Elephant ossicles in the middle ear cavity, and μCT images of elephant and human ossicles.

Elephant temporal bones were prepared in order to open the middle ear cavity widely enough to access the ossicles in such a way that the three beams of the 3D LDV laser could hit the targets with no obstructions. (A) Image through the microscope after placement of targets. Reflective targets were placed on all three bones and the promontory: Four along the malleus from inferior at the umbo (M1), across the lateral process to superior, on the head of the malleus near the incudomalleolar joint (IMJ) (M4). Four along the incus long-process from superior (I4) near the IMJ to at the distal tip of the incus, close to the incudostapedial joint (ISJ) (I1). Two on the stapes head SH1,2 and three on the promontory (PRM) 1, 2, 3. (B) The malleus, incus and stapes reconstructed from μCT image for both the elephant (left) and human (right). Estimated malleus lengths are shown in yellow. (Image from ETB1 and μCT from ETB2 and TB24; refer to Table 1 for measurements). (C) Additional view of the axis of rotation (solid black line).