Diphallia or penile duplication is a rare congenital variant with an estimated frequency of 1 per 5 to 6 million live births. The extent of duplication varies widely and typically occurs with other malformations including urogenital, gastrointestinal, and musculoskeletal anomalies. Here we present a case of human diphallia that was detected during routine dissection of an 84-year-old cadaver. Upon thorough examination, this case was characterized as a complete bifid penis which was accompanied by hypospadias with no other anatomical abnormalities detected. To gain insights into the etiology of this case, we analyzed DNA procured from the body for putative genetic variants using Next Generation Sequencing (NGS) technology. Our results support clinical observations consistent with human diphallia being a polygenic syndrome and identify new genetic variants that might underlie its etiology.

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Background Previous research on the musculocutaneous nerve (MCN) has focused on its motor and sensory branching pattern. Defining the branching pattern is important for selective neurectomy in the treatment of elbow flexor spasticity (EFS). Very limited data, however, exists regarding its internal topography, which is important for surgical procedures. Several neurotization techniques of the MCN, such as intercostal nerve transfer, rely on the location of motor and sensory fascicles of the MCN from the lateral cord. The purpose of this study is to confirm the MCN branching pattern and define its internal topography. Results The study was performed on 15 arms (9 left and 6 right) in 12 Caucasians cadavers. Branches of the MCN nerve to the coracobrachialis, biceps brachii and brachialis muscles were assessed and presented as a percentage of the distance from the coracoid process to the medial epicondyle. The internal topography of each fasciculus was identified at proximal, middle and distal levels following blunt intraneural dissection from the respective branch termination up to the lateral cord. It was found that the coracobrachialis muscle was innervated by 1–3 primary branches arising from MCN at an average of 17.7% of the arm length. The biceps brachii was innervated by 1–2 primary branches arising at an average 45% of the arm length. The brachialis was innervated by a single branch arising at an average 60% of the arm length. Regarding its internal topography, the lateral cutaneous nerve to the forearm occupied the medial and anteromedial one fourth at proximal and middle levels, but the lateral and posterolateral one fourth at the distal level. The branches to the coracobrachialis and biceps brachii occupy the anterior and anterolateral one fourth at the proximal level, and the branches to the brachialis occupy the lateral and posterolateral one fourth at proximal and middle levels, and the medial and posteromedial one fourth at the distal level. Conclusions Compared to the respective data found in the literature, our present results indicate that the branching points of the nerves to coracobrachialis, biceps brachii, and brachialis are relatively constant at approximately 20%, 40%, and 60% respectively, of the distance between the coracoid process and the medial epicondyle. Additionally, regarding the internal topography, our results indicate that while at the distal level the lateral cutaneous nerve to the forearm was located lateral and the brachialis branch was located medial, at the proximal level of MCN the nerves to the coracobrachialis, biceps brachii and brachialis occupy the lateral three fourths and lateral cutaneous nerve of the forearm occupies the medial one fourth. Based on the data obtained, it appears that the lateral half of the proximal and middle levels and the medial half of distal level of MCN would be the preferred site for any motor nerve transfer. These findings are important for the development of more efficient microsurgical procedures to treat EFS and for neurotization of the MCN...

Low back pain (LBP) is a globally prevalent and costly societal problem with multifactorial etiologies and incompletely understood pathophysiological mechanisms. To address such shortcomings regarding the role of neurotrophins in the underlying mechanisms of pain, an LBP model was developed in rats involving two unilateral intramuscular injections of nerve growth factor (NGF) into deep trunk muscles. To date, behavioral investigations of this NGF-LBP model have been limited, especially as it pertains to female pain behaviors. This study compared mechanical sensitivity to noxious (hyperalgesia) and non-noxious (hypersensitivity) stimuli in control and NGF-injected male and female rats through pain resolution. Although the baseline testing revealed no differences between males and females, NGF-injected females demonstrated prolonged ipsilateral deep trunk mechanical hyperalgesia that resolved seven days later than males. Moreover, females showed bilateral trunk mechanical sensitivity to noxious and non-noxious stimuli compared to only ipsilateral behaviors in males. Sex differences were also observed in the severity of behavioral responses, with females displaying greater mean differences from baseline at several timepoints. Overall, these NGF-LBP behavioral findings mirror some of the sex differences reported in the clinical presentation of LBP and accentuate the translatability of this NGF-LBP model. Future studies using this LBP-NGF model could help to elucidate the neurobiological mechanisms responsible for the development, severity, and/or resolution of muscular LBP as well as to provide insights into the processes governing the transition from acute to chronic LBP.

In the current report, we describe an 83-year-old biological male who selfidentified as a female by legally changing his first and middle names to female ones and whose death certificate states his sex as a female. The medical history of this individual indicated complete penectomy without further specification. Postmortem physical examination revealed an absence of penis with a large scrotum, transposed urethral orifice, and small testes. The histological analysis of the testes identified abnormal epithelium in the seminiferous tubules that lacked germ and Sertoli cells as well as the interstitium without Leydig cells present. The exome sequencing of the individual's DNA using the Next Generation Sequencing (NGS) Illumina platform revealed no genetic variants associated with either penile or urethral cancer that could have explained the complete penectomy, but pointed toward a potentially impaired production of T3 and T4 thyroid hormones which could account for the observed testicular malformation. Overall, the data obtained raise an important question as to whether the thyroid hormone axis could be an important part of the hormonal architecture supporting male sexual behavior.An 83-year-old TF cadaver was received through Saint Louis University (SLU) School of Medicine Gift of Body Program from an individual who had given his written informed consent. The body was embalmed through the right femoral artery with a mixture of water and a solution (2:1) containing 33.3% glycerin, 28.8% phenol, 4.6% formaldehyde, and 33.3% methanol. Anatomical DissectionThe cadaveric body was dissected according to [11].A. Frolov et al. Histological AnalysisTesticular tissue was procured from the embalmed body. Tissue fixation, paraffin embedding, sectioning, and staining with hematoxylin & eosin were performed by Research Microscopy and Histology Core, Department of Pathology, Saint Louis University (SLU) School of Medicine according to the standardized procedures. Images were captured on Olympus 41BX-EPI microscope equipped with the 10× UPlan FL N, 20× LUCPlan FL, and 40× UPlan FL N objectives. The data acquisition and image analysis were performed by using CellSens Standard software. Bone DensitometryBone density of the lumbar spine and left femoral neck of the embalmed body was measured in triplicates using certified Hologic QDR-4500 X-ray Bone Densitometer in the dual energy X-ray absorptiometry (DEXA) mode following the manufacturer's protocol. The respective average T-score values were used throughout the text. LimitationsThe deleterious (pathologic) genetic variants were identified by the exome sequencing of a single proband. The high scientific value of a single proband approach to unique human cases has been recently demonstrated [27].