Replacement by mouth is appropriate for people with mild symptoms, while intravenous replacement is recommended for people with severe effects.Numerous oral magnesium preparations are available. In two trials of magnesium oxide, one of the most common forms in magnesium dietary supplements because of its high magnesium content per weight, was less bioavailable than magnesium citrate, chloride, lactate or aspartate. Magnesium citrate has been reported as more bioavailable than oxide or amino-acid chelate forms.Intravenous magnesium sulfate (MgSO4) can be given in response to heart arrhythmias to correct for hypokalemia, preventing pre-eclampsia, and has been suggested as having a potential use in asthma. Food
Food sources of magnesium include leafy green vegetables, beans, nuts, and seeds. Epidemiology
The condition is relatively common among people in hospital. History
Magnesium deficiency in humans was first described in the medical literature in 1934. Plants
Magnesium deficiency is a detrimental plant disorder that occurs most often in strongly acidic, light, sandy soils, where magnesium can be easily leached away. Magnesium is an essential macronutrient constituting 0.2-0.4% of plants dry matter and is necessary for normal plant growth. Excess potassium, generally due to fertilizers, further aggravates the stress from magnesium deficiency, as does aluminium toxicity.Magnesium has an important role in photosynthesis because it forms the central atom of chlorophyll. Therefore, without sufficient amounts of magnesium, plants begin to degrade the chlorophyll in the old leaves. This causes the main symptom of magnesium deficiency, interveinal chlorosis, or yellowing between leaf veins, which stay green, giving the leaves a marbled appearance.
Boutonniere deformity is a deformed position of the fingers or toes, in which the joint nearest the knuckle (the proximal interphalangeal joint, or PIP) is permanently bent toward the palm while the farthest joint (the distal interphalangeal joint, or DIP) is bent back away (PIP flexion with DIP hyperextension). Causes include injury, inflammatory conditions like rheumatoid arthritis, and genetic conditions like Ehlers-Danlos syndrome. Pathophysiology
This flexion deformity of the proximal interphalangeal joint is due to interruption of the central slip of the extensor tendon such that the lateral slips separate and the head of the proximal phalanx pops through the gap like a finger through a button hole (thus the name, from French boutonnière "button hole"). The distal joint is subsequently drawn into hyperextension because the two peripheral slips of the extensor tendon are stretched by the head of the proximal phalanx (note that the two peripheral slips are inserted into the distal phalanx, while the proximal slip is inserted into the middle phalanx). This deformity makes it difficult or impossible to extend the proximal interphalangeal joint. Diagnosis
Stages
Mild extension lag, passively correctable
Moderate extension lag, passively correctable
Mild flexion contracture
Advanced flexion contractureHigher numbers indicate a more severe problem and greater likelihood of a poor outcome. Treatment
Usually treated with a splint placing the proximal interphalangeal joint in extension for 4–6 weeks. Occasionally surgery is needed when splinting is unsuccessful. See also
Swan neck deformity
Z-deformity

References
Further reading
Coons, Matthew S.; Green, Steven M. (August 1995). "Boutonniere deformity". Hand Clinics. 11 (3): 387–402. doi:10.1016/S0749-0712(21)00060-3. PMID 7559817. Souter, William A. (October 1974).