Os tibiale externum or sesamoid in the tendon of tibialis posterior.

From a total of 165 foot and lower leg cadaveric specimens, 38 specimens were selected by palpation of the region of the tuberosity of the navicular for the possible presence of an accessory bone. Specimens were radiographed and dissected to reveal the presence of an accessory bone and its relationship to the tibialis posterior tendon. Nineteen of the specimens exhibited hypertrophy of the tibialis posterior tendon and 19 specimens exhibited an accessory bone. Specimens exhibiting an accessory bone were divided into two categories. In one group, the accessory bone was located in the tibialis posterior tendon prior to its division and was separated from the tuberosity by at least 3 mm. In the other group, the accessory bone was located in the main segment of the tibialis posterior tendon, connected to the tuberosity of the navicular by fibrous tissue, and, in some cases, exhibited a central cavity between the accessory bone and tuberosity. The accessory bone of specimens in the first group was considered to be a sesamoid in the tibialis posterior tendon and the accessory bone in the second group was an ossicle considered to be the os tibiale externum. Linking the os tibiale externum to the tibiale component of the primitive tetrapod foot rather than to the prehallux component eliminates the use of the term "prehallux" as an alternative name for this ossicle.

Variation in the division of the tibial nerve: application to nerve blocks.

One hundred and twenty-six human cadaver lower extremities were dissected to determine the level of division of the tibial nerve into medial and lateral plantar nerves. While there is a considerable amount of variance in the level of division, there is a higher incidence of division proximal to the usual description. This is deep to the flexor retinaculum between the calcaneus and medial malleolus.

Peroneus digiti minimi.

298 human cadaver feet were dissected to determine the incidence of occurrence and size of the peroneus digiti minimi. It was found to be present in 59.7% of the specimens and ranged in size from 0.5 mm to 2 mm. This was a much higher incidence of occurrence than had previously been documented. The significance of this finding is in question at the present time and needs further investigation.