 Union of the anterior primary divisions of C5-8 and the T1 nerve. › C4 and T2 may contribute as well.  Roots  Trunks  Divisions  Cords  Terminal nerves (branches). “Robert Taylor Drinks Cold Beer”.  Terminal Branches: Axillary, Radial, Median, Musculocutaneous, and Ulnar. “ARM MU”.

 Performed at the C6 level (cricoid cartilage level). › Ask patient to turn head to side. › Locate groove.  Between the anterior and middle scalene muscles. › The anterior scalene is an important landmark that should be identified.  Posterior to the posterior aspect of the SCM at the level of the cricoid.  Enter behind the External Jugular at 45 degrees caudad and posterior.

 Needle enters 1.2cm above the middle of the clavicle.  Administer anesthetic while advancing needle towards the first rib. › Anterior-posterior direction until parasthesias are elicited.

 L4-5 and S1-3 › Runs between the ischial spine and greater trochanter of the femur. › Becomes superficial at the base of the gluteus maximus.  Cutaneous innervation to posterior thigh and all of the leg below the knee minus a small medial strip.  Two approaches: Posterior and Anterior.  Usually block is combined with femoral, obturator, or lateral fem cutaneous nerve blocks.  Disadvantages: technically difficult, painful, possible hematoma, nerve damage, slight drop in BP due to blood pooling.

 Lateral decub position with leg to be blocked flexed at the knee with the heel resting on the opposite knee.  Connect the posterior superior iliac spine with the greater trochanter with a drawing pen. Bisect this line perpendicularly, extending caudal.  Needle entry point: 3cm downward from the perpendicular line.

 Supine position.  Line from ASIS to pubic tubercle. Mark point 2/3 of the way.  Draw parallel line from greater trochanter.  From point of first line, continue down to second line. Inject at this site until bone is hit, then direct medially.