Anatomy of the Plantar Intermetatarsal Tunnel: A Cadaveric Study.

The contents of the plantar intermetatarsal tunnel (PIMT) and the relationship between the common plantar interdigital nerve (CPIN) and the PIMT were recorded. The width of the PIMT was measured at the metatarsal neck (MTN), metatarsophalangeal (MTP) joint and the base of the proximal phalanx (BPP). The length of the deep transverse metatarsal ligament (DTML), the PIMT and the intracapsular ligament (ICL) were also measured. The PIMT was revealed to be a narrow osseofibrous tunnel divided into 3 segments by the DTML: the distal section, the area under the DTML (middle) and the proximal section. The length of the middle section was 12.77 mm in the second intermetatarsal (IM) space and 10.18 mm in the third IM space. The lengths of the distal sections were 15.52 and 14.95 mm in the second and third IM spaces, respectively. There was some soft tissue between the CPIN and PIMT, and the CPIN was observed not to glide freely within the tunnel. The widths of the PIMT at the MTN, MTP joint and BPP were respectively 2.87, 2.56, and 3.42 mm in the second IM space and 3.10, 2.68 and 3.61 mm in the third IM space. The ICL lies between the capsules of the MTP joint, and the length of the ICL was 2.76 and 3.03 mm in the second and third IM spaces, respectively. The PIMT was found to be a complex spatial structure, and the ICL might prevent the CPIN from being squeezed into the IM space.