Muscle bulk For presentation distribution Muscle bulk assessment
Muscle bulk For presentation & distribution
Muscle bulk assessment procedures 1. Visually compare symmetry of muscle bulk and coverage of bony processes 2. Measure the circumference of the limbs (“girth”) with a tape measure a. UE: measure 3” above and below elbow (olecranon) b. LE: measure 6” above and below knee (joint line)
Analysis Maximal normal variation between dominant and nondominant sides is often identified as 1 inch. However, differences of greater than 1” may be WNL, and differences of less than 1” may be abnormal. Consider the following examples:
a. Difference greater than 1”, but normal *right handed individual *right arm = 15”; left arm = 13 ½” *individual has occupation &/or recreational activity that uses right UE significantly more than the left resulting in hypertrophy on the right *the remainder of neurologic exam is WNL
b. Difference less than 1”, but abnormal *right handed individual *right arm = 14”; left arm = 13 ½” *individual has recent onset of symptoms in left UE (pain, paresthesia, numbness, weakness) *limited difference on left due to recent onset (imagine measurement prior to onset to be 14” on the right and 13 ¾” on the left) .
Findings and interpretation/significance 1. atrophy a. physiologic: disuse atrophy b. pathologic (1) neurologic (a) LMN lesion – loss of the direct connection to muscle results in greater atrophy (b) UMN lesion (2) myopathy (muscle disease)
Findings and interpretation/significance - continued 2. Hypertrophy (increased muscle bulk with corresponding increase in muscle strength) *physiologic adaptation to imposed demand (exercise increased muscle bulk and strength) 3. Pseudohypertrophy (enlarged, but without corresponding increase in muscle strength) *rare; seen in children with Duchenne’s muscular dystrophy (calves)
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