title: Patterns of muscle involvement in inclusion body myositis: clinical and magnetic resonance imaging study.
abstract: The differential patterns of muscle involvement in the upper and lower limbs in sporadic inclusion body myositis (sIBM) were examined in 18 patients using both quantitative and manual muscle testing as well as magnetic resonance imaging (MRI) in 9 patients. Weakness of the quadriceps femoris and the forearm flexors was present in most patients, but there was considerable variability in the patterns and severity of muscle involvement. MRI disclosed preferential patterns of muscle involvement within functional groups such as the quadriceps femoris, in which there was severe involvement of the vasti with relative sparing of the rectus femoris, and the triceps surae, in which selective involvement of the medial gastrocnemius was common. Involvement of flexor digitorum profundus on MRI was found in only one third of patients. The results emphasize the variability in the clinical phenotype and differential susceptibility of muscles to the disease process in sIBM.
authors.affiliation: Centre for Neuromuscular and Neurological Disorders, Australian Neuromuscular Research Institute, University of Western Australia, Perth, Western Australia, Australia. b.phillips@unimelb.edu.au
authors.forename: B A
authors.initials: BA
authors.lastname: Phillips
authors.forename: L A
authors.initials: LA
authors.lastname: Cala
authors.forename: G W
authors.initials: GW
authors.lastname: Thickbroom
authors.forename: A
authors.initials: A
authors.lastname: Melsom
authors.forename: P J
authors.initials: PJ
authors.lastname: Zilko
authors.forename: F L
authors.initials: FL
authors.lastname: Mastaglia
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000473:pathology; D018482:Muscle, Skeletal / Q000473:pathology*; D018979:Myositis, Inclusion Body / Q000473:pathology*