KEY FACTS Terminology Tarsal tunnel syndrome Imaging Denervation of affected plantar intrinsic muscles Uniform high signal intensity on fluid-sensitive sequences Mass in tarsal tunnel Ganglion cyst: Follows fluid signal intensity, homogeneous, ± thin rim of enhancement with gadolinium Nerve sheath…
KEY FACTS Terminology Synonyms: Common peroneal nerve (CPN) palsy, CPN entrapment CPN entrapment at fibular head Imaging CPN swelling, abnormal T2 hyperintensity Fascicular architecture preserved in milder cases (neuropraxic injury) Loss of internal fascicular architecture in more severe cases (axonotmetic,…
KEY FACTS Terminology Pronator syndrome: Nerve entrapment at pronator teres Carpal tunnel syndrome: Nerve entrapment at carpal tunnel Imaging Nerve enlargement distal to region of entrapment Fascicles indistinct Perineural enhancement ± mass compressing nerve Denervation changes in muscles distal to…
KEY FACTS Terminology Suprascapular nerve impingement with muscle denervation Imaging Suprascapular nerve impingement may occur at either spinoglenoid or suprascapular notch Spinoglenoid notch: Between neck and blade of scapula, roofed by spinoglenoid ligament Entrapment affects infraspinatus muscles only Suprascapular notch:…
KEY FACTS Terminology Synonyms: Ulnar nerve (UN) entrapment, cubital tunnel syndrome Partial fixation, compression, or distortion of UN Imaging UN enlargement ± abnormal T2 hyperintensity, architectural distortion Most commonly occurs within cubital tunnel (elbow); uncommon at Guyon tunnel (wrist) or…
KEY FACTS Terminology Synonyms: Femoral neuropathy, femoral mononeuropathy, femoral nerve (FN) palsy FN entrapment or injury secondary to direct trauma, compression, stretch injury, or ischemia Imaging Nerve enlargement ± loss of internal fascicular architecture, ↑ T2 hyperintensity Injury most common…
KEY FACTS Terminology Group of inherited disorders characterized by focal or diffuse peripheral nerve enlargement Hereditary motor-sensory neuropathy (HMSN), hypertrophic neuropathy (HN), hereditary sensory neuropathy (HSN), hereditary motor neuropathy (HMN), hereditary sensory and autonomic neuropathy (HSAN), Charcot-Marie-Tooth (CMT) syndrome Imaging…
KEY FACTS Terminology Parsonage-Turner syndrome Imaging Can affect any muscle innervated by brachial plexus Most common: Rotator cuff, deltoid, biceps, triceps Denervation edema is earliest finding Diffuse, homogeneous high signal on T2WI, STIR throughout affected muscle – Often, muscles innervated…
KEY FACTS Terminology Synonyms: Brachial plexus stretch injury, brachial plexus avulsion, avulsion pseudomeningocele Stretch injury or avulsion of ≥ 1 cervical roots, brachial plexus Imaging Stretch injury: Enlargement, abnormal edema of neural elements Avulsion: Abnormal cerebrospinal fluid signal intensity within…
KEY FACTS Terminology Secondary muscle injury resulting from denervation following nerve injury Imaging Acute denervation Muscle appears normal on T1WI Diffusely increased signal intensity on T2WI, STIR Mild, homogeneous enhancement with gadolinium Chronic denervation Fatty atrophy evident on T1WI Muscle…