Vastus Intermedius

Gluteus medius, minimus, and tensor fascia lata Vastus lateralis and vastus intermedius... 

Fig. 4.21. EFOV ultrasound demonstrates well defined ossification (arrowheads) in the vastus intermedius (VI) muscle, with posterior acoustic shadowing consistent with myositis ossificans...

Gluteus medius, minimus, and tensor fascia lata Vastus lateralis and vastus intermedius Vastus medialis and vastus lateralis Tibialis anterior and extensor digitorum longus Gastrocnemius, soleus, and flexor hallucis longus Iliopsoas "... 

Fig. 13.2a-c Normal quadriceps muscle, a-c Schematic drawings of a coronal view through the anterior thigh showing the muscle bellies forming the quadriceps from deep (a) to superficial (c). a,b The vastus intermedius (VI) is the deepest muscle. On each side, it is partially covered by the vastus lateralis (VX) and the more distal vastus medialis (VM). c The rectus femoris (RF) is located more superficially. It arises from a direct (DT) and an indirect (IT) tendon from the anterior inferior iliac spine and inserts into a long flat tendon (asterisk) that forms the superficial layer of the quadriceps tendon... 

Fig. 13.6a-c Rectus femoris muscle, a-c Transverse 12-5 MHz US images obtained at the (a) proximal, (b) middle and (c) distal thirds of the muscle demonstrate the central aponeurosis (straight arrow) as a comma-shaped, sharply delineated hyperechoic band oriented in the sagittal plane and located in the superficial portion of the cranial two thirds (a,b) of the muscle. In a, note the superficial aponeurosis (arrowhead) as a fascial thickening on the anterior aspect of the muscle. In c, the central aponeurosis is no longer appreciated whereas the distal aponeurosis (curved arrow) becomes visible along the posterior boundary of the muscle. VI, vastus intermedius F, femoral shaft... 

Fig. 13.23a,b Acute partial tear of the distal aponeurosis of the rectus femoris. a Long-axis 12-5 MHz US image over the rectus femoris (RF) muscle demonstrates focal disruption of the normal pattern of insertion of libroadipose septa and muscle libers into the distal aponeurosis (white arrow). Observe the normal-appearing distal portion of the muscle (open arrow), b Transverse fat-suppressed T2-weighted MR image confirms the partial tear of the muscle along the distal aponeurosis (arrow). Observe the central aponeurosis (arrowhead) which is intact. VI, vastus intermedius VL, vastus lateralis F, femur. 

Fig. 13.25a,b Chronic complete disinsertion of the rectus femoris at the level of the distal aponeurosis. a Midsagittal and b transverse 12-5 MHz US images demonstrate a retracted rectus femoris (asterisk). Note the volume loss of the muscle, which appears diffusely hyperechoic as a result of fatty degeneration and has a distal rounded appearance. Echogenic fibrous scar (arrow) can be seen distal to the blunted end of the muscle. VI, vastus intermedius F, femur... 

Muscle tears can be followed by cystic transformation of the hematoma consisting of an ovoid fluid-filled anechoic cavity with well-defined margins located within the muscle (Fig. 13.28). A significant complication of vastus intermedius tears secondary to direct contusion trauma is myositis ossificans circumscripta, which is also referred to as heterotopic bone formation. This self-limiting condition starts with undefined chronic pain in the middle thigh... 

Fig. 13.27a,b Complete tear of the vastus intermedius. Transverse 12-5 MHz US images obtained over the a middle and b distal third of the anterior thigh reveal the torn vastus intermedius VI) as a heterogeneous hypoechoic mass (arrows) located deep to the vastus lateralis (VI) and medialis (VM). More distally, an anechoic fluid collection (arrowheads) reflecting the hematoma is found deep to the superficial (I) and intermediate (2) layers of the quadriceps tendon. F, femur... 

Fig. 13.30a,b Myositis ossificans, a Longitudinal 12-5 MHz US split-screen image obtained over the vastus lateralis muscle in a patient with a previous history of local blunt trauma with b radiographic correlation reveals multiple, irregularly shaped gross calcifications (arrows) within the vastus intermedius muscle. The vastus lateralis (open arrowheads) is displaced superficially by the bulk of the calcifications... 

If the electrode is inserted too medially and too deeply it will be in the vastus intermedius if inserted too laterally it will be in the vastus lateralis if inserted too distally and medially it will be in the vastus medialis. 

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