Enthesis strength, toughness and stiffness: an image-based model comparing tendon insertions with varying bony attachment geometries

Tendons of the body differ dramatically in their function, mechanics and range of motion, but all connect to bone via an enthesis. Effective force transfer at the enthesis enables joint stability and mobility, with strength and stiffness arising from a fibrous architecture. However, how enthesis toughness arises across tendons with diverse loading orientations remains unclear. To study this, we performed simultaneous imaging of the bone and tendon in entheses that represent the range of tendon-to-bone insertions and extended a mathematical model to account for variations in insertion and bone geometry. We tested the hypothesis that toughness, across a range of tendon entheses, could be explained by differences observed in interactions between fibre architecture and bone architecture. In the model, toughness arose from fibre reorientation, recruitment and rupture, mediated by interactions between fibres at the enthesis and the bony ridge abutting it. When applied to tendons sometimes characterized as either energy-storing or positional, the model predicted that entheses of the former prioritize toughness over strength, while those of the latter prioritize consistent stiffness across loading directions. Results provide insight into techniques for surgical repair of tendon-to-bone attachments, and more broadly into mechanisms for the attachment of highly dissimilar materials.

Prosthodontic rehabilitation of compromised upper and lower residual alveolar ridges: A case report

Residual ridge resorption is the reduction in size of the bony ridge under the mucoperiosteum. Obtaining retention and stability in a severely resorbed ridges using a conventional technique is a tedious task. The resorption occurs at a faster rate in mandibular arch as compared to the maxillary arch. In order to have a favorable prognosis for the denture therapy, impression technique selected should be based on the present state of the basal tissue support for mandible. In this article neutral zone concept was incorporated in to impression making in an effort to achieve successful mandibular complete denture. The anterior region of maxilla is the most affected area in edentulous patients. Complete denture wearers with flabby ridges may face a number of difficulties, of which major complaints would be pain, compromised stability, support, and retention and an ill-fitting denture. Special impressions often involve window technique for static impression of flabby area, which present multiple challenges. This article presents a case report of modified widow impression technique for maxillary anterior flabby tissues along with a hollow maxillary complete denture in a patient with resorbed maxillary and mandibular ridges with increased interridge distance to reduce the weight of the prosthesis and thereby enhances the retention.

A DEVICEFUL APPROACH OF MANAGING HOLLOW MAXILLARY COMPLETE DENTURE

Retention, stability and support are the most fundamental and basic principles on which the success of an entire denture relies on. However this factor is often compromised in cases of resorption. Residual ridge resorption is the reduction in size of the bony ridge under the mucoperiosteum. The rate of resorption in mandibular arch is at an increased rate as compared to the maxillary arch; but severely atrophic maxillae with large inter-ridge distance often pose a clinical challenge during fabrication of a successful maxillary complete denture because of the increased weight of the denture, retention is compromised. The present article describes a case of a completely edentulous patient who was successfully rehabilitated with a hollow denture where a simple and deviceful technique of fabricating a light-weight maxillary denture. The present article describes a case of a completely edentulous patient who was successfully rehabilitated with a hollow denture where a simple and deviceful technique of fabricating a light-weight maxillary denture was used using the hollow tubing of salivary ejector apparatus to bring the uniform hollowness.

The Anterolateral Triangle: Implications for a Transnasal Prelacrimal Approach to the Floor of the Middle Cranial Fossa

Background The anterolateral triangle enclosed by the foramen rotundum and foramen ovale constitutes part of the floor of the middle cranial fossa (MCF). Objective To assess the feasibility of a transnasal prelacrimal approach for accessing the floor of MCF via an anterolateral triangle corridor and to determine the extent of maximal exposure while safeguarding neurovascular structures. Methods A transnasal prelacrimal approach was performed in 5 cadaveric specimens (10 sides). Following the identification of foramen rotundum and foramen ovale, the bony ridge between 2 was drilled to expose the MCF. The temporal lobe dura was then elevated laterally, and the distances from foramen ovale to the respective borders of the area of the MCF window were measured using a surgical navigation device. Results The MCF was exposed with a 0° scope in all specimens also exposing significant landmarks including the middle meningeal artery, greater superficial petrosal nerve, superior petrous sinus, and arcuate eminence. Average distances from foramen ovale to the anterior, posterior, and lateral exposed borders were 22.86 ± 1.87 mm, 27.24 ± 0.94 mm, and 24.23 ± 1.61 mm, respectively. The average area of exposed MCF window was 554.12 ± 60.22 mm2. Preservation of vidian nerve, greater palatine nerve, lateral nasal wall, and nasolacrimal duct was possible in all 10 sides. Conclusion It is feasible to access the floor of MCF via an endoscopic transnasal prelacrimal approach with seemingly low risk.

Arnoglossus nigrofilamentosus n. sp., a new species of flounder (Teleostei: Bothidae) from off the Mediterranean coast of Israel, probably a new case of Lessepsian migration

The filamentous flounder Arnoglossus nigrofilamentosus n. sp. is described from four specimens collected in the southeastern Mediterranean near Tel-Aviv, Israel on 5 May 2017. The new species is characterized as follows: second to sixth dorsal-fin rays elongate and filamentous, dorsal-fin rays 78-84, anal-fin rays 61-66, pectoral-fin rays on ocular side 12-13, on blind side 7-9, caudal-fin rays iii,11,iii , lateral-line scales 52-54, gill rakers 0 + 4-5, not serrated, interorbital a narrow bony ridge without scales in the middle, interorbital width 11% to 16% of upper orbit diameter, no enlarged teeth anteriorly in upper jaw, and prevomer small, not enlarged, weakly projecting into mouth cavity; body in fresh specimens pale (may have been dark before the epidermis was abrased), head, peritoneum and vertical fins black. The new species is described and compared with similar species. Though the species has not yet been observed in the northern Red Sea, it probably originates from the Gulf of Suez, so this finding represents a probable new case of Lessepsian migration.

Quantitative and Qualitative Analysis of the Medial Patellar Ligaments: An Anatomic and Radiographic Study

Background: The qualitative and quantitative anatomy of the medial patellar stabilizers has been reported; however, a quantitative analysis of the anatomic and radiographic attachments of all 4 ligaments relative to anatomic and osseous landmarks, as well as to one another, has yet to be performed. Purpose: To perform a qualitative and quantitative anatomic and radiographic evaluation of the medial patellofemoral ligament (MPFL), medial patellotibial ligament (MPTL), medial patellomeniscal ligament (MPML), and medial quadriceps tendon femoral ligament (MQTFL) attachment sites, with attention to their relationship to pertinent osseous and soft tissue landmarks. Study Design: Descriptive laboratory study. Methods: Ten nonpaired fresh-frozen human cadaveric knees were dissected, and the MPFL, MPTL, MPML, and MQTFL were identified. A coordinate measuring device quantified the attachment areas of each structure and its relationship to pertinent bony landmarks. Radiographic analysis was performed through ligament attachment sites and relevant anatomic structures to assess their locations relative to pertinent bony landmarks. Results: Four separate medial patellar ligaments were identified in all specimens. The center of the MPFL attachments was 14.3 mm proximal and 2.1 mm posterior to the medial epicondyle and 8.3 mm distal and 2.7 mm anterior to the adductor tubercle on the femur and 8.9 mm distal and 19.9 mm medial to the superior pole on the patella. The MQTFL had a mean insertion length of 29.3 mm on the medial aspect of the distal quadriceps tendon. The MPTL and MPML shared a common patellar insertion and were 9.1 mm proximal and 15.4 mm medial to the inferior pole. The MPTL attachment inserted on a newly identified bony ridge, which was located 5.0 mm distal to the joint line. The orientation angles of the MPTL and MPML with respect to the patellar tendon were 8.3° and 22.7°, respectively. Conclusion: The most important findings of this study were the correlative anatomy of 4 distinct medial patellar ligaments (MPFL, MPTL, MPML, MQTFL), as well as the identification of a bony ridge on the medial proximal tibia that consistently served as the attachment site for the MPTL. The quantitative and radiographic measurements, while comparable with current literature, detailed the meniscal insertion of the MPML and defined a patellar insertion of the MPTL and the MPML as a single attachment. The data allow for reproducible landmarks to be established from previously known bony and soft tissue structures. Clinical Relevance: The findings of this study provide the anatomic foundation needed for an improved understanding of the role of medial-sided patellar restraints. This will help to further refine injury patterns and/or soft tissue deficiencies that result in lateral patellar instability, which can then be addressed with an anatomic-based reconstruction or repair technique and potentially lead to improved outcomes.

Residual Ridge Resorption– Revisited

The Residual Ridge Resorption (RRR) is a major unsolved oral disease with unidentifiable characteristics and unwanted squealae causing physical, psychologic, and economic problems for millions of people all over the world. RRR is basically a term used to describe a condition that affects the alveolar ridge after tooth extractions even after healing of the wounds. RRR is a chronic, progressive, irreversible, and disabling disease, probably of multifactorial origin. The possible etiological factors could be divided into four categories: anatomic, metabolic, functional, and prosthetic. The primary structural change in the reduction of residual ridges is the loss of bone or reduction in the size of bony ridge under mucoperiosteum. The reduction in the ridge mainly occurs labially, lingually and on the crest. The reduction of the residual ridge leads to a variety of stages of ridge form, including high well-rounded, knife-edge, low well-rounded, and depressed forms. Alveolar bone atrophy is cumulative and irreversible, since alveolar bone cannot regenerate. It differs from one individual to the other. It also varies at different times and different sites. Some authors feel RRR as a normal physiologic process and not a disease but the cost in economic and human terms makes RRR as a major oral disease that can be described in terms of its pathology, pathophysiology, pathogenesis, epidemiology, etiology, treatment and prevention.

Cranioplasty for the Relief of Chronic Pain: 70 Years after the Debridement of the War-Penetrating Craniocerebral Injury

We report the case of a 75-year-old female patient who underwent primary debridement of the penetrating craniocerebral injury at the age of 5 years. The injury was caused by the explosive shrapnel wound in the parietal right-side region because of an air raid in Yugoslavia in 1944 during World War II (WWII) combat. The scull defect that remained was not repaired. The patient developed the severe allodinic pain syndrome in the skin over the cranial defect, 70 years after the surgery. The skin over the cranial defect was infolded inside the skull and stretched over the bony ridge. The pain was relieved by cranioplasty that restored the cranial vault and reversed the infolding skin over the craniectomy defect. The mechanism of the pain and its relation with the morphologic changes of the primary craniectomy and brain debridement over time are discussed.