Establishment of Mathematical Models for Skeletal Age Determination of Extremitas Sternalis of Clavicle in Shanxi Adolescents / 法医学杂志

Objective To develop mathematical models for skeletal age determination with multiple statistic method based on the correlation between age and the growth of the epiphysis of extremitas sternalis of clavicle in Shanxi adolescents. Methods The 562 Shanxi sternoclavicular joint samples （454 cases of modelling, 108 cases of external verification） were scanned by the thin-section computed tomography. After volume rendering was obtained, indicators such as area of epiphysis, area of metaphysis, longest diameter of epiphysis and longest diameter of metaphysis of both extremitas sternalis of clavicle were collected. Indicators such as the ratio of area of epiphysis to area of metaphysis, and the ratio of longest diameter of epiphysis to longest diameter of metaphysis of both sides were calculated. Then multiple linear regression and random forest discriminant models were used to build mathematical models for age determination of adolescents. Results The obtained indicators exhibited a strong correlation with age （r>0.85）. The multiple linear regression model for males and females （all 4 indicators entering the model） based on the ratio of longest diameter of epiphysis to longest diameter of metaphysis and the ratio of area of epiphysis to area of metaphysis had an internal validation accuracy rate （±1.0 year） of over 92% and 108 cases had an external validation accuracy rate of over 70% （±1.0 year）. The out of bag error rates of random forest discriminant models were less than 2% for people over 18.0 years old （≥18.0 years old） and under 18.0 years old. The external validation accuracy rates of the 108 cases were over 80%. Conclusion The regression and discriminant models established in this study have certain reliability and accuracy and can be used in age determination of Shanxi adolescents.

Useful tools for the age 18 estimation in forensic radiology / 中国法医学杂志

The age of 18 is an important criterion in judicial trial, immigrant and competitive sports. Consequentially, the estimation of age 18 is a key issue in forensic practice and research. The extremitas sternalis claviculae, iliac crest, third molar, and the proximal limb of the limb bone were usually used as indictors of age 18. The results of the previous studies demonstrated that those indictors could be beneficial to the estimation of age 18. The X-ray, CT, ultrasound and MRI of different indictors were widely utilized for the estimation of age 18, particularly the thin-layer CT. But due to the non-radiation, MRI will be a trend for forensic age estimation in the future. Whilst in the previous studies, the descriptive analysis was applied for the estimation of age 18, but due to the low statistic efficiency, it is unsuitable for forensic age estimation, and the future studies should pay attention to the high efficiency statistical methods, for instance, the ROC curve or the data mining.

A Bilateral Double Sternalis Muscle in a Korean Cadaver / 체질인류학회지

Although the sternalis muscle has been well known to anatomists, it is quite unfamiliar to clinicians. During routine educational dissection, we came across a well-defined bilateral double sternalis muscle innervated by the intercostal nerve, respectively. The right sternalis muscle 1) became tendinous to insert into the sternum and 2) crossed midline and then intermingled with the left pectoralis major muscle, which could be classified into a double with single cross based on Snosek et al.'s criteria. The left sternalis muscle was composed of two bellies, which were combined at the midway, and became tendinous to insert into the contralateral manubrium, which could be classified into a bicipital diverging with double cross based on Snosek et al.'s criteria. The detailed knowledge on the sternalisis is important for clinicians as well as for anatomists, since the clinical importance of the sternalis muscle has been highlighted in recent years.

Sternalis muscle: an anatomic variation of the anterior chest wall

The sternalis muscle’s presence is an uncommon anatomic variation of the anterior chest wall’s musculature. It is insufficiently mentioned by the most of anatomical textbooks, although it has been well described by the literature. The study of this anatomic variation is extremely relevant, principally for the interpretation of image’s exams that approach this region. For this study’s achievement, 102 cadavers were dissected (97 of the male sex and 5 of the female sex). The study of the sternalis muscle avoids the expenses with exams and the indication of aggressive treatments in a wrong way.

Sternalis muscle: Anatomical variations in Thais.

Objective: To study and classify the types of the sternalis muscle in Thais, who has lived in Bangkok and the surrounding area, and compare its incidence to that of the other races. Methods: The sternalis muscles were dissected and classified in Thai cadavers. The morphology of each type was shown by photograph. Tables showed numbers and percentage of the muscle in male and female, right and left sides. Results: The study of 126 Thai cadavers, the sternalis muscle was found in 9 cadavers. The incidence was 7.14%. The muscle was divided into 2 types, type A was the bilateral type and type B was the unilateral type. Conclusion: The sternalis muscle was an anatomical variation of the thoracic wall musculature. Its incidence in Thais was 7.14%. The morphology of the muscle was shown and divided into 2 types.

Development of the Rectus Abdominis and Its Sheath in the Human Fetus

PURPOSE: Although the rectus abdominis and its sheath are well known structures, their development in the human fetus is poorly understood. MATERIALS AND METHODS: We examined rectus abdominis and sheath development in semiserial horizontal sections of 18 fetuses at 5-9 weeks of gestation. RESULTS: Rectus muscle differentiation was found to commence above the umbilicus at 6 weeks and extend inferiorly. Until closure of the anterior chest wall via fusion of the bilateral sternal anlagen (at 7 weeks), the anterior rectal sheath originated from the external oblique and developed towards the medial margin of the rectus abdominis at all levels, including the supracostal part. After formation of the anterior sheath, fascial laminae from the internal oblique and transversus abdominis contributed to formation of the posterior rectus sheath. However, the posterior sheath was absent along the supracostal part of the rectus abdominis, as the transversus muscle fibers reached the sternum or the midline area. Therefore, it appeared that resolution of the physiological umbilical hernia (8-9 weeks) as well as chest wall closure was not required for development of the rectus abdominis and its sheath. Conversely, in the inferior part of the two largest fetal specimens, after resolution of the hernia, the posterior sheath underwent secondary disappearance, possibly due to changes in mechanical stress. CONCLUSION: Upward extension of the rectus abdominis suddenly stopped at the margin of the inferiorly developing pectoralis major without facing the external intercostalis. The rectus thoracis, if present, might correspond to the pectoralis.

A unilateral rectus sternalis: An important variant in the thoracic region.

During a routine dissection in the Anatomy dissection hall, a unilateral muscle was observed on the left thoracic wall present superficial to pectoralis major muscle. The name of this muscle was Rectus Sternalis muscle and the history of the development of the rectus sternalis muscle provided with interesting explanations by different authors and even in the Anatomy textbooks. Since this muscle was found for the first time in five years by dissecting 70 cadavers, it is considered as a very rare anomaly. The description of rectus sternalis muscle might provide useful details for clinicians exploring the pectoral region.

Sternalis Muscle Encountered during Immediate Breast Reconstruction: 2 Case Reports

The sternalis muscle is an uncommon variation in the anterior chest wall which is located superficial to the pectoralis major, coursing vertically almost parallel to the sternum. It exists unilaterally or bilaterally, as thin muscle strips or a broad band of muscles. We report two cases of skin sparing mastectomy and immediate breast reconstruction in which the sternalis muscle was encountered. This unusual variation might puzzle radiologists to mistake it for a tumor or an abnormal bulging of the pectoralis. Surgeons also must not be surprised to encounter this muscle during surgery of the breast or pectoralis and keep the appropriate dissection plane.

Implication of Sternalis Muscle on Staged Breast Reconstruction with Implant

PURPOSE: The sternalis muscle is an accessory muscle of the anterior chest wall. This is a rare anatomic variant reported in approximately 8 percent of the population, with variation among races. While several anatomic studies of the sternalis muscle exist, nothing in the literature addresses the implications of this muscle on staged breast reconstruction with implant. METHODS: We encountered two consecutive patients with a left sternalis muscle who underwent immediate staged breast reconstruction with a tissue expander. We offer a strategy for dealing with this rare, but known, anatomic variant during staged implant reconstruction. Firstly, recognizing the presence of a sternalis muscle mandates the elevation of the pectoralis major muscle and the sternalis muscle in continuity. Secondly, slight modifications must be made during the submuscular dissection to create a properly placed pocket for the tissue expander. RESULTS: While our encounters with this anatomic variant are few, our experiences with two consecutive patients illustrate that the reconstructive surgeon must be familiar with the sternalis muscle and be prepared to adapt his or her technique for tissue expander placement when faced with this accessory muscle. CONCLUSION: To date, no reports exist in the literature describing the operative implications of this anatomic variant. We offer our technique for dealing with this accessory muscle during staged implant reconstruction of the breast.

Bilateral Sternalis with Unusual Left-Sided Presentation: A Clinical Perspective

An unusual variation creates interest among anatomists, but is a cause of concern among clinicians when it mimics a pathology. The sternalis muscle is one such variant of the anterior chest wall located subcutaneously over the pectoralis major, ranging from a few short fibers to a well-formed muscle. We observed a bilateral case, which was accompanied by an atypical presentation on the left side where a huge, bulky sternalis muscle was associated with the absence of the sternal fibers of the pectoralis major. The fibers arose as a lateral strip from the upper two-thirds of the body of the sternum and costal cartilages 2 through 6 with the intervening fascia and aponeurosis of the external oblique. The right sternalis was strap-like and was placed vertically over the sternal fibers of the pectoralis major, arising from the underlying fascia and aponeurosis of the external oblique. The sternalis muscles, on each side, converged into an aponeurosis over the manubrium that was continuous with the sternal heads of the right and left sternocleidomastoid muscle, respectively. This rare anomaly has puzzled radiologists and surgeons in confirming diagnosis, missing it all together or mistaking it for a tumor on mammography or CT scan. These findings prompted us to review its topography, development, and application in relation to the anterior chest wall.