S5L1 - Functional Anatomy Of The Foot And Ankle Flashcards
1
Q
What 3 groups can the bones of the foot be divided into?
A
- Tarsal bones
- Metatarsals
- Phalanges
2
Q
What are the tarsal bones?
A
7 irregularly shaped bones, situated proximally in the foot
3
Q
What are the metatarsals?
A
5 bones that connect the phalanges to the tarsal bones
4
Q
What are the phalanges?
A
The bones of the toes. Each toe has 3 phalanges (proximal, middle and distal), except the big toe which only has 2 (proximal and distal)
5
Q
What is the plantar and dorsal view of the foot?
A
Plantar view = from the sole
Dorsal = from above
6
Q
What 3 regions can the foot bones be divided into?
A
- Hindfoot - talus and calcaneus
- Mid foot - navicular, cuboid and cuneiforms
- Forefoot - metatarsals and phalanges
7
Q
Describe the talus bone
A
Most superior of the tarsal bones.
Function ; transmits weight of the body to the foot, from the tibia to the calcaneus bone
8
Q
What articulations occur with the talus bone?
A
3 articulations:
- Superiorly - ankle joint, between the talus, tibia and fibula
- Inferiorly - subtalar joint, between the talus and calcaneus
- Anteriorly - talonavicular joint, between the talus and the navicular.
9
Q
What is the trochlear of the talus
A
A groove that articulates with the tibia and fibula. The trochlear is wider anteriorly than posteriorly to give additional stability to the dorsiflexed ankle.
10
Q
What muscles are attached to the talus?
A
None
11
Q
Why is the blood supply to the talus described as retrograde?
A
The arteries enter the talus at its distal end.
12
Q
Why is there a high risk of avascular necrosis if the talus is fractured?
A
- No muscle attachments (which would improve the vascularity)
- Retrograde blood supply.
13
Q
What articulations does the calcaneus bone have?
A
- Superiorly ; subtalar (talocalcaneal) joint, between the calcaneus and the talus.
- Anteriorly : calcaneocuboid joint. Between the calcaneus and the cuboid.
14
Q
What is the function of the calcaneus?
A
It protrudes posteriorly from the foot, taking the entire weight of the body when the heel contacts the ground when walking.
15
Q
Where is the calcaneal tuberosity? What is its function?
A
On the posterior aspect of the calcaneus bone. Attachment site for the Achilles’ tendon.
16
Q
What are the proximal row of tarsal bones?
A
The calcaneus and the talus.
17
Q
What are the intermediate row of tarsal bones?
A
The navicular.
18
Q
What is the navicular?
A
An intermediate tarsal bone, positioned medially. The navicular articulates with the talus posteriorly, all 3 cuneiform bones anteriorly, and the Cupid bone laterally. On the plantar surface of the navicular there is a tuberosity for the insertion for part of the tibialis posterior tendon.
19
Q
What are the distal row of the tarsal bones?
A
4 different bones. the cuboid, the lateral, the intermediate and the medial cuneiforms.
20
Q
What is the cuboid bone?
A
The furthest lateral, cuboidal distal row tarsal bone. Articulates proximally with the calcaneus and distally with the fourth and fifth metatarsals. The inferior surface of the cuboid is marked by a groove for the tendon of the peroneus longus
21
Q
Describe the cuneiform bones
A
3 different bones, the medial, intermediate and lateral. Wedge shaped. Articulate proximally with the navicular bone. Articulate distally with the first, second and third metatarsals.
Tibialis anterior, tibialis posterior and peroneus all insert onto the medial cuneiform.
22
Q
Describe the structure of the metatarsals.
A
Between the tarsal bones and the phalanges. Numbered 1 to 5 from medial to lateral. Convex dorsally and consists of a base, shaft, neck and head.
23
Q
What are the tarsometatarsals?
A
The joints between the metatarsal bases and the tarsal bones.
24
Q
Where are the intermetatarsal joint?
A
Joints between adjacent metatarsal bones
25
Where are the metatarsophalangeal joints?
The joints between the metatarsal head and the proximal phalanx
26
Describe the structure of the ankle joint
A synovial joint between the bones of the leg (tibia and fibula) the foot . Functionally, it is a hinge joint, permitting dorsiflexion and plantarflexion of the foot.
27
What is the mortise?
A bracket-shaped socket deformed from the tibiofibular ligaments at the distal tibiofibular joint.
28
When is the ankle joint most/ least stable?
Most stable during dorsiflexion as the anterior part (wider part) of the talus trochlear is held in the ankle mortise.
Least stable is in plantarflexion when the posterior part of the trochlear ( the narrow part) is held in the mortise.
29
What muscles are used to produce plantarflexion of the foot
```
Muscles in the posterior compartment of the leg:
Gastrocnemius
Soleus
Plantaris
Tibialis posterior
```
30
What muscles are used to produce dorsiflexion of the foot?
```
Muscles in the anterior compartment of the leg:
Tibialis anterior
Extensor hallucis longus
Extensor digitorum longus
Peroneus Tertius
```
31
How is the range of dorsiflexion limited?
By passive resistance form the muscle of the posterior compartment
32
What are the 3 parts of the lateral ligament of the ankle joint?
1. The anterior talofibular ligament - between the lateral malleolus and the neck of the talus
2. The posterior talofibular ligament - between the malleolus fossa/mortise and the lateral tubercle of the talus
3. The calcaneofibular ligament between the tip of the lateral malleolus and the lateral surface of the calcaneous
33
What is the function of the lateral ligaments of the ankle?
To prevent inversion of the foot.
34
What is the function of the medial ligament?
To resist excessive eversion of the foot
35
Where does inversion and eversion of the foot occur?
Not at the ankle joint
At the subtalar, calcaneocuboid and the talocalcaneonavicular joints of the mid foot.
36
What is the functional significance of inversion and eversion of the foot?
For walking on uneven surfaces
37
Describe the subtalar joint
The articulation between the talus and the calcaneus.
Plane type of synovial joint.
The major joint for inversion and eversion of the foot as it is on an oblique axis.
No role in dorsiflexion or plantarflexion
38
What muscles are used to produce eversion of the foot?
Muscles of the lateral compartment of the leg (Peroneus longus and peroneus brevis)
And muscles from the anterior compartment of the leg ( peroneus tertius )
39
What muscles are used to produce inversion of the foot?
Anterior compartment = tibialis anterior
Deep posterior compartment = tibialis posterior
40
What are the main weight bearing bones during standing?
The calcaneus and the heads of the metatarsals
41
How are the tarsal and metatarsal bones traditionally described as being arranged? (Arches)
Medial longitudinal, lateral longitudinal and anterior transverse arches.
42
How are the 3 arches of the foot maintained?
1. By the shape of the interlocking bones
2. By the ligaments of the foot
3. By the intrinsic muscles of the foot
4. Pull of the long tendons of extrinsic muscles.
43
What is the transverse arch?
The anterior arch of the foot. A half arch that forms a complete arch when the feet are together
44
What is the medial longitudinal arch?
Formed by the calcaneus, talus, navicular, the three cuneiforms and the medial three metatarsals.
45
What maintains the integrity of the medial longitudinal arch?
The plantar aponeurosis and the spring ligament (plantar calcaneonavicular ligament), together with the tibialis anterior and the peroneus longus tendons.
Muscles supporting the medial longitudinal arch are the tibialis anterior, tibialis posterior, peroneus longus and flexor hallucis longus.
46
What forms the lateral longitudinal arch?
The calcaneus, cuboid and lateral two metatarsals.
47
What supports the lateral longitudinal arch?
Contraction of the peroneus brevis muscle
48
What four muscles are in the anterior compartment of the leg?
Tibialis anterior
Extensor digitorium longus
Extensor hallicus longus
Peroneus (fibularis) tertius
49
What actions do the muscles of the anterior compartment of the leg complete?
Dorsiflexion and inversion.
The extensor digitorum longus and extensor hallucis longus also extend the toes.
50
What is the nerve and blood supply to the muscles in the anterior leg compartment?
Innervated by the deep peroneal nerve (L4 and L5)
| Blood supply is the anterior tibial artery
51
Describe the tibialis anterior
Strongest dorsiflexor of the foot. Originates on the lateral surface of the tibia, in the anterior compartment of the leg.
Inserts onto the medial cuneiform and the base of the first and the base of the first metatarsal.
Action is dorsiflexion and inversion of the foot
Innervation by the deep peroneal nerve
52
How do you test the power of the tibialis anterior?
Ask patient to stand on their heels with their forefeet raised off the ground.
53
Describe the extensor digitorum longus
Muscle is in the anterior leg compartment. Lies lateral and deep to the tibialis anterior muscle. Can be felt on the dorsal of the foot.
Origin : lateral condyle of the tibia, medial surface of the fibula and the interosseous membrane
Divides after passing deep to the extensor retinacula into 4 different tendons on the dorsal of the foot to insert onto the middle and distal phalanges on the second to the fifth toes.
Actions: Extension of the 4 lateral toes, assists in dorsiflexion of the foot
Innervation: Deep peroneal nerve
54
Describe the extensor hallucis longus
In the anterior leg compartment.
Lies deep to the extensor digitorum longus and the tibialis anterior muscle.
Origin: Medial surface of the fibular shaft.
Crosses medially anterior to the ankle joint, beneath the extensor retinacula and attaches to the base of the distal phalanx of the great toe.
Action: Extension of the great toe and assists in dorsiflexion of the foot.
Innervated by the deep peroneal nerve.
55
Describe the peroneus tertius
Not present in all individuals.
Origin; medial surface of the fibular, inferior to the origin of the extensor digitorum longus.
Descends with the EDL to the dorsal of the foot.
Where it diverges and inserts onto the base of the fifth metatarsal
Action: Eversion and assists in dorsiflexion
Innervated by the deep peroneal nerve
56
What muscles are in the lateral compartment of the leg?
Peroneus longus and peroneus brevis.
57
Describe the peroneus longus
Location : Larger superficial muscle within the lateral compartment of the leg
Origin : Upper lateral surface of the fibula and the lateral tibial condyle.
Tendon of the peroneus longus passes posterior to the lateral melliolus
Insertion: the plantar surface of the medial cuneiform and base of the first metatarsal (crosses foot inferomedially)
Action : Peroneus longus everts and assists in plantarflexion of the foot. Supports medial and traverse arches of the foot.
Innervated by the superficial peroneal nerve
58
What is the function of the muscles of the lateral compartment of the leg?
The peroneus longus and the peroneus brevis both evert the foot. Main function is to stabilise the medial margin of the foot during running and prevent excessive inversion.
59
What innervated the lateral compartment of the leg?
The superficial peroneal nerve (L4 to S1)
60
Describe the peroneal brevis muscle
Muscle in the lateral compartment of the leg.
Location : deep to the peroneal longus, shorter.
Origin: Inferolateral surface of the fibular shaft.
Insertion: onto a tubercle on the base of the fifth metatarsals
Action : Everts foot, supports the lateral longitudinal arch
61
What muscles are in the superficial posterior compartment?
Gastrocnemius
Plantaris
Soleus
62
What smaller compartments make up the posterior compartment of the leg?
The superficial posterior compartment
The deep posterior compartment
Separated by fascia
63
What function do muscles of the posterior compartment have?
Plantarflexion
| Inversion
64
What innervated the posterior compartment of the leg?
The tibial nerve (branch of sciatic nerve)
65
What do the muscles of the superior posterior compartment insert into?
Achilles’ tendon
66
What bursae are associated with the Achilles’ tendon?
1. Subcutaneous calcaneal bursa ( between skin and Achilles)
| 2. Deep calcaneal bursa (between Achilles and calcaneus)
67
Describe the gastrocnemius
Most superficial of posterior leg muscles.
Origin : lateral head from lateral femoral condyle, medial head from the medial femoral condyle.
Insertion : Combines with other superior posterior muscles in the Achilles’ tendon. This inserts onto the calcaneal tuberosity
Actions: Gastrocneumius plantarflexes the foot. Also involved in knee flexion.
Innervation : tibial nerve
68
Describe the plantaris muscle
Absent in 10% of people
Small muscle with long thin tendon.
Origin : Lateral supracondylar line of the femur.
Descends medially, condensing into a tendon as it runs down the leg between gastrocnemius and soleus.
Insertion : into the Achilles’ tendon.
Action: weak plantarflexor. Weak flexor of knee.
69
Describe the soleus
Action: deep to gastrocnemius and plantaris.
Origin: Soleal line of tibia and proximal fibula.
Action: Plantarflexes
70
What muscles reside in the deep Posterior compartment of the leg?
Popliteus
Flexor digitorum longus
Tibialis posterior
Flexor hallucis longus
71
Describe popliteus
Superiorly in the deep posterior compartment.
Posterior to knee joint.
forms floor of the popliteal fossa.
Origin: Tibia proximal to the soleal line.
Insertion : Lateral condyle of femur, posterior horn of lateral meniscus. (Moves superolaterally)
Action: laterally rotates the femur on the tibia, unlocking the kne joint to allow flexion.
72
What innervated the posterior leg compartment?
Tibial nerve
73
Describe the tibialis posterior
Deepest of 4 muscles in deep posterior compartment of the leg.
Lies between the FDL and FHL
Origin: interosseous membrane and posterior surfaces of the tibia and fibula
Insertion: passes posterior to the medial malleolus to insert into the plantar surface of the navicular and medial cuneiform bones
Action: inverts and plantarflexed. Maintains the medial arch of the foot.
Innervation: tibial nerve
74
What binds the tibia and fibula together at the distal tibiofibular joint?
Tibiofibular ligaments
75
What forms the ankle joint?
Ankle Mortise - formed by the tibia and fibula (also known as the malleolus fossa)
Trochlear of the talus
76
Describe the structure of the medial/ deltoid ligament of the ankle?
Origin is the medial malleolus and fibres fan out to attach to the talus, calcaneus and navicular.
77
What innervates the muscles of the lateral compartment of the leg?
The superficial peroneul nerve
78
What compartments are there in the posterior leg?
Superficial and deep compartments
| Separated by fascia.
79
Collectively, what is the action and innervation of muscles in the posterior compartments of the leg?
```
Inversion and plantarflexion
Tibial nerve ( terminal branch of the sciatic nerve )
```
80
Describe the flexor digitorum longus
Medially in the deep posterior compartment of the leg
Origin: medial surface of the tibia
Insertion: passes superficial to the FHL in the sole of the foot. Divides into 4 tendons with each one inserting onto the base of the distalphalanx of the corresponding lateral four digits.
Action: flexes the lateral four digits. Assists in plantar flexion and invertion of the foot.
Innervation: tibial nerve
81
Describe the flexor hallucis longus
Lateral side of the deep posterior compartment
Origin: posterior surface of the fibula, passes posterior to the medial malleolus
Insertion: plantar surface of the base of the distal phalanx of the great toe
Action: flexes the great toe. Assist in plantarflexion and invertion
Innervation: tibial nerve
82
What does the tibial nerve innervate?
Skin on the posterolateral side of the leg, lateral side of the foot and the sole of the foot.
Deep and superficial posterior compartments of the leg.
83
How is the tibial nerve formed?
Terminal branch of the sciatic nerve. Arises from the sciatic nerve at the apex of the popliteal fossa.
84
How is the sural nerve formed?
The tibial nerve gives off a branch after it crosses the popliteal fossa. This branch, together with a branch from the common peroneal nerve forms the sural nerve.
85
What does the sural nerve innervate?
Posterolateral aspect of the leg and the lateral border of the foot
86
What muscles does the tibial nerve lie between in the deep posterior compartment of the leg?
Flexor digitorum longus and flexor hallucis longus.
87
Describe the path of of the tibial nerve in the lower leg?
After innervation the muscles of the deep posterior leg, it passes beneath the flexor retinaculum behind the medial malleolus.
88
What branches are given off from the tibial nerve in the foot?
Medial calcaneal branch to the heel.
| Later divides into the medial and lateral plantar nerves to supply the sole of the foot.
89
What muscle compartments does the tibial nerve supply?
Posterior thigh
Superficial posterior leg
Deep posterior leg
Intrinsic muscles of the foot ( through medial and lateral plantar nerves)
90
What are the sensory branches of the tibial nerve?
Medial sural cutaneous
Medial calcaneal branches
Medial plantar nerve
Lateral plantar nerve
91
How is the common peroneal nerve formed?
A smaller terminal branch of the sciatic nerve
92
What are the root values of the common peroneal nerve?
L4 to S2. Unlike sciatic nerve, it does not contain S3
93
What muscles does the common peroneal nerve innervate?
Short head of biceps femoris
Muscles of the lateral and anterior compartments of the thigh
Cutaneous innervation to the skin of the anterolateral leg and the dorsum of the foot.
Lateral sural cutaneous nerve
94
Where does the sciatic nerve bifurcate?
Bifurcation occurs at the apex of the popliteal fossa into the tibial nerve and the common peroneal nerve.
95
Which muscle does the common peroneal nerve pierce?
The peroneus longus muscle.
96
How does the common peroneal nerve terminate?
Gives off cutaneous branch before dividing into the superficial and deep peroneal nerves
97
What does the superficial peroneal nerve supply?
Lateral compartment of the leg (peroneus longus, peroneus brevis)
Supplies cutaneous innervation to the anterolateral leg, dorsum of the foot (excluding the first webspace, medial and lateral border)
98
What nerve roots supply the superficial peroneal nerve?
L4 to S1
99
What spinal nerve roots supply the deep peroneal nerve?
L4,L5
100
What does the deep peroneal nerve supply?
Anterior compartment of the leg (tibialis anterior, extensor hallucis longus, extensor digitorum longus, fibularis longus)
Cutaneous innervation is the dorsum of the first webspace.
101
How is the sural nerve formed?
By the union of the medial and lateral sural cutaneous branches from the tibial nerve and common peroneal nerve respectively.
102
What does the sural nerve innervate?
Passes behind the lateral malleolus into the foot to supply the lateral border of the foot. No motor branches.
103
How is the popliteal artery formed?
Continuation of the superficial femoral artery as it passes through the adductor hiatus
104
What is the blood supply of the knee joint?
The genicular branches given off from the popliteal artery in the popliteal fossa.
105
How does the popliteal artery terminate?
At the inferior border of the popliteus muscles divides into the anterior tibial artery and the tibioperoneal trunk.
106
What does the tibioperoneal trunk bifurcate into?
Posterior tibial artery and peroneal artery
107
The anterior tibial artery passes down the anterior of the leg with what other structure?
Deep peroneal nerve
108
What is the dorsalis pedis artery?
A continuation of the anterior tibial artery once it has entered the dorsum of the foot.
109
What structure accompanies the posterior tibial artery down the leg into the tarsal tunnel?
Tibial nerve
110
What is the arrangement of structures behind the medial malleolus?
```
Tibialis posterior tendon
Flexor digitorum longus tendon
Posterior tibial artery ( with accompanying tibial veins)
Tibial nerve
Flexor hallucis longus.
```
111
What does the peroneal artery supply?
Gives rise to perforating branches that supply the muscles in the lateral compartment of the leg
112
What vessels supply blood to the foot?
Dorsalis pedis
| Posterior tibial artery
113
What arteries anastomose to form the plantar arch?
The lateral plantar artery (a division of the posterior tibial artery)
Deep branch of the dorsalis pedis
114
What does the posterior tibial artery divide into in the foot?
Divides into the lateral and medial plantar arteries
115
What are the 4 pulses of the lower limb?
Femoral pulse (MIPA)
Popliteal artery
Dorsalis pedis
Posterior tibial
116
What aids venous return in the lower leg?
Shared vascular sheath with artery - arterial pulsations
| Contraction of muscles within the leg.
117
What does the dorsal venous arch drain into?
The great and small saphenous veins at its medial and lateral ends respectively
118
What is the popliteal fossa?
Diamond shaped depression on the posterior surface of the knee.
119
What forms the 4 borders of the popliteal fossa?
Superomedial border : semimembranosus
Superolateral border: biceps femoris
Inferolateral border: lateral head of gastrocneumius and plantaris
Inferomedially border: medial head of gastrocneumius
120
What forms the floor and roof of the popliteal fossa?
Floor: popliteal surface of the femur, the posterior surface of the knee joint capsule and the oblique popliteal ligament and the popliteus muscle
Roof: popliteal fascia and skin
121
What are the structure that pass through the popliteal fossa?
Popliteal artery
Popliteal vein
Short saphenous vein
Tibial nerve and medial sural cutaneous branch
Common peroneal nerve and lateral sural cutaneous branch
Popliteal lymph nodes
