3 thoughts on “Upper Arm MRI, 37M arm weakness 7 months after fall, please help”
avneesh.chhabra
Hi,
Few imp points-
1. Triceps tortousty is normal similar to quad tendon in extension- see pics below- two diff cases.
2. Edema-like signal- yes denervation- also some in brachialis- meaning injury is higher up.
3. Flat muscle muscle margin on sag is good enough for atrophy. We see such cases frequently- may be 2-3 every month.
4. Radial nerve is slightly bright at spiral groove- if it was MRN- will show more changes. Radial nerve shouldn’t show any signal change. But the lesion should be in plexus. Slight signal change as lesion is higher otherwise would see more changes. I would have asked for brachial pl MRN and posterior cord evaluation.
Best!
AC
Avneesh Chhabra, M.D. M.B.A.
Associate Professor Radiology & Orthopedic Surgery
________________________________
Sent: Monday, July 12, 2021 7:29 PM
EXTERNAL MAIL
Initial MRI was Elbow to Rule out Triceps Tear[1.jpg]
Distal triceps tendon looks wiggly but intact; I recommended humerus MRI to evaluate possible more proximal injury.
[2.jpg]
Securely united varus angulated fracture, triceps muscle edema
[3.jpg]
Don’t see T1 muscle atrophy, diffuse edema lateral head (tendon looks wiggly but intact from myotendinous junction on down…why?)
[4.jpg]
Edema throughout lateral head, but also superficially in the Long head
[5.jpg]
I suppose this is neuropathic edema…but without atrophy, it should be acute. The fracture is old and healed, so I don’t see how it results from the fracture.
Please help.
Hilary
[gallery]
hilary.umans
I considered that the tortuosity of the tendon might be positional so I looked at recent elbow MRI and the triceps looked taut.
Regardless, my stupidity was fortuitous as it prompted me to recommend the humerus MRI—-and the denervation edema was not visible in the initial elbow images.
ptirmanmd
Although the fracture is more proximal than the typical holstein lewis fracture that typically injures the entire radial nerve, I think it might be high enough to only entrap the branch to the triceps (analogous to the axillary branch to the teres minor leaving the deltoid unaffected). That might explain why the distal muscles innervated by the radial nerve are OK? That’s my best guess because it certainly looks like denervation change in the triceps.
Hi,
Few imp points-
1. Triceps tortousty is normal similar to quad tendon in extension- see pics below- two diff cases.
2. Edema-like signal- yes denervation- also some in brachialis- meaning injury is higher up.
3. Flat muscle muscle margin on sag is good enough for atrophy. We see such cases frequently- may be 2-3 every month.
4. Radial nerve is slightly bright at spiral groove- if it was MRN- will show more changes. Radial nerve shouldn’t show any signal change. But the lesion should be in plexus. Slight signal change as lesion is higher otherwise would see more changes. I would have asked for brachial pl MRN and posterior cord evaluation.
Best!
AC
Avneesh Chhabra, M.D. M.B.A.
Associate Professor Radiology & Orthopedic Surgery
Chief, Division of Musculoskeletal Radiology
UT Southwestern Medical Center, Dallas, Tx
5373 Harry Hines Blvd.
Dallas, Tx-75390-9178
Office: 214-648-2122
avneesh.chhabra@utsouthwestern.edu<mailto:avneesh.chhabra@utsouthwestern.edu>
http://www.utsouthwestern.edu<http://www.utsouthwestern.edu/>
________________________________
Sent: Monday, July 12, 2021 7:29 PM
EXTERNAL MAIL
Initial MRI was Elbow to Rule out Triceps Tear[1.jpg]
Distal triceps tendon looks wiggly but intact; I recommended humerus MRI to evaluate possible more proximal injury.
[2.jpg]
Securely united varus angulated fracture, triceps muscle edema
[3.jpg]
Don’t see T1 muscle atrophy, diffuse edema lateral head (tendon looks wiggly but intact from myotendinous junction on down…why?)
[4.jpg]
Edema throughout lateral head, but also superficially in the Long head
[5.jpg]
I suppose this is neuropathic edema…but without atrophy, it should be acute. The fracture is old and healed, so I don’t see how it results from the fracture.
Please help.
Hilary
[gallery]
I considered that the tortuosity of the tendon might be positional so I looked at recent elbow MRI and the triceps looked taut.
Regardless, my stupidity was fortuitous as it prompted me to recommend the humerus MRI—-and the denervation edema was not visible in the initial elbow images.
Although the fracture is more proximal than the typical holstein lewis fracture that typically injures the entire radial nerve, I think it might be high enough to only entrap the branch to the triceps (analogous to the axillary branch to the teres minor leaving the deltoid unaffected). That might explain why the distal muscles innervated by the radial nerve are OK? That’s my best guess because it certainly looks like denervation change in the triceps.