The Leg & Ankle Anatomy Flashcards

1
Q

What are the two articulations of the tibia?

A

the proximal tibia articulates with the medial and lateral condyles of the femur to form the knee joint

the distal tibia articulates with the talus at the ankle joint

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2
Q

Why does the tibia look triangular in cross section?

A

it has a medial, lateral and posterior surface

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3
Q

How is the fibula positioned relative to the tibia?

A

the fibula is much thinner than the tibia and is positioned more laterally

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4
Q

What are the articulations of the fibula?

A

it does NOT contribute to the knee joint

it articulates distally with the talus at the ankle joint

the tibia and fibula articulate with each other at their proximal and distal ends

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5
Q

What is within the space between the tibia and the fibula

A

interosseous membrane

this is a thick dense fibrous sheet of connective tissue

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6
Q

Label the features of the tibia and fibula

A
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7
Q

In which locations may the tibia be fractured?

A
  1. proximally
  2. mid-shaft
  3. distally - as part of an injury to the ankle

the tibia is a strong bone and a significant force is required to cause a mid-shaft fracture in a healthy tibia

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8
Q

As the tibia’s medial surface is extensive and superficial, what 2 clinical procedures is it exploited for?

A
  1. as a donor site for bone grafts
  2. interosseous “IO” access

IO access is obtained in emergencies when the peripheral vasculature is shut down and the superficial veins cannot be cannulated

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9
Q

What are the roles of the interosseous membrane?

A
  1. it is a fibrous joint that unites the tibia and fibula
  2. it separates the muscles of the anterior and posterior compartments of the leg
  3. it acts as an attachment site for muscles
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10
Q

What passes through the foramina of the interosseous membrane?

A

above the free concave border of the upper margin is a foramen for the passage of the anterior tibial vessels to the front of the leg

in the lower part there is a foramen for the anterior peroneal vessels

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11
Q

label the diagram

A
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12
Q

What is the role of the lateral intermuscular septae?

A

They separate the small lateral compartment of the leg from the anterior and posterior compartments

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13
Q

What is compartment syndrome?

A

it occurs when there is a large amount of pressure within a muscle compartment (bleeding or swelling)

this restricts blood flow to the area and can potentially damage the nerves and muscles

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14
Q

What are the 2 types of compartment syndrome?

A

acute:

  • happens suddenly, usually after a fracture or severe injury
  • is a medical emergency and requires urgent treatment
  • can lead to permanent muscle damage if not treated quickly

chronic:

  • happens gradually, usually during and immediately after repetitive exercise (such as running or cycling)
  • usually passes within minutes of stopping the activity
  • is not a medical emergency and does not cause permanent damage
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15
Q

What are the typical symptoms of acute compartment syndrome?

A
  1. intense pain, especially when the muscle is stretched, which seems much worse than would normally be expected for the injury
  2. tenderness in the affected area
  3. tightness in the muscle
  4. a tingling or burning sensation
  5. in severe cases, numbness or weakness (these are signs of permanent damage)
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16
Q

What are the typical symptoms of chronic compartment syndrome?

A
  1. cramping pain during exercise, most often in the legs
  2. swelling or a visibly bulging muscle
  3. a tingling sensation
  4. the affected area turning pale and cold
  5. in severe cases, difficulty moving the affected body part
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17
Q

What articulation is involved in the ankle joint?

A

the ankle is a synovial hinge joint formed by the articulation between the distal tibia, distal fibula and talus

the distal tibia and 2 malleoli form a ‘socket’ called the ankle mortise, into which the talus fits

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18
Q

What is shown by the yellow line?

A

the ankle mortise

formed by the distal tibia and the 2 malleoli

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19
Q

Label the diagram of the ankle joint

A
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20
Q

Is the ankle more stable in flexion or extension?

Why?

A

dorsiflexion (extension)

the talus is wedged in between the two malleoli

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21
Q

What are the two movements possible at the ankle joint?

A

dorsiflexion:

this is the toes up towards the leg

plantarflexion:

this is toes pointing to the floor

these movements are allowed by the contraction of the muscles in the anterior and posterior compartments of the leg, respectively

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22
Q

What are the 4 muscles in the anterior compartment of the leg?

A
  1. tibialis anterior
  2. extensor digitorum longus
  3. extensor hallucis longus
  4. peroneus (fibularis) tertius
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23
Q

Label the muscles of the anterior compartment

A
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24
Q

What movements are the anterior compartment muscles primarily involved in?

A

they act to dorsiflex and invert the foot at the ankle joint

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25
What is the origin and insertion of tibialis anterior?
**origin:** lateral surface of the tibia **insertion:** medial cuneiform and base of metatarsal I
26
What is the action and innervation of tibialis anterior?
**action:** dorsiflexion and inversion of the foot **innervation:** deep fibular nerve
27
What action do extensor hallucis longus and extensor digitorum longus have on the toes?
they are **extrinsic extensors** of the toes they originate in the leg but their tendons insert onto bones within the foot the tendons cross the ankle joint as well as the toes
28
What is the origin and insertion of extensor digitorum longus?
**origin:** tibia, anterior fibula and interosseous membrane **insertion:** middle and distal phalanges of digits 2-5
29
What is the action of extensor digitorum longus?
it extends the lateral 4 toes (2-5) it is involved in dorsiflexion
30
What is the origin and insertion of extensor hallucis longus?
**origin:** anterior fibula and interosseous membrane **insertion:** distal phalanx of the big toe
31
What is the action of extensor hallucis longus?
extends the great toe dorsiflexion of the foot
32
What is the common innervation of extensor digitorum longus and extensor hallucis longus?
deep fibular nerve
33
What is the role of peroneus (fibularis) tertius? What is significant about this muscle?
it assists in dorsiflexion of the ankle and eversion of the foot it is not present in all individuals
34
What is meant by 'shin splints'?
pain along the edge of the tibia due to inflammation of tissue in the area complications may include stress fractures
35
From which vessel does the anterior tibial artery arise? How does it gain access to the anterior compartment?
it originates at the distal end of popliteus muscle from the popliteal artery it arises within the popliteal fossa and passes through the interosseous membrane to enter the anterior compartment
36
Which artery is shown?
37
What artery does the anterior tibial artery give rise to?
it travels over the anterior aspect of the ankle joint and into the foot as the **dorsalis pedis** artery this is palpable on the dorsum of the foot
38
How are the muscles in the posterior group divided? What is their innervation?
they are divided into a **superficial** and **deep** group by the **transverse intermuscular septum** ALL muscles in the posterior leg are innervated by the **tibial nerve**
39
What are the 3 superficial muscles in the posterior leg?
1. gastrocnemius 2. soleus 3. plantaris
40
What is the relationship between gastrocnemius and soleus?
gastrocnemius is more superficial than soleus their tendons converge to form the calcaneal (Achilles) tendon this inserts onto the calcaneum (heel bone)
41
What do the two large muscle bellies of gastrocnemius form?
the inferomedial and inferolateral boundaries of the popliteal fossa
42
label the muscles of the superficial compartment of the posterior leg
43
What are the origins and actions of gastrocnemius?
**origins:** superior to articular surfaces of lateral and medial condyles of the femur **action:** plantarflexion of foot and flexion of knee
44
What are the origin and actions of soleus?
**origin:** soleal line **action:** plantarflexion
45
What is the usual mechanism of Achilles tendon rupture?
it occurs when the tendon is stretched beyond its capacity Forceful jumping or pivoting, or sudden accelerations of running, can overstretch the tendon and cause a tear an injury to the tendon can also result in falling and tripping
46
What symptoms or signs would you expect if someone had ruptured their Achilles tendon?
sudden onset of sharp pain in heel walking, standing on tiptoe, running or climbing stairs may become difficult swelling in the calf and limp bruising on the lower leg
47
How is the ankle jerk reflex tested in a peripheral neurological examination?
1. hold the ankle in dorsiflexion 2. tap the Achilles tendon with a tendon hammer 3. tap the tendon superior to its insertion point on the calcaneum
48
What is seen in a normal ankle jerk reflex? Which peripheral nerve and which spinal nerves/cord segments are being tested?
the foot jerks towards its plantar surface this reflex tests if the S1 and S2 nerve roots are intact failure of the foot to jerk can indicate sciatic nerve pathology
49
What are the 4 deep muscles of the posterior leg?
1. tibialis posterior 2. flexor digitorum longus 3. flexor hallucis longus 4. popliteus
50
What is the function of popliteus?
it functions in unlocking the extended knee
51
label the deep muscles of the posterior leg
52
What is the origin, insertion and action of tibialis posterior?
**origin:** posterior tibia and fibula, interosseous membrane **insertion:** navicular and medial cuneiform bone **action:** * inversion of the foot * plantarflexion of the ankle
53
What is the insertion, origin and action of flexor digitorum longus?
**origin:** posterior tibia and fibula **insertion:** plantar surface, base of distal phalanges of digits 2-5 **action:** flexion of digits 2-5
54
What is the origin, insertion and action of flexor hallucis longus?
**origin:** posterior fibula and interosseous membrane **insertion:** plantar surface, base of distal phalanx of the big toe **action:** * flexes all the joints in the big toe * plantarflexion of the ankle
55
How can the arrangement of the tendons of TP, FDL and FHL be remembered?
they all pass posterior to the medial malleolus from the medial (closest to medial malleolus) to lateral: **T**om - **T**P is the most medial tendon, immediately behind the medial malleolus **D**ick - F**D**L is lateral to the tendon of TP **H**arry - F**H**L is lateral to the tendon of FDL
56
Which artery and nerve pass posterior to the medial malleolus? How can this be remembered?
**tibial nerve** and **posterior tibial artery** remember as **T**om, **D**ick **a**nd **n**ervous **H**arry as the artery and nerve pass between the tendons of FDL and FHL
57
Where is the posterior tibial pulse palpable?
behind the medial malleolus
58
label the tendons of the ankle joint
59
Which paired deep veins accompany the arteries in the ankle joint? Which larger vein to they drain into?
1. anterior and posterior tibial veins 2. fibular vein They drain into the popliteal vein
60
What are the 2 muscles in the lateral compartment of the leg? Where do their tendons pass?
1. fibularis longus 2. fibularis brevis their tendons pass posterior to the lateral malleolus
61
label the muscles of the lateral compartment
62
Where is the common fibular nerve most vulnerable to injury?
as it enters the lateral compartment of the leg it winds around the neck of the fibula it is most vulnerable to injury here
63
Where do the tendons of fibularis longus and fibularis brevis insert? What is their innervation?
**fibularis longus:** first metatarsal, medial cuneiform **fibularis brevis:** fifth metatarsal **innervation:** peroneal nerve (superficial fibular nerve)
64
What are the actions of fibularis brevis and fibularis longus?
plantarflexion of the ankle and eversion of the foot
65
Which vessels provide blood supply to the lateral compartment?
fibular (peroneal) artery
66
How might the fibula neck and common fibular nerve be injured? What problem does this result in?
injured by fracture of the fibula or using a tight plaster cast this results in **foot drop -** dorsiflexion of the foot is compromised and the foot drags during walking (plantarflexion)
67
What are the 2 movements present at the ankle joint and which compartments of the leg are repsonsible?
**dorsiflexion:** * bringing the dorsum of the foot and toes upwards towards the leg * performed by extensors in anterior compartment **plantarflexion:** * when the toes point to the floor * performed by muscles in the posterior compartment
68
Which nerves innervate the dorsiflexors and plantarflexors?
the dorsiflexors in the anterior compartment are innervated by the **deep fibular nerve** the plantarflexors in the posterior compartment are innervated by the **tibial nerve**
69
At which joint does inversion and eversion occur at?
the subtalar joint, NOT the ankle
70
What is the role of the ligaments of the ankle joint? What happens if they become injured?
they are critical for stability if they are injured, this may result in instability of the ankle joint
71
What causes a sprain of the lateral ligaments of the ankle? What happens if the lateral ligaments are torn?
it is caused by **forced inversion** of the foot e.g. falling over a kerb or step, walking or running on uneven ground or toppling over in heels if the lateral ligaments are torn there will be pain, swelling and bruising along the lateral aspect of the foot and ankle
72
What may some severe inversion injuries lead to?
ligament injuries heal slowly and can destabilise the joint inversion injuries may result in fracture of the lateral malleolus (distal fibula)
73
Which blood vessels supply the ankle joint?
the malleolar branches of the anterior tibial, posterior tibial and fibular arteries
74
if an ankle joint is dislocated, which 2 pulse points would be assessed? if it was difficult to palpate the pulses, how could it be assessed if the foot was being adequately perfused?
dorsalis pedis and posterior tibialis pulses if these are absent, it shows that the distal circulation has been compromised ankle brachial index can also be used using a doppler and a blood pressure cuff