Treating Muscular Dysfunction of Lower Limbs
Muscular dysfunction of the lower limb muscles, stemming from an array of etiologies, is associated with pain.1 Common etiologies include peripheral vascular insufficiency, lumbo-sacral radiculopathy, lower limb arthropathy especially prevalent in obese individuals, myofascial type trauma and referral of trigger points or diabetic neuropathy. Less commonly, one can find muscular pain from psychosomatic or somatoform disorders, osteo-articular trauma or mixed etiologies. Although the categories named above are not exhaustive, they may serve as a reminder to the busy pain practitioner in terms of differential diagnosis. In addition, one may have to consider whether the pain pattern is derived from the structures of the lower limb or may be secondary to a referred pattern from the trunk or viscera.1,2
Acute muscular lower limb pain lasts usually less than 6-12 weeks. Sub-acute pain and recurrent pain may last beyond 12 weeks. Chronic pain is usually the result of delayed or unresolved healing and may last for several months or years, until the underlying condition is resolved. Chronic lower limb muscular or myofascial pain may lead in time to hyperalgesia and allodynia.1,2,3 Phantom limb pain is a neural phenomenon associated more commonly with total or partial traumatic amputation of the lower limb.
The discussion below will refer mainly to lower limb musculo-skeletal dysfunction pain and other symptoms related mainly to myofascitis and related disorders.
A summary evolutionary review of the lower limb shows it to have undergone several changes.4 It has evolved primarily from a tree climbing and branch prehensile tool in the pre-ape simian ancestor to an ambulatory instrument in the bipedal ape and early ancestor of man. Part of the functional change involved the ability to sustain an erect body against gravity as in standing and walking for prolonged periods of time such as presumably needed to enable the individual to see above the grass height of the Savannah. Several changes through evolution included the gradual lengthening of the lower limb by comparison to that of the trunk and upper limb. At the same time, the early prehensile function of the great toe had just about disappeared in the post-infant stage of modern man.
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