Ulnar Neuropathy
Injury sites
- Supracondylar fracture
- Medial epicondyle compression
- Cubital tunnel entrapment (the tendinous arch that joins the heads of flexor carpi ulnaris).
- Guyon’s canal (aka Guyon’s tunnel) formed from the palmar carpal ligament.
- The vast majority of Guyon canal entrapments only affect the deep, motor branch, which passes between the hook of the hamate and the pisiform bone.
- Fracture of the hook of the hamate can cause ulnar neuropathy.
Weakness pattern
- Ulnar neuropathy produces weakness of the medial flexors and a more restricted clawing of the hand, so-called ulnar claw, with clawing of digits 4 and 5 (vs Klumpke's palsy affects both median and ulnar nerve distal musculature).
- Note that 4th and 5th digit clawing forms the shape of a Pope's blessing and thus is also called the Benediction Sign.