Gross Anatomy- Ankle

Question 1

What part of the body does the term Ankle refer to?

Answer 1

• Refers to narrowest and malleolar parts of distal leg, proximal to dorsum and heel of foot

Question 2

Describe the location Ankle (Talocrural) Joint and name what kind of joint it is.

Answer 2

• Palpated between tendons on anterior surface of ankle as slight depression
o Approximately 1cm proximal to tip of medial malleolus
• Synovial joint

Question 3

Describe some Features of the Ankle (Talocrural) Joint

Answer 3

• Hinge type joint
o Permits dorsiflexion/plantarflexion
• Between distal ends of tibia and fibula and superior part of talus
o Medial surface of lateral malleolus articulates with lateral articular surface of talus
o Tibia articulates in two places:
 Inferior surface forms roof of malleolar mortise
• Transfers body weight to talus
 Lateral surface of medial malleolus articulates with medial articular surface of talus
• Joint capsule thin anterior/posterior
o Strengthened by medial and lateral collateral ll.

Question 4

What posiion is the Ankle (Talocrural) Joint most stable and unstable?

Answer 4

• Most stable in dorsiflexed position:
o Wider, anterior part of trochlea between malleoli

• Relatively unstable in plantarflexed position:
o Narrow, posterior part of trochlea between malleoli
 Relatively loose in mortise
 Small amounts of ABD/ADD and inversion/eversion are possible
o Most injuries occur in this position
 Usually with unexpected inversions of foot

Question 5

Name the two main Ligaments of the Ankle (Talocrural) Joint

Answer 5

• **Lateral collateral l. of ankle – **

**• Medial collateral l. of ankle – **

Question 6

Descrobe the Lateral collateral l. of ankle and the 3 ligaments it is composed of.

Answer 6

• Lateral collateral l. of ankle –
o Reinforces joint laterally
o Resists inversion
o Composed of 3 separate ligaments:
 Anterior talofibular l. –
• Flat, weak band
• Extends anteromedially from lateral malleolus to neck of talus
 Posterior talofibular l. –
• Thick, fairly strong band
• From malleolar fossa to lateral tubercle of talus
 Calcaneofibular l. –
• Round cord
• From tip of lateral malleolus to lateral surface of calcaneus

Question 7

Describe the Medial collateral l. of ankle and the 4 ligaments it is composed of.

Answer 7

o Also known as deltoid l.
o Reinforces joint medially
o Resists partial dislocation of joint during eversion

o Composed of 4 parts:

 Tibionavicular l.
 Anterior tibiotalar l.
 Posterior tibiotalar l.
 Tibiocalcaneal l.

Question 8

Describe an Ankle Sprain and how it occurs.

Answer 8

• Most common ankle injury
• Tears fibers of ligaments

• Most common type is inversion sprain:
o Involves twisting of weight-bearing plantarflexed foot
o Foot is forcibly inverted
o Injures lateral ligaments:
 Anterior talofibular l. most commonly torn
• Either partially or completely
• Results in instability in ankle joint
o Severe sprain may injure calcaneofibular l.
o May also fracture lateral malleolus

• Eversion sprains much less common
o Involves medial collateral l. complex

Question 9

Describe an Ankle Fracture and how it occurs

Answer 9

• Dislocation fracture
• Known as “Pott’s” fracture”
• Occurs when foot is forcibly everted
o Pulls on medial collateral l.
o Often avulses (pulls off) medial malleolus
o Talus then moves laterally
 Shears off lateral malleolus or breaks fibula superior to syndesmosis
o If tibia moves anteriorly, the posterior margin of the tibia is also sheared off by talus
o Produces “trimalleolar fracture”