Patellar tendon

Andrew Murphy and Dr Geon Oh et al.

The patellar tendon, also referred to as the patellar ligament, attaches the patella to the tibia and is part of the extensor mechanism of the knee.

  • origin: patellar apex
  • insertion: tibial tuberosity
  • action: aids in knee extension, as the distal part of the extensor mechanism of the knee

The patellar tendon is biconvex and, similarly to the calcaneal tendon, does not have a tendon sheath but only a paratenon composed of loose areolar tissue. It measures approximately 5 cm in length (i.e. height of the patella) and 20-30 mm in width, being wider proximally and narrower distally, and is 4-6 mm thick 2-4.

The patellar tendon begins at the patellar apex, but is actually considered the distal part of the quadriceps tendon - or, more accurately, a continuation of the rectus femoris tendon over the patella - while the patella itself is a sesamoid bone embedded in the quadriceps tendon 1,2.

Tibial tuberosity (tubercle).

It is bounded posteriorly by the infrapatellar fat pad.

The patellar tendon is supplied by the following arteries and their anatomoses 3:

  • descending genicular artery, a branch of the deep femoral artery
  • inferior medial genicular artery, a branch of the popliteal artery
  • superior and inferior lateral genicular arteries, branches of the popliteal artery
  • anterior tibial recurrent artery, a branch of the anterior tibial artery

Assists in proper patellar alignment and knee extension.

Variation of >20% between the patellar tendon length and patellar height will result in either 4

Shows striated appearance with predominanty high echogenicity, similarly to any other tendon. Deep to it, the infrapatellar fat pad is homogeneously hyperechoic 3.

Shows low homogeneous signal on all sequences 4.

Anatomy: Lower limb
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Article information

rID: 45363
Section: Anatomy
Tag: refs
Synonyms or Alternate Spellings:
  • Infrapatellar tendon
  • Patellar ligament

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