Q8-2. Crural Fascia/Retinacula Flashcards

1
Q

Define crural fascia.

A

Deep fascia completely surrounding the leg.

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2
Q

What is the crural fascia continuous with superiorly?

A

The fascia lata (of the thigh)

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3
Q

What is the popliteal fascia formed from?

A

The posterior blending of the crural fascia and the fascia lata with the thigh.

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4
Q

What is the crural fascia continuous with posteriorly?

A

The fascia over the foot.

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5
Q

What structures are formed by the crural fascia?

A
  1. Osteofascial compartments
  2. Retinacula
    (Bonus: popliteal fossa is formed by the blending of the crural fascia and the fascia lata of the thigh.)
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6
Q

In addition to forming the osteofascial compartments and the retinacula, what other purpose can deep fascia serve?

A

Muscle attachment site

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7
Q

What are the three osteofascial compartments of the leg?

A
  • Anterior
  • Posterior (2 subcompartments in 1)
  • Lateral
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8
Q

What three fibrous sheets divide the leg into the three osteofascial compartments?

A
  1. Anterior crural intermuscular septum
  2. Posterior crural intermuscular septum
  3. Interosseous membrane
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9
Q

What are the contents of the anterior compartment of the leg?

A

Muscles:

  1. Extensor digitorum longus
  2. Extensor hallucis longus
  3. Tibialis Anterior
  4. Peroneus Tertius

Neurovascular:

  1. Anterior tibial artery/veins
  2. Deep Fibular Nerve
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10
Q

What are the contents of the lateral compartment of the leg?

A

Muscles:

  1. Peroneus longus
  2. Peroneus brevis

Neurovascular:

  1. Superficial fibular nerve
    * *no artery or vein runs w/in this compartment–> blood supply comes from the anterior tibial and fibular arteries
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11
Q

How is the posterior osteofascial compartment divided?

A

Two sub-compartments:

  • Deep
  • Superficial

The deep transverse intermuscular septum runs from the medial border and soleal line of the tibia–> medial crest of the fibula and the posterior crural intermuscular septum
**Add picture!!

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12
Q

What are the contents of the superficial posterior compartment of the leg?

A

Muscles:

  1. Gastrocnemius
  2. Plantaris
  3. Soleus
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13
Q

What are the contents of the deep posterior compartment of the leg?

A

Muscles:

  1. Flexor hallucis longus
  2. Flexor digitorum longus
  3. Tibialis posterior
  4. Popliteus

Neurovascular:

  1. Fibular Artery & Vein
  2. Posterior Tibial Artery
  3. Tibial Nerve
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14
Q

What is compartment syndrome?

A

Any condition causing swelling w/in a compartment, which increases intracompartmental pressure–> can in turn reduce blood supply to surrounding structure.

Keep in mind that because the crural fascia is dense and inelastic, it does not yield to swelling.

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15
Q

Which compartment is most susceptible to compartment syndrome?

A

Anterior compartment–> largely bounded by bone

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16
Q

What purpose do retinacula serve?

A

Bind tendons in place to prevent bowstringing and assuring the correct line of pull.

17
Q

What are the main five retinacula in the foot/ankle region?

A
  1. Superior extensor
  2. Inferior extensor
  3. Flexor
  4. Superior peroneal
  5. Inferior peroneal
18
Q

What differentiates retinacula from their surrounding deep fascia?

A
  • Thickness

- Borders (more difficult to define for retinacula)

19
Q

What is the course of the superior extensor retinaculum?

A

Binds anterior borders of tibia & fibula just above both malleoli.

20
Q

What passes deep to the superior extensor retinaculum?

A

In order of medial to lateral:

  1. Tibialis Anterior
  2. Extensor Hallucis Longus
  3. Extensor Digitorum Longus
  4. Fibularis Tertius
21
Q

What is the telltale characteristic of the Inferior Extensor Retinaculum?

A

Sideways “Y” shape

22
Q

What are the three sections of the inferior extensor retinaculum? What do they connect to?

A
  1. Frondiform/Fundiform (stem)–> calcaneus, taulus; continuous w/ inferior peroneal retinaculum
  2. Superior arm–> medial malleolus
  3. Inferior arm–> blends w/ deep fascia of the sole near the navicular/medial cuneiform joint
23
Q

What tendons travel deep to the inferior extensor retinaculum?

A

Ordered medial to lateral:

  1. Tibialis anterior
  2. Extensor hallucis longus
  3. Extensor digitorum longus
  4. Fibularis tertius
24
Q

What nerve passes superficially to both the superior and inferior extensor retinacula?

A

superficial fibular nerve–> medial and intermediate dorsal cutaneous nerves

25
Q

What neurovascular structures pass deep to both the superior and inferior extensor retinacula?

A

anterior tibial blood vessels and the deep fibular nerve

26
Q

What two tendons run deep to both the superior peroneal and inferior peroneal retinacula?

A
  1. Fibularis brevis

2. Fibularis longus

27
Q

What is the course of the inferior peroneal retinaculum?

A

Runs from the stem of the inferior extensor frundiform to the calcaneus

28
Q

What is the course of the course of the superior peroneal retinaculum?

A

Runs from the lateral malleolus to the calcaneus

29
Q

The flexor retinaculum serves as the superficial boundary to the beginning of what passageway between deep posterior compartments of the leg and plantar foot?

A

Tarsal Tunnel

AKA Calcaneal Canal & Porta Pedis

30
Q

What is the course of the flexor retinaculum?

A

Runs from medial malleolus to the calcaneus

31
Q

What is the mnemonic to remember the order of structures in the tarsal tunnel?

A

“Tom, Dick, And Very Nervous Harry “

32
Q

What are the structures that travels through the tarsal tunnel?

A

Ordered anterior to posterior:

  1. Tibialis Posterior
  2. Flexor Digitorum
  3. Posterior Tibial Artery
  4. Posterior Tibial Vein
  5. Tibial Nerve
  6. Flexor Hallucis Longus
33
Q

What is the purpose of tendon synovial sheaths?

A

Cover tendons to protect them from friction and chafing through their course beneath the retinacula.

34
Q

How many synovial sheaths protect the tendons from each compartment of the leg?

A

Anterior= 3
Lateral= 1 then splits
Posterior (Deep)= 3