A new injection method for identifying the subpopliteal recess of the knee

The posterolateral region of the knee has a complex and diverse anatomy. Hydrarthrosis of the knee can potentially communicate with other parts of the joint space. The joint fluid distribution reflects anatomical communications between synovial spaces. To observe the continuity between the knee joint cavity and the surrounding bursa, we devised a dissection method with a new injection agent, an eosin-containing congealed liquid that spreads uniformly over the entire space. The purpose of this study was to perform a detailed examination of the subpopliteal recess (SPR) where a bursa connects to the knee joint capsule. We also reported the advantages of this new injection agent compared with conventional materials (latex and epoxy resin). Twenty-two formalin-fixed cadavers (34 knees), two N-vinyl-pyrrolidone (NVP)-fixed cadavers (4 knees), and two cadavers (3 knees) fixed by Thiel's method were used. After filling the knee joint space and SPR with eosin congealed liquid, the specimens were dissected to investigate the morphology of the SPR. In addition, three different types of injection agents were assessed. The SPR extended distally along the popliteus tendon. The SPR length was 22.64 ± 11.38 mm from the upper end of the lateral tibial condyle to the lower end of the depression. The existence of a fabellofibular ligament made the SPR significantly longer, but abrasion of the femoral articular cartilage did not affect the SPR. Furthermore, the relationship between the popliteus muscle and the SPR was classified into three types (types 1-3). Types 2 and 3 in which the SPR extended to the proximal tibiofibular joint may cause instability of the knee joint. The eosin congealed liquid was highly useful in many aspects, such as fluidity and injection workability. The new dissection method with eosin congealed liquid provides insights into the anatomy of the posterior lateral knee, which are useful for radiological diagnoses and clinical treatments.

Contribution of the complex comprising the masticatory fascia, disc, and capsule to temporomandibular joint stabilization: An anatomical study

BACKGROUND

Anterior displacement of the temporomandibular joint (TMJ) disc is the most typical pathological condition of TMJ disorders. Structures attached to the articular disc may support the disc in various directions and contribute to stabilizing the TMJ. However, the relationship between the articular disc, capsule, and masticatory muscles remains unclear. Therefore, this study aimed to clarify the relationship between the masticatory muscles, related masticatory fascia, articular disc, and capsule.

METHODS

We examined 10 halves from adult Japanese cadavers, with five halves macroscopically analyzed and the remaining five histologically analyzed. The TMJ was dissected from the lateral aspect for gross anatomical analysis. For histological analysis, the relationship between the temporal and masseteric fasciae and the articular capsule was observed in the coronal section. Additionally, we evaluated relationships among the disc, capsule, temporal fascia, and masseteric fascia in 10 living and healthy volunteers using magnetic resonance imaging.

RESULTS

The articular disc was attached to the capsule without a clear border. The capsule continued into the masseteric and temporal fasciae. Consequently, the articular disc, capsule, masseteric, and temporal fasciae were considered a single complex.

CONCLUSIONS

The single complex of the temporalis, masseter, capsule, masticatory fascia, and disc may antagonize the force in the posterolateral direction through the fascia.

Why Does Hip Arthroscopy Fail? Indications and PEARLS for Revision Success

The surgical treatment of femoroacetabular impingement has been shown to have successful early and mid-term clinical outcomes. Despite these favorable clinical outcomes that have been published in the literature, there is a subgroup of patients that present with continued or recurrent symptoms after surgical treatment. Not only has there been an increase in the number of hip arthroscopy procedures, but also there has been a corresponding increase in the number of revision hip arthroscopy and hip preservation surgeries. Previous studies have reported residual deformity to be the most common reason for revision hip arthroscopy. However, chondral, labral, and capsular considerations also are important when addressing patients not only in the primary but also, the revision setting. In this review, we outline the evaluation and treatment of the patient that presents with continued hip and groin pain after undergoing a hip.

The glenohumeral ligaments: Superior, middle, and inferior: Anatomy, biomechanics, injury, and diagnosis

The three glenohumeral ligaments (superior, middle, and inferior) are discrete thickenings of the glenohumeral joint capsule and are critical to shoulder stability and function. Injuries to this area are a cause of significant musculoskeletal morbidity. A literature search was performed by a review of PubMed, Google Scholar, and OVID for all relevant articles published up until 2020. This study highlights the anatomy, biomechanical function, and injury patterns of the glenohumeral ligaments, which may be relevant to clinical presentation and diagnosis. A detailed understanding of the normal anatomy and biomechanics is a necessary prerequisite to understanding the injury patterns and clinical presentations of disorders involving the glenohumeral ligaments of the shoulder.

Hip Joint Capsular Anatomy, Mechanics, and Surgical Management

➤Hip joint capsular ligaments (iliofemoral, ischiofemoral, and pubofemoral) play a predominant role in functional mobility and joint stability. ➤The zona orbicularis resists joint distraction (during neutral positions), and its aperture mechanism stabilizes the hip from adverse edge-loading (during extreme hip flexion-extension). ➤To preserve joint function and stability, it is important to minimize capsulotomy size and avoid disrupting the zona orbicularis, preserve the femoral head size and neck length, and only repair when or as necessary without altering capsular tensions. ➤It is not fully understood what the role of capsular tightness is in patients who have cam femoroacetabular impingement and if partial capsular release could be beneficial and/or therapeutic. ➤During arthroplasty surgery, a femoral head implant that is nearly equivalent to the native head size with an optimal neck-length offset can optimize capsular tension and decrease dislocation risk where an intact posterior hip capsule plays a critical role in maintaining hip stability.

Anatomy of the ankle capsule: A cadaveric study

Although bony and ligamentous injuries of the ankle are well understood, little is known about the degree to which injury of the ankle capsule can be a component of such injuries. The purpose of this study was to determine the dimensions of the ankle capsule and its relationship to adjacent structures. Thirteen fresh-frozen ankle specimens were systematically dissected. Methylene blue solution was injected to identify the dimensions of the ankle capsule. External dimensions were measured as the distance from the capsular reflection to the bony margin of the ankle. Internal dimensions were measured as the distance from the capsular attachment of the distal tibia, fibula, and talus to the cartilage margin. The anterior aspect of the capsule demonstrated the most proximal capsular reflection in all specimens. The most proximal reflections of the anteromedial, anterior middle and anterolateral capsule were 10.3, 13.5, and 9.8 mm, respectively. The most proximal reflections of the posteromedial, posterior middle and posterolateral region were 8.7, 6.2, and 3.5 mm, respectively. There was no capsular reflection over the medial malleolus and less than 1 mm over the posterior lateral malleolus. There was a confluence of the capsule and ligamentous complex on the medial side, and also with the transverse tibiofibular ligament about the posterolateral ankle. The most proximal attachment of the ankle capsule was located at the anterior aspect of the distal tibia. The medial and posterolateral capsules were confluent with the ligamentous complexes of the ankle in those regions. Clin. Anat. 31:1018-1023, 2018. © 2018 Wiley Periodicals, Inc.

The glenocapsular ligament and the posterosuperior part of the joint capsule of the shoulder are well vascularized

PURPOSE

A detailed structural anatomy of the posterosuperior shoulder capsule and "glenocapsular ligament" is still rather unknown. The purpose of this study was meticulously to investigate and describe the structure and blood supply of the glenocapsular ligament on the posterosuperior shoulder joint capsule.

METHOD

Sixteen fixed and twelve fresh cadaveric shoulder specimens with a mean age of 73.4 (±6.4) years were analysed. Dissection without arterial injection was performed on the 16 fixed specimens-using an alcohol-formalin-glycerol solution. Before dissection, the 12 fresh specimens received of arterial injection a 10% aqueous dispersion of latex solution. After the injection, these shoulders were also fixed in an alcohol-formalin-glycerol solution.

RESULTS

The glenocapsular ligament was found in all 28 specimens. Single or double parallel-running bundles of connective tissue fibres were found to form a capsular-ligamentous structure on the posterosuperior part of the joint capsule. One part of the ligament was mediosuperior, another posterosuperior. The mediosuperior part varied in shape, and in 12 of 28 cases, it was absent. The glenocapsular ligament arose from the supraglenoid tubercle and posterior part of the collum scapulae and inserted into the semicircular humeral ligament. The posterior ascending branch of the circumflex scapular artery directly fed small branches laterally and medially to the joint capsule, supplying the glenocapsular ligament and the deep layer of the joint capsule.

CONCLUSION

The glenocapsular ligament is a constant anatomical structure that consists of one or two different parts. The glenocapsular ligament and the posterosuperior part of the joint capsule appear well vascularized via the posterior ascending branch of the circumflex scapular artery.

CLINICAL RELEVANCE

It is the hope of the authors that this anatomical study can help surgeons who perform open or arthroscopic surgery to the posterior part of the shoulder. Knowledge of the vascular anatomy presented in this study may be especially important when incisions are made to the posterior part of the shoulder, and should minimize the risk of complications.

Capsular distance in the hip of the healthy child – normal values with sonography and MR imaging

Purpose: To determine the normal values of the anterior and posterior capsular distances of the hip joint in healthy children by means of US, using MR imaging as reference, and to evaluate any possible correlation between age, length, weight and anterior capsular distance (ACD).

Material and Methods: In our first study both hips in 14 healthy children (5-18 years old) were examined with US and MR to obtain measurements of the ACD and the posterior capsular distance (PCD). The distance from the anterior or posterior aspect of the femoral neck to the anterior or posterior aspect, respectively, of the outer limit of the capsule was determined. The distances were measured both with the hips in spontaneous external rotation of 10-15° and in internal rotation of 45°. In our second study, both hips in 28 healthy children (3-16 years old) were examined with US to determine the ACD. Age, length and weight were recorded.

Results: Study I: There was good correlation between the US and MR measurements in all positions. The ACD measured by US was significantly increased in inward rotation of the hip. Study II: There was no correlation between ACD and age, length or weight.

Conclusion: The PCD of the hip joint can be accurately measured by US with the hip in internal rotation of 45°. When compared with MR values, the ACD measured by US was dependent on the degree of rotation of the leg and increased significantly in internal rotation. Because the outer limit of the external layer of the joint capsule is sonographically more distinct, we suggest that the capsular distance should be measured from the outer limit of the joint capsule to the anterior or posterior aspect of the femoral neck. The measurement should be made perpendicular to the femoral neck, at the position where the greatest numerical value is obtained.

A cadaveric study of the anterolateral ligament: re-introducing the lateral capsular ligament

PURPOSE

The purpose of this study was to verify and characterize the anatomical properties of the anterolateral capsule, with the aim of establishing a more accurate anatomical description of the anterolateral ligament (ALL). Furthermore, microscopic analysis of the tissue was performed to determine whether the ALL can morphologically be classified as ligamentous tissue, as well as reveal any potential functional characteristics.

METHODS

Three different modalities were used to validate the existence of the ALL: magnetic resonance imagining (MRI), anatomical dissection, and histological analysis. Ten fresh-frozen cadaveric knee specimens underwent MRI, followed by anatomical dissection which allowed comparison of MRI to gross anatomy. Nine additional fresh-frozen cadaveric knees (19 total) were dissected for a further anatomical description. Four specimens underwent H&E staining to look at morphological characteristics, and one specimen was analysed using immunohistochemistry to locate peripheral nervous innervation.

RESULTS

The ALL was found in all ten knees undergoing MRI and all nineteen knees undergoing anatomical dissection, with MRI being able to predict its corresponding anatomical dissection. The ALL was found to have bone-to-bone attachment points from the lateral femoral epicondyle to the lateral tibia, in addition to a prominent meniscal attachment. Histological sectioning showed ALL morphology to be characteristic of ligamentous tissue, having dense, regularly organized collagenous bundles. Immunohistochemistry revealed a large network of peripheral nervous innervation, indicating a potential proprioceptive role.

CONCLUSION

From this study, the ALL is an independent structure in the anterolateral compartment of the knee and may serve a proprioceptive role in knee mechanics.

A quantitative analysis of hip capsular thickness

PURPOSE

The purpose of this study was to provide a comprehensive quantitative analysis of capsular thickness adjacent to the acetabular rim in clinically relevant locations.

METHODS

Dissections were performed and hip capsular measurements were recorded on 13 non-paired, fresh-frozen cadaveric hemi-pelvises using a coordinate measuring device. Measurements were taken for each clock-face position at 0, 5, 10 and 15 mm distances from the labral edge.

RESULTS

The capsule was consistently thickest at 2 o'clock for each interval from the labrum with a maximum thickness of 8.3 at 10 mm [95 % CI 6.8, 9.8] and 15 mm [95 % CI 6.8, 9.7]. The capsule was noticeably thinner between 4 and 11 o'clock with a minimum thickness of 4.1 mm [95 % CI 3.3, 4.9] at 10 o'clock at the labral edge. Direct comparison between 0 and 5 mm between 9 and 3 o'clock showed that the hip capsule was significantly thicker at 5 mm from the labrum at 9 o'clock (p = 0.027), 10 o'clock (p = 0.032), 1 o'clock (p = 0.003), 2 o'clock (p = 0.001) and 3 o'clock (p = 0.001).

CONCLUSIONS

The hip capsule was thickest between the 1 and 2 o'clock positions for all measured distances from the acetabular labrum and reached its maximum thickness at 2 o'clock, which corresponds to the location of the iliofemoral ligament.

[Anatomic features of posterior septum of knee joint and its application in posterior trans-septal portal for arthroscopic surgery]

OBJECTIVE

To summarize the anatomic features of the posterior septum of the knee joint and its application in posterior trans-septal portal for arthroscopic surgery.

METHODS

The literature related to posterior septum of the knee joint and arthroscopic surgery was extensively reviewed and analyzed.

RESULTS

The posterior septum of the knee joint has more mechanoreceptors and blood vessels in the upper part, which are close to arteria popliteal at the tibial plateau level; the posterior compartment is divided into wider posteromedial and narrower posterolateral compartments. A safe arthroscopic trans-septal portal is established, in the knee flexion of 90 degrees, in a lateral-to-medial direction, and with an inserting location below the middle of posterior septum.

CONCLUSION

The establishment method of posterior trans-septal portal is not uniform and all the features of posterior septum should be considered to decrease the complications.

Relation of the radial nerve to the anterior capsule of the elbow: anatomy with correlation to arthroscopy

PURPOSE

To determine the location and proximity of the radial nerve to the anterior capsule and to delineate and describe the anatomy of the brachialis as it relates to the radial nerve and anterior capsule.

METHODS

Arthroscopy was performed on 24 cadavers using only a standard anteromedial portal. A Beath pin was placed laterally, entering the joint at the most lateral edge of the radiocapitellar joint space, and a suture was placed through the pin and into the joint for reference during the dissection. The second phase was to perform open anatomic dissections.

RESULTS

We found that in all specimens the radial nerve coursed longitudinally medial to the capitellum. The brachialis muscle was found to lie between the radial nerve and the joint capsule at the joint line and all proximal levels. Only at the most distal aspect of the joint line (corresponding to the level of the radial neck) did the nerve run in direct contact with the capsule in 11 specimens (55%). The brachialis muscle thickness was 4 mm or greater at the joint line and at all proximal measurement points.

CONCLUSIONS

We found that the radial nerve is more medially located than previously thought. At the level of the radiocapitellar joint line, the radial nerve runs medial to the capitellum. The brachialis muscle lies between the radial nerve and the joint capsule at the level of the joint line and proximally.

CLINICAL RELEVANCE

Arthroscopic capsular release laterally should be performed at the level of the joint line or above. The most dangerous area for capsular resection is distally over the radial head/neck, where 50% of our specimens had no brachialis protecting the nerve.

Exploring the anatomy of dorsal radiocarpal ligament of the wrist and its ulnar part: a cadaveric study

The current study aimed to explore the anatomy of the dorsal radio-carpal ligament (DRC ligament) and to investigate the presence and histological structure of ulnar part of the DRC ligament. Twenty cadaveric wrist joints were dissected and attachments of the DRC ligament and the newly described ulnar part of the DRC ligament were identified and noted. Samples of both ligaments were sent for histological examination. The DRC ligament was identified in all 20 specimens with type I Mizuseki arrangement of fibres seen in 60% of wrists. The ulnar part of the DRC ligament was successfully identified in 18 of the 20 wrists. The histological observation of the ulnar part of the DRC ligament showed the highly uniform arrangement of collagen bundles typical of ligaments. This study explores the anatomy of the DRC ligament and confirms the presence of the ulnar part of DRC ligament through histological analysis not undertaken in previous studies.

The retinacula of Weitbrecht in the adult hip

PURPOSE

The aim of the study was to describe the retinacula of Weitbrecht in the adult hip.

MATERIALS AND METHODS

Specimens were obtained from 30 adult hips, average age was 77 years (age range 43-91 years), 8 specimens were fixed by formalin solution and 22 were not fixed.

RESULTS

Anterior retinaculum was found in 40% of examined specimens. The anterior retinaculum was in 83% of cases formed by a flat plate and in 17% by two to three parallel bands. Medial retinaculum was present constantly, extending from the attachment of the articular capsule at the base of the lesser trochanter towards the fovea capitis femoris as far as the edge of the articular cartilage. Typically, the retinaculum had the form of an inverted "T". Of the three retinacula, the medial one was the strongest. Lateral retinaculum was also present constantly. In 89% of cases, it had the form of a quadrilateral plate adjacent to the upper surface of the femoral neck. This plate arises from the insertion of the articular capsule on the upper part of the femoral neck at the base of the greater trochanter close to the trochanteric fossa. The plate extended along the upper edge of the femoral neck as far as the edge of the articular cartilage. Microscopic examination revealed fine blood vessels running through the retinacula.

CONCLUSION

Lateral retinaculum and medial retinaculum are constant synovial plicae in terms of both occurrence and localization. Nutritive arteries run through both the plicae to supply the femoral head.

The anterior tibio-talar ligament: one reason for anterior ankle impingement

The purpose of this study was the evaluation of the ankle's anterolateral ligament structures. We documented the anatomic situation of the ankle's anterolateral ligament structures in 33 Thiel-embalmed specimens. The ligaments had been isolated. We performed measurements on both length and orientation and additionally classified the ligaments. We also conducted histologic tissue staining. We were able to document a regular appearance of a so far not well-realized structure between the talus and the tibia, present in 26 (79%) specimens. Average length of this structure was 26 mm (in 20 degrees plantarflexion). The angular orientation in relation to the ant. tibio-fibular lig. was on average 43.7 degrees. This structure could be classified as being either isolated or widespread, with a further four sub-classifications for the orientation. Histologic staining showed parallel orientated dense collagen fibers as well as elastic fibers and hyaline cartilage in different stages of proliferation. In addition, there were neural fibers in the perivascular and the soft tissue. The histologic findings proved that the structure was a ligament. Since the ant. tibio-talar lig. is constantly present in most ankle joints, it could be considered as a regular finding. Its morphology and histology show that this ligament is loaded under tension as well as under compression. This could be one reason for anterior ankle impingement.

Magnetic resonance imaging after surgery for shoulder instability

Interpretation of MR imaging of the shoulder after instability repair can be significantly hampered by (susceptibility) artifacts and/or distortion of normal anatomy. Knowledge of the surgical procedures performed including the (ferromagnetic) materials used is important to adjust the imaging protocol, in order to reduce artifacts. MR arthrography is probably the optimal tool for assessment of postoperative capsular-labral structures and rotator cuff defects. More general postoperative complications can be determined or excluded using conventional fast spin echo sequences with or without fat-suppression.

Anatomic relation between the posterior cruciate ligament and the joint capsule

PURPOSE

The aim of this anatomic study on cadavers was to determine the anatomic relation between the posterior cruciate ligament (PCL) and the posterior joint capsule attachment.

METHODS

Thirty knees were dissected by means of a posterior approach to the knee. The presence of the posterior popliteal ligament and Wrisberg meniscofemoral ligament was observed and a U-shaped capsulotomy was performed while preserving the distal insertion of the ligament. After detaching the PCL and determining its area on the tibia, we determined its geometric center and posterior margin and measured the distances between the tibial insertion of the capsule and these points.

RESULTS

The distance between the center of the PCL and the posterior capsule was 10.3 mm, and the distance between the posterior margin of the PCL and the capsule was 1.7 mm. The posterior popliteal ligament was easy to see in all the specimens, measuring around 42 mm in length. The Wrisberg meniscofemoral ligament was seen in 12 specimens.

CONCLUSIONS

We can conclude that the distances from the center of the tibial insertion and the margin of the PCL to the joint capsule were 10.3 mm and 1.7 mm, respectively, thus enabling greater knowledge of the anatomy of the posterior compartment of the knee.

CLINICAL RELEVANCE

Our findings provide anatomic data that increase the safety and knowledge regarding the surgical procedures related to the PCL, because we have supplied information that can contribute to obtaining the best arthroscopic view of this area, thus decreasing the risk of vascular and nerve damage.

[Optimization of capsulotomy of enhanced posterior soft tissue repair in total hip arthroplasty]

OBJECTIVE

To investigate the anatomic feature of the posterior hip joint capsule and its distributional difference of collagen fibers and to probe the optimization of the capsulotomy which can reserve the best strength part.

METHODS

Ten adult cadaver pelvises (6 males and 4 females, aged 28-64 years) fixed with formalin were used. Ten right hips were used for anatomical experiment of hip joint capsule. The posterior hip joint capsules were divided into 3 sectors (I-III sectors) and 9 parts (I(A-C), II(D-F), III(G-I). The average thickness of each part was measured and the ischiofemorale ligaments were observed. Five capsules selected from ten left hips were used for histological experiment. The content of collagen fibers in sector I and sector II was analyzed by Masson's staining. Two fresh frozen specimens which were voluntary contributions were contrasted with the fixed specimens. The optimal incision line of the posterior capsule was designed and used.

RESULTS

The thickness in the posterior hip joint capsule [I(A) (2.30 +/- 0.40), I(B) (4.68 +/- 0.81), I(C) (2.83 +/- 0.69), II(D) (2.80 +/- 0.79), II(E) (4.22 +/- 1.33), II(F) (2.50 +/- 0.54), III(G) (1.57 +/- 0.40), III(H) (2.60 +/- 0.63), III(I) (1.31 +/- 0.28) mm] had no uniformity (P < 0.01). The III(G) part and the III(I) part were thinner than the I(B) part and the II(E) part (P < 0.01). Two weaker parts located at obturator externus sector (sector III), the ischiofemorale ligament trunk went through two thicker parts (I(B) and II(E)). The distribution of the collagen fibers in sector I and sector II(I(A) 20.34% +/- 5.14%, I(B) 48.79% +/- 12.67%, I(C) 19.87% +/- 5.21%, II(D) 17.57% +/- 3.56%, II(E) 46.76% +/- 11.47%, II(F) 28.65% +/- 15.79%) had no uniformity (P < 0.01). The content of collagen fibers in I(B) part and II(E) part were more than that of other parts (P < 0.01). There were no statistically significant difference in the distribution feature of the thickness and the ischiofemorale ligaments between the fresh frozen specimens and the fixed specimens. The optimal incision line C-A-B-D-E of the posterior capsule was designed and put into clinical application. The remaining capsular flap comprise the most of the ischiofemorale ligament trunk and the part of gluteus minimus.

CONCLUSION

Although enhanced posterior soft tissue repair in total hip arthroplasty was investigated deeply and obtained great development, but the postoperative dislocation rate was not eliminated. It is significant for optimizing the capsulotomy to reserve the best strength part of the posterior capsule and to bring into full play the function of the ischiofemorale ligaments.

[The rotator interval: hidden lesions?]

The rotator interval corresponds to a defined triangular shaped anatomical region at the anterosuperior portion of the shoulder where specific pathological processes may occur. First, the morphological and functional anatomy of the region will be reviewed. Then, the role of different imaging modalities will be described along with pathological imaging features. Normal structures of the rotator interval may be imaged with modern techniques, including MR and CT arthrography. On the other hand, clinical evaluation of rotator interval pathology remains difficult; and no consensus exists concerning their management. Imaging characterization of rotator interval pathology could be a key factor for pre-therapeutic work-up.

Definition of the capsular insertion plane on the proximal humerus

The aim of this work was quantitatively to establish the relationship between the plane that hosts the humeral head lateral margin (anatomical neck) and that of the capsular insertion. Eight cadaveric shoulders were used. These were dissected, exposing the humeral head margin and the root of the capsular humeral insertion to extract digitally their outlines using a mechanical 3-d digitizer. The datasets of the digitized outlines were applied and the geometric planes they best fitted mathematically calculated. Vector analysis techniques were finally applied to the two planes to quantify the relationship between them. The humeral head margin is circular (+/- 2.2% of radius), having each of its outlining points on the same plane (within +/- 1.5 mm.) The capsular attachment outlining points also insert on a plane (+/- 1.4 mm). The two planes are related to one another by an inclination of 14.5 +/- 3.6 degrees. The relationship described here would allow for in vivo prediction of humeral attachment of capsular structures by using radiological datasets of the anatomical neck. This would be useful in patient-specific modelling to study and understand the glenohumeral ligament kinematics during clinical examinations and to plan surgical reconstructive procedures.

Arthroscopic glenohumeral folds and microscopic glenohumeral ligaments: the fasciculus obliquus is the missing link

This study tested the hypotheses that the folds in the inferior glenohumeral capsule appear at the borders and crossings of the underlying capsular ligaments and that embalming may result in misinterpretation of these folds as ligaments. The inferior capsular structures in 80 unembalmed cadaver shoulders were compared with 24 embalmed shoulders. During arthroscopy and dissection, an anteroinferior fold was more prominently seen in internal rotation and was almost obliterated in external rotation. A posteroinferior fold appeared in external rotation and almost disappeared in internal rotation. During dissection, the anteroinferior fold developed at the border of the anterior band of the inferior glenohumeral ligament (ABIGHL) and where this ligament crossed with the fasciculus obliquus (FO). Several patterns of crossing of the ABIGHL and the FO were seen that determined the folding-unfolding mechanism of the anteroinferior fold and the appearance of possible synovial recesses. The axillary part of the IGHL is formed by the FO on the glenoid side and by the ABIGHL on the humeral side. The posteroinferior fold was determined by the posterior band of the IGHL. The folds in the embalmed specimens did not necessarily correspond with the underlying fibrous structure of the capsule. The folds and recesses observed during arthroscopy indicate the underlying capsular ligaments but are not the ligaments themselves. The IGHL complex is formed by its anterior and posterior bands and also by the FO. Both findings are important during shoulder instability procedures because the ligaments need to be restored to their appropriate anatomy and tension. Because the FO may also be involved, Bankart-type surgery may have to reach far inferiorly. Midsubstance capsular shift procedures also need to incorporate this ligament.

[Is the posterior segment of the temporomandibular joint capsule well defined?]

The temporomandibular joint (TMJ) is a complex joint due its development and filogeny. This complexity explains the lack of descriptions of the posterior joint capsule. Nowadays it is necessary to establish the limits of this joint part owing to a correct arthroscopic access. Dissecting human cadavers it will determine this joint segment and describe its anatomic relations.

Anatomy of the temporomandibular joint

The temporomandibular joint (TMJ), also known as the mandibular joint, is an ellipsoid variety of the right and left synovial joints forming a bicondylar articulation. The common features of the synovial joints exhibited by this joint include a fibrous capsule, a disk, synovial membrane, fluid, and tough adjacent ligaments. Not only is the mandible a single bone but the cranium is also mechanically a single stable component; therefore, the correct terminology for the joint is the craniomandibular articulation. The term temporomandibular joint is misleading and seems to only refer to one side when referring to joint function. Magnetic resonance imaging has been shown to accurately delineate the structures of the TMJ and is the best technique to correlate and compare the TMJ components such as bone, disk, fluid, capsule, and ligaments with autopsy specimens.

The internervous safe zone for incision of the capsule of the hip. A cadaver study

In order to determine the potential for an internervous safe zone, 20 hips from human cadavers were dissected to map out the precise pattern of innervation of the hip capsule. The results were illustrated in the form of a clock face. The reference point for measurement was the inferior acetabular notch, representing six o'clock. Capsular branches from between five and seven nerves contributed to each hip joint, and were found to innervate the capsule in a relatively constant pattern. An internervous safe zone was identified anterosuperiorly in an arc of 45 degrees between the positions of one o'clock and half past two. Our study shows that there is an internervous zone that could be safely used in a capsule-retaining anterior, anterolateral or lateral approach to the hip, or during portal placement in hip arthroscopy.