At elbow - cubital tunnel syndrome

At wrist - Guyons canal syndrome (Cyclists/handlebar palsy)

Aetiology

• Repetetive compression - leaning on elbows/wrists
• Prolonged elbow flexion
• Trauma

Guyon’s canal syndrome - Ulnar nerve entrapment between hook of hamate and transverse carpal ligament. Commonly caused by direct pressure, can also be excess gripping, twisting, repeated wrist and hand motions

Ulnar nerve paradox:

Ulnar nerve lesion at elbow - Less severe clawing of digits 4/5.

Ulnar nerve lesion at the wrist - will present more severely with much worse clawing of digits 4 and 5 Because lumbricals have been lost (which normally extends PIPS and DIPS) FDS muscle is again still in tact however this time… the FDP muscle is still in tact on the ulnar half providing a much stronger tonic flexion to the digits and without the lumbricles to oppose this, the fingers will be clawed more severely

PC

• Parasthesia - tingling in ulnar nerve distrubution of hand
• Cubital tunnel syndrome - Flexing elbow puts the ulnar nerve under tension (patients may awake at night as elbows flexed, also may complain of pain when using a phone for prolonged periods
• weak grip strength
• Weakness of ulnar nerve controlled muscles in hand (PADs, DABs, Lumbricals 1 and 2
• Clawing of digits 4 and 5 (more severe in distal nerve palsy) - paradox

Examination:

• Muscle wasting in hand