Fig 1.
Connection of the DS to the LLSAN.
(A) The DS was connected to the originating fibers of the LLSAN by the muscle fibers (arrowheads). (B) Some connecting muscle fibers (arrowheads) between the DS and LLSAN were connected with the OOc INF (arrows). (C) The DS was connected to the middle portion of the LLSAN by a thin aponeurosis (arrowheads). (D) The DS was connected to the originating fibers of the LLSAN by a thin aponeurosis (arrowheads).
Fig 2.
Connection of the DS to the OOc INF.
(A) The DS was connected to the OOc INF by the muscle fibers (arrowheads). (B) The DS was connected to the OOc INF by the thin aponeurosis (arrows). Some muscle fibers (arrowheads) of the OOc INF were connected to the thin aponeurosis (arrows) coursing on the medial palpebral ligament, and the thin aponeurosis (arrows) of the OOc INF was connected to the DS.
Fig 3.
Connections of the DS to both the LLSAN and OOc INF.
(A) Connecting muscle fibers were found between the DS and LLSAN (arrowheads) and between the DS and OOc INF (arrows). (B) Connecting aponeuroses were found between the DS and LLSAN (arrowheads) and between the DS and OOc INF (arrows). Some muscle fibers (white arrows) of the OOc INF were connected to the thin aponeurosis (black arrows) coursing on the medial palpebral ligament, and the thin aponeurosis (black arrows) of the OOc INF was connected to the DS.
Fig 4.
Contractions and vectors of the glabellar muscles and the fibers connecting the DS and the LLSAN and OOc INF while grimacing.
Contracting the DS (yellow arrow) will pull the medial eyebrow down. Contracting the CS (orange arrow) pulls the eyebrow medially and down. Contracting the P (dark-blue arrow) depresses the medial eyebrow. Contracting the superior fibers of OOc (purple arrow) lowers and protrudes the eyebrow inferomedially. Contracting the OOc INF (pink arrow) elevates the cheek superomedially. Contracting the frontalis (black arrows) elevates the eyebrow. Contracting the LLSAN (green arrow) elevates the nasal ala and upper lip. The fibers (yellow and green arrows) connecting the DS and LLSAN (green arrow) and those (light-blue arrows) connecting the DS and OOc INF (pink arrow) may assist in depressing the medial eyebrow, elevating the nasal ala, upper lip, and cheek.