Flexor Digitorum brevis (FDB)

This super muscle inserts from the calcaneus (heel bone) to the middle part of toes 2–5. Its action is to flex the toes (not the big toe) and this muscle is known as an intrinsic muscle of the foot. This muscle along with others assists with maintaining the arch of the foot and assists with stability when increasing postural demands.  Well, I don’t know if you have noticed, but ballet puts lots of postural demand on the foot.

Chronic weakness of this muscle makes the toes go into a “hammer toe” position and weightbearing falls into the tips of the toes.  Some research has looked at the association between FDB weakness and stress fractures in the toes in dancers as well as the development of plantar fasciitis.

How do we look after them?  Attempts to exercise this muscle are clinically ineffective if there is tarsal tunnel syndrome (a topic for another post).  Soft tissue therapy to the origin and insertion of the muscle can be useful and making sure the toes 2-5 and calcaneus are moving properly is a good place to start.