Philip J. Adds

A cadaveric study of ethmoidal foramina variation and its surgical significance in Caucasians

Aims To describe the morphometric and geometric relationships of the medial orbital wall ethmoidal foramina and the orbital apex in a Caucasian population. Methods 47 orbits from 24 formalin-fixed cadavers were exenterated. Morphometric measurements were taken between anatomical landmarks located on the medial orbital wall and geometric values were calculated. Results The average distances from the anterior lacrimal crest to the anterior ethmoidal foramen, posterior ethmoidal foramen and optic canal were 25.61 mm (±2.25), 36.09 mm (±3.86) and 43.77 mm (±2.52), respectively. The average distances from the anterior ethmoidal foramen to the first posterior ethmoidal foramen, last posterior ethmoidal foramen and optic canal were 13.88 mm (±3.51), 16.60 mm (±2.19) and 21.65 mm (±2.59), respectively. The average distances from the first and last posterior ethmoidal foramen to the optic canal were 11.63 mm (±3.79) and 7.25 mm (±2.59), respectively. Conclusion The distance between the posterior ethmoidal foramen and optic canal is more than double the distance quoted in the surgical literature. This is due to a high incidence of ethmoidal foramina variation. Surgeons operating on the medial orbital wall of a Caucasian population must be aware of these variations as they are a source of haemorrhage and act as landmarks of proximity to the optic canal.

Using ultrasound to measure the fibre angle of vastus medialis oblique: A cadaveric validation study

BACKGROUND The assumption that the vastus medialis oblique (VMO) is involved in medial patellar stabilisation has led to speculation that patellofemoral pain (PF) may be a result of abnormal patellar tracking, due to weakness or difference in fibre orientation of the VMO. Recent studies have reported that the VMO fibre angle, measured in vivo with ultrasound (US), is reduced in patellofemoral pain (PF) patients. However, the validity of US in measuring this parameter was not investigated and this would inevitably cast doubt on whether the US results are comparable to direct measurement. The aim of this study was to validate the use of ultrasound (US) in measuring VMO fibre angle by comparing results obtained both from US and direct measurement. METHODS The VMO fibre angle was determined in relation to the femoral axis in nine lower limbs from five soft-fixed cadavers, first using US and then by direct measurement. RESULTS The Pearson correlation coefficient between the two methods was 0.92 (p<0.01) indicating a very strong relationship. The average difference in measurements between the two methods was 0.20. Bland/Altman analysis showed 95% limit of agreement to be between -2.550 and 30, showing minimal discrepancies between results obtained by the two methods. CONCLUSION In conclusion, the VMO fibre angle values obtained by the US method were proved to be valid and comparable to those obtained from direct measurement. We show, therefore, that US can be used with confidence to measure VMO fibre angles in the cadaver, and, by implication, in clinical practice.

A cadaveric study of the cranio-orbital foramen and its significance in orbital surgery.

Background: The cranio-orbital foramen is an osseous anatomical landmark located adjacent to the superior orbital fissure. It is a potential source of hemorrhage during deep orbital dissection because it is the location of an anastomosis between the lacrimal artery and the middle meningeal artery. The purpose of this study was to determine the incidence, location, and number of cranio-orbital foramina within a Caucasian population. Methods: Forty-seven orbits from 24 formalin-fixed Caucasian cadavers were exenterated. If the cranio-orbital foramen was present within an orbit, its distance from the frontozygomatic suture, supraorbital notch, and Whitnalls tubercle was measured. The gender variations and asymmetric presentations of foramina were studied. Results: The cranio-orbital foramen was present in 26 orbits (55 percent). The average distance from the frontozygomatic suture, supraorbital notch, and Whitnalls tubercle was 30.92 mm (±4.37 mm), 37.77 mm (±3.55 ±), and 29.69 mm (±3.89 mm), respectively. In nine orbits (19 percent), an additional accessory cranio-orbital foramen was identified. The average distance from the frontozygomatic suture, supraorbital notch, and Whitnalls tubercle was 28.56 mm (±5.00 mm), 32.64 mm (±3.20 mm), and 27.78 mm (±5.24 mm), respectively. Conclusion: The presence of the cranio-orbital foramen and other accessory foramina represents a source of hemorrhage that surgeons should be aware of when operating along the lateral orbital wall.

A cadaveric study of the morphometric relationships and bony composition of the caucasian nasolacrimal fossa.

Aims: To describe the morphometric relationships and bony composition of the nasolacrimal fossa in a Caucasian population with particular reference to the lacrimo-maxillary suture (LMS). Methods: Forty-seven orbits from 24 formalin fixed cadavers were exenterated. Morphometric measurements were taken between anatomical landmarks forming the lacrimal fossa on the medial orbital wall. Results: The mean recorded distance from the anterior lacrimal crest (ALC) to the posterior lacrimal crest (PLC) and the LMS were 8.8 mm (± 1.6) and 4.3 mm (± 1.1), respectively. In 25.5% of the orbits the LMS was at the mid-vertical line (MVL), defined as a line equidistant from the ALC and PLC. In 42.5% the LMS was located anterior to the MVL toward the ALC. In 66% of the orbits the LMS was at or within one standard deviation (SD) of the MVL. The LMS was >1 SD away from the MVL toward the ALC and PLC in 19% and 15% of orbits, respectively. Conclusions: In a quarter of the orbits in our Caucasian population the nasolacrimal fossa was formed equally by the maxillary and lacrimal bones. However, in nearly a third of the cases the LMS was located closer to the PLC, indicating predominance of the thicker maxillary bone. This may result in greater difficulty in initiating the surgical osteotomy when performing a dacryocystorhinostomy. These data contribute to our understanding of the variation in lacrimal fossa anatomy and encourage further studies in different racial groups.

Morphometric and Geometric Anatomy of the Caucasian Orbital Floor

Introduction: To describe the morphometric and geometric relationships of the orbital floor in a Caucasian population. Materials and Methods: Exenterations of 47 orbits from 24 formalin fixed cadavers were performed. Morphometric measurements were taken between anatomical landmarks located along the orbital floor and the orbital apex. The mean measurements were used to calculate geometric data. These results were analysed according to sex and side and compared to results from other ethnic populations. Results: The average distances from the infraorbital foramen to the nasolacrimal fossa, inferior orbital fissure, optic canal and inferior orbital rim were 20.67 mm (± 2.42), 25.40 mm (±2.70), 43.23 mm (±3.35) and 8.95 mm (± 1.53), respectively. The average distances from the tip of the infraorbital groove to the tip of the inferior orbital fissure, lateral aspect of the inferomedial strut, optic canal and the intersection with the inferior orbital fissure were 14.08 mm (±2.41), 12.12 mm (±2.42), 35.02 mm (±3.17) and 20.05 mm (± 2.87), respectively. The distances from the tip of the inferior orbital fissure to the optic canal and the intersection with the inferior orbital groove were 29.56 mm (±2.73) and 13.37 mm (±2.76), respectively. Discussion: Orbital surgeons should be aware of the morphometric relationships of the orbital floor due to the degree of variation that exists between different ethnic groups. Geometric data may be used to provide orbital surgeons with a navigational template that can be used to plan surgery and as a guide intraoperatively.

A cadaveric study of the morphometric and geometric relationships of the orbital apex.

Introduction: To define the morphometric and geometric relationships which exist at the orbital apex. Materials and Methods: Forty-seven orbits from twenty-four formalin-fixed Caucasian cadavers were exenterated and the relevant sutures, fissures and foramina identified. Measurements were taken from the optic canal to anatomical landmarks located along the medial wall, inferior wall and lateral wall of each orbit. Based on the mean results the geometric angles between the different anatomical structures were calculated and used to create three-dimensional models. Results: The mean distances from the midpoint of the optic canal to the superior orbital fissure, inferior orbital fissure and anterior ethmoidal foramen were 10.22 mm, 29.56 mm and 21.65 mm, respectively. The mean distances from the anterior ethmoidal foramen to the superior and inferior orbital fissures were 24.27 mm and 31.93 mm, respectively. The mean distance between the tips of the superior and inferior orbital fissures was 27.70 mm. The mean distances directly from the tips of the superior and inferior orbital fissures and the anterior ethmoidal foramen to the orbital rim were 39.23 mm, 17.11 mm and 18.94 mm, respectively. These values were used to calculate geometric values and create three-dimensional models. Discussion: The orbital apex is a congested structure and the practicing orbital surgeon must have an intimate knowledge of its contents. We have presented novel data, which in conjunction with radiology may be used as both a navigational aid to plan orbital surgery and to guide the surgeon intraoperatively to assess proximity to key anatomical structures.

Supraorbital notch and foramen: positional variation and relevance to direct brow lift.

Purpose: Forehead paresthesia after brow lift is well-documented with rates as high as 40.7%. The authors describe an anatomical study to identify the variation in position of the supraorbital notch/foramen to define safe limits for deep dissection during this procedure. Methods: Sixty-six orbits from 23 dry skulls and 9 formalin-fixed cadavers were analyzed photographically using ImageJ software. The cadaveric specimens were dissected using a coronal incision, which allowed the inferior resection of the frontalis muscle and periosteum. The exit point of the supraorbital neurovascular bundle was noted as a foramen or notch. The position of the supraorbital notch or foramen was recorded in relation to the midline as defined by the sagittal suture at the level of the highest point of the supraorbital rim. The distance and angle for each foramen/notch were calculated. Results: Thirty-three percent of orbits had a foramen. The average distance from the midpoint to the foramen was 25.24 mm (standard deviation 3.78 mm) and to the notch was 22.69 mm (22.69 mm). The range of distance between the midpoint and the foramen/notch was 17.62 to 32.35 mm. The average angle between the horizontal meridian and the foramen was 81/57° (standard deviation 4.69°). Conclusions: A wide variation in anatomy was seen. Greater caution is required when performing deep dissection around the supraorbital notch because of the variation in position of the supraorbital foramen.

The potential complications of open carpal tunnel release surgery to the ulnar neurovascular bundle and its branches: A cadaveric study

This study investigated the ulnar artery and the ulnar nerve and its branches in the palm to assess how frequently they may be at risk of damage during open carpal tunnel release surgery. Twenty‐one formalin‐embalmed cadaveric hands were dissected, and the proximity of the ulnar neurovascular bundle to two different lines of incision, the 3rd and 4th interdigital web space axis and the ring finger axis, was assessed and compared. It was found that an incision in the latter (ring finger) axis put the ulnar artery at risk in 12 of 21 specimens, whereas an incision in the former axis (3rd/4th interdigital web space) put the ulnar artery at risk in only two specimens. In 15 hands at least one structure (the ulnar artery or a branch of the ulnar nerve) was at risk in the ring finger axis compared to only seven hands in the axis of the 3rd/4th interdigital web space. We conclude that the ulnar artery and branches of the ulnar nerve are at increased risk of damage with an incision in the axis of the ring finger. The importance of using a blunt dissection technique under direct vision during surgery to identify and preserve these structures and median nerve branches is emphasized. Clin. Anat. 23:545–551, 2010.

The effect of exercise on vastus medialis oblique muscle architecture: An ultrasound investigation.

The vastus medialis oblique (VMO) is thought to be implicated in patellofemoral pain (PFP), and weakness in this portion of the vastus medialis muscle may lead to PFP. Management includes physiotherapy to strengthen the VMO. Although this intervention has been shown to be effective, the effects on the architecture of the muscle have not been investigated. This study aims to determine the changes in VMO architecture following a program of strengthening exercises. Twenty‐one male participants underwent an initial ultrasound scan to measure the fiber angle and the insertion level of the VMO on the patella. Each subject then undertook a 6‐week quadriceps femoris strengthening program; the scan and measurements were then repeated. A significant increase in VMO fiber angle and insertion length was observed. Average fiber angle increased by 5.24°; average insertion length increased by 2.7 mm. There was found to be a significant negative correlation between the initial values and the degree of change. Pearsons coefficient of correlation for measurements of patella length taken before and after exercise was 0.921, indicating a high degree of reliability. There was a significant positive correlation between fiber angle change and declared level of compliance (R2 = 0.796). The results reported here indicate that physiotherapy leads to a significant change in VMO morphology. Given the inverse correlation noted between initial architectural parameters and the degree of change, we suggest that patients who would benefit most from physiotherapy can be identified in clinic using a simple ultrasound technique. Clin. Anat. 29:752–758, 2016.

Lessons from the Past: Cribra Orbitalia, An Orbital Roof Pathology

Aims: To define a computed tomography protocol that may be used in future clinical practice for the reliable detection and analysis of cribra orbitalia. Materials and Methods: Two osteological assemblages from the Museum of London were used to select 13 cribratous skulls and 5 non-cribratous skulls. Area of cribra orbitalia was measured using image analysis. Morphology of cribra orbitalia, orbital roof density and the associated optic canal diameter was analysed using computed tomography reconstructions. Results: The presence of cribra orbitalia was associatedwith changes in the internal diploë layer as well as the cortical bone table. A novel radiological grading system and protocol was developed to identify the pathology. A decrease in the orbital roof density by 210 Hounsfield units and a reduction in the optic canal diameter, up to 1 mm, were found to be associated with the presence of cribra orbitalia. Conclusions: The occurrence of cribra orbitalia is found to be associated with stenosis of the optic canal, and could explain a proportion of cases ofoptic nerve entrapment. This study provides a guideline for radiologists and oculoplastic surgeons to help detect the presence of cribra orbitalia in suspected patients.