Post-Lab Q7: In actuality, the bicep does not attach perpendicular like this. Da
ID: 145909 • Letter: P
Question
Post-Lab Q7: In actuality, the bicep does not attach perpendicular like this. Data taken from MRI scans have shown that the insertion angle actually has a range that changes as the arm moves. When the bicep is fully extended, this insertion angle is 15°. When the muscle is flexed and the forearm is at a 90° angle, this insertion angle increases to 20°. Based on what we found from Q6, what purpose does this increase in insertion angle serve? Aside from a change in insertion angle, what else could be changed anatomically to increase the overall performance of the bicep?Explanation / Answer
Biceps helps in flexion of the arm at elbow joint. The long head of the muscle originates from supraglenoid tubercle and short head from coracoid process. It gets inserted to the radial tuberosity by means of biceps tendon. The angle if insertion of biceps changes from 10 degrees to 20 degrees. This serves to pull the forearm bone (radius) helping in flexion at the elbow joint. If the biceps takes origin from humerus, the flexible at elbow joint could be made more easily.