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Designing for Upper Torso and Arm Anatomy
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
The rotator cuff muscle on the rib cage side of the scapula (subscapularis), plus the fourth muscle, the teres major from the trapezius side, rotate the humerus medially. The large latissimus dorsi and pectoralis major also help to rotate the humerus medially. The anterior portion of the deltoid also acts as a medial rotator at this joint. The humerus laterally rotates approximately 90 degrees, when raising the hand on the bent arm up near the head. Medial rotation is usually limited to about 80 degrees. Throwing athletes, such as baseball pitchers, often have far greater lateral rotation than the average person, seen as they cock the pitching arm back before releasing the ball.
Functional Anatomy and Biomechanics
Published in Emeric Arus, Biomechanics of Human Motion, 2017
Musculus pectoralis minor is a smaller muscle than the pectoralis major and lies underneath. Insertion: The origin has three portions and is inserted on the anterolateral surfaces of the third, fourth, and fifth ribs a little bit further from the costal cartilages. Distal insertion is on the coracoid process of the scapula on the medial margin of the superior surface.
Stemless total shoulder arthroplasty in elderly patients with primary osteoarthritis of shoulder – a developing country experience
Published in Expert Review of Medical Devices, 2021
Vishwajeet Singh, Sanjay S Desai
All the patients were operated in beach chair position once regional block was given followed by Sedation or GA (general anesthesia). The incision starts above the coracoid process and terminates above the insertion of the pectoralis major on the shaft of the humerus. The cephalic vein is mobilized laterally with deltoid muscle, and conjoint tendon is protected. A retractor is placed under CA (coracoacromial ligament) to protect it and provide exposure to superior aspect of subscapularis, and the humerus. Subscapularis is cut at 5 mm from insertion over lesser tuberosity and secured using number 2 fiberwire. Capsular release is done at anterior and inferior levels. The axillary nerve is secured and protected. The humerus is gently dislocated from the glenoid. The arm is held in 90° of external rotation, 20° −30° of extension, and adducted against the operating room table.
A musculoskeletal shoulder simulation of moment arms and joint reaction forces after medialization of the supraspinatus footprint in rotator cuff repair
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Tim Leschinger, Stefan Birgel, Michael Hackl, Manfred Staat, Lars Peter Müller, Kilian Wegmann
Dependent on its size and the dimension of the attachment site, each muscle was represented by three or more lines of actions (LA) as shown in Figure 1 (supraspinatus = 4 LA, teres minor = 3 LA, infraspinatus = 6 LA, subscapularis = 11 LA, deltoid = 15 LA, pectoralis major = 8 LA, pectoralis minor = 4 LA, biceps = 3 LA, latissimus dorsi = 6 LA, triceps = 14 LA, teres major = 4 LA) (Chadwick et al. 2009). The change of moment arms of the scapular muscles were not measured. However, in this study only the motion of the glenohumeral joint was evaluated.