Model organisms with soft skulls, such as the mouse and the neonatal rat, have traditionally been difficult to secure firmly in a stereotaxic instrument. The stainless steel ear bars used for adult rats are too heavy to position precisely enough to provide a secure hold while still avoiding flexing the sides of the skull inward (which compresses the airways and impedes blood flow.) Further, the neonatal rat pup has no external opening of the auditory canal into which to insert the ear bar points.

The Cunningham™ Mouse and Neonatal Rat Adaptor, manufactured by Stoelting, employs light, Delrin® ear bars with tapered points on one end, and rubber pads on the other, to facilitate surgery on such animals. Neonatal surgery may be accomplished with minimally invasive procedure by using the rubber pad ends of the ear bars. Ear bars may be independently adjusted in height, a unique feature in stereotaxic instrumentation, to achieve the skull flat position. Laser engraved scales shows the vertical position of the ear bars. A tooth bar and nose clamp secures the nose. A well carved in the thick aluminum body may be filled with dry ice and alcohol for hypothermic anesthesia of neonatal animals. The Cunningham™ Mouse and Neonatal Rat Adaptor clamps securely on the right side of the “U” frame of the Lab Standard™, which provides the stereotaxic manipulator.

New improvements to this popular stereotaxic adaptor include an increased overall length to accommodate larger, more mature animals, and the addition of specialized jaw holder cuffs (51647), which securely clamp the zygomatic processes of the skull. The jaw holder cuffs fit over the ends of the ear bars, replacing the rubber pads, providing an alternative non-invasive means of securing the animal’s head in the stereotaxic stage. These options for “triple point” securing of the animal’s head in this adaptor make it the most versatile mouse stereotaxic available. Set of two jaw holder cuffs included.