Twisting injury to Foot : Avulsion injury to base of 5th Metatarsal






The fractures at the base of the 5th metatarsal are transversely oriented to the shaft of metatarsal.
Unfused apophysis is laterally located and is longitudinally oriented ( It is seen on radiograph  at 10 to 12 yrs in girls and boys respectively and fuses within next 2-4yrs).

Another case:

Here the line at the base of 5th metatarsal is transversely oriented and only involves the tip so it is a avulsion fracture.

This is most common avulsion injury of foot and most common type of injury ( 90%) at the base of the 5th metatarsal.  It is caused due to forceful plantar inversion in flexed foot of postion with avulsion of the insertion of peroneus brevis. It may or may not extend into the metatarso-cuboid joint.

Accesory ossicle just at the base of 5th metatarsal is called Os Vesalianum( very rare) while lateral to the cuboid is called Os Peroneum are other differentials but they are well corticated seasmoids.

Islein Disease: is apophysitis of the base of 5th metatarsal due to repetitive traction by peroneus brevius usually in young persons engaged in the sports activities. There is irregularity of the apophysis or bony specks in this region.

Thus Most common fracture at the base of 5th metetarsal is Avulsion injury , f/b Jones f/b Stress fracture.