Chapter Five: The Leg Flashcards
1
Q
Leg bones: Fibula
A
- straight narrow shaft extending distally from its neck
- ends in the lateral malleolus that provides the lateral wall of the ankle socket
2
Q
lateral and medial malleoli
A
- together with the inferior tibial articular surface forms the socket for the ankle joint
3
Q
fibula
A
- has a sharp medial interosseous border that provides attachment for the interosseous membrane
- separates the anterior and posterior compartments of the leg
4
Q
Leg bones: tibia
A
- weight-bearing bone of the leg
- shaft is triangular and stout
- sharp anterior border and sharp lateral interosseous border
5
Q
medial border of tibia
A
- not as pronounced
- medial surface is superficial
- the shaft flares out distally giving rise to the talar articular surface
6
Q
distal end tibia
A
- has a medial tuberosity extending down called the medial malleolus
- this is a large hump at the inside of the ankle
7
Q
posterior tibia
A
- has a prominent soleal line
- runs downwards and medially
- provides attachment for soleus muscle
8
Q
how many tarsal bones?
A
- 7
9
Q
the talus and calcaneus
A
- the first two
- both very large
10
Q
the talus
A
- articulates with the leg
- body has an upper round articular surface for the ankle joint
- distal to the body is the narrow part which is the neck
- neck is naturally capped by the head
- head articulates with the navicular bone
- below talus is the articular surface for the talocalcaneal joint
11
Q
the calcaneus
A
- is the bone of the heel
- largest tarsal bone
- articulates with the talus, navicular and cuboid bones
- runs below talus
- has a shelf like process medially called the sustentaculum tali which supports the talus
12
Q
the navicular
A
- articulates with the head of the talus
- articulates laterally with the cuboid bone
- articulates anteriorly with the three cuneiforms
13
Q
the cuboid
A
- articulates with the calcaneus
- articulates with metatarsal four and five
14
Q
the cuneiforms
A
- three of them
- wedge shaped
- connect the navicular with metatarsals one, two and three
15
Q
metatarsals
A
- the big toe (hallux) has no capability of opposition but bears half the weight load for each foot
- has no saddle joint
- stout base
- other metatarsals are much thinner and all have round heads for the MTP joints
16
Q
phalanges
A
- smaller but similar to hand ones
17
Q
the leg muscles
A
- made up of compartments like the thigh
- anterior posterior and lateral compartments
18
Q
anterior compartment
A
- contains the extensors (dorsi flexors)
- muscles draw toes upwards
- all take origin from leg bones and interosseous membrane and insert on the dorsum of the foot
- innervated by the deep peroneal nerve which is a branch of the common peroneal nerve
19
Q
the lateral compartment
A
- contains the two peronei
- these muscles are evertors (turn the sole out)
- they originate on the fibula
- insertion on the foot
- innervated by the superficial peroneal nerve
20
Q
the posterior compartment
A
- contains the flexors or plantar flexors
- they originate on the leg bones and interosseous membrane
- inserts onto the heel and sole of the foot
- innervated by the tibial nerve
21
Q
tibialis anterior
A
- powerful muscle
- originating from the upper two thirds of the tibia and the adjoining interosseous membrane
- thick tendon runs down in front of the ankle underneath the extensor retinaculum
- inserts on the first cuneiform and the base of the first metatarsal
- powerful dorsi flexor and inverter
22
Q
extensor hallucis longus
A
- long extensor of the big toe
- originates in the middle half of the outside of the fibula
- tendon crosses the ankle lateral to tibialis anterior
- runs up the back of the toe
- inserts on the base of the distal phalanx
23
Q
extensor digitorum longus
A
- long extensor of the digits
- originates from most of the length of the fibula and interosseous membrane
- single tendon crosses the ankle and splits into four tendons, one for each of the lateral four toes
- the peroneus tertius is a separate tendon that separates from the main bulk of the muscle
- it crosses the ankle and inserts on the base of the fifth metatarsal
- peronei everts and extends
24
Q
extensor digitorum brevis
A
- muscle is located on the dorsum of the foot
- sends four tendons to the medial four toes
- arises from the upper calcaneus near the cuboid
- medial tendon inserts on the proximal phalanx of the big toe (extendor hallusis brevis)
- the other three insert on their extensor expansions
- muscle is innervated by a branch of the deep peroneal nerve which passes into the foot
25
Q
the lateral compartment: peroneus longus
A
- long evertor of the foot
- originates from the head and upper two thrids of the fibula
- tendon passes behind the lateral malleolus and runs under the sole of the foot
- inserts on the medial side at the base of the first metatarsal and first cuneiform
- plantar flexes and everts
26
Q
the lateral compartment: peroneus brevis
A
- short evertor
- originates on the distal two thirds of the fibula
- deep to the peroneus longus
- tendon runs behind the lateral malleolus before inserting onto the top of the base of the fifth metatarsal
27
Q
the posterior compartment: sub groups
A
- 2 sub groups
- the superficial group
- the deep group
- nerve to all the muscles in the compartment is the tibial nerve
28
Q
the superficial group
A
contains
- the gastrocnemius
- the soleus
- the plantaris
29
Q
superficial group: gastrocnemius
A
- wide fleshy superficial muscle
- two bellies originating from the femoral condyles
- inserting via a large tendon called the tendocalcaneus
- inserts on the calcaneus on the heel
- flexes the ankle and the knee at different times
30
Q
superficial group: soleus
A
- wide muscle with a large flat tendon
- originates from the back of the head of the fibula and the soleal line of the tibia
- there is an arch between the two origins allowing vessels and nerves to pass through
- flat tendon inserts into the tendocalcaneus
- muscle is a strong ankle flexor
31
Q
superficial group: plantaris
A
- has a tiny belly and thin tendon
- belly is attached to the lateral femoral condyle
- tendon runs between the gastrocnemius and the soleus
- inserts on the Achilles tendon
32
Q
the deep group
A
contains
- the popliteus
- tibialis posterior
- flexor hallucis longus
- felxor digitorum
33
Q
the deep group: popliteus
A
- originates behind the proximal tibia
- tendon runs up and laterally
- inserts on the lateral femoral condyle
- when it contracts it laterally rotates the femur on the tibia
- unlocking the knee at the commencement of flexion
34
Q
the deep group: tibialis posterior
A
- the deepest of the three long plantar flexors
- arises from the back of the interosseous membrane
- its tendon passes around the medial malleolus
- inserts into the sole by various slips into the navicular and cuneiforms
- plantar flexor and inverter
35
Q
the deep group: flexor hallucis longus
A
- the long big toe flexor
- originates on the lower 2/3 of the fibula
- tendon passes behind the base of the tibia and runs under the talus and sustentaculum tali
- passes through the foot
- inserts onto the base of the distal phalanx
- flexes the big toe and ankle
36
Q
the deep group: flexor digitorum longus
A
- muscle flexes the ankle and the lateral four toes
- belly occupies the back of the lower tibia
- tendon runs around the medial malleolus
- before entering the foot it splits into four tendons
- runs to the distal phalanges of the lateral four toes
- gives rise to the four lumbricles
- the quadratus plantae runs from the heel to insery on its tendon
37
Q
tendons of the long flexors
A
- tendons passing behind the ankle joints pass under the flexor and peroneal retinacula
- the four tendons pass behind the medial malleolus with the posterior tibial artery and nerve
38
Q
blood supply to the leg
A
- popliteal artery enters the leg at the base of the popliteal fossa and bifurcates into the anterior and posterior tibial arteries
39
Q
anterior tibial artery
A
- runs deep in the leg on top of the interosseous membrane
- crosses in front of the ankle joint and enters the foot as the doraslis pedis artery
40
Q
posterior tibial artery
A
- the larger of the two
- runs through the arch of the soleus and down between the superficial and deep muscle groups
- then behind the medial malleolus through the palmar side of the foot
- divides into the medial and lateral plantar arteries
41
Q
innervation of the leg
A
- common peroneal nerve leaves the popliteal fossa and curves around the head of the fibula
- divides into two large and important branches, the superficial and deep peroneal nerves
42
Q
superficial peroneal nerve
A
- supplies the lateral compartment
- travels superficially to supply the skin of the lateral leg and dorsum of the foot
43
Q
deep peroneal nerve
A
- runs down the anterior compartment on the interosseous membrane with the artery
- supplies the compartment and enters the foot to become cutaneous in the space between the big and second toe
44
Q
posterior compartment innervation
A
- innervated by the tibial nerve
- runs in concert with the posterior tibial artery
- divides in the foot into the medial and lateral plantar nerves
- the skin of the medial leg is innervated by a branch of the femoral nerve (saphenous nerve)
- the posterior cutaneous calf is innervated by the sural nerve, a branch of the tibial nerve
