This occurs due to nerve compression at the elbow (cubital tunnel) or at the wrist (Guyon's canal) (Ulnar canal)
Muscle weakness and atrophy predominate the clinical presentation
Cubital Tunnel Syndrome
Frequent bending of the elbow
Leaning on the elbow, resting it on an elbow, rest during a long distance drive or running machinery may cause repetitive pressure and irritation on the nerve.
A direct hit on the cubital tunnel may damage the ulnar nerve
Guyon's Canal Syndrome
A cyst within the canal.
Clotting of the ulnar artery.
Fracture of the hamate bone.
Arthritis of the wrist bones
Symptoms and signs:
numbness and tingling in the ring and little finger and the sides and back of the hand. At Guyon's Canal, sensory supply to the skin of the back of the hand is spared.
The hand may become weaker resulting in trouble opening bottles or jars
Clawing may occur in the ring and little fingers
Froment's test: by asking the patient to hold a piece of paper between their thumb and index finger (hence checking adductor pollicis). In a patient with Ulnar nerve palsy the interphalangeal joint of the thumb will flex to compensate
Nonsurgical therapy: elbow or wrist splints to limit mobility in addition to an anti-inflammatory drug such as ibuprofen.
Surgical decompression maybe required in some cases
Radial nerve palsy
Caused by excessive compression of the radial nerve against a hard surface in individuals insensitized by the intake of alcohol or sedatives
Stab wounds to the chest at or below the clavicle. Damage the posterior cord of the brachial plexus
Occasionally, the back of the hand may lose feeling
Due to brachial plexus damage, by excessive lateral neck flexion away from sholder:
Falling on the neck
Leads to loss of the lateral rotators of the shoulder, arm flexors, and hand extensor muscles.
The position of the limb, under such conditions, is characteristic:
the arm hangs by the side and is rotated medially;
the forearm is extended and pronated.
The hand is flexed
The arm cannot be raised from the side; all power of flexion of the elbow is lost, as is also supination of the forearm...