. 2021 Jul 19;21:101510. doi: 10.1016/j.jcot.2021.101510

Table 7.

Simplified imaging-based classification of nerve injuries with corresponding findings on ultrasound and MRI.

Severity	Sunderland Grade	Injured structures	Imaging findings		Management
Mild	1	Demyelination	Nerve is Normal or shows mild edema	Nerve is Normal or shows Diffuse changes	Non-operative management
Mild	2	Axonal loss (intact connective tissue)	Edema and Bulkiness∗ (distal to site of injury)	Nerve is Normal or shows Diffuse changes	Non-operative management
Moderate	3	Endoneurium	Focally enlarged nerve (thickened fascicles) with altered echogenicity (Heteroechoic/hypoechoic) and heterogeneous signal intensity	Focal changes [Fascicles echogenic/enlarged (thickened)/effaced/disrupted]	Usually needs surgery, especially with grade 4 injury
Moderate	4	Perineurium	Disruption of the fascicles/Focal loss of internal architecture with intact epineurium (Neuroma-in-continuity)		Usually needs surgery, especially with grade 4 injury
Severe	5	Epineurium	Epineurium discontinuity (in addition to fascicular disruption)		Surgery
Severe	5	Epineurium	+/− Nerve gap with end neuromas		Surgery

•Edema and bulkiness are most apparent acutely and may resolve with time.