ULTRASOUND EVALUATION OF
MUSCLE HERNIA
Most muscle hernias
occur in the lower leg and affect the tibialis anterior muscle , and are
attributed to occupational and sporting activities, trauma , chronic
compartment syndrome, and weakness in the overlying fascia due to perforating
vessels. It is seen as a result of muscle protrusion through a defect in the muscle fascia
into the subcutaneous fat and eventually seen as an overlying bulging soft-tissue mass , making slight contour hump. The adolescents
or young adults are affected more. Clinically a swelling is seen that usually
enlarges when the affected muscle is contracted or the patient is in standing or erect posture , and reduces when the muscle is relaxed . Mostly muscle hernias are
asymptomatic and requires no treatment . Those with mild symptoms that may be relieved
by support stockings. Patients with severe pain or cramps may require surgery.
At USG - 1 ] Focal thinning and slight elevation of
the fascia.
2] Focal fascial defect with
protrusion or bulge of muscle fibres
through the defect when the muscle is
contracted , and making a contour hump. [ fig 1,2]
3] Prominent arterial pulsation
on color or power Doppler - support the theory that muscle herniation occurs at
sites of weakness in which vessels penetrate the fascia [ fig 3]
Fig 1 - A 20 yrs young boy presented with a small swelling at mid part of right anterolateral leg , which becomes conspicuous & painful on exercise or on continuous walking . Long US scan shows focal bulge in tibialis anterior muscle [ arrows] on muscle contraction or on standing
Fig 2 - Both LS & TS ultrasound scans of the same case , shows a small focal defect in the Fascia of tibialis anterior muscle [ arrow in TS scan ] with focal muscle fibres bulge or contour hump [ arrow in LS scan ]
Fig 3 - TS & LS ultrasound with color doppler scans shows a prominent vessel , likely perforating artery , at the site of fascial defect & muscle bulge or hernia
Most muscle hernias do
not require any treatment [ or requires just reassurance]
, but some painful cases may needs surgery. Importantly ultrasound is very
helpful in apprehensive patients to exclude muscle tears and tumors .
PS – This presentation
is intended for academic purpose esp. for medical professionals &
radiologists
Ref - American Journal of Roentgenology. 2003;180: 395-399
Ref - American Journal of Roentgenology. 2003;180: 395-399
