- See:
- Achilles Tendon:
- Gastrocnemius Flap: (see reconstructive surgery for the leg):
- Anatomy: (see superficial posterior compartment);
- origin:
- lateral head: lateral condyle and posterior surface of femur;
- medial head: medial condyle and adjacent part of femur;
- insertion: posterior surface of calcaneus by means of calcaneal tendon;
- action:
- plantar flexion of the foot;
- rervesed origin insertion of action: flexes leg at the knee;
- doriflexion of the foot increases knee flexion capability;
- synergists: soleus, tibialis posterior, peroneus longus and brevis, flexor hallucis longus, flexor digitorum longus;
- nerve supply: tibial, S1 > L5, (see innervation)
- Function During Gait: (gait)
- triceps surae help to support knee during stance phase;
- helps decelerate tibial advancement during stance phase;
- exam: normally patients should be able to perform more than 20 heel raises;
- Parlysis of the Triceps Surae Muscle:
- paralysis of the triceps leads to a calcaneal deformity of the foot;
- deformity occurs as a result of unopposed dorsiflexor function combined with attenuation of of the triceps surae;
- when the triceps surae is weak, the tibialis posterior, peronei, and long toe flexors are ineffective hind foot plantarflexors;
- the ability to decelerate the tibia is lost and therefore, flexion of the knee will persist throughout stance phase;
- in order to prevent this, the patient may attempt to compensate with increased quadriceps activity during a larger portion of stance phase;
- there is an increase in ankle dorsiflexion as talus is displaced upward & as os calcis rotates under and into a more verticle position;
- patient will be noted to maintain heel contact during the terminal stance phase;
- forefoot develops equinus position, therby creating cavus deformity;
- effect on contra-lateral (uninvolved limb):
- unilateral paralysis of the triceps surae will shorten the stride length of the contralateral limb;
- management:
- a dorsiflexion stop should be provided to patients w/ normal dorsiflexion;
- equinus contracture can compensate for weak triceps surae, since contracture will resist tendency for excessive dorsiflexion
during terminal stance phase;
- in addition an equinus contracture would lessen the work load of the quads, in trying to prevent knee flexion during stance phase;
- in contrast, heel cord lengthening would be expected to dramatically worsen the function of a patient w/ a weakened triceps
Knee dysfunction secondary to dislocation of the fabella.
Function of the triceps surae during gait. Compensatory mechanisms for unilateral loss.
Isolated Recession of the Gastrocnemius Muscle: The Baumann Procedure