Inter- and Intraspecific Variations in the Pectoral Muscles of Common Chimpanzees (Pan troglodytes), Bonobos (Pan paniscus), and Humans (Homo sapiens)

Anatomical Variations in the Pectoralis Minor Muscle Origin and Insertion: A Systematic Review

The pathology of the shoulder is among the most widespread medical presentations and may be a result of existing anatomical variations. Therefore, the knowledge of the variations is vital for physicians and clinicians, tasked with treating patients presenting similar complaints to minimize misdiagnosis and prevent iatrogenic injuries. Therefore, the main objective of the present systematic review the variations in pectoralis minor muscle origin and insertion/attachment point. The study also seeks to better inform physicians and clinicians of the task of treating patients with various pathology problems and to ascertain that, upon identification, the pectoralis minor muscle variants are aptly appreciated. The search method used in this systematic review entails the use of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol, and the searching of several online databases, for studies focusing on variations in pectoralis minor muscles. The author reviewer evaluated the studies for eligibility, and the selection criteria for the studies used are described below. This systematic review has disclosed that, in some individuals, the pectoralis minor muscles have their origins in the second, third, and fourth ribs, even as others have their origin in the third and fourth ribs. Still, the systematic review has disclosed that, in certain individuals, the insertion of the pectoralis minor muscle occurs at the supraspinatus tendon, even as there are anomalies in the pectoralis minor insertion points linked to subacromial impingement, possible compression of the brachial plexus anteromedial and the axillary artery, and the subcoracoid impingement.

Gross anatomical description of the extrinsic and intrinsic scapular and brachial muscles of Sapajus apella (Linnaeus, 1758)

BACKGROUND

The robust brown capuchin monkey (Sapajus apella) is a South American primate with preferences for arboreal locomotion, which requires specific thoracic limb muscle adaptations. The present investigation studied the gross anatomy of the extrinsic and intrinsic scapular and brachial muscles.

METHODS

Gross dissections were performed in both thoracic limbs of four formaldehyde-fixed specimens.

RESULTS

Three rhomboideus muscles were present (capitis, cervicis, and thoracis). The trapezius muscle was divided into two parts (cervicis and thoracis). The pectoralis abdominalis and omotransversarius muscles were present. The anconeus muscle was found as an individual muscle or fused to the caput mediale of the triceps brachii muscle. The brachialis muscle had among one and two heads. The anconeus epitrochlearis was absent.

CONCLUSION

These muscles of Sapajus apella are adapted for arboreal locomotion and some terrestrial habits, since these have many similarities with other primates with a similar locomotor patterns.

Ultrasound-guided parasternal intercostal nerve block for postoperative analgesia in mediastinal mass resection by median sternotomy: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Ultrasound-guided parasternal intercostal nerve block is rarely used for postoperative analgesia, and its value remains unclear. This study aimed to evaluate the effectiveness of ultrasound-guided parasternal intercostal nerve block for postoperative analgesia in patients undergoing median sternotomy for mediastinal mass resection.

METHODS

This randomized, double-blind, placebo-controlled trial performed in Renmin Hospital, Wuhan University, enrolled 41 participants aged 18-65 years. The patients scheduled for mediastinal mass resection by median sternotomy were randomly assigned were randomized into 2 groups, and preoperatively administered 2 injections of ropivacaine (PSI) and saline (control) groups, respectively, in the 3rd and 5th parasternal intercostal spaces with ultrasound-guided (USG) bilateral parasternal intercostal nerve block. Sufentanil via patient-controlled intravenous analgesia (PCIA) was administered to all participants postoperatively. Pain score, total sufentanil consumption, and postoperative adverse events were recorded within the first 24 h.

RESULTS

There were 20 and 21 patients in the PSI and control group, respectively. The PSI group required 20% less PCIA-sufentanil compared with the control group (54.05 ± 11.14 μg vs. 67.67 ± 8.92 μg, P < 0.001). In addition, pain numerical rating scale (NRS) scores were significantly lower in the PSI group compared with control patients, both at rest and upon coughing within 24 postoperative hours. Postoperative adverse events were generally reduced in the PSI group compared with controls.

CONCLUSIONS

USG bilateral parasternal intercostal nerve block effectively reduces postoperative pain and adjuvant analgesic requirement, with good patient satisfaction, therefore constituting a good option for mediastinal mass resection by median sternotomy.