Anatomy Review
Now, let's look at some important muscle actions that may have been hard to glean from the text. These are separate from the muscle actions described in anatomy texts.
- Functional muscle roles: Posterior tibialis controls and reverses pronation at mid-stance as well as supports the arch of the foot (picture its insertion).
- Flexor hallucis longus and digitorum longus support the medial longitudinal arch.
- Peroneus longus and peroneus brevis pronate at the subtalar joint and peroneus longus supports the transverse and lateral longitudinal arch.
- Soleus prevents dorsiflexion of the tibia due to the effect of gravity during static stance.
- Gastrocnemius controls anterior translation of the tibia during stance phase. This can also be termed as eccentrically controlling dorsiflexion in closed chain.
Compartment Syndrome
There are four anatomical compartments in the lower leg:
- anterior: foot dorsiflexors
- lateral: everters and retinaculum
- superficial posterior: plantar flexors
- deep posterior: foot flexors
When there is a fracture, hemorrhage, crush injury, burn, or prolonged compression, and emergency situation can develop due to extreme pressure on nerves and vessels in the affected limb. The limb is often swollen, severely tender, and there may be skin changes (shiny, darkened) There are 5 "P"s when assessing for possible compartment syndrome, and indicators are a medical emergency:
- pain
- paralysis
- parasthesia
- pallor
- pulses (diminished)
Patients with overuse injuries in the foot and ankle can develop non-emergent compartment syndrome over time due to prolonged and persistent inflammation and resultant swelling