Lamina papyracea

Orbital lamina of ethmoid bone
Ethmoid bone from the right side. (Lamina papyracea visible at center left.)
The seven bones which articulate to form the orbit. (Ethmoid is brown.)
Details
Latin	Lamina orbitalis ossis ethmoidalis
Dorlands /Elsevier	l_02/12476524
Anatomical terminology []

The lamina papyracea (or orbital lamina) is a smooth, oblong bone plate which forms the surface of the labyrinth of the ethmoid bone in the skull. The plate covers in the middle and posterior ethmoidal cells and forms a large part of the medial wall of the orbit.

It articulates above with the orbital plate of the frontal bone, below with the maxilla and the orbital process of palatine bone, in front with the lacrimal, and behind with the sphenoid.

Its name lamina papyracea is an appropriate description, as this part of the ethmoid bone is paper-thin and fractures easily. A fracture here could cause entrapment of the medial rectus muscle.

Orbital lamina of ethmoid bone

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)