Anatomic Relationship Between the Hook of the Hamate and the Distal Transverse Carpal Ligament: Implications for Ultrasound-Guided Carpal Tunnel Release

Anatomy of the Palmar Region of the Carpus of the Dog

The palmar region of the canine carpus is anatomically complex, and the information found in the literature about its anatomy is inconsistent. The aims of this prospective, descriptive, anatomic study were (1) the clarification and (2) the description of the precise anatomic composition of the palmar region of the canine carpus, with special reference to the canalis carpi. For this study, 92 cadaveric specimens were obtained from 46 dogs that had died for reasons unrelated to this study. Of these, 43 medium-to-large-breed dogs were randomly selected for the dissection of transverse slices of the carpus. Samples of the flexor retinaculum and flexor carpi radialis tendon and surrounding tissues were taken for complementary histology. For additional histology of the palmar structures in their anatomical position, three small breed dogs were randomly selected for obtaining transverse slices. The anatomic characteristics of the components of the palmar region of the canine carpus were qualitatively described, with special attention to the following structures: flexor retinaculum, flexor carpi radialis muscle, arteria and vena mediana, nervus medianus, interflexorius muscle, flexor digitorum profundus muscle, canalis carpi, and arteria and nervus ulnaris. The findings from this study provide reference information about the anatomy of the palmar region of the canine carpus.

Thenar and Hypothenar Muscle Coverage on the Transverse Carpal Ligament

Background  The purpose of the study was to examine the coverage of thenar and hypothenar muscles on the transverse carpal ligament (TCL) in the radioulnar direction through in vivo ultrasound imaging of the carpal tunnel. We hypothesized that the TCL distance covered by the thenar muscle would be greater than that by the hypothenar muscle, and that total muscle coverage on the TCL would be greater than the TCL-alone region. Methods  Ultrasound videos of human wrist were collected on 20 healthy subjects. Automated algorithms were used to extract the distal cross-sectional image of the trapezium-hamate level. Manual tracing of the anatomical features was conducted. Results  Thenar muscles covered a significantly larger distance (11.9 ± 1.8 mm) as compared with hypothenar muscles (1.7 ± 0.8 mm) ( p  < 0.001). The TCL covered by thenar and hypothenar muscles was greater than the TCL-alone length ( p  < 0.001). The thenar and hypothenar muscle coverage on the TCL, as normalized to the total TCL length, was 61.0 ± 7.5%. Conclusions  More than 50% of the TCL at the distal carpal tunnel is covered by thenar and hypothenar muscles. Knowledge of muscular attachments to the TCL improves our understanding of carpal tunnel syndrome etiology and can guide carpal tunnel release surgery.

The Superficial Face Dissection as an Example for Integrating Clinical Approaches, Authentic Learning, and Changing Perspectives in Anatomy Dissection

Hands-on dissection-based learning of anatomy offers an unique and valued experience for medical students. Too often however, the inexperienced student's focus is to avoid damage to unfamiliar structures instead of understanding spatial relationships between structures. This results in unfortunate surrender of a critical learning experience. Additionally, approaches to dissection and anatomic exposure share little alignment to clinical approaches, making it less powerful in clinical applicability. The goal of this viewpoint commentary is based on the experience of the two authors and aims to demonstrate opportunity to introduce clinical approaches for dissection while incorporating relevant anatomical concepts in medical school curriculum that aligns with authentic healthcare practice. Using the dissections of the superficial face as a relevant and current topic of clinical interest, we point out that applying the currently performed dissection approach (medial-to-lateral) falls short of providing sufficient knowledge and understanding of the layered arrangement of facial structures. The lateral-to-medial approach, as performed in surgical face lifting procedures would offer a better understanding of the layers of the face and especially the superficial musculoaponeurotic system (SMAS) accounting for the difficulties of facial dissections on embalmed cadavers. This commentary could offer a potential change in paradigm for students and course facilitators for how to maximize the knowledge transfer during facial dissections. It potentially opens a door to rethink dissection-based learning of anatomy toward techniques and approaches that are aligned to surgical access pathways and thus considered more clinically relevant.

Ultrasound-Guided Surgery for Carpal Tunnel Syndrome: A New Interventional Procedure

Carpal tunnel syndrome (CTS) may be treated surgically if medical treatment fails. The classical approach involves release of the flexor retinaculum by endoscopic or open surgery. Meta-analyses have shown that the risk of nerve injury may be higher with endoscopic treatment. The recent contribution of ultrasound to the diagnosis and therapeutic management of CTS opens new perspectives. Ultrasound-guided carpal tunnel release via a minimally invasive approach enables the whole operation to be performed as a percutaneous radiological procedure. The advantages are a smaller incision compared with classical techniques; great safety during the procedure by visualization of anatomic structures, particularly variations in the median nerve; and realization of the procedure under local anesthesia. These advantages lead to a reduction in postsurgical sequelae and more rapid resumption of daily activities and work. Dressings are removed by the third day postsurgery. Recent studies seem to confirm the medical, economic, and aesthetic benefits of this new approach.