarcopenia?
Decrease in muscle mass due to loss of muscle fibres and decreased muscle cross sectional area
What happens with muscle contractility with age?
Which neuron fibres are most affected by loss of neuronal innervation?
Alpha-motor (type II fast twitch)
Does the fact that men have a greater muscle mass in proportion to fat than women alter the rate of muscle loss b/w genders?
How can ageing exacerbate injury to the rotator cuff muscles?
Muscles become marbled w/fat --> tear --> cannot repair due to fat content
What four factors can increase fall risk and combined with bone weakness lead to fracture?
MSK-related posture and gait changes
Neuro-related gait and proprioception changes
What is type 1 osteoporosis caused by?
Post menopausal loss of oestrogen
What is type 2 osteoporosis caused by?
What are the risk factors for osteoporosis?
Decreased bone mass
Previous fragility fracture
What is the WHO definition of osteoporosis?
Skeletal disease characterised by decreased bone mass per unit volume
Deterioration of bone micro architecture leading to increased bone fragility and susceptibility to trauma #
How do bisphosphonates prevent bone resorption?
Taken up by osteoclasts
Inhibits mevalonate pathway
Osteoclast loses ruffled border so cannot sit on bone lining
What effects do bisphosphonates have on bone turnover, mineralisation and bone volume?
Minimal effect on volume
Give some examples of types of bisphosphonates.
What do bisphosphonates to do fragility fracture risk?
Decrease by 50%
What is the most important source of blood to the femoral head?
Medial circumflex artery
What will happen to 1 in 3 hip # patients?
Drop one level in mobility
How is an intracapsular hip # fixed?
How is an extracapsular hip # fixed?
Dynamic hip screw
What is the NICE definition of osteoarthritis?
Disorder of synovial joints w/focal areas of damage to the articular cartilage, remodelling of underlying bone, formation of osteophytes and mild synovitis
What percentage of cartilage loss prevents bone from healing in osteoarthritis?
How does osteoarthritis appear histiologically?
Loss of smoothness
Fibrillation and crevices present
Loss of cartilage means greater proportion of view is subchondral bone
What are the four radiological features associated with osteoarthritis?
Decreased joint space
Where are bone cysts more commonly seen?
How can osteoarthritis be treated?
Physiotherapy (improves proprioception)
What is an osteotomy?
Procedure to cut bone to offset loading which has manifested as bowing of the legs
What is arthrodesis?
Artificial joint ossification
Give some examples of complications associated with osteoarthritis treatments.
Leg length inequality
DVT (rare but treated prophylactically)
What is the problem with using a metal on metal hip replacement?
Release of metal ions into blood causing large losses of soft tissue
Give some examples of the type of joints that can be used for hip replacement.
Metal on polythene (mainly)
Highly X-linked polyethylene
Metal on metal
Describe the passage of the arteries of the lower limb.
External iliac --> femoral artery (-> deep artery of thigh -> medial and lateral circumflex femoral) --> popliteal artery --> anterior tibial, posterior tibial and fibular
Which arteries support the adductor muscles?
Deep artery of thigh
Obturator artery from internal iliac
Where does the artery to head of femur arise from?
Is the artery to head of femur important in the blood supply of the adult femoral head?
How can catheter access to the left side of the heart be achieved?
Femoral artery at mid-inguinal point
Where is the mid-inguinal point?
B/w ASIS and pubic tubercle
Why can catheter access to the right side of the heart not use veins in the arms?
Venae comitantes are too small
What venous access is used to access the right side of the heart with a catheter?
What is the contents of the adductor canal?
What are the changes to the path of the femoral artery in the adductor canal?
Crosses to posterior aspect via adductor hiatus
Why is the popliteal artery not easily felt?
Deepest structure in the popliteal fossa
Fascia surrounds fossa
What are the arteries of the posterior knee?
Superior, middle and inferior genicular arteries
Why are anastomoses needed in the anterior knee?
In full flexion the popliteal artery is obstructed so needed for sufficient blood supply
What position would you ask a patient to assume in order to palpate the popliteal pulse?
Prone with knee flexed to relax fascia
Why do you ask the patient to invert the foot when palpating the posterior tibial pulse posterior to the medial malleolus?
Relax flexor retinaculum
How does the anterior tibial artery enter the anterior compartment?
Pierces interosseous membrane
Where can the dorsalis pedis pulse be felt?
Just lateral to EHL tendon
Which artery is bigger, posterior tibial or anterior tibial?
What are risk factors for formation of atherosclerotic plaque?
What are the 8 stages of atheromatous plaque formation?
LDL through vascular endothelium
Monocytes and macrophages migrate
Scavenger receptors activated
Smooth muscle migration
Foam cell formation
In which part of the BV wall do atheromatous plaques develop?
Where are the 5 most common sites for atheromatous plaque formation, starting with the most common?
Abdominal aorta and iliac arteries
Proximal coronary arteries
Thoracic aorta, femoral and popliteal arteries
Internal carotid arteries
Vertebral basilar and middle cerebral
Why might you not be able to palpate a dorsalis pedis pulse in a patient?
Arterial occlusion in lower limb
They are one of the ~2% of population with no dorsalis pedis pulse
What should an ankle brachial pressure index show if there is no arterial occlusion?
Similar blood pressures in arm and leg whilst lying down
What imaging methods can be used to assess arterial occlusion?
If the radius of an artery decreases by a half, how much will the flow reduce by?
What are the S/S of peripheral artery disease?
Lack of hair
Improper healing after injury
Loss of pulses
What are the Tx for peripheral artery disease?
Modify risk factors
Increase exercise to stimulate angiogenesis
What occurs in atherosclerosis to cause acute ischaemia?
How would a patient with a popliteal aneurysm present?
Oedema and pain in popliteal fossa with a palpable pulsatile mass
In which two lower leg injuries is the popliteal artery at risk of rupture?
# of distal femur
Dislocation of the knee
What is the superficial venous drainage of the lower limb?
Great and small saphenous veins
Describe the course of the great saphenous vein.
Arises from dorsal venous arch of foot
Courses anterior to medial malleolus
Passes about a hand's breadth medially of the patella
Through fascia lata at saphenous opening
Drains into femoral vein
What follows the great saphenous vein along its course?
Describe the passage of the small saphenous vein.
Arises from lateral marginal vein of foot
Passes posterior to lateral malleolus
Course up posterior aspect of calf
Drains into popliteal vein in popliteal fossa
What is saphenous cut down?
Incision anterior to medial malleolus to gain access to great saphenous vein
When is saphenous cutdown used?
Emergencies e.g. hypovolaemic shock when veins have collapsed and venepuncture/cannulation is required
What is the pathogenesis of varicose veins?
Valve flaps become incompetent
Stasis of blood in veins
Dilated, tortuous superficial veins
What is the pathogenesis of venous insufficiency?
Valvular incompetence --> dull, aching, tingling legs combined with ulcers and slow healing wounds
What is postphlebitic syndrome a consequence of?
Chronic deep venous insufficiency
What is the pathogenesis of postphlebitic syndrome?
Damage to venous valves --> lymphedema from high hydrostatic pressure in veins