Surface Markings of Nerves of Upper Limb

Topic Overview

Axillary Nerve

• Line: A short horizontal line on the deltoid muscle.

• Location: 2 cm above the midpoint between the tip of the acromion process and the insertion of the deltoid.

• Clinical Note: Intramuscular injections in the deltoid are given below this line to avoid injury to the axillary nerve and posterior circumflex humeral vessels.

Musculocutaneous Nerve

• Line joining two points:

  • Point 1: Just lateral to the axillary artery, about 3 cm below the coracoid process.

  • Point 2: Midway between the biceps tendon and brachialis muscle at the elbow.

• Course: Passes downward and laterally between biceps brachii and brachialis, becoming the lateral cutaneous nerve of the forearm near the elbow.

Median Nerve

• Line: From medial side of the brachial artery in the arm to the midpoint of the wrist.

• Landmarks: Crosses anterior to the elbow joint (medial to the biceps tendon) and passes through the carpal tunnel deep to the flexor retinaculum.

• Clinical relevance: Site of compression in carpal tunnel syndrome.

Ulnar Nerve

• Line joining three points:

  • Point 1: Behind the medial epicondyle of the humerus.

  • Point 2: Along medial border of forearm (beneath flexor carpi ulnaris).

  • Point 3: To the pisiform bone at wrist.

• Note: Palpable behind the medial epicondyle (“funny bone”). Runs superficial to the flexor retinaculum.

Radial Nerve

• Posterior arm: From lower border of teres major to lateral epicondyle, running in the spiral groove of humerus.

• Anterior forearm: From lateral epicondyle to anatomical snuffbox, where it divides into superficial and deep branches.

• Clinical Note: Injury in spiral groove causes wrist drop.