What is new in flexor tendon pulleys and the gaps between them in triphalangeal fingers of the hand?

The flexor tendon pulleys in the fingers of the hand are fibrous structures of variable size, shape, and thickness that cover the synovial sheath of these tendons. Despite their clinical relevance, their arrangement and configuration in each of the triphalangeal fingers have been little studied and with small sample sizes. 192 triphalangeal fingers belonging to 48 fresh body donors' hands were dissected. Multivariate analysis was carried out. Twenty-five cases (52%) were left hands, and 26 of the 48 hands belonged to female donors (54.2%). The results were analyzed by fingers for each of the 5 annular pulleys, the 3 cruciform pulleys and the gaps between them. In addition, the most and least frequent configurations of the pulleys in each of the fingers were studied, observing that the classic pattern with all the pulleys appeared only in 3 fingers (1.56%), while the most frequent pattern was A1-A2-C1-A3-A4, which was seen in 35 fingers (18.22%). CONCLUSIONS: The flexor pulleys in the triphalangeal fingers of the hand have shown enormous variability in arrangement and shape, and also rarely appear all in the same finger. This peculiar anatomical arrangement can help the different professionals who perform their clinical work in this region.

The lateral ulnar collateral ligament: Anatomical and structural study for clinical application in the diagnosis and treatment of elbow lateral ligament injuries.

The lateral ulnar collateral ligament (LUCL) is considered one of the main stabilizers of the elbow. However, its anatomical description is not well established. Imaging techniques do not always have agreed upon parameters for the study of this ligament. Therefore, herein, we studied the macro and microanatomy of the LUCL to establish its morphological and morphometric characteristics more precisely. Fifty-five fresh-frozen human elbows underwent dissection of the lateral collateral ligament. Morphological characteristics were studied in detail. Ultrasound (US) and magnetic resonance (MR) were done before dissection. Two specimens were selected for PGP 9.5 S immunohistochemistry. Ten additional elbows were analyzed by E12 sheet plastination. LUCL was identified in all specimens and clearly defined by E12 semi-thin sections. It fused with the common extensor tendon and the radial ligament. The total length of the LUCL was 48.50 mm at 90°, 46.76 mm at maximum flexion and 44.10 mm at complete extension. Three morphological insertion variants were identified. Both US and MR identified the LUCL in all cases. It was hypoechoic in the middle and distal third in 85%. The LUCL was hypointense on MR in 95%. Free nerve endings were present on histology. The LUCL is closely related to the anular ligament. It is stretched during flexion and supination. US and MR can reliably identify its fibers. Anatomical data are relevant to the surgeon who repairs the ligaments of the elbow. Also, to the radiologist and pain physician who interpret imaging and treat patients with pain syndromes of the elbow.

Connections between postparotid terminal branches of the facial nerve: An immunohistochemistry study.

It has been assumed that connections between the postparotid terminal branches of the facial nerve are purely motor. However, the nature of their fibers remains unexplored. The aim of this study is to determine whether these connections comprise motor fibers exclusively. In total 17 connections between terminal facial nerve branches were obtained from 13 different facial nerves. Choline acetyltransferase antibody (ChAT) was used to stain the fibers in the connections and determine whether or not all of them were motor. All connections contained ChAT positive and negative fibers. The average number of fibers overall was 287 (84-587) and the average proportion of positive fibers was 63% (37.7%-91.5%). In 29% of the nerves, >75% of the fibers were ChAT+ (strongly positive); in 52.94%, 50%-75% were ChAT+ (intermediately positive); and in 17.65%, <50% were ChAT+ (weakly positive). Fibers traveling inside the postparotid terminal cranial nerve VII branch connections are not exclusively motor.

Novel therapeutic avenues for the study of chronic liver disease and regeneration: The foundation of the Iberoamerican Consortium for the study of liver Cirrhosis.

Unfortunately, there is a gap of understanding in the pathophysiology of chronic liver disease due to the lack of experimental models that exactly mimic the human disease. Additionally, the diagnosis of patients is very poor due to the lack of biomarkers than can detect the disease in early stages. Thus, it is of utmost interest the generation of a multidisciplinary consortium from different countries with a direct translation. The present reports the meeting of the 2021 Iberoamerican Consortium for the study of liver Cirrhosis, held online, in October 2021. The meeting, was focused on the recent advancements in the field of chronic liver disease and cirrhosis with a specific focus on cell pathobiology and liver regeneration, molecular and cellular targets involved in non-alcoholic hepatic steatohepatitis, alcoholic liver disease (ALD), both ALD and western diet, and end-stage liver cirrhosis and hepatocellular carcinoma. In addition, the meeting highlighted recent advances in targeted novel technology (-omics) and opening therapeutic avenues in this field of research.

Classification of the popliteofibular ligament.

The purpose of this study was to characterize the morphological variations in the distal attachment of the popliteofibular ligament (PFL) and create an accurate classification for use in planning surgical procedures in this area and in evaluating radiological imaging. One hundred and thirty-seven lower limbs of body donors fixed in 10% formalin solution were examined for the presence and course of the PFL. The PFL was present in 88.3% of cases. We propose the following three-fold classification: type I (72.3%), the most common type, characterized by the attachment onto the apex of the head of the fibula, type II (8.7%), characterized by a bifurcation, with the dominant band inserting on the anterior slope of the styloid process of the fibula and the smaller band onto the posterior surface of the styloid process of the fibula and type III (7.3%), characterized by a double PFL: the first PFL (main) originated from the popliteus tendon and inserted onto the anterior slope of the styloid process of the fibula, while the second originated from the musculotendinous junction of the popliteus muscle and inserted on the posterior surface of the styloid process of the fibula. The PFL was characterized by high morphological variation, as reflected in our proposed classification. This variation may present clinical and biomechanical issues for both medical personnel and researchers. Our proposed classification may be valuable for clinicians who evaluate and perform surgical procedures within the knee joint area.

Standardized statement for the ethical use of human cadaveric tissues in anatomy research papers: Recommendations from Anatomical Journal Editors-in-Chief.

Human cadaveric donors are essential for research in the anatomical sciences. However, many research papers in the anatomical sciences often omit a statement regarding the ethical use of the donor cadavers or, as no current standardized versions exist, use language that is extremely varied. To rectify this issue, 22 editors-in-chief of anatomical journals, representing 17 different countries, developed standardized and simplified language that can be used by authors of studies that use human cadaveric tissues. The goal of these editor recommendations is to standardize the writing approach by which the ethical use of cadaveric donors is acknowledged in anatomical studies that use donor human cadavers. Such sections in anatomical papers will help elevate our discipline and promote standardized language use in others non anatomy journals and also other media outlets that use cadaveric tissues.

Quadriceps or multiceps femoris?-Cadaveric study.

PURPOSE: The quadriceps femoris (QF) consists of four muscles: the rectus femoris; vastus medialis; vastus lateralis, and vastus intermediate. The tendons of all of these parts join together into a single tendon that attaches to the patella. The QF is a powerful extensor of the knee joint that is needed for walking. A growing number of publications have examined the fifth head of the QF muscle. There is no information about the possibility of other heads, and there is no correct classification of their proximal attachments. Further, the frequency of occurrence of additional heads/components of the QF remains unclear. METHODS: One hundred and six lower limbs (34 male and 18 female) fixed in 10% formalin solution were examined. RESULTS: Additional heads of the QF were present in 64.1% of the limbs. Three main types were identified and included subtypes. The most common was Type I (44.1%), which had an independent fifth head. This type was divided into two subtypes (A-B) depending on its location relative to the vastus intermediate. The second most common type was Type II (30.8%), which originated from other muscles: IIA from the vastus lateralis; IIB from the vastus intermediate, and IIC from the gluteus minimus. In addition, Type III (25%) was characterized by multiple heads: IIIA-two heads with a single common tendon; IIIB-two heads with two separate tendons; IIIC-three heads (lateral, intermediate, medial), and IIID-four heads (bifurcated lateral and bifurcated medial). CONCLUSION: The introduction of a new classification based on a proximal attachment is necessary. The presence of the fifth, sixth, seventh, or eighth head varies.

Acknowledging the use of human cadaveric tissues in research papers: Recommendations from anatomical journal editors.

Research within the anatomical sciences often relies on human cadaveric tissues. Without the good will of these donors who allow us to use their bodies to push forward our anatomical knowledge, most human anatomical research would come to a standstill. However, many research papers omit an acknowledgement to the donor cadavers or, as no current standardized versions exist, use language that is extremely varied. To remedy this problem, 20 editors-in-chiefs from 17 anatomical journals joined together to put together official recommendations that can be used by authors when acknowledging the donor cadavers used in their studies. The goal of these recommendations is to standardize the writing approach by which donors are acknowledged in anatomical studies that use human cadaveric tissues. Such sections in anatomical papers will not only rightfully thank those who made the donation but might also encourage, motivate, and inspire future individuals to make such gifts for the betterment of the anatomical sciences and patient care.

Is it the coracobrachialis superior muscle, or is it an unidentified rare variant of coracobrachialis muscle?

The coracobrachialis muscle (CBM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. The CBM demonstrates variability in both the proximal and distal attachment, with some extremely rare varieties, such as the coracobrachialis superior, coracobrachialis longus and coracocapsularis muscle. This case report describes an extremely rare variant of the coracobrachialis superior muscle, or a very rare variant of the CBM. Our findings highlight the importance of muscle variants in the shoulder region, especially the coracoid region, and are significant for radiologists, anatomists, physiotherapists and surgeons specializing in the shoulder joint.

The anconeus muscle revisited: double innervation pattern and its clinical implications.

PURPOSE: The aim of the present study is to describe in detail the morphology and innervation pattern of the anconeus muscle, bearing in mind clinical implications such as iatrogenic injuries during surgical elbow approaches. METHODS: A cadaveric study was performed; 56 elbows from 28 formalin-fixed cadavers belonging to the Anatomy Department of Universidad Complutense of Madrid were dissected. The triceps-anconeus nerve was located and dissected. A second innervation to the anconeus muscle from a branch of the posterior interosseous nerve (PIN) was occasionally detected. Taking the lateral epicondyle as a landmark, the entry points of both nerves in the muscle were referenced, the triceps-anconeus nerve was referenced at 0°, 30°, 45°, 70° and 90° of elbow flexion, and the PIN branch at 0°. RESULTS: Anconeus muscle was present in all specimens. The triceps-anconeus nerve was present in all of the dissected elbows. A branch from PIN to the anconeus muscle was present in 38 of the 54 elbows (70.4%). There were statistically significant differences in all measurements regarding the specimens' gender, being higher for men. CONCLUSIONS: There is evidence of a high frequency of a double innervation pattern for the anconeus muscle: the main branch of triceps-anconeus muscle depending on the radial nerve, which is liable to being damaged during posterior elbow approaches, and a secondary branch depending on the PIN. There are very few references to this finding in Anatomical literature and none with such a large sample size.

Symmetrical Apophyses on the Posterior Margins of the Thyroid Cartilage: A Previously Undescribed Anatomical Variation With Potential Forensic Implications.

Differential diagnosis between normal/variant anatomy and pathological/traumatic findings represents one of the main matters of investigation of the so-called forensic clinical anatomy. In the literature, many anatomical variations of the laryngeal thyroid cartilage have been reported, with potential implications in forensic pathology. They include triticeal cartilages, foramen thyroideum, asymmetry, segmentation or agenesis of the superior thyroid horns, bone connections with the hyoid bone, absence of cricothyroid facets, hypertrophy of the inferior thyroid tubercle, and asymmetries in the thyroid notch, isthmus, or length of the inferior horn. In this report, we describe a laryngeal anatomical variation never described before, consisting of 2 apophyses symmetrically arising from the posterior margins of the thyroid laminae. Postmortem computed tomography performed on the laryngeal visceral block excluded previous traumatic injuries or natural pathologies of the laryngeal cartilages, confirming the congenital origin of the finding. An "omega epiglottis" and 3 laryngeal cysts in the piriform sinuses also coexisted, suggesting the possibility of underlying common developmental mechanisms.

The morphogenesis of the renal plexus: Renal artery and sympathetic fibers.

To examine the origin and development of the renal plexus and its relationship to the renal vessels in embryos and early human fetuses. Serial sections of 34 human embryos (stages 16 to 23 of Carnegie, 4 or 5-8 weeks) and 38 fetuses (9-19 weeks) were analyzed. Throughout the embryonic period, the kidney was not innervated by the renal plexus. Those nerves appeared at the beginning of the early fetal period (9 weeks) as branches given off by the immature autonomic abdominal plexus. The renal nerves started to approach to the kidney during the early fetal period at 9-10 weeks of development. They were distributed in close proximity to the renal arteries and their branches. They were observed first with the settlement of the renal veins. The renal artery is present as a branch of the abdominal aorta at stage 19 (between 6 and 7 weeks) prior to development of the renal plexus. The renal veins were not present during the embryonic period but appeared at the start of the fetal period, along with the renal nerves that emerged from segmented sympathetic para-aortic bodies (SPBs). Clin. Anat. 32:272-276, 2019. © 2018 Wiley Periodicals, Inc.

Which is the function of a martin-gruber connection?

Clinical and diagnostic variations may occur due to the variable presence of a connection between the median and ulnar nerves in the forearm (Martin-Gruber anastomosis). This incidence has a wide range at 7%-40%. Most commonly, the connection between the nerves is considered to be composed of motor fibers; although, a sensory role has also been described. It is important to note that the number of axons, or the nature of the fibers in this connection, have not yet been elucidated. Fifty upper limbs were examined evaluating morphometric characteristics of the Martin Gruber connection, dissected out, sectioned, and immunohistochemically stained for choline acetyltransferase (ChAT) and analyzed with ImageJ© . The connection was observed in 32% of all cases (16/50). The nerve connections were identified as those in Pattern 1 group (12%-type 1b, 19%-type 1a, and 69%-type 1c) and contained motor (ChAT positive) fibers (40.42 ± 10.5% per connection) with three to four fascicles in each. No statistically significant differences were found according to sex, side, or laterality. There were statistically significant differences in the percentages of ChAT positive fibers; however, this was dependent on the distribution being greater in those not distributed zonally. The presence of this connection is prevalent in almost a third of the cadavers dissected; the understanding of this complex composition in sensory and motor fibers allows for the optimization of diagnosis and treatment of certain median-ulnar nerve injuries. Clin. Anat. 32:501-508, 2019. © 2019 Wiley Periodicals, Inc.

Anatomical study of the masseteric and obturator nerves: Application to face transplant and reanimation procedures.

The masseteric nerve (MN) and the anterior branch of the obturator nerve (ON) that innervate the transferred gracilis muscle have proved highly efficient for reanimating paralyzed facial muscles when muscle transfer is required. Previous researchers have published the total axonal load for myelinated fibers in both nerves. However, the real motor axonal load has not been established. We performed the study on 20 MN and 13 ON. The segments of the MN and the ON were embedded in paraffin, sectioned at 10 µm, and stained following a standard immunohistochemical procedure using anti-choline acetyltransferase to visualize the motor fibers. The MN has a higher axonal load than the ON. There were statistically significant differences between the axonal load of the proximal segment of the MN and the ON. These findings confirm that end-to-end anastomoses between the MN and the ON should preferably use the proximal segment. However, MN neurotomy should ideally be performed between the proximal and distal segments, preserving innervation to the deep fascicles. Our results show that the MN is ideal as a donor motor nerve for reinnervating transplanted muscle for dynamic reanimation of the paralyzed face. The neurotomy should ideally be performed between the first and second collateral branches of the MN. Clin. Anat. 32:612-617, 2019. © 2019 Wiley Periodicals, Inc.

Anatomical Significance of the Spatial Distribution of the Palatopharyngeus With Regard to Velopharyngeal Closure.

OBJECTIVE: Coordination of the various soft palate and pharyngeal muscles should be considered while evaluating velopharyngeal closure. However, it remains unclear whether different muscle bundles have specific functions during velopharyngeal closure. We macroscopically and microscopically examined these muscles in detail and particularly clarified the morphology of the palatopharyngeus (PP) in velopharyngeal closure. DESIGN: Forty halves of 21 heads from Japanese cadavers (average: 83.9 years) were used for analysis; 37 halves of 19 heads were macroscopically examined and 3 halves of 2 heads were histologically examined. RESULTS: The PP consisted of muscle bundles originating from the superior and inferior surfaces of the palatine aponeurosis. The most superior part of the superior constrictor (SC) and most lateral part of PP on the palatine aponeurosis initially ran in parallel and subsequently, in superoposterior and inferoposterior directions, respectively. The PP appeared as a single continuous sheet that was radially spread as a whole. Its medial margins, located superior and inferior to the aponeurosis, formed a fold that established the palatopharyngeal arch. The stylopharyngeus (StP) adjoined the base of this arch. CONCLUSIONS: Since PP consisted of muscle bundles running in various directions, various functions of these bundles should be considered during velopharyngeal closure. The PP can function as a sphincter with SC and as an elevator with StP. In addition, PP forms the medial protrusion in collaboration with StP and SC. Thus, PP plays an important role in velopharyngeal closure with the coordination of various muscles.

Ultrasound-guided decompression surgery of the distal tarsal tunnel: a novel technique for the distal tarsal tunnel syndrome-part III.

BACKGROUND: The aim of this study was to provide a safe ultrasound-guided minimally invasive surgical approach for a distal tarsal tunnel release concerning nerve entrapments. METHODS AND RESULTS: The study was carried out on ten fresh-frozen feet. All of them have been examined by high-resolution ultrasound at the distal tarsal tunnel. The surgical approach has been marked throughout the course of the medial intermuscular septum (MIS, the lateral fascia of the abductor hallucis muscle). After the previous steps, nerve decompression was carried out through a MIS release through a 2.5 mm (± 0.5 mm) surgical portal. As a result, an effective release of the MIS has been obtained in all fresh-frozen feet. CONCLUSION: The results of our anatomic study indicate that this novel ultrasound-guided minimally invasive surgical approach for the release of the MIS might be an effective, safe and quick decompression technique treating selected patients with a distal tarsal tunnel syndrome.

Ultrasound-guided decompression surgery of the tarsal tunnel: a novel technique for the proximal tarsal tunnel syndrome-Part II.

BACKGROUND: The aim of this study is to provide a safe ultrasound-guided minimally invasive surgical approach for a proximal tarsal tunnel release concerning nerve entrapments. METHODS AND RESULTS: The study was carried out on ten fresh-frozen feet. All of them were examined by high resolution ultrasound at the medial ankle region. The surgical approach was marked throughout the course of the flexor retinaculum (laciniate ligament). Once the previous steps were done, the flexor retinaculum release technique was carried out with a 2-mm entry only. As a result, an effective and safe release of the flexor retinaculum was obtained in all fresh-frozen feet. CONCLUSION: The results of our anatomic study indicate that our novel ultrasound-guided minimally invasive surgical approach for the release of the flexor retinaculum might be an effective, safe and quick decompression technique treating selected patients with a proximal tarsal tunnel syndrome.

The anterolateral ligament: A cadaveric study in fetuses.

The aim of this study was to determine the presence and morphology of the anterolateral ligament (ALL) of the knee in a sample of fetuses. We hypothesized that the ALL is present in sample fetuses and its origin is not related to repetitive stresses throughout life. Forty fresh-frozen knees from cadaveric fetuses were dissected using a standard technique. The ALL and other structures in the anterolateral compartment of the knee were identified. The details of the femoral and tibial attachments, course and relationships with anatomical structures of the ALL were identified, recorded, and quantitatively characterized. The ALL was identified in 100% of the dissected knees. We found three anatomical patterns regarding the femoral attachment: (1) Proximal and posterior to the fibular collateral ligament (55%); (2) Together with the fibular collateral ligament (25%); and (3). Anterior and distal to it (20%). The ALL was extracapsular with an oblique course attaching into the anterolateral aspect of the tibia, midway between the midpoint of Gerdy's tubercle and the fibular head. The ALL has a strong attachment to the lateral meniscus, creating two fascicles: proximal or meniscofemoral and distal or meniscotibial. The ALL is a constant, extracapsular anatomical structure in the anterolateral compartment of the knee, present from the later prenatal period of life. Its morphology shows three different patterns of femoral attachment in relation to the fibular collateral ligament position, a strong attachment in the lateral meniscus, and a constant tibial attachment. Clin. Anat. 30:625-634, 2017. © 2017 Wiley Periodicals, Inc.

New insights into the morphogenesis of the gubernaculum testis and the inguinal canal.

There is no consensus about the role of the gubernaculum testis (GT). Nineteen human embryos (Carnegie stages 15-23), 36 fetuses (9 weeks to term), and eight neonates were examined. All the embryos and 25 fetuses (from weeks 9-16) were processed for paraffin wax histology and serially sectioned at 10 µm thickness. The remaining 11 fetuses and the eight neonates were fresh specimens that were dissected under a surgical microscope. The GT appeared during the embryonic period (stages 17-23) with a horseshoe-shaped mesenchyme condensation of the superior concavity, which was observed in four different topographical regions sequentially through development. The GT was not attached at either of its ends in any of the specimens, not to the gonad or in the scrotal sac. The inguinal canal differentiates around the inguinal portion of the GT during the late embryonic period. After stage 21, the GT appears enveloped by an evagination of the peritoneal cavity. It has few striate muscular fibers and vessels. Although the GT does not appear to have the role traditionally attributed to it, it is still an essential structure and indirectly facilitates the descent of the testes. It contributes to the formation of the inguinal canal and then forges the pathway that the testes will subsequently take through the inguinal canal as they migrate from the abdominal cavity into the scrotal sac. Clin. Anat. 30:599-607, 2017. © 2017 Wiley Periodicals, Inc.