# The Flexor Retinaculum Connects the Surrounding Structures into the Medial Ankle Complex
## 3 Results  
Connections of the FR with other structures are common and have been found in most cases. In 97% of cases, the FR is connected with the DL (Table 1, Figures 1 and 2), most often with the anterior tibialotalar part (ATTP) (93.2%) (Table 1 and Figure 2). The FR frequently merges in a smooth transition with the FTCL (84.1%) (Figure 3) and the FFS (83.3%) (Figure 4). Inferiorly, the FR joins the AbH (72.7%) (Figure 5); anteriorly, the FR merges with the IER (64.4%) (Figure 3). A direct projection to the paratenon was found in 62.1% of cases (Figure 6); additionally, accessory projection from the FTCL was seen in 39 cases (29.5%). An interconnection between the FR and the SL was noticed in 31.1% of cases (Figure 7) and was directly related to the posterior tibial tendon attachment. Figure 3: (**a**,**b**)—a 39-year-old patient with clinical suspicion of posterior impingement. (**a**,**b**)—PD weighted images. FR (curved arrow) communicates with the inferior extensor retinaccumulation (IER) (straight arrow). Posterior FR gives projection (curved dashed arrow) to fibulotalocalcaneal ligament (FTCL) (dashed arrow). Figure 2: A 43-year-old patient with clinical suspicion of a ganglion. (**a**–**c**)—PD weighted images. Figure 4: (**a**,**b**)—a 23-year-old patient with clinical suspicion of anterior impingement. (**c**,**d**)—a 39-year-old patient with clinical suspicion of rheumatoid arthritis. (**a–d**)—PD weighted images. FR (straight arrow) communicates with the fibrous sheath of flexors (FFS) (curved arrow) and with the anterior tibiotalar part (ATTP) (dashed arrow). Figure 5: A 32-year-old patient with clinical suspicion of a lipomatous tumor in the lateral side of the ankle. (**a**,**b**)—PD weighted sequences. FR (straight arrow) communicates with the FTCL (curved arrow) in the [PERSON]’s fat pad. The projection (dashed arrow) from FR to abductor hallucis (AbH) (curved arrow) can be identified inferior from the medial malleolus. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline  & **ATTP** & **TNP** & **PTTP** & **DL** & **SL** & **IER** & **Paraeton** & **FTCL** & **AbH** & **FFS** &
\begin{tabular}{c} **Accessory** \\ **Navicular Bone** \\ \end{tabular} & **Plantaris** \\ \hline Total & 123 & 69 & 18 & 128 & 41 & 85 & 82 & 111 & 96 & 110 & 14 & 10 \\ \(n=132\) & 93.2\% & 52.3\% & 13.6\% & 97.0\% & 31.1\% & 64.4\% & 62.1\% & 84.1\% & 72.7\% & 83.3\% & 10.6\% & 7.6\% \\ R & 65 & 39 & 10 & 70 & 26 & 52 & 53 & 55 & 51 & 59 & 9 & 10 \\ L & 58 & 30 & 8 & 58 & 15 & 33 & 29 & 56 & 45 & 51 & 5 & 0 \\ Intraobserver & 0.97 & 0.90 & 0.90 & 0.96 & 0.80 & 0.95 & 0.94 & 0.97 & 0.96 & 0.95 & 1.0 & 1.0 \\ Interobserver & 0.79 & 0.78 & 0.70 & 0.71 & 0.58 & 0.89 & 0.87 & 0.9 & 0.89 & 0.79 & 1.0 & 1.0 \\ Side & *** & *** & \textgreater{}0.05 & * & \textgreater{}0.05 & \textgreater{}0.05 & \textgreater{}0.05 & * & ** & \textgreater{}0.05 & \textgreater{}0.05 \\ Plantaris Contributing Deep & \textgreater{}0.05 & \textgreater{}0.05 & \textgreater{}0.05 & * & *** & *** & \textgreater{}0.05 & *** & \textgreater{}0.05 & \textgreater{}0.05 \\ Crumal Fascia & \textgreater{}0.05 & \textgreater{}0.05 & \textgreater{}0.05 & \textgreater{}0.05 & \textgreater{}0.05 & \textgreater{}0.05 & \textgreater{}0.05 & \textgreater{}0.05 & \textgreater{}0.05 & X & \textgreater{}0.05 \\ \hline \multicolumn{10}{c}{Abbreviation used in the Table 1. ATP\(-\)the anterior tibialular part, TNP\(-\)the tibialocular part, PTTP\(-\)the posteriori tibialular part, DL\(-\)the delibed ligament, SL\(-\)the right figure, IER\(-\)the inferior extensor retinaculum, FTCL\(-\)the fibulatoxicolomeal ligament, Abl\(-\)the fascia on the abductor hallucics, FRS\(-\)the flexor fibrous sheath. \({}^{*}p<0.05\), \({}^{*}p<0.01\), \({}^{**}p<0.001\).} \\ \end{tabular}
\end{table} 
Table 1: Number of connections of FR with other structures included in the study. \(p\) values for the differences in the number of connections in the groups of patients with plantaris tendon type 4 and with accessory navicular bone.