Muscle involvement pattern
Why certain muscles are preferentially affected in FSHD remains unknown. There are multiple trends of involvement seen in FSHD, possibly hinting at underlying pathophysiology. Individual muscles can weaken while adjacent muscles remain healthy. The right shoulder and arm muscles are more often affected than the left upper extremity muscles, a pattern also seen in Poland syndrome and hereditary neuralgic amyotrophy; this could reflect a genetic, developmental/anatomic, or functional-related mechanism. The deltoid is often spared, which is not seen in any other condition that affects the muscles around the scapula.Medical imaging (CT and MRI) have shown muscle involvement not readily apparent otherwise
A single MRI study shows the teres major muscle to be commonly affected. The semimembranosus muscle, part of the hamstrings, is commonly affected,  deemed by one author to be "the most frequently and severely affected muscle." Of the quadriceps muscles, the rectus femoris is preferentially affected
Of the  gastrocnemius, the medial section is preferentially affected;
The iliopsoas, a hip flexor muscle, is very often spared. Retinopathy
Tortuosity of the retinal arterioles, and less often microaneurysms and telangiectasia, are commonly found in FSHD. Abnormalities of the capillaries and venules are not observed. One theory for why the arterioles are selectively affected is that they contain smooth muscle. The degree of D4Z4 contraction correlates to the severity of tortuosity of arterioles. It has been hypothesized that retinopathy is due to DUX4-protein-induced modulation of the CXCR4–SDF1 axis, which has a role in endothelial tip cell morphology and vascular branching.
Physical and occupational therapy
Aerobic exercise has been shown to reduce chronic fatigue and decelerate fatty infiltration of muscle in FSHD. The ANN recommends that people with FSHD engage in low-intensity aerobic exercise to promote energy levels, muscle health, and bone health. Moderate-intensity strength training appears to do no harm, although it has not been shown to be beneficial. Physical therapy can address specific symptoms; there is no standardized protocol for FSHD. Anecdotal reports suggest that appropriately applied kinesiology tape can reduce pain. Occupational therapy can be used for training in activities of daily living (ADLs) and to help adapt to new assistive devices. Cognitive behavioral therapy (CBT) has been shown to reduce chronic fatigue in FSHD, and it also decelerates fatty infiltration of muscle when directed towards increasing daily activity.Braces are often used to address muscle weakness. Scapular bracing can improve scapular positioning, which improves shoulder function, although it is often deemed as ineffective or impractical. Ankle-foot orthoses can improve walking, balance, and quality of life. Pharmacologic management
No pharmaceuticals have definitively proven effective for altering the disease course. Although a few pharmaceuticals have shown improved muscle mass in limited respects, they did not improve quality of life, and the AAN recommends against their use for FSHD. Reconstructive surgery
Scapular winging is amenable to surgical correction, namely operative scapular fixation. Scapular fixation is restriction and stabilization of the position of the scapula, putting it in closer apposition to the rib cage and reducing winging.