Fifty shades of the xiphoid process anatomy: the challenging world of virtual dissections

Advances in technology have created new teaching tools, such as digital dissection tables, which provide both new learning and research opportunities, conjoining pure and clinical anatomy. Through touchscreen technology, three-dimensional volume rendering (3DVR) images are obtained by the software from DICOM files belonging to real clinical cases contained in the public library image dataset of our digital anatomical table Sectra F18. Starting from the most canonical anatomical description of the sternum, and particularly, the xiphisternum or xiphoid process (XP), our aim was to observe some clinical cases with their anatomical variants. Clinical cases including images of the thorax -and particularly the sternum- were searched within the public library of the table. A total of 39 cases were analyzed, of which 14 men, 11 women and 14 patients with undetermined genre. The following parameters were considered: genre; age (if supplied by the institutions); general conditions of the patient (presence of any pathology); presence or absence of XP; if present, shape, alignment, calcification, and presence of foramina/ pseudoforamina were also evaluated. The human XP appeared in morphological diversity, displaying pointed, oval, monofid, bifid (forked, crab-like), and trifid processes. Heterogeneous foramina/pseudoforamina were observed in 13/39 cases. In 3 cases the xiphoid process was absent/not identified. Knowing the postnatal development, maturation, and anatomy of the sternum is important for treating several bone, hematological, and developmental diseases and for planning thoracic surgery, identifying possible perioperative and postsurgery complications, and preventing mediastinal organ injury. In particular, the presence of foramina along the whole sternum may represent a clinical risk. The terminology classifying XP morphology and foramen patterns is not universally accepted [1- 4]. It is also important to consider the risk of sternal fracture during cardiopulmonary resuscitation maneuvers, which may lead to heart tamponade. Anatomic variations may mimic sternal fractures if only plain imaging is considered. Therefore, 3D imaging is useful to display any anatomical variations or abnormalities of the XP, especially considering that axial CT may miss variants or fractures because of the slicing. Color presets are to be adopted and adapted according to the tissues intended to better interpret clinical images. In this way the filter becomes the tailored suit.