The axial and appendicular muscles become atrophied, which causes difficulty developing motor skills including standing, sitting, and walking.
en.wikipedia.org The word appendicular is the adjective of the noun "appendage", which itself means a part that is joined to something larger.
en.wikipedia.org Patients may also experience delayed walking, a characteristic waddling gait, complain of stiffness and pain, and have an appendicular muscle weakness (especially in the thighs) consistent with nonprogressive myopathy.
en.wikipedia.org Other symptoms such as inflammation in eyes and axial and appendicular skeleton, lymphadenopathy and splenomegaly, are less common.
en.wikipedia.org The appendicular skeleton, which is attached to the axial skeleton, is formed by the pectoral girdles, the pelvic girdle and the bones of the upper and lower limbs.
en.wikipedia.org