The lateral canthal tendon, ligament, or raphe as it is frequently called, is a fibrous extension of the tarsal plates laterally toward the orbital rim (fig. 2-7). As will be seen in the medial canthal tendon, the lateral tendon has a superficial and deep component. The base of the ligamentous complex is shaped like a Y and is attached to the external angle of the two tarsi (Fig. 2-8). The two divisions diverge from the tarsi and the superficial component extends laterally just under, or intermingling with the orbicularis oculi muscle. It continues lateral to the orbital rim and inserts into the periosteum overlying the lateral orbital rim and the temporalis fascia just lateral to the orbital rim. The thicker, stronger deep component of the lateral canthal tendon courses posterolaterally, inserting into the periosteum of the orbital tubercle of the zygoma, approximately 2 to 3 mm posterior to the orbital rim. The space between the two bundles of the lateral canthal tendon is filled with loose connective tissue.
Figure 2- 8 Medial and lateral canthal tendon complexes. Note that the anterior limb of the medial canthal tendon (AL, MCT) and the posterior limb of the lateral canthal tendon (PL LCT) are thicker. The thicker anterior portion of the medial canthal tendon attaches to the anterior lacrimal crest of the maxilla and the frontal process of the maxilla. The thinner posterior limb of the medial canthal tendon (PL MCT) attaches along the posterior lacrimal crest of the lacrimal bone. The thick posterior portion of the lateral canthal tendon (PL LCT) attaches to the orbital (Whitnall's) tubercle of the zygoma, 3 to 4 mm posterior to the lateral orbital rim. The thinner anterior fibers course laterally to mingle with the orbicularis oculi muscle fibers and the periosteum of the lateral orbital rim.
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