Causes of Bunions

You can see in the following illustration comparing a foot without a bunion to one with a bunion, that the 1st metatarsal is mal-positioned from the base (bottom) of the bone. The 1st metatarsal is not crooked, bowed, or deformed – its straight and just mal-aligned from the base (bottom).

Skeleton with Bunion (Inner most metatarsal is mal-aligned)

Skeleton with Bunion
(Inner most metatarsal is mal-aligned)

Skeleton without Bunion (Metatarsal bones are all aligned straight)

Skeleton without Bunion (Metatarsal bones are all aligned straight)

 

While visual appearance of a bunion occurs at the big toe joint, its this midfoot joint that is thought (by some) to cause the bunion. Also, some believe that this joint (1st metatarsocuneiform joint) is malstructured or too mobile causing the bunion in the first place.

IF

Bunions are thought to occur for several reasons.  In most situations, a bunion is caused by a combination of factors leading the deformity.

Heredity

  •     Genetics
  •     Family history
  •     Evolutionary influence

Gender

  • Females are more likely to develop bunions
  • Men may develop bunions too

Malignment

  • Biomechanical
  • Flatfeet or fallen arches
  • Pronation
  • Unequal Limb lengths

Structural

  • Morton’s foot

A type of foot where the 1st metatarsal is shorter than the others

  • Loose ligaments in the foot

May be associated with a genetic condition
May occur with prenancy

  • Bone structure deformities

Malshaped bones
Malshaped big toe joint
Congenital absence of certain foot bones – particulary the tibial sesamoid
Tight calf muscle and achilles tendon
This often occurs from long-term high heel shoes

Improper Shoe gear

  • Small shoes
  • Pointy shoes
  • Shoes with a tight toe box
  • High heels

Injury

  • Acute injury
  • Chronic injury

Disclaimer: All information on SurgeryBunion.com is informational.  It does not constitute medical advice.  For medical advice consult a licensed physician.