Chapter 1: Topographical Anatomy as Landmarks

INTRODUCTION

The utilization of topographical anatomic landmarks to assist anesthesiologists during procedural care includes a multitude of regional nerve blocks, interventional pain procedures, neuraxial techniques, and vascular access cannulation. Specialty care for regional and interventional pain medicine relies greatly on a thorough understanding of anatomic relationships to effectively deliver anesthesia and to avoid potential morbidity and mortality.

TOPOGRAPHICAL LANDMARKS ALONG THE VERTEBRAL COLUMN

• C6: Chassaignac tubercle

• C7: Vertebra prominens, level of stellate ganglion

• T1-T4: Cardioaccelerator fibers

• T3: Axilla

• T4: Nipple line

• T7: Xiphoid process

• T8: Inferior border of scapula

• T9-L2: Origin of artery of Adamkiewicz in 85% of patients

• T10: Umbilicus

• T12-L4: Lumbar plexus

• L1: Level of celiac plexus

• L2: Termination of spinal cord (adults)

• L3: Termination of spinal cord (pediatrics)

• L4: Iliac crest

• L4-S3: Sacral plexus

• S2: Posterior superior iliac spine (PSIS), termination of subarachnoid space (adults)

• S3: Termination of subarachnoid space (pediatrics)

NERVE BLOCK LANDMARKS

Upper Extremity Blocks

1. Interscalene—Mark the sternal and clavicular heads of the sternocleidomastoid (SCM) muscle, the cricoid cartilage, and the clavicle. The needle insertion should be in the interscalene groove at C6 that is posterior to the clavicular head of the SCM and between the anterior and middle scalene muscles.

2. Infraclavicular—Mark the coracoid process and the needle insertion is 2 cm inferior and 2 cm medial to the coracoid process.

3. Axillary—Palpate or visualize the pulse of the axillary artery and guide the needle through the artery until arterial blood is aspirated. Penetrate further until blood return stops (you have now passed through the axillary artery) then inject anesthetic. This will cover the radial nerve as it is directly posterior to the axillary artery. Withdraw needle and again pass through the axillary artery. Once you exit the artery and are anterior to it, inject again to cover the median and ulnar nerves.

4. Musculocutaneous—Typically combined with the axillary approach to ensure lateral forearm anesthesia. Local anesthetic can be injected into the belly of the coracobrachialis muscle, which sits just posterior to the biceps.

5. Ulnar—Isolated block can be done at the elbow between the medial epicondyle and olecranon process, medial to the ulnar artery.

6. Radial—Isolated block can be done at elbow between the brachioradialis and biceps tendons. A block can also be done at the wrist in the anatomic snuff box between brachioradialis and biceps tendons.

7. Median—Isolated block can be done at elbow medial to the brachial artery at the pronator teres muscle. A block can also be done at the wrist between the palmaris longus and flexor carpi radialis tendons.

Lower Extremity Blocks

1. Femoral—Below inguinal ligament, insert needle lateral to femoral artery at the level of the femoral crease.

2. Sciatic

   1. Classic posterior approach—A line is drawn between the greater trochanter of the femur and the PSIS. The needle insertion is ...