An anatomic study of the morphologic characteristics of the dorsal capitolunate ligament.

PURPOSE: There is consensus in favor of a description of the dorsal ligaments of the carpus as not including a direct ligament between the lunate and capitate. On the other hand, there is an anatomical formation which, according to the currently accepted description, corresponds to the dorsal midcarpal capsule, itself thickened by the dorsal intercarpal ligament. The question is whether the capsule at this point deserves to be called an individualizable ligament. In our operative experience of the dorsal carpus, we have encountered a stout structure adherent to the lunate and capitate. In this article, we present the anatomic evidence of this structure's existence. METHODS: Seven adult fresh frozen upper extremities were dissected. Three wrists were longitudinally sectioned in line with the middle finger metacarpal. The remaining 4 were dissected dorsally. Two representative samples of the stout structure connecting the lunate to the capitate were sent to pathology for histologic analysis and staining. RESULTS: In all 3 of the longitudinally sectioned wrists, a thick band of tissue could clearly be seen, originating on the lunate, spanning the dorsal interval between the lunate and the capitate, and inserting on the capitate. With this structure intact, dorsal dislocation of the capitate was not possible, but preliminary sectioning of the structure allowed dislocation. In the 4 dorsally dissected wrists, the same connection was observed, palmar to the dorsal intercarpal ligament, in every specimen. The average dimensions of the dorsal capitolunate were: 15.25 ± 1 mm long, 8.75 ± 1 mm wide at the midpoint, and 1.75 ± 1 mm thick. The two specimens sent to pathology after sectioning showed longitudinally oriented collagen fibers. This structure also stained positive for elastin and contained intrasubstance vascular structures. CONCLUSION: There is a stout ligamentous structure connecting the lunate to the capitate, palmar to the dorsal intercarpal ligament. Disruption of this structure appears to be necessary for dorsal dislocation of the capitate. Clinical studies are needed to gain better understanding of the exact function and importance of this structure.

Association of Lunate Morphology With Progression to Scaphoid Fracture Nonunion.

Background: The purpose of our study was to review a series of patients with scaphoid fractures to determine whether there was an association between lunate morphology and progression to delayed union or nonunion when treated operatively or nonoperatively. Secondary aims included evaluation of the relationship between lunate morphology and scaphoid fracture location. Methods: A retrospective review of all patients with a diagnosis of scaphoid fracture was performed at our institution between 2014 and 2017. Medical records and radiographs were evaluated to determine lunate morphology, scaphoid fracture location, treatment, and time to union. Differences between groups were determined using χ2 analysis with significance set at P <.05. Multiple logistic regression analyses were used to evaluate scaphoid union in the setting of lunate morphology when controlling for confounders. Results: A total of 169 patients were included; 45.0% (n = 76) of patients had type I lunate morphology, and 55.0% (n = 93) had type II. In all, 64.5% (n = 49) of patients with type I lunate and 68.8% (n = 64) with type II lunate had a fracture at the scaphoid waist. Among all patients with a scaphoid fracture, type II lunates were more likely than type I lunates to progress to nonunion when treated both operatively and nonoperatively (18.3% vs 4.0%, P = .0042). Lunate facet size was not shown to be a significant risk factor for nonunion among patients with a type II lunate (P = .4221). Conclusions: Patients with a scaphoid fracture and type II lunate morphology were more likely to progress to nonunion than patients with a type I lunate.

The Effect of Lunate Morphology in Carpal Disorders: Review of the Literature.

Variation in lunate morphology can exist based on the absence (Type I) or presence (Type II) of medial facet on the distal articular surface of the lunate that contacts the proximal pole of the hamate. This additional lunatohamate articulation can affect load transmission across the radiocarpal joint and exert an influence on carpal kinematics. A Type II lunate is protective against carpal instability patterns associated with scaphoid nonunions and scapholunate dissociations. It may also play a role in the progression of carpal collapse that occurs in Kienböck disease. This review summarizes the effect of lunate morphology in the outcomes of non-operative and operative treatment of carpal disorders.

Capitate and Lunate Morphology in Normal Wrist Radiographs-A Pilot Study.

BACKGROUND: Morphology may provide the basis for the understanding of wrist mechanics. METHODS: We used classification systems based on cadaver dissection of lunate and capitate types to evaluate a normal database of 70 wrist radiographs in 35 subjects looking for associations between bone shapes. Kappa statistics and a log-linear mixed -effects model with a random intercept were used. RESULTS: There were 39 type-1, 31 type- 2 lunates, 50 spherical, 10 flat and 10 V-shaped capitates. There was a significant difference in lunate and capitate shape between the hands of the same individual p <0.001. This may be due to different loads on the dominant vs. nondominant hands in the same individual. CONCLUSION: Further study to better understand the development of radiographic parameters of the midcarpal joint may aid in our understanding of the morphology and mechanics of the wrist.

Role of Ligament Stabilizers of the Proximal Carpal Row in Preventing Dorsal Intercalated Segment Instability: A Cadaveric Study.

BACKGROUND: Isolated injuries of the scapholunate interosseous ligament (SLIL) are insufficient to produce dorsal intercalated segment instability. There is no consensus about which additional ligamentous stabilizers are critical determinants of dorsal intercalated segment instability. The aim of this study was to evaluate the role of the long radiolunate (LRL), scaphotrapeziotrapezoid (STT), and dorsal intercarpal (DIC) ligaments in preventing dorsal intercalated segment instability. METHODS: Thirty fresh-frozen forearms were randomized to 5 ligament section sequences to study the SLIL, LRL, STT, and DIC ligaments. The DIC-lunate insertion (DIC) and scaphoid insertion (DIC) were studied separately; the DIC insertions on the trapezium and triquetrum were left intact. Loaded posteroanterior and lateral fluoroscopic images were obtained at baseline and repeated after each ligament was sectioned. After each sequence, the wrists were loaded cyclically (71 N). The radiolunate angle was measured with load. Dorsal intercalated segment instability was defined as an increase of >15° in the radiolunate angle compared with baseline. RESULTS: Division of the SLIL did not increase the radiolunate angle. Section of the SLIL+LRL or SLIL+DIC significantly increased the radiolunate angle but did not produce dorsal intercalated segment instability. Section of the SLIL+STT or SLIL+DIC+DIC produced dorsal intercalated segment instability. CONCLUSIONS: In order to produce dorsal intercalated segment instability, complete scapholunate injuries require the disruption of at least 1 critical ligament stabilizer of the scaphoid or lunate (the STT or DIC+DIC). CLINICAL RELEVANCE: When treating SLIL tears with dorsal intercalated segment instability, techniques to evaluate the volar and dorsal critical stabilizers of the proximal carpal row should be considered.

Radiographic prediction of lunate morphology in Asians using plain radiographic and capitate-triquetrum distance analyses: reliability and compatibility with magnetic resonance arthrography (MRA) findings.

BACKGROUND: The purpose of this study was to examine the reliability of plain radiographic methods of determining the lunate type and its compatibility with magnetic resonance arthrography (MRA) findings. METHODS: Plain radiographs of a total of 150 wrists were reviewed by three observers. Lunate types were evaluated using both conventional posteroanterior (PA) radiographic analysis and the capitate-triquetrum distance (CTD) analysis. Cohen kappa and Fleiss kappa statistics were used to estimate intra- and inter-observer reliabilities. Compatibility with the MRA findings, as assessed by each observer, was investigated. RESULTS: The overall intra-observer reliability was 0.517 for the analysis and 0.589 for the CTD analysis. The overall inter-observer agreement was 0.448 for the PA radiographic analysis and 0.581 for the CTD analysis. The PA radiographic analysis and MRA findings for the detection of medial lunate facets were compatible in 119 of the 150 patients (79.3%). Twenty-eight (90.3%) of the 31 incompatible wrists had a medial facet on MRA (Type II), which was not detected in the PA radiographic analysis. In the CTD analysis, the results for 27 of 29 Type II lunates (93.1%) and 39 of 45 Type I lunates (86.7%) were compatible with the MRA. CONCLUSIONS: This study suggests that predicting the lunate type by plain radiographs alone is insufficient, as both radiographic analyses showed moderate intra- and inter-observer reliabilities. Although both radiographic analyses showed good compatibility with the MRA for Type II lunates, clinicians should be alert to undetected medial facets in Type I lunates on PA radiographic analysis.

Ulnolunate Distance and Lunate Height: Reliability Testing.

PURPOSE: Many methods for measuring ulnar variance have been described. The purpose of this study was to introduce the use of both lunate height and ulnolunate distance on the zero-rotation view as well as to assess the intra- and interobserver reliabilities of these measurements. The hypothesis was that the use of concave surfaces in the measurement of both lunate height and ulnolunate distance will yield a higher intra- and interobserver reliability than ulnar variance, which uses the convex surface of the distal radius. METHODS: Seven hand fellows reviewed 32 radiographs. Measurements of lunate height, ulnolunate distance, and ulnar variance, using the method of perpendiculars, were recorded to the nearest 0.5 mm. Intraclass correlation coefficient (ICC) was then calculated for each radiograph for intra- and interobserver reliability. RESULTS: The ICC measurements were similar for lunate height, ulnolunate distance, and ulnar variance. The inter- and intraobserver reliability was similar for all 3 measurements. CONCLUSIONS: Measurements of ulnar variance utilize the concave surface of the distal radius. The use of the convex surface of the lunate and pole of the ulna does not seem to improve the reliability of these measurements. Further studies are necessary to confirm the clinical utility of these measurements. CLINICAL RELEVANCE: The use of ulnolunate distance and lunate height as an adjunct to ulnar variance may assist in evaluation of distal radius fractures and ulnocarpal abutment, improve surgeon communication, and contribute to our overall knowledge of the wrist.

[Anatomy and pathobiomechanics of the scaphoid]. / Anatomie und Pathobiomechanik des Skaphoids.

Among the carpal bones the scaphoid (Os scaphoideum) is the most important. The most frequent fracture of the carpus is a fracture of the scaphoid bone. The frequently occurring absence of healing of these fractures as well as unhealed ruptures of the ligament complex between the scaphoid and lunate, lead to the most severe biomechanical and thus the most severe clinical changes of the wrist. The detailed anatomy of the scaphoid, blood flow, ligament attachments, injury mechanisms and pathobiomechanics are described and illustrated.

Anatomical relationship of palmar carpal bone landmarks used in locating the lunate and capitate during palpation: A cadaveric investigation.

STUDY DESIGN: Descriptive in situ cadaveric study. INTRODUCTION: Performing accurately directed examination and treatment to the wrist requires clinicians to orient to carpal bone structures. PURPOSE OF THE STUDY: To examine the anatomical relationships that exist within the wrist-hand complex and identify the accuracy of surface anatomy mapping strategies for localizing anatomical landmarks using a palmar approach. METHODS: Twenty-three embalmed cadavers were dissected using standardized procedures. Metal markers were placed in the most prominent palmar landmark of key carpal structures. Relationships between the most prominent palpation landmarks and the carpal bones of interest were visualized using fluoroscopy. RESULTS: The most successful methods of palmar capitate localization included the midpoint of a line from trapezium tubercle to pisiform; the midpoint of a line from scaphoid tubercle to hamate hook; or the intersection (cross) of these 2 diagonal lines, with successful capitate identification 100% (23/23) of the time. The most successful method for locating the lunate included the midpoint of a line from the radial styloid process to the ulnar styloid process, which identified the lunate in 100% (23/23) of cases. DISCUSSION: The results of this cadaveric anatomical relationship study support the use of the midpoint of a line from pisiform to trapezium tubercle, the midpoint of a line from scaphoid tubercle to hamate hook, or a combination (cross) of these lines to locate the capitate from a palmar approach. In addition, the anatomical relationships examined in this study support the use of the midpoint of a line from the radial styloid process to ulnar styloid process to locate the lunate from a palmar approach. Knowledge of these anatomical relationships may improve the clinician's confidence in locating the capitate and lunate during intercarpal examination, special testing, and treatment. CONCLUSION: Results of this study provide information of the anatomical relationships of the carpal bones from a palmar approach, giving clinicians a foundation for proper orientation to the carpal bones during clinical examination and intervention. Further research is needed to evaluate the reliability and accuracy of these methods for surface palpation on live patients.

The Quantitative Anatomy of the Dorsal Scapholunate Interosseous Ligament.

BACKGROUND: The anatomy of the scapholunate interosseous ligament (SLIL) has been described qualitatively in great detail, with recognition of the dorsal component's importance for carpal stability. The purpose of this study was to define the quantitative anatomy of the dorsal SLIL and to assess the use of high-frequency ultrasound to image the dorsal SLIL. METHODS: We used high-frequency ultrasound imaging to evaluate 40 wrists in 20 volunteers and recorded the radial-ulnar (length) and dorsal-volar (thickness) dimensions of the dorsal SLIL and the dimensions of the scapholunate interval. We assessed the use of high-frequency ultrasound by comparing the length and thickness of the dorsal SLIL on ultrasound evaluation and open dissection of 12 cadaveric wrists. Student's t test was used to assess the relationship between measurements obtained on cadaver ultrasound and open dissection. RESULTS: In the volunteer wrists, the mean dorsal SLIL length was 7.5 ± 1.4 mm and thickness was 1.8 ± 0.4 mm; the mean scapholunate interval was 5.0 mm dorsally and 2.5 mm centrally. In the cadaver wrists, there was no difference in dorsal SLIL length or thickness between ultrasound and open dissection. CONCLUSIONS: The dorsal SLIL is approximately 7.5 mm long and 1.8 mm thick. These parameters may be useful in treatment of SLIL injuries to restore the native anatomy. High-frequency ultrasound is a useful imaging technique to assess the dorsal SLIL, although further study is needed to assess the use of high-frequency ultrasound in detection of SLIL pathology.

Lunate morphology as a risk factor of idiopathic ulnar impaction syndrome.

AIMS: Positive ulnar variance is an established risk factor for idiopathic ulnar impaction syndrome (UIS). However, not all patients with positive ulnar variance develop symptomatic UIS and other factors, including the morphology of the lunate, may be involved. The aim of this study was to clarify the relationship between lunate morphology and idiopathic UIS. PATIENTS AND METHODS: A cohort of 95 patients with idiopathic UIS (UIS group) was compared with 95 asymptomatic controls with positive ulnar variance. The shape of the lunate was measured using the capitate-triquetrum distance (CTD), ulnar coverage ratio (UCR), radiolunate distance and radiolunate angle. The association of radiographic parameters and lunate types with the development of UIS was investigated in univariable and multivariable analyses. Receiver operating characteristic curves were used to estimate a cutoff for any statistically significant variables. RESULTS: The proportion of type II lunates, which have a medial hamate facet, were significantly higher in the UIS group than in the control group in the univariable analysis (p = 0.001). CTD (odds ratio (OR) 1.52; 95% confidence interval (CI) 1.11 to 2.06; p = 0.008) and UCR (OR 44.78; 95% CI 5.35 to 374.90; p = 0.002) showed a positive association with UIS in the multivariable analysis. Estimated cutoff values were 2.5 mm for the CTD (area under the curve (AUC) = 0.65) and 0.4 for the UCR (AUC = 0.64). CONCLUSION: The proportion of type II lunates was greater in the UIS group than in the control group. A large UCR, which represents the broad base of the lunate, was positively associated with the development of idiopathic UIS. Cite this article: Bone Joint J 2017;99-B:1508-14.

Microstructure study of normal lunates with micro-computed tomography.

In order to study the microstructure characteristics of normal lunate bones, eight fresh cadaver normal lunates were scanned with micro-computed tomography. High-resolution images of the micro-structure of normal lunates were obtained and we analyzed the nutrient foramina. Then nine regions of interest (ROI) were chosen in the central sagittal plane so that we could obtain the parameters of trabecular bones of ROIs. The distal lamellar-like compact structure had statistically significant differences when it was compared with the ROIs in the volar and dorsal ends of the distal cortex. The difference of diameter between the volar and dorsal foramina was significant (P<0.05). However, there was no significant difference regarding the number. The trabecular bones of the volar and dorsal distal ends had lower intensity than those of the distal central subchondral bone plate. The diameters of the nutrient foramina on the volar cortex were larger than those on the dorsal. This research provided more detailed information about microstructure of normal lunate and the nutrient foramina on cortex, and a reference for further study about diseased lunate.

Morphology and morphometry of the distal articular surface of lunate bone in a Kenyan population / Morfología y morfometría de la superficie articular distal del hueso semilunar en una población de Kenia

The morphology and morphometry of the distal articular surface of the lunate exhibits inter-population variations. They are of clinical importance to hand surgeons due to their influence on the occurrence of proximal pole arthrosis which is a cause of ulnar-side wrist pain. The objective of the study was to determine the morphology and morphometry of the distal articular surface of the lunate bone in an adult Kenyan population. A descriptive cross-sectional study at the Department of Human Anatomy, University of Nairobi. Fifty-six human hands obtained for routine dissection were used. The morphology of the distal articular surface of the lunate was classified as either Type I or Type II depending on the absence or presence of a medial facet for articulation with the hamate respectively. The width of the wrists and of the medial facet in Type II lunates was measured with SOMETTM CN-25 1234 vernier calipers (accurate to 1mm). Photomacrographs of representative lunate were taken. Data were analyzed using SPSS version 17.0. The Pearson correlation test was used to check for any correlations. Type II lunate morphology was more common with a prevalence of 34 (61 %) while 19 (34 %) were Type I. The mean width of wrists with Type I lunate was 41.1±2.8 mm while those with Type II had a mean width of 46.1±4.3 mm. The mean width of the medial facet in lunate type II was 4.4±1.4 mm. Lunotriquetral fusion was demonstrated in 3 (5 %) wrists. Prevalence of Type II lunate was higher than Type I. Wrists with a Type II lunate were wider than those with Type I. There was no correlation between the width of the wrist and the width of the medial facet of the lunate.

La morfología y morfometría de la superficie articular distal del hueso semilunar muestra variaciones entre la población. Es de importancia clínica para los cirujanos de mano debido a su influencia en la incidencia de la artrosis del polo proximal, que causa dolor ulnar en la muñeca. El objetivo fue determinar la morfología y morfometría de la superficie articular del hueso semilunar en una población adulta de Kenia. Estudio descriptivo de corte transversal, realizado en el Departamento de Anatomía Humana de la Universidad de Nairobi. Se utilizaron 56 manos humanas que fueron sometidas a disección de rutina. La morfología de la superficie articular distal del hueso semilunar se clasificó en Tipo I o Tipo II en función de la ausencia o presencia de una faceta medial de la articulación. El ancho de las muñecas y de la faceta medial en el Tipo II se midió con el caliper SOMETTM CN-25 1234 (precisión de 1 mm). Se tomaron macrofotografías representativas del hueso semilunar. Los datos fueron analizados con el programa SPSS versión 17.0. Se utilizó la prueba de correlación de Pearson. La morfología del hueso semilunar Tipo II fue más frecuente con una prevalencia de 34 casos (61 %), mientras que 19 casos (34 %) eran de Tipo I. El ancho promedio de las muñecas del hueso semilunar Tipo I fue de 41,1±2,8 mm, mientras que las de Tipo II fue de 46,1±4,3 mm. El ancho promedio de la cara medial del hueso semilunar Tipo II fue de 4,4±1,4 mm. Se demostró fusión semilunar-piramidal en 3 casos (5 %). La prevalencia del hueso semilunar Tipo II fue mayor que la del hueso semilunar Tipo I. Las muñecas que presentaban hueso semilunar Tipo II fueron más anchas que las de Tipo I. No hubo correlación entre el ancho de la muñeca y el ancho de la faceta medial del hueso semilunar.

The Effect of Capitate Position on Coronal Plane Wrist Motion After Simulated 4-Corner Arthrodesis.

PURPOSE: The objective of this study was to examine the effect of altering the capitolunate relationship on coronal-plane wrist motion after scaphoidectomy and simulated 4-corner arthrodesis. Two positions of different capitolunate alignments were compared: "anatomic" (unchanged from pre-fusion) and "lunate-covered" (capitate translated to cover the lunate). We hypothesized that wrist resting posture would be altered and radial-ulnar motion would diminish after 4-corner arthrodesis in the lunate-covered position when compared with normal wrists. METHODS: Six human cadaveric limbs were disarticulated at the elbow and mounted on a custom jig. The resting position of the wrist was recorded with no load applied, followed by a load of 44 N applied to the flexor carpi radialis, extensor carpi radialis longus, and extensor carpi radialis brevis tendons to simulate radial deviation and to the flexor carpi ulnaris and extensor carpi ulnaris tendons to simulate ulnar deviation. Scaphoidectomy was performed and 2 methods of 4-corner arthrodesis with different capitolunate coronal alignments were studied in random order. Range of motion was compared using one-way analysis of variance and Bonferroni correction. RESULTS: The "lunate covered" wrist demonstrated significantly greater radial resting posture than that of the preoperative wrist. Under a 44 N load, the lunate-covered position had significantly greater radial motion than the preoperative radial motion. Wrists fused in the "anatomic" position did not differ significantly from the preoperative wrists in posture or range of motion. CONCLUSIONS: In this cadaveric model, complete covering of the capitate head by the lunate placed the wrist in increased radial deviation compared with the anatomic posture. Changes induced in the resting tension of the extrinsic wrist ligaments serve as a reasonable explanation for the increased radial posture and motion. In a clinical setting, these changes may affect postoperative wrist posture and function. CLINICAL RELEVANCE: Maintaining anatomic lunate position leads to preservation of greater wrist motion and anatomic alignment in a patient undergoing 4-corner arthrodesis.

The Role of Lunate Morphology on Scapholunate Instability and Fracture Location in Patients Treated for Scaphoid Nonunion.

BACKGROUND: To determine the association between lunate morphology and the scapholunate instability using radiographic images, and investigate the association between lunate morphology and scaphoid fracture location. METHODS: Between January 2003 and December 2011, we retrospectively evaluated the plain radiographs and computed tomography (CT) images of 70 patients who underwent surgical intervention for a scaphoid nonunion, in order to determine the association between lunate type (I or II) and scapholunate instability or scaphoid fracture location. We determined the scaphoid fracture location using the fragment ratio and measured the radiolunate angle and capitate-triquetrum (C-T) distance. RESULTS: A type II lunate was present in 68.6% (48 of 70 cases). Mean fragment ratio of fracture location was 50.6% in the type II lunate group and 56.2% in the type I lunate group (p = 0.032). Sixteen of the 70 patients had dorsal intercalated segmental instability (DISI) deformities. Nine of 22 cases showed DISI deformity in type I lunate and 7 of 48 cases showed DISI deformity in type II lunate (p = 0.029). However, there were no significant differences between the presence of DISI deformity and fracture location (p = 0.15). Morphologic comparisons by both plain radiography and CT indicated a mean C-T distance in the type I lunate group (22 cases) of 2.3 mm and 5.0 mm in the type II lunate group (48 cases). The C-T distances were significantly correlated with lunate morphology (p = 0.001). CONCLUSIONS: A type II lunate was associated with low incidence of DISI deformity and proximal location of fracture in patients presenting with a scaphoid nonunion.

Management of lunotriquetral instability: a review of the literature.

UNLABELLED: Lunotriquetral ligament injury is a relatively common cause of ulnar-sided wrist pain. Injury ranges from partial stable ligament tears to extensive perilunate instability. Clinical decision-making largely depends on the chronicity, instability and cause of the ligament injury. Conservative treatment is generally regarded as first choice of treatment of mild lunotriquetral instability; however, outcome studies on conservative treatment are lacking. Temporary arthroscopic pinning and/or debridement are minimally invasive procedures of preference. In the case of more dissociative injury, surgical interventions may be performed. The literature suggests that soft tissue reconstruction is an effective procedure in this group. Arthrodesis of the lunotriquetral joint is associated with high rates of non-union (up to 57%) and the indications for surgery should therefore be very clear. Methodological issues make it hard to draw firm conclusions from the data. Studies on the effectiveness of conservative management and prospective comparative studies will further improve clinical decision-making in lunotriquetral instability. LEVEL OF EVIDENCE: N/A.

[Morphometric anatomic study and clinical significance of lunate fossa]. / Lunat fossanin morfometrik anatomik çalismasi ve klinik önemi.

OBJECTIVES: This study aims to investigate the depth, transverse and sagittal diameters of lunate fossa which is a significant structure of the wrist in terms of reducing the risk for volar plate screws, which are administered in distal radius fractures, from penetrating into the joint. MATERIALS AND METHODS: Depth, transverse and sagittal diameters of lunate fossa in 50 right and 50 left adult dried radius bones without distal tip damage were measured by using MicroscribeG2X from the MicroScribe G series. RESULTS: Mean lunate fossa depth: left 2.419886±0.51 mm/right 2.543052±0.78 mm, mean lunate fossa sagittal diameter: left 19.656±1.57 mm/right 18.796±1.53 mm, mean lunate fossa transverse diameter: left 11.382±0.65 mm/right 11.106±0.91 mm. There was no statistically significant difference between right and left depth values of lunate fossa (p=0.320), whereas there was statistically significant difference between right and left transverse and sagittal diameters (p=0.006, p=0.048). CONCLUSION: Measurements involving depth of lunate fossa may guide the development of new anatomic plates and decrease complications like the penetration of screw into joint whilst volar plate administrations.

Contact areas of the scaphoid and lunate with the distal radius in neutral and extension: correlation of falling strategies and distal radial anatomy.

The functional neutral of wrist movement is about 10° extension yet the distal radius has a volar tilt. This has not previously been explained. Assuming that the contact area between the carpus and the distal radius increased in wrist extension this would also help stabilize the carpus on the distal radius in positions where typically there is greater loading. To test this hypothesis we reconstructed three-dimensional structures of the carpal bones and distal radius using computed tomography scans of 13 normal wrists. The contact areas of the scaphoid with the distal radius were measured and were found progressively increased from flexion 20°, neutral, extension 20°, to extension 40°. The maximal increases in the contact area of the scaphoid and the distal radius was at full wrist extension. No significant changes in the contact areas of the lunate with the distal radius were found between the different positions. The contact characteristics provide greater stability to the carpus on the distal radius, and to help spread forces from impact to the wrist reducing the transmitted peak forces and thus the risk of distal radius and carpal injuries.

[The most common pitfalls in magnetic resonance imaging of wrist]. / Najczesciej wystepujace pulapki diagnostyczne w obrazowaniu rezonansu magnetycznego nadgarstka.

Aim of this study is to present the most common diagnostic pitfalls in the diagnostics of wrist MRI. Wrist MRI was performer in 30 healthy individuals, with no history of wrist inflammation or wrist trauma. Particular attention was returned to intraosseous blood vessels and ligaments. If they were bigger than 2mm it was called "pseudo-erosion". In 13% of examined wrist we noted "pseudo-erosion". Intraosseous blood vessel canals were visible in all individuals, most commonly in capitate and lunate bones. Evaluation of MR images of wrist requires thorough training in interpretation of MR images. It is necessary to correlate the MRI findings with laboratory examinations and a clinical interview for minimizing the risk of misinterpretation.