what is the function of the supraspinatus muscle
Supraspinatus muscle The supraspinatus muscle performs abduction of the arm, and pulls the head of the humerus medially towards the glenoid cavity.[5] It independently prevents the head of the humerus to slip inferiorly.[5] The supraspinatus works in cooperation with the deltoid muscle to perform abduction, including when the arm is in adducted position.[5] Beyond 15 degrees the deltoid muscle becomes increasingly more effective at abducting the arm and becomes the main propagator of this action.[6]
Sciatic nerve The sciatic nerve is formed from the L4 to S3 segments of the sacral plexus, a collection of nerve fibres that emerge from the sacral part of the spinal cord. The fibres unite to form a single nerve in front of the piriformis muscle. The nerve passes beneath piriformis and through the greater sciatic foramen, exiting the pelvis.[2]:422â€“4 From here, it travels down the posterior thigh to the popliteal fossa. The nerve travels in the posterior compartment of the thigh behind (superficial to) the adductor magnus muscle, and is itself in front of (deep to) one head of the biceps femoris muscle. At the popliteal fossa, the nerve divides into its two branches:[2]:532