Rectus femoris muscle

Dr Henry Knipe and Dr Geon Oh et al.

The rectus femoris muscle is one of four quadriceps muscles in the anterior compartment of the thigh. It is distinct from the other quadriceps muscles (vastus medialis, vastus intermedius, vastus lateralis) in that crosses both the hip and knee joints 1.

The rectus femoris has two heads with separate origins 5,6:

  • direct/straight head: AIIS
  • indirect/reflected head: superior acetabular ridge

These two tendons merge ~1cm below their origin to form the conjoined tendon with two components 5,6:

  • superficial/anterior component: blends more so with the anterior fascia
  • deep/posterior component: forms the deep tendon with a long myotendinous junction

There is an intermingling of ~15% of muscle fibers related to each origin, and rectus femoris can be thought of as two muscles 7. The distal myotendinous junction forms a short free tendon that joins with the vastus tendons to form the quadriceps tendon. 

Patient in a supine position in hip extension and probe placed of the AIIS in a longitudinal plane 4:

  • direct head: seen directly at insertion on AIIS
  • indirect head: hypoechoic appearance due to oblique course

Commonly injured in athletes including 4-6:

Other pathology includes:

Anatomy: Lower limb
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Article information

rID: 44281
Section: Anatomy
Synonyms or Alternate Spellings:
  • Rectus femoris muscles

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Cases and figures

  • Case 1: proximal rectus femoris avulsion injury
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  • Case 2: Bull's eye sign of intramuscular degloving
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  • Case 3: distal myotendinous junction rupture
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  • Case 4: calcific tendinosis of the rectus femoris
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