leg, ankle, foot prac

Question 1

external tibial torsion

Answer 1

20 – 40˚ normal values

Question 2

tibia

Answer 2

most common bone prone to stress fracture: 90% of tibial stress fractures affect the posteromedial tibia near the junction of the middle and distal 1/3 of the bone, where the cortex of the shaft is narrow.

tibia is the larger of the 2 bones in the leg, both distally & proximally indicating its importance in force transfer / weight-bearing.

Question 3

foot (pes)

Answer 3

The skeleton of the foot consists of 7 tarsal bones, 5 metatarsal bones, 14 phalanges and a variable number of sesamoid bones.

Question 4

hindfoot

Answer 4

talus and calcaneus

Question 5

midfoot

Answer 5

rest of tarsals

Question 6

forefoot

Answer 6

metatarsals and phalanges

Question 7

Which metatarsal is shortest?

Answer 7

1st

Question 8

Which metatarsal is longest?

Answer 8

2nd

Question 9

Which metatarsal has the thickest diaphysis?

What does this suggest?

Answer 9

1st - shock absorption/weight transfer

Question 10

Compare the relative length of the metatarsals & phalanges of the foot with the metacarpals & phalanges of the hand.

Answer 10

The metacarpal bone of the thumb - great mobility, is directed at an acute angle from that of the index finger, and is capable of a considerable range of movements at its articulation with the carpus.
* The metatarsal bone of the great toe assists in supporting the weight of the body, is constructed with great solidity, lies parallel with the other metatarsals, and has a very limited degree of mobility.
Phalanges: those of the foot are smaller and their movements are more limited than those of the hand.

Question 11

Compare the mobility and function of the 1st ray & hallux with the that of the thumb.

Answer 11

hallux = very stable, force transfer
thumb = mobile

Question 12

medial longitudinal arch

Answer 12

higher = calcaneus, talus, navicular, medial cuneiform and 1st MT - reference point is tubercle of navicular

Question 13

lateral longitudinal arch

Answer 13

calcaneus, cuboid, 5th MT

Question 14

transverse arch

Answer 14

head of talus, cuneiform, cuboid, base of MTs

Question 15

Give 3 functions of the arches of the foot:

Answer 15

shock absorption
energy return in locomotion
protection

Question 16

DISTAL TIBIOFIBULAR JOINT:

Answer 16

a fibrous syndesmosis and its stability is crucial to the integrity of the talocrural joint.

Question 17

Inferior tibiofibular joint injury

“high ankle sprain”

Answer 17

combination of DF & external rotation of the foot relative to the leg. During DF the anterior portion of the talar dome is located between the distal tibia & fibula, additional ER of the foot rotates the talus in the mortise forcing a separation of the distal tibia & fibula. This can tear the anterior tibiofibular ligament and as the talus pushes on the fibula it can produce a spiral fracture of the distal fibula. More severe injuries affect the talar dome and/or the medial malleolus.

Question 18

ANKLE JOINT (TALOCRURAL JOINT)

Answer 18

The talocrural joint is synovial hinge joint supported.

Question 19

what supports the tibiofibular joint

Answer 19

• anterior tibiofibular ligament
• posterior tibiofibular ligament
• interosseous membrane

Question 20

ankle joints ligament

Answer 20

medial deltoid ligament:
- anterior tibiotalar
- posterior tibiotalar
- tibiocalcaneal
- tibionavicular
•	lateral ligaments
- anterior talofibular ligament
- calcaneofibular ligament
- posterior talofibular ligament

Question 21

Which ligament is most commonly injured in an ankle sprain? Explain why.

Answer 21

ATFL - generally spain laterall ligaments

- withstrands least force to failure, when in PF, loose pack position which stresses ligament

Question 22

SUBTALAR JOINT:

Answer 22

joint between the 3 articulating facets of the talus and the 3 of the calcaneus (complex motion). The subtalar joint translates rotation of the foot into motion of the tibia and vice versa. The axis of the STJ is inclined ~ 450 anterior to posterior and directed slightly medial to the long axis of the foot.

Question 23

SUBTALAR JOINT: ligaments

Answer 23

• calcaneofibular & tibiocalcaneal ligaments A/A
• interosseous ligament within the sinus tarsi
• cervical ligament

Question 24

TRANSVERSE TARSAL JOINT

Answer 24

talonavicular + calcaneocuboid move together

Movements = supination & pronation.

Question 25

pronation at transverse tarsal

Answer 25

can ‘functionally’ increase foot DF range of motion, however, excessive mobility of the midfoot requires stabilisation by the passive supporting structures and increased activity in the extrinsic and intrinsic foot muscles which may lead to overload and injury.

Question 26

Note the bifurcate ligament

Answer 26

dorsal calcaneocuboid + dorsal calcaneonavicular

Question 27

Ligamentous support for the talonavicular / talocalcaneonavicular joint is provided by the:

Answer 27

• dorsal calcaneonavicular ligament (superior portion of bifurcate ligament)
• plantar calcaneonavicular (spring) ligament (=primary support)

Question 28

Ligamentous support for the calcaneocuboid joint is provided by the:

Answer 28

• dorsal calcaneocuboid ligament (inferior portion of bifurcate ligament)
• plantar calcaneocuboidal ligament (short plantar ligament)
• long plantar ligament
• The last 2 provide substantial support for the lateral longitudinal arch of the foot.