Leg & Ankle

• Role of Foot & Ankle:

  • Stability
  • Stable base to support body weight during stance & locomotion
  • Rigid lever for effective push-off during gait (+ BW transmitted to the ground)
  • Mobility
  • Influences other joints (e.g. sprained ankle walking affected)
  • Flexible for shock absorption (when jumping, walking, running)
  • By arches in the foot
  • Conform to changing surfaces (adapt to uneven surfaces)
• Bones of the Leg & Foot:

  • Tibia (medially)
  • Tibial tuberosity
  • Attachment site for patella tendon
  • Medial malleolus (distal end boney part)
  • Fibula (laterally)
  • Head of fibula (at the top) - can easily feel
  • Common peroneal/fibular nerve (quite superficial so can get damaged) runs down near here
  • Lateral malleolus (forms a socket w/ medial malleolus)
  • Interosseous membrane (between the 2 bones)
• Joints of the Leg:

  • Superior tibiofibular joint: synovial joint
  • e.g. knee rotation - head of fibular rotate during this movement
  • Inferior tibiofibular joint: syndesmosis (fibrous joint - limited movement)
  • Inferior tibiofibular joint is strengthened by:
  • Anterior tibiofibular ligament
  • Posterior tibiofibular ligament
• Bones of the Foot:

  • Phalanges (14)
  • Only 2 for big toe (hallux), lateral 4 have 3
  • Metatarsals (5)
  • Tarsals (after metatarsals)
  • Cuneiforms (3):
  • Lateral
  • Immediate
  • Medial
  • Cuboid
  • Navicular
  • Talus (form ankle joint)
  • Calcaneus (heal)
• Arches of the Foot (Medial - Lateral):

  • Foot bones form multiple arches
  • Medial longitudinal arch
  • Contains 3 medial sets of phalanges
  • Cuneiforms, Navicular, Talus, Calcaneus
  • Lateral longitudinal arch
  • Lateral 2 sets of phalanges
  • Cuboid, part of Calcaneus
• Arches of the foot (Front - Back):

  • Transverse arch
  • Between metatarsal & tarsal bones
  • Best seen in coronal section
• 3 Arches of the Foot:

  1. Medial longitudinal
  2. Lateral longitudinal
  3. Transverse
• Arches of Foot Formed & Supported by:

  • Bones
  • Ligaments
  • Plantar fascia
  • Muscles
  • Tendons
• Arches of Foot Functions:

  • Stability & flexibility
  • Absorb & distribute force (act like a spring)
  • Aid propulsion (during walking)
• Ankle Joint Movements:

  • Is a hinge joint; allowing dorsiflexion & plantarflexion
  • Muscles passing over the dorsal surfaces:
  • Dorsiflex the ankle joint
  • Extend the toes
  • Muscles passing over the plantar surfaces:
  • Plantarflex the ankle joint
  • Flex the toes
• Ankle Joint:

  • Bones that form the socket:
  • Medial malleolus (tibia)
  • Lateral malleolus (fibula)
  • Inferior surface of the distal end of tibia
  • Tibia & fibula articulate with the talus (location of joint)
• Subtalar Joint Movements:

  • The subtalar joint (between talus & calcaneus) allows inversion & eversion
  • Medial - muscles inserting from the medial side invert the foot
  • Lateral - muscles inserting from the lateral side evert the foot
• Ankle Ligaments:

  • Lateral collateral ligaments
  • Multiple ligaments
  • Anterior tibiofibular (TF) ligament
  • Calcaneofibular ligament
  • Posterior TF ligament
  • Commonly damaged in ankle sprain
  • More prone to injury as has multiple small ligaments
  • Function: restrict inversion
  • Medial collateral (deltoid) ligament
  • Stronger than the lateral collateral ligaments (bc/ is 1 big ligament)
  • Functions: Restrict eversion
• Ankle Sprain:

  • Incidence: Female > Male; Children > Adolescents > Adults; High heels
  • As become older becomes more stabilised
  • More common wearing high heels as foot in plantarflexion; ankle joint less stable. Distal end is bent to point that it's not in natural position so contact force transmitted to that distal joint
  • Symptoms
  • Discolouration; swelling, pain
• Ankle sprain caused by 1 or more LCL (Lateral Collateral Ligaments) being sprained
• Muscle compartments - Leg:

  • 3 compartments:
  • Anterior - dorsiflexion
  • Innervated by deep peronal nerve (PN)
  • Lateral - eversion
  • Innervated by superficial PN
  • Posterior - plantarflexion
  • Innervated by tibial nerve (division from sciatic nerve - sciatic into tibial & CPN into deep & superficial PN)
  • Divided into 2 compartments - superficial & deep
• Plantar flexors:

  • Posterior + superficial
  • 2 muscles make up triceps surae:

  1. Gastrocnemius
  2. Soleus
• Gastrocnemius (Plantarflexor):

  • Medial & lateral femoral condyles (crosses knee joint) → Calcaneus via calcaneal (Achilles) tendon (distal attachment)
  • Functions:
  • Knee: Flexes (as crosses knee joint)
  • Ankle: Plantarflexes
  • Propulsion during gait
  • Nerve: Tibial nerve