# The Flexor Retinaculum Connects the Surrounding Structures into the Medial Ankle Complex
## 3 Results
The plantaris tendon merged with the deep crural fascia in 7.6% of cases (Figure 8), giving projections to the FR, the FTCL, and the paratenon. Statistically significant differences were noticed in connections of the FR to the paratenon, the SL, the IER, the AbH, and the FFS (\(p<0.05\)) (Table 1). Figure 6: (**a**,**b**)—a 38-year-old patient with clinical suspicion of chondropathy. (**c**,**d**)—a 31-year-old patient with clinical suspicion of a ganglion. (**a**–**d**)—PD weighted images. FR (straight arrow) communicates with FTCL (curved dashed arrow). Communication between FR and the paratenon (dashed arrow) is visible on (**a**,**b**), but on (**c**,**d**), the paratenon receives projection only from FTCL (curved arrow). Figure 7: (**a**–**c**)—a 51-year-old patient after kidney transplantation with clinical suspicion of avascular necrosis of the talus. (**a**,**b**)—PD weighted images. FR (straight arrow) gives projection (curved arrow) to communicate with SL (dashed arrow). Deeply to FR (straight arrow), TNP (curved dashed arrow) is present. Significant differences in the relationship between the examined side and the presence of connections were visible in the DL, the AbH, and the FFS (\(p<0.05\)) (Table 1). The interconnections between the FR and the DL were statistically significantly correlated with the connection of the FR to the IER, the paratenon, and the SL (\(p<0.05\)) (Table 2). Connection to the ATTP was associated with a linking band with the FTCL, the FFS, and the AbH (Table 2). A negative correlation between the coexistence of FR-ATTP and FR-SL connections was noticed (Table 2). The connection between the FR and the posterior tibiotalar part (PTTP) was correlated with connections of the FR with the SL, the FFS, or the FTCL (Table 2). An accessory navicular bone was found in 10.6% of cases; however, no statistically significant differences (\(p>0.05\)) were noticed in the presence of the connections between groups of patients with and without the accessory nav \begin{table}
\begin{tabular}{c c c c c c c} \hline
**FR** & **SL** & **AbH** & **FFS** & **FTCL** & **IER** & **Paratenon** \\ \hline DL & 0.12 & \(-0.11\) & \(-0.08\) & \(-0.08\) & 0.24 & 0.23 \\ \hline \(p\) & *** & *** & *** & *** & *** & *** \\ \hline ATTP & \(-0.14\) & 0.17 & 0.28 & 0.29 & 0.05 & 0.35 \\ \hline \(p\) & *** & *** & *** & *** & *** & *** \\ \hline TNP & 0.02 & 0.02 & \(-0.06\) & 0.08 & 0.14 & 0.25 \\ \hline \(p\) & *** & *** & *** & *** & *** & \(>\)0.05 \\ \hline PTTP & 0.16 & 0.00 & 0.18 & 0.17 & \(-0.07\) & 0.08 \\ \hline \(p\) & *** & *** & *** & *** & *** & *** \\ \hline \end{tabular} Abbreviation used in the Table 2. ATTP—the anterior tibiotalar part, TNP—the tibionavicular part, PTTP—the posterior tibiotalar part, DL—the deltoid ligament, SL—the spring ligament, IER—the inferior extensor retinculum, FTCL—the fibibulotalocalcaneal ligament, AbH—the fascia on the abductor hallucis, FFS—the flexor fibrous sheath. ***\(p<0.001\).  
\end{table} 
Table 2: Coexistence of connections between FR and PTTP, TNP, ATTP and its correlation with the interconnection between FR with SL, AbH, FFS, FTCL, IER, and paratenon. Figure 8: **(a,b)—a 20-year-old patient with clinical suspicion of tenosynovitis. (c,d)—a 19-year-old patient with clinical suspicion of Achilles tendinopathy. (a–d)—PD weighted images. The plantaris tendon branches (straight arrow) anteriorly to the Achilles tendon. Communication between the plantaris tendon and the FR can be seen (dashed arrow). A thick FTCL (curved arrow) with communication with one of the terminal branches (curved dashed arrow) from the plantaris tendon can be noticed. **  
Perfect or almost perfect agreement between reviewers was noted for connections of the FR with the IER, the paratenon, the FTCL, the AbH, and the FFS, while moderate agreement was noted for FR connections to the SL, and substantial agreement was seen for FR connections to the DL (Table 1).