At which anatomical point does the ulnar nerve enter the forearm after passing through the cubital tunnel?

Explanation

## Ulnar Nerve Course in the Forearm **Key Point:** The ulnar nerve enters the forearm by passing between the two heads of the flexor carpi ulnaris (FCU) — the humeral head (arising from the medial epicondyle) and the ulnar head (arising from the olecranon and posterior ulna). ### Anatomical Sequence After exiting the cubital tunnel (between the olecranon and medial epicondyle), the ulnar nerve immediately pierces the aponeurosis connecting the two heads of FCU. This is a critical landmark in forearm anatomy and a common site of compression injury. ### Clinical Significance **High-Yield:** Compression at this point (between FCU heads) can occur from: - Hypertrophied FCU muscle - Fibrous bands or aponeurotic thickening - Trauma or repetitive flexion-extension - This is distinct from cubital tunnel syndrome (compression proximal to this point) **Clinical Pearl:** Palpating the groove between the medial epicondyle and olecranon, then following the nerve distally, the point where it disappears between the FCU heads is the "second compression point" of the ulnar nerve in the upper limb. ### Mnemonic: **"FCU Splits the Ulnar"** - **F**lexor **C**arpi **U**lnaris has two heads - Ulnar nerve passes **between** them to enter forearm proper