Answer for BIR CoW 19 Jul 2026
Brachial plexus pre and post ganglionic injury / Morel lavallee lesion
Findings
T2 hyperintense CSF intensity outpouching noted in the right neural foramen at C6 -C7 and C7-D1 level -Psudomeningocele -Suggestive of preganglionic injury STIR hyperintensity with thickening noted in right C8 root and upper trunk , T1 iso/hyperintense , T2 hyperintense hematoma noted adjacent to right first rib near insertion of scalenus muscle causing compression of cords of right brachial plexus. -suggestive of post ganglionic injury relatively well defined T1 isointense ,T2 hyperintense Collection with multiple internal septations noted involving the deep subcutaneous plane of right shoulder extending between muscle fibres of transverse part of trapezius and deltoid muscle showing fluid - fluid level and no diffusion restriction -Morel - lavell'ee lesion Displaced fracture noted in middle 1/3rd of right clavicle. Visualized chest cuts shows - Multiple loculated pleural collection noted - Possibility of hemothorax
IMPRESSION: Psudomeningocele -Suggestive of preganglionic injury Hematoma causing compression of cords of right brachial plexus with STIR hyperintensity with thickening of right C8 root and upper trunk . -suggestive of post ganglionic injury Morel - lavell'ee lesion
Discussion
Brachial plexus is a complex network of nerves originating from the cervical spinal nerves C5–C8 and the first thoracic spinal nerve T1, responsible for the innervation of the upper extremity. Just distally of the dorsal root ganglion, the spinal nerves split into ventral and dorsal rami the dorsal rami innervate the paraspinal muscles ,the five ventral rami C5, C6, C7, C8 and T1 form the brachial plexus LOCATION OF INJURY a) Preganglionic - proximal to the dorsal root ganglion and intradural - nerve root avulsion (directly from the spinal cord or ruptured in between the cord and ganglion) - nearly impossible to be repaired by surgical intervention b) Postganglionic - distal to the sensory root ganglion and further classified into -nerve rupture (most severe type of injury), requiring nerve repair/grafting -lesion in continuity (neuropraxia), requiring rehabilitation/neurolysis c) Combination of the two. Pre ganglionic injury: DIRECT SIGN avulsion of the nerve roots at their origin INDIRECT SIGN pseudomeningoceles displacement of cord to the contralateral side post contrast enhancement of intradural nerves post contrast enhancement of paraspinal muscles and their denervation/atrophy. other spinal cord abnormality → oedema, haemorrhage Post ganglionic injury: thickened nerves or abnormal signal (hyperintensity on fluid-sensitive images) → neuropraxic injury discontinuity of neural structures with distal nerve contraction denervation oedema/atrophy within the affected muscles direct brachial plexus compression by a haematoma, fracture fragment or callus formation, which can also cause brachial plexopathy. Morel-Lavallée lesions are closed degloving injuries associated with severe trauma which then present as hemolymphatic collections or masses occurring deep to subcutaneous plane due to disruption of capillaries. MRI and ultrasound are useful modalities for evaluation. Location: classically occur over the greater trochanter of the femur, the thigh. Also occurs lumbar region, over the scapula, or over the knee USG - anechoic or hypoechoic , no vascularity MRI - clearly determine the relationship between the collection and the underlying fascia. The fluid has variable signal intensity depending on its staging and show a fluid-fluid level Mellado-Bencardino classification type I: laminar-shaped and seroma-like with increased T2 signal type II: oval-shape that resembles a subacute hematoma with increased T1 and T2 signal; thick capsule and variable enhancement type III: oval shaped resembling a chronic organizing hematoma; thick capsule and internal/peripheral enhancement type IV: linear; looks like a closed laceration with hypointense T1 signal and hyperintense T2 signal; no capsule and variable enhancement type V: pseudonodular with a round shape, variable T1 and T2 signal, a thin or thick capsule, internal/peripheral enhancement type VI: infected with variable T1 and T2 signal; variable sinus tract formation, a thick capsule, and internal/peripheral enhancement
REFERENCES:
Brachial plexus injuries: imaging features https://dx.doi.org/10.26044/ecr2019/C-2719 Mellado JM, Bencardino JT. Morel-Lavallée lesion: review with emphasis on MR imaging. (2005) Magnetic resonance imaging clinics of North America. 13 (4): 775-82. doi:10.1016/j.mric.2005.08.006 - Pubmed
Findings
T2 hyperintense CSF intensity outpouching noted in the right neural foramen at C6 -C7 and C7-D1 level -Psudomeningocele -Suggestive of preganglionic injury STIR hyperintensity with thickening noted in right C8 root and upper trunk , T1 iso/hyperintense , T2 hyperintense hematoma noted adjacent to right first rib near insertion of scalenus muscle causing compression of cords of right brachial plexus. -suggestive of post ganglionic injury relatively well defined T1 isointense ,T2 hyperintense Collection with multiple internal septations noted involving the deep subcutaneous plane of right shoulder extending between muscle fibres of transverse part of trapezius and deltoid muscle showing fluid - fluid level and no diffusion restriction -Morel - lavell'ee lesion Displaced fracture noted in middle 1/3rd of right clavicle. Visualized chest cuts shows - Multiple loculated pleural collection noted - Possibility of hemothorax
IMPRESSION: Psudomeningocele -Suggestive of preganglionic injury Hematoma causing compression of cords of right brachial plexus with STIR hyperintensity with thickening of right C8 root and upper trunk . -suggestive of post ganglionic injury Morel - lavell'ee lesion
Discussion
Brachial plexus is a complex network of nerves originating from the cervical spinal nerves C5–C8 and the first thoracic spinal nerve T1, responsible for the innervation of the upper extremity. Just distally of the dorsal root ganglion, the spinal nerves split into ventral and dorsal rami the dorsal rami innervate the paraspinal muscles ,the five ventral rami C5, C6, C7, C8 and T1 form the brachial plexus LOCATION OF INJURY a) Preganglionic - proximal to the dorsal root ganglion and intradural - nerve root avulsion (directly from the spinal cord or ruptured in between the cord and ganglion) - nearly impossible to be repaired by surgical intervention b) Postganglionic - distal to the sensory root ganglion and further classified into -nerve rupture (most severe type of injury), requiring nerve repair/grafting -lesion in continuity (neuropraxia), requiring rehabilitation/neurolysis c) Combination of the two. Pre ganglionic injury: DIRECT SIGN avulsion of the nerve roots at their origin INDIRECT SIGN pseudomeningoceles displacement of cord to the contralateral side post contrast enhancement of intradural nerves post contrast enhancement of paraspinal muscles and their denervation/atrophy. other spinal cord abnormality → oedema, haemorrhage Post ganglionic injury: thickened nerves or abnormal signal (hyperintensity on fluid-sensitive images) → neuropraxic injury discontinuity of neural structures with distal nerve contraction denervation oedema/atrophy within the affected muscles direct brachial plexus compression by a haematoma, fracture fragment or callus formation, which can also cause brachial plexopathy. Morel-Lavallée lesions are closed degloving injuries associated with severe trauma which then present as hemolymphatic collections or masses occurring deep to subcutaneous plane due to disruption of capillaries. MRI and ultrasound are useful modalities for evaluation. Location: classically occur over the greater trochanter of the femur, the thigh. Also occurs lumbar region, over the scapula, or over the knee USG - anechoic or hypoechoic , no vascularity MRI - clearly determine the relationship between the collection and the underlying fascia. The fluid has variable signal intensity depending on its staging and show a fluid-fluid level Mellado-Bencardino classification type I: laminar-shaped and seroma-like with increased T2 signal type II: oval-shape that resembles a subacute hematoma with increased T1 and T2 signal; thick capsule and variable enhancement type III: oval shaped resembling a chronic organizing hematoma; thick capsule and internal/peripheral enhancement type IV: linear; looks like a closed laceration with hypointense T1 signal and hyperintense T2 signal; no capsule and variable enhancement type V: pseudonodular with a round shape, variable T1 and T2 signal, a thin or thick capsule, internal/peripheral enhancement type VI: infected with variable T1 and T2 signal; variable sinus tract formation, a thick capsule, and internal/peripheral enhancement
REFERENCES:
Brachial plexus injuries: imaging features https://dx.doi.org/10.26044/ecr2019/C-2719 Mellado JM, Bencardino JT. Morel-Lavallée lesion: review with emphasis on MR imaging. (2005) Magnetic resonance imaging clinics of North America. 13 (4): 775-82. doi:10.1016/j.mric.2005.08.006 - Pubmed
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!