An unusual digital neural loop in a cadaver with bilateral high branching median nerves - case report.

Digital neural loops are present in the palms of most individuals. They can arise within the common palmar digital nerves (CPDNs) or proper palmar digital nerves (PPDNs). Typically, common palmar digital arteries (CPDAs) pass through digital neural loops, however there are reports of loops forming around the superficial palmar arch or proper palmar digital arteries (PPDAs). We describe an unusual digital neural loop that involved both a CPDN and a PPDN. To our knowledge, this is the first documented case of a digital neural loop of this type and therefore anatomists and surgeons may benefit from an awareness of its existence. A modification to a current classification system for digital neural loops is presented to include this novel loop. Interestingly, the cadaver documented in this report featured a high division of the median nerve in each forearm. On both sides, the ulnar component of the bifid median nerve followed an intramuscular course in which it pierced the flexor digitorum superficialis and then continued into the palm as the 3rd CPDN. A brief review of the literature is provided for both digital neural loops and the high division of the median nerve variant. Documented muscle associations noteworthy to the bifid median nerve are discussed. Developmental connections, if any, that exist between the unique digital neural loop and the high division of the median nerve are not speculated upon.

An online catalog of muscle variants: Student perceptions of a new opportunity for self-directed learning.

OBJECTIVE:: Muscle variants are common findings in dissection laboratories. These anomalous structures can be relevant in the diagnosis and management of certain conditions and therefore could be incorporated into anatomy curricula at chiropractic colleges. We aimed to create an online resource of muscle variants to facilitate student self-directed learning within this area of study. METHODS:: At the time of their discovery during routine educational dissection, muscle variants included in the catalog were documented and subsequent case reports written. All content created for this resource, including photographs and videos, was hosted on the institution's learning management system. Students enrolled in our doctor of chiropractic program were invited to view the catalog and encouraged to leave feedback by completing an online survey. RESULTS:: Student responses to Likert-style survey questions generally indicated high levels of satisfaction regarding the utility and features of the catalog. Open-ended and Likert-style survey questions were used to help guide the future directions of this developing resource. Concurrent anatomy students were not more likely to contribute to the catalog compared to students who had previously completed the university's anatomy course series ( p = .75, 2-tailed Fisher exact test). CONCLUSION:: An online supplement to graduate-level gross anatomy courses can aid in the instruction of muscle variants by providing an opportunity for student self-directed learning. This resource will be updated continually and will be expanded on to include neurovascular and visceral variants. Student participation will be sought in developing future content to be included in this catalog.