Prepatellar quadriceps continuation

The prepatellar quadriceps continuation is formed by the extension of the rectus femoris tendon connecting the patellar and quadriceps tendons.

Gross anatomy

The quadriceps tendon is a multilayer structure, where each of the four components of the muscle (vastus medialis, vastus lateralis, vastus intermedius, and rectus femoris), can end in a separate aponeurotic layer.

While the rest of the quadriceps tendons are inserted into the anterosuperior surface of the patella, the rectus femoris attaches to the anterior surface of the patella, and a distal extension continues from there to attach to the superficial part of the patellar tendon, forming the prepatellar quadriceps continuation.

An anatomical study ¹ showed that the prepatellar quadriceps continuation is located between an anterior fibrocartilage layer and an aponeurotic layer immediately above the patella.

This is a chondroapophyseal type of attachment, which is also called an enthesis, where the tendon gradually transforms into fibrocartilage as it attaches to bone.

Function

This layer of fibrocartilage serves to decrease friction between the anterior surface of the patella and the overlying aponeurotic fibers that form the continuation of the prepatellar quadriceps.

Radiographic features

MRI

It is normally not separable from the underlying patella but can sometimes be observed as a continuity of the most superficial layer of the quadriceps tendon with low signal in all sequences, covering the entire surface of the patella and then connecting down to the patellar tendon.

Sagittal MRI is essential in the evaluation of this layer of the extensor mechanism ².

Related pathology

• lesions of the prepatellar quadriceps continuation