The main cause of sinus pathology is disease in the middle meatus, therefore, unless nasal drops are deposited in this site they will not be effective. Currently, one of three standard head positions are used by patients for the instillation of nasal drops, 'head back', 'praying to Mecca', and 'Mygind's', all are uncomfortable and only one, Mygind's position, effectively deposits the drops in the middle meatus. In this paper, we review these three positions by utilizing a preserved cadaver head and conducting a simple gravitational flow study using white liquid latex as a nasal drop substitute. We also describe a new fourth 'Ragan' position, on the side, head down, that is effective in consistently delivering nasal drops into the middle meatus and should prove a most comfortable position for patients to adopt.

The position, dimension and thickness of the exposed lacrimal bone at the lateral nasal wall in 10 cadaveric half-heads were examined. In all cases, the lacrimal bone at the lateral nasal wall was found to be just anterior to the mid-third of the uncinate process. The average length and width was 7.4 mm and 2.5 mm, respectively. In nine of the 10 half-heads, the lacrimal bone was very thin with an average thickness of 57 mm. In all the cases, the position of the lacrimal passage covered by the lacrimal bone corresponded to the postero-medial aspect of the upper lacrimal duct and the lower lacrimal sac. This study shows that the uncinate process is a reliable landmark for the lacrimal bone in endoscopic nasal surgery. The paper-thin lacrimal bone allows a bone rongeur to infracture through and nibble away the bony covering of the lacrimal sac in a dacryocystorhinostomy.

The deep (motor) branch of the ulnar nerve is not frequently seen during surgery, but is vulnerable to penetrating injury and may be injured during surgery. Its anatomy is poorly described and its three-dimensional configuration is poorly appreciated. In this study, dissections of ten cadaveric specimens have been performed to demonstrate the branching pattern of the nerve and its skeletal relations have been clarified by superimposing images on radiographs. The deep branch passes downwards (anatomical posterior) through a hypothenar fibro-muscular tunnel and courses radially on the surface of the interossei. It has four major divisions that are consistent and readily identifiable. Twenty branches were documented supplying hypothenar muscles, medial two lumbricals, interossei, adductor pollicis, all the carpometacarpal and the ring and little metacarpophalangeal joints, and opponens pollicis in 40% and flexor pollicis brevis in 20% of subjects.

Cadaveric material is often used to guide and validate the interpretation of magnetic resonance imaging (MRI) studies. Direct correlation is achieved when the cadaver material is imaged and then directly sectioned in the plane of the image. Indirect correlation, where the cadaveric sections are compared with unrelated in-vivo images, is easier and more commonly used. Technical difficulties associated with the direct method include preservation of form and composition of the tissues, and the choice of the correct location and plane in which to section the cadaver. Using an MRI compatible ruler, designed to assist the direct correlation of MRI and cadaveric sections, we have examined 10 preserved (embalmed) cadaveric knees using different MRI sequences on several occasions. Despite these variations, subsequent sectioning of the cadaveric knees has shown good correlation with the MR images. Of 54 MR images compared with cadaveric sections, anatomical correlation was rated by independent observers as good or perfect in 47 (87%). This new, versatile and simple method can make better use of our preserved human cadaveric material and has potentially wide application; we are now developing it further to assess the technical capabilities of novel imaging sequences.