Musculoskeletal: Anatomy - Leg Flashcards

1
Q

Four muscles of the anterior compartment of the leg

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

Seven muscles of the posterior compartment of the leg

A

Superficial:
1. Gastrocnemius
2. Soleus
3. Plantaris

Deep:
4. Popliteus
5. Flexor hallucis longus
6. Flexor digitorum longus
7. Tibialis posterior

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3
Q

Two muscles of the lateral compartment of the leg

A
  1. Fibularis longus
  2. Fibularis brevis
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4
Q

Describe the anatomy of the superior extensor retinaculum

A

Thickening of deep fascia
Extends from anterior surface of distal tibia to fibula, proximal to malleoli

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5
Q

Describe the anatomy of the inferior extensor retinaculum

A

Y-shaped band of deep fascia
Arises from lateral aspect of anterosuperior calcaneus, loops around tendons of FT and EDL (in common synovial sheath)

Two limbs:
1. Attaches to medial malleolus
2. Arches across tendons, blends with plantar aponeurosis under medial longitudinal arch of foot

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6
Q

What structures are deep to the superior extensor retinaculum?

A

From medial to lateral: Timmy Has A Very Nasty Disease, ParaTyphoid

Tibialis anterior, extensor Hallucis longus, anterior tibial Artery and Vein, deep fibular Nerve, extensor Digitorum longus, Peroneus Tertius

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7
Q

What is the function of the anterior compartment of the leg?

A

Foot dorsiflexors
Toe extensors

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8
Q

Proximal and distal attachment, innervation, and action of tibialis anterior

A

Proximal: lateral condyle and surface of tibia, interosseous membrane
Distal: medial cuneiform, base of 1st metatarsal
Innervation: deep fibular nerve (L4-5)
Action: ankle dorsiflexion, foot inversion

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9
Q

What is the common innervation of the muscles of anterior compartment of the leg?

A

Deep fibular nerve (L4-5)

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10
Q

Proximal and distal attachment, innervation, and action of extensor hallucis longus

A

Proximal: mid anterior fibula, interosseous membrane
Distal: distal phalanx of 1st toe
Innervation: deep fibular nerve (L4-5)
Action: ankle dorsiflexion, great toe extension

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11
Q

Proximal and distal attachment, innervation, and action of extensor digitorum longus

A

Proximal: lateral tibial condyle, medial surface of fibula, interosseous membrane
Distal: middle and distal phalanges of 2nd-5th toes
Innervation: deep fibular nerve (L4-5)
Action: ankle dorsiflexion, extension of 2nd-5th toes

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12
Q

Proximal and distal attachment, innervation, and action of fibularis tertius

A

Proximal: inferior 1/3 of fibula, interosseous membrane
Distal: base of 5th metatarsal
Innervation: deep fibular nerve (L4-5)
Action: ankle dorsiflexion, aids foot eversion

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13
Q

What blood vessel supplies the anterior compartment of the leg?

A

Anterior tibial

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14
Q

Describe the course of the anterior tibial artery in the leg and foot. What branches does it give off?

A

Branch of popliteal artery at inferior border of popliteus (under fibrous arch of soleus)
Becomes dorsalis pedis as it passes the ankle joint between the malleli
Passes into 2nd layer of sole at 1st intermetatarsal space
Joins lateral plantar artery to form plantar arch

Also gives off branches:
- Anterior recurrent branch (to arterial anastomosis around proximal tibia)
- Malleolar branches

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15
Q

Describe the venous supply of the anterior compartment of the leg

A

Two companion veins accompany anterior tibial artery on either side, anastomose at frequent intervals

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16
Q

Describe the course of the deep fibular nerve and its function

A

Forms as branch from common fibular nerve, arising between fibularis longus and neck of fibula (at risk with fracture)
Accompanies anterior tibial artery in leg
Supplies all muscles of anterior compartment, and some intrinsic foot muscles (EDB and EHB)
Also provides cutaneous sensation to 1st webspace

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17
Q

Describe the sensory supply of the anterior compartment of the leg

A

Branches from:
1. Saphenous nerve (including infrapatellar branch)
- Supplies medial leg and posteromedial foot
2. Common fibular nerve
- Lateral sural cutaneous nerve: supplies deep fascia and posterolateral leg
- Superficial fibular nerve: supplies skin of anterolateral leg dorsum of foot (excluding 1st web space)

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18
Q

What are the two tibiofibular joints? What movement is possible at these joints?

A
  1. Superior tibiofibular joint
  2. Tibiofibular syndesmosis (inferior tibiofibular joint)

Both joints only move slightly with dorsiflexion

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19
Q

Describe the anatomy of the superior tibiofibular joint

A

Synovial joint between lateral tibial condyle and fibular head
Joint capsule strengthened by anterior and posterior ligaments of fibular head

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20
Q

Which bursa does the superior tibiofibular joint occasionally communicate with?

A

Popliteus bursa (which in turn communicates with the knee joint)

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21
Q

Which two arteries supply the superior tibiofibular joint?

A
  1. Inferior lateral genicular (from popliteal)
  2. Anterior tibial recurrent
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22
Q

Which two nerves innervate the superior tibiofibular joint?

A
  1. Common fibular nerve
  2. Nerve to popliteus
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23
Q

What is the interosseous membrane continuous with inferiorly?

A

Interosseous tibiofibular ligament

24
Q

Describe the anatomy of the tibiofibular syndesmosis. What is its function? Which ligament is the most important for the joint’s integrity?

A

Fibrous joint involving interosseous membrane, and anterior, interosseous, and posterior tibiofibular ligaments
Principal connection is provided by the interosseous tibiofibular ligament
Holds the lateral malleolus against the lateral talus to provide stability to the ankle

25
Q

Which arteries supply the tibiofibular syndesmosis?

A

Perforating branch of fibular artery
Medial malleolar branches of anterior and posterior tibial arteries

26
Q

Which three nerves supply the tibiofibular syndesmosis?

A
  1. Deep fibular nerve
  2. Tibial nerve
  3. Saphenous nerve
27
Q

What are the two muscles of the lateral compartment of the leg?

A
  1. Fibularis longus
  2. Fibularis brevis
28
Q

What is the common innervation of the muscles of the lateral compartment of the leg?

A

Superficial fibular nerve (L5, S1-2)

29
Q

What is the shared action of the muscles of the lateral compartment of the leg?

A

Ankle eversion
Weak plantarflexion

30
Q

Proximal and distal attachment, innervation, and action of fibularis longus

A

Proximal: head and proximal 2/3 of lateral fibula
Distal: base of 1st metatarsal and medial cuneiform (same insertion as tibialis anterior)
Innervation: superficial fibular nerve (L5, S1-2)
Action: ankle eversion, weak plantarflexion

31
Q

Proximal and distal attachment, innervation, and action of fibularis brevis

A

Proximal: inferior 2/3 of lateral fibula
Distal: lateral tuberosity of base of 5th metatarsal
Innervation: superficial fibular nerve (L5, S1-2)
Action: ankle eversion, weak plantarflexion

32
Q

Describe the passage of fibularis longus and brevis through the superior and inferior extensor retinaculum

A

Share a common sheath as they pass through superior retinaculum
Fibularis brevis passes through superior compartment of inferior extensor retinaculum, ABOVE fibular trochlea
Fibularis longus passes through inferior compartment of inferior extensor retinaculum, BELOW fibular trochlea (on calcaneus)

33
Q

Describe the motor and sensory innervation of the lateral compartment of the leg

A

Motor and sensory by superficial fibular nerve (L5, S1-2)

34
Q

Describe the course of the superficial fibular nerve in the leg

A

Begins at division of common fibular nerve within substance of fibularis longus
Pierces deep fascia to provide cutaneous innervation to anterolateral leg and dorsum of foot (excluding 1st webspace)

35
Q

Describe the arterial supply of the lateral compartment of the leg

A

Proximally by perforating branches of anterior tibial artery
Distally by perforating branches of fibular artery

36
Q

Which nerve innervates the muscles of the posterior compartment of the leg?

A

Tibial nerve

37
Q

What is the common function of the muscles of the posterior compartment of the leg?

A

Plantarflexion (except popliteus)

38
Q

Which muscles make up the triceps surae?

A

Gastrocnemius
Soleus

39
Q

Which of the muscles of the leg are vestigial, and absent in 5-10%?

A

Plantaris

40
Q

Proximal and distal attachment, innervation, and action of gastrocnemius

A

Proximal: lateral head from lateral femoral condyle, medial head from popliteal surface of femur (superior to medial condyle)
Distal: posterior calcaneus via calcaneal tendon (lateral aspect)
Innervation: tibial nerve (S1-2)
Action: ankle plantarflexion when knee extended, raises heel when walking, knee flexion

41
Q

Proximal and distal attachment, innervation, and action of soleus

A

Proximal: soleal line on medial tibia, head and superior 1/4 of fibula, with tendinous arch in between
Distal: posterior calcaneus via calcaneal tendon (medial aspect)
Innervation: tibial nerve (S1-2)
Action: ankle plantarflexion (independent of knee position), steadies leg on foot

42
Q

Proximal and distal attachment, innervation, and action of plantaris

A

Proximal: lateral supracondylar line of femur, oblique popliteal ligament
Distal: posterior calcaneus via calcaneal tendon
Innervation: tibial nerve (S1-2)
Action: weak plantarflexion

43
Q

Proximal and distal attachment, innervation, and action of popliteus

A

Proximal: lateral femoral condyle, lateral meniscus
Distal: posterior tibia
Innervation: tibial nerve (L4-5, S1)
Action: weakly flexes and unlocks knee

44
Q

Proximal and distal attachment, innervation, and action of flexor digitorum longus

A

Proximal: posterior tibia below soleal line, with broad tendon to fibula
Distal: base of 2nd-5th distal phalanges
Innervation: tibial nerve (S2-3)
Action: flexion of 2nd-5th digits, ankle plantar flexion, supports longitudinal arches

45
Q

Proximal and distal attachment, innervation, and action of flexor hallucis longus

A

Proximal: inferior 2/3 of fibula, inferior interosseous membrane
Distal: base of 1st distal phalanx
Innervation: tibial nerve (S2-3)
Action: great toe flexion, supports medial longitudinal arch, weak plantarflexion

46
Q

Proximal and distal attachment, innervation, and action of tibialis posterior

A

Proximal: posterior tibia below soleal line, posterior fibula, interosseous membrane
Distal: base of 2nd to 4th metatarsals navicular tuberosity, all 3 cuneiforms, cuboid, sustentaculum tali of calcaneus
Innervation: tibial nerve (L4-5)
Action: ankle plantarflexion, foot inversion

47
Q

List the structures posterior to the medial malleolus, in order of most anterior to posterior

A

“Tom, Dick And Very Naughty Harry” (anterior to posterior:
- Tibialis posterior tendon
- flexor Digitorum longus
- posterior tibial Artery and Vein
- tibial Nerve
- flexor Hallucis longus

48
Q

Describe the motor and sensory supply of the posterior compartment of the leg. What is the course of this nerve in the leg?

A

Motor and sensory by tibial nerve:
- Branch of sciatic nerve
- Runs down middle of calf deep to soleus
- Divides into lateral and medial plantar nerves posteroinferior to medial malleolus, which provide
motor innervation to the intrinsic muscles of the foot, and cutaneous innervation to the sole of the foot and nail beds (medial -> medial 3 1/2 nailbeds; lateral -> lateral 1 1/2 nailbeds)
- Also gives off medial calcaneal nerve which pierces the flexor retinaculum and supplies the skin of the heel

49
Q

Which supplies a greater area over the sole: medial or lateral plantar nerve?

A

Medial plantar nerve

50
Q

Describe the vascular supply of the posterior compartment of the leg

A

By posterior tibial artery and its branches:
- Fibular (largest branch and also gives rise to nutrient artery to fibula)
- Circumflex fibular
- Nutrient artery to tibia

51
Q

Draw a cross-section through the ankle indicating where the various tendons and neurovascular structures pass

A
52
Q

What are the three specific deficits seen with anterior compartment syndrome?

A
  1. Decreased dorsiflexion
  2. Decreased toe extension
  3. Sensory loss to 1st webspace
53
Q

What are the three specific deficits seen with lateral compartment syndrome?

A
  1. Decreased eversion
  2. Decreased plantarflexion
  3. Sensory loss to dorsum of foot (sparing 1st webspace)
54
Q

What are the two specific deficits seen with superficial and deep posterior compartment syndrome?

A

Superficial:
1. Decreased plantarflexion
2. Decreased sural nerve sensation (posterolateral leg and foot)

Deep:
1. Decreased plantar and toe flexion
2. Decreased tibial nerve sensation (sole and heel of foot)

55
Q

What are the spinal nerve roots of the tibial nerve?

A

Same as sciatic: L4-5, S1-3

56
Q

What are the eight nerves relevant to the foot? Describe the sensory and motor function of each

A
  1. Saphenous nerve:
    - Sensory: to medial foot to head of 1st metatarsal
  2. Sural nerve:
    - Sensory: to posterolateral leg and lateral margin of the hindfoot and midfoot
  3. Medial plantar nerve:
    - Sensory: to medial sole and nail beds of medial 3 1/2 digits
    - Motor: flexor hallucis brevis, abductor hallucis, flexor digitorum brevis, medial lumbrical
  4. Lateral plantar nerve:
    - Sensory: to lateral sole and nailbeds of lateral 1 1/2 digits
    - Motor: flexor digiti minimi brevis (superficial branch), adductor hallucis (deep branch), abductor digiti minimi, quadratus plantae, lateral 3 lumbricals, dorsal and plantar interossei
  5. Superficial fibular nerve:
    - Sensory: to dorsum of foot
  6. Deep fibular nerve
    - Sensory: to 1st webspace
    - Motor: extensor digitorum and hallucis brevis
  7. Calcaneal branches
    - Sensory: to heel