DUC DUC goose
The ulnar nerve is derived from these roots, this trunk, and this cord.
C8 and T1 roots
Lower trunk
Medial cord
These are two common sites of atrophy with moderate-severe ulnar neuropathy at the elbow.
First dorsal web space and ADM/ulnar edge of the hand
This is the most common entrapment site of the ulnar nerve.
What is ulnar neuropathy at the elbow or cubital tunnel syndrome
Proper ulnar NCS is done with the elbow placed in this position.
Describe the factitious finding if NCS is preformed in an extended elbow position for 100 point bonus!
Flexed to 90 degrees
Artifactual slowing of conduction velocity across the elbow due to underestimation of the true nerve length
Brent attended this medical school
The University of Arizona
The ulnar nerve has these three sensory branches (from proximal to distal).
1) Dorsal ulnar cutaneous branch
2) Palmar cutaneous branch
3) Ulnar digital sensory branches
Weakness of these muscles results in Froment's sign.
Describe the exam findings for 100 point bonus!
1) Adductor pollicis muscle
2) First dorsal interosseous muscle
Ulnar neuropathy at the wrist is due to nerve entrapment by this structure.
Guyon's canal
This key sensory finding can help distinguish between Neuropathy at the Elbow vs. the Wrist.
Dorsal ulnar cutaneous SNAP (Normal with UNW as this sensory nerve arises 5-8 cm proximal to the wrist).
This is the all-time record temperature recorded in Phoenix, occurring on June 26, 1990.
122 degrees F
Just distal to the ulnar groove, in the proximal forearm, the ulnar nerve travels through the cubital tunnel.
The tendinous arch of this muscle comprises the cubital tunnel.
Two heads of the flexor carpi ulnaris (FCU)
This sign results from involuntary abduction the 5th digit.
Explain the etiology for 300 point bonus!
Wartenberg's sign
A mechanic presents with painless weakness and atrophy of both the thenar and hypothenar eminences. Ulnar SNAP is abnormal, ulnar CMAP is abnormal, DUC SNAP is normal. Where is the lesion?
Ulnar neuropathy at the wrist (Guyon's canal)
In ulnar neuropathy at elbow, these are the NCS findings would you suspect to see.
1) Conduction velocity slowing across the elbow
2) Prolongation of distal latency
3) Possibly decreased CMAP amplitudes (if conduction block is present)
Name 3 of the common causes of ulnar neuropathy at the wrist.
1) Repetitive trauma (cyclists, hand tools, etc.)
2) Ganglion cyst (most common)
3) Ulnar artery thrombosis/aneurysm
4) Hook of Hamate Fracture
In Guyon's canal the ulnar nerve divides to become the Deep and Superficial branches. The Superficial branch is known to be mainly sensory, but also supplies motor fibers to this muscle.
Palmaris brevis
This hand posture can be seen in moderate or advanced cases of ulnar neuropathy at the elbow.
Explain the etiology for 300 point bonus!
Benediction posture (Ulnar claw hand)
Thenar atrophy can be seen in ulnar neuropathy due to involvement of these two muscles.
1) Adductor pollicis
2) Flexor pollicis brevis (deep head)
Describe the proper setup of the DUC NCS.
Hand in the pronated position.
Recording electrodes placed in the dorsal web space between digits 4 and 5.
Stimulation site is 8-10 cm proximal to the active electrode over the ulna or between the ulna and FCU.
This anatomical variant is the crossing over of median motor fibers to distal ulnar fibers most commonly through the forearm.
Martin-Gruber anastomosis
This thin fibrous band extends from the medial head of the triceps to the intermuscular septum and is a potential site of ulnar nerve entrapment within the arm.
Arcade of Struthers
The Palmaris brevis sign (in ulnar neuropathy at the wrist).
Puckering of the skin along the medial border of the hand seen in ulnar nerve lesions at the wrist isolated to the deep motor branch
Distal deep palmar motor lesion.
Affects all muscles supplies by the deep palmar motor branch except the hypothenar muscles (the lesion is distal to the takeoff of the hypothenar muscle branch.
This is Dr. Fleischman's response when you state the patient "has numbness over the palmar aspects of digits 4 and 5".
What is "how do you define numbness?"
A Proximal Martin-Gruber anastomosis could result in this NCS finding .
A drop in amplitude between the below-elbow and above-elbow stimulation sites (pseudo conduction block across the elbow)