眼球外筋力の分析

An Analysis of Extraocular Muscle Forces in the Piked Dogfish (Squalus acanthias).

• Matthew Gurley
• Philip Motta

抄録

脊椎動物は、眼球を回転させるために丈夫な保護強膜に付着した6つの眼球外筋を利用している。本研究の目的は、眼球に作用する力を理解するために、最大の眼球外筋力と6つの眼球外筋が生み出す力を記述することであった。眼球外筋の外側直筋は平行繊維状であり、筋線維は離散した筋線維に束ねられていることが判明した。眼球外筋は筋肉の挿入によって強膜に付着している。眼球外筋によって発生した総引張力は1.18Nから2.21Nであった。眼球外筋のトルクは0.39Nから2.34Nであった。側方直筋は最大の総引張力と最大のトルク力成分を生み出したが、内側直筋は2番目に大きな力を生み出した。これは、水泳中の有効視野を広げるだけでなく、視覚像を安定させるために、眼球の前方と後方に一定の回転運動が行われているためと考えられます。脊椎動物の眼球で発生する多筋収縮時には、運動の主方向以外の次元での回転力が主方向以外の運動に寄与している可能性がある。Anat Rec, 2018. © 2018 Wiley Periodicals, Inc.Anat Rec, 302:837-844, 2019. © 2018 Wiley Periodicals, Inc.

Vertebrates utilize six extraocular muscles that attach to a tough, protective sclera to rotate the eye. The goal of the study was to describe the maximum tetanic forces, as well as the torques produced by the six extraocular muscles of the piked dogfish Squalus acanthias to understand the forces exerted on the eye. The lateral rectus extraocular muscle of Squalus acanthias was determined to be parallel fibered with the muscle fibers bundled into discrete fascicles. The extraocular muscles attach to the sclera by muscular insertions. The total tensile forces generated by the extraocular muscles ranged from 1.18 N to 2.21 N. The torques of the extraocular muscles ranged from 0.39 N to 2.34 N. The torques were greatest in the principal direction of movement for each specific muscle. The lateral rectus produced the greatest total tensile force, as well as the greatest torque force component, while the medial rectus produced the second greatest. This is likely due to the constant rotational movement of the eye anteriorly and posteriorly to stabilize the visual image, as well as increase the effective visual field during swimming. Rotational forces in dimensions other than the primary direction of movement may contribute to motion in directions other than the principal direction during multi-muscle contraction that occurs in the vertebrate eye. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. Anat Rec, 302:837-844, 2019. © 2018 Wiley Periodicals, Inc.

© 2018 Wiley Periodicals, Inc.