RIU 360 Lecture Notes - Lecture 10: Orbicularis Oris Muscle, Pectoralis Major Muscle, Skeletal Muscle

• School: GVSU
• Department: Radiation and Imaging - Ultrasound
• Course: RIU 360
• Professor: Jennifer Vanderpool

Document Summary

Skeletal muscle contains long organized units called muscle fibers. Long fibers under voluntary control: to contract muscle and move joint. Blood vessels, lymphatics, and nerves follow fibrous partitions between bundles of muscle. Location- bone or body region associated with the muscle. Relative size- e. g. maximus (largest), minimus (smallest), longus (long) Direction of fibers or fascicles- e. g. rectus (fibers run straight), transversus, and oblique (fibers run at angles to an imaginary defined axis) Number of origins- e. g. biceps ( 2 origins) and triceps (3 origins) Location of attachments- named according to point of origin or insertion. Action- e. g. flexor or extensor, muscles that flex or extend, respectively. Fascicles arranged in concentric rings (e. g. orbicularis oris) Fascicles converge toward a single tendon insertion (e. g. pectoralis major) Fascicles parallel to the long axis of a straplike muscle (e. g. sartorius) Spindle- shaped muscles with parallel fibers (e. g. biceps brachii)