The bony bridges of the atlas over the "groove of the vertebral artery" are commonly seen in plain radiographs of the cervical spine, and it is a subject of controversy whether they cause compression of the underneath lying vertebral artery. To clarify this we examined a total of 176 dried and complete atlas vertebrae and found the presence of a "canal for the vertebral artery" (CVA) in 10.23% and an incomplete "canal for the vertebral artery" in 24.43%. The CVA and incomplete CVA is more common in males (11.11% and 24.9%) than in females (9.3% and 24.42%). We found a higher incidence of CVA in laborers (37.5%) than in nonlaborers (4.16%). The incomplete CVA appeared to be more characteristic in the age group of 5-44 years. In the age group of 45-90 years the CVA was characteristic, which probably means that an incomplete CVA is the precursor of a CVA. The superoinferior diameter of the CVA canal ranged from 5.1 to 6.1 mm at the right side and from 4.6 to 5.8 mm at the left side, while the anteroposterior diameter was 5.6-6.9 mm at the right side and 6.1-7.2 mm at the left side. We also found a high incidence of coexistence of CVA and the "retrotransverse foramen" (72.22%) which means that because of possible compression of the vertebral veins the blood flow is directed into the small vein of the retrotransverse foramen. Finally, in 93.5% of unilateral CVA a deeply excavated contralateral "groove of the vertebral artery" was found.

Context: Piriform muscle syndrome can be caused by abnormal passage of the sciatic nerve or one of its parts through the belly of the piriform muscle. Objective: To analyze the anatomical and measurement relationships between the piriform muscle and the sciatic nerve in order to contribute towards better anatomoclinical understanding of the gluteal region. Method: Twenty adult cadavers of both sexes were used. The sciatic nerve and piriform muscle were dissected, measured and photodocumented. Results: The sciatic nerve was seen to be a single trunk passing through the lower margin of the piriform muscle in 85% of the 40 gluteal regions, and 15% showed bilateral variation characterized by the passage of the common fibular nerve through the piriform muscle. The data obtained did not show any statistically significant differences.

Over the recent years, an increased alertness for thorough knowledge of anatomical variants with clinical significance has been recorded in order to minimize the risks of surgical complications. We report a rare case of bilateral strap-like sternalis muscle of the anterior chest wall in a female cadaver. Its presence may evoke alterations in the electrocardiogram or confuse a routine mammography. The incidental finding of a sternalis muscle in mammography, CT, and MRI studies must be documented in a patient's medical records as it can be used as a pedicle flap or flap microvascular anastomosis during reconstructive surgery of the anterior chest wall, head and neck, and breast. Moreover, its presence may be misdiagnosed as a wide range of benign and malignant anterior chest wall lesions and tumors.

Purpose The present study aimed at summarizing and presenting the anomalous muscles that a surgeon might encounter during axillary lymphadenectomy (AL). Methods For this purpose, both the anatomical and surgical literature was reviewed and an anatomical study on 107 cadavers was carried out. Furthermore, based on the anatomical features of the anomalous muscles that came up during our study and taking into consideration the landmarks of the AL, we further analyzed the complications that may arise from each of these muscles, along with their preoperative and intraoperative recognition and management. Results The literature review revealed that there are three supernumerary muscles that may affect the AL, namely the Langer's axillary arch, the pectoralis quartus and the chondroepitrochlearis muscles, as well as the aplasia of the lower part of the pectoralis major muscle. Eight out of the 107 (7.48%) cadavers that we dissected had such an abnormal muscle in the axilla. Specifically, the axillary arch was found unilaterally in five cadavers (4.67%) and the pectoralis quartus muscle was present unilaterally in three cadavers (2.8%). One cadaver had both an axillary arch and a pectoralis quartus muscle in the right side. The abdominal and almost the whole sternocostal portion of the pectoralis major as well the pectoralis minor muscle were absent in one cadaver (0.93%). The chondroepitrochlearis muscle was not found in any of the cadavers that we dissected. Conclusions The present study offers the necessary preoperative knowledge for recognizing these muscles during AL, avoiding thus the complications that may arise from them.

A "true" anatomical preshaped olecranon plate should have both varus and anterior angulation close to the average angulations of the normal ulna and located in a certain distance from its proximal edge. The olecranon part of the plate should primarily not exceed the olecranon length and secondarily be close to the average olecranon angle. We believe that such a plate may facilitate intraoperative restoration of the proximal ulna complex anatomy, when dealing with comminuted or Monteggia fractures, thus leading to better postoperative results.