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Chapter 2: Surgical Anatomy :
Lockwood’s ligament
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Lockwood’s ligament may be compared to a hammock supporting the globe (Figure 36). It forms a dense condensation of tissue that engulfs the inferior rectus and inferior oblique muscles beneath the globe. The attachment of Lockwood’s ligament to the inferior oblique affects globe movement from the inferior oblique muscle when it contracts, even when the inferior oblique is transected on both sides of Lockwood’s!
Attachments between Lockwood’s ligament and neighboring muscle and fascial structures are connected to the lower lid. This makes lower lid ptosis a potential complication of inferior rectus recession (Figure 37). To avoid this, the inferior rectus should be freed extensively during surgery. Guyton, et. al., have recommended that Lockwood’s ligament be advanced when recession of the inferior rectus muscle is carried out. When resection of the inferior rectus is performed, persistent attachment of this muscle to Lockwood’s ligament can cause just the opposite, a bothersome and cosmetically unacceptable elevation of the lower lid resulting in narrowing of the palpebral fissure. Freeing the inferior rectus muscle from Lockwood’s ligament also helps avoid this complication.
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Figure 36
A The ligament of Lockwood could be compared to a hammock supporting the globe.
B The inferior oblique passes beneath the inferior rectus, through Lockwood’s ligament and orbital fat approximately 12 - 14 mm from the limbus.
C The inferior fat pad is prominent and should not be disturbed during surgery of the inferior rectus.
Figure 37
A saggital section of the complex anatomy of the orbit shows the intimate relationship of the inferior rectus, inferior oblique, and Lockwood’s ligament. This complex, in turn, is connected to the lower lid tarsus and inferior orbital septum. The inferior extraconal fat protrudes farther forward compared to the extraconal fat of the superior globe. Recession of the inferior rectus causes recession of the lower lid and widening of the fissure. Advancement or resection of the inferior rectus causes narrowing of the palpebral fissure. Placement of the conjunctival incision too far from the limbus inferiorly can result in disturbance of the extraconal fat compartment.
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