Patellar tendon
Updates to Article Attributes
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.
Summary
- origin: patellar apex
- insertion: tibial tuberosity
- action: aids in knee extension, as the distal part of the extensor mechanism of the knee
Gross anatomy
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.
Origin
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.
Insertion
Tibial tuberosity (tubercle).
Relations
It is bounded posteriorly by the infrapatellar fat pad.
Blood supply
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
Action
Assists in proper patellar alignment and knee extension.
Variant anatomy
Variation of >20% between the patellar tendon length and patellar height will result in either 4
- patella alta: tendon longer than patella
- patella baja: tendon shorter than patella
Radiographic features
Ultrasound
Shows striated appearance with predominanty high echogenicity, similarly to any other tendon. Deep to it, the infrapatellar fat pad is homogeneously hyperechoic 3.
MRI
Shows low homogeneous signal on all sequences 4.
Related pathology
-
p
Patellaratellar tendon rupture -
p
Paratenonitisaratenonitis - Osgood-Schlatter disease
- Sinding-Larsen-Johansson disease
-
j
Jumperumper's knee
Related articles
-<strong>origin:</strong> <a title="Patella" href="/articles/patella">patellar</a> apex</li>- +<strong>origin:</strong> <a href="/articles/patella">patellar</a> apex</li>
-</ul><h4>Gross anatomy</h4><p>The patellar tendon is biconvex and, similarly to the <a href="/articles/calcaneal-tendon-1">calcaneal tendon</a>, does not have a tendon sheath but only a <a href="/articles/paratenon">paratenon</a> 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 <sup>2-4</sup>.</p><h5>Origin</h5><p>The patellar tendon begins at the patellar apex, but is actually considered the distal part of the <a href="/articles/quadriceps-tendon">quadriceps tendon</a> - or, more accurately, a continuation of the <a href="/articles/rectus-femoris-muscle">rectus femoris</a> tendon over the patella - while the <a title="Patella" href="/articles/patella">patella</a> itself is a <a href="/articles/sesamoid-1">sesamoid bone</a> embedded in the quadriceps tendon <sup>1,</sup><sup>2</sup>.</p><h5>Insertion</h5><p>Tibial tuberosity (tubercle).</p><h4>Relations</h4><p>It is bounded posteriorly by the <a href="/articles/infrapatellar-fat-pad">infrapatellar fat pad</a>.</p><h4>Blood supply</h4><p>The patellar tendon is supplied by the following arteries and their anatomoses <sup>3</sup>:</p><ul>- +</ul><h4>Gross anatomy</h4><p>The patellar tendon is biconvex and, similarly to the <a href="/articles/calcaneal-tendon-1">calcaneal tendon</a>, does not have a tendon sheath but only a <a href="/articles/paratenon">paratenon</a> 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 <sup>2-4</sup>.</p><h5>Origin</h5><p>The patellar tendon begins at the patellar apex, but is actually considered the distal part of the <a href="/articles/quadriceps-tendon">quadriceps tendon</a> - or, more accurately, a continuation of the <a href="/articles/rectus-femoris-muscle">rectus femoris</a> tendon over the patella - while the <a href="/articles/patella">patella</a> itself is a <a href="/articles/sesamoid-1">sesamoid bone</a> embedded in the quadriceps tendon <sup>1,</sup><sup>2</sup>.</p><h5>Insertion</h5><p>Tibial tuberosity (tubercle).</p><h4>Relations</h4><p>It is bounded posteriorly by the <a href="/articles/infrapatellar-fat-pad">infrapatellar fat pad</a>.</p><h4>Blood supply</h4><p>The patellar tendon is supplied by the following arteries and their anatomoses <sup>3</sup>:</p><ul>
-<a title="Patella alta" href="/articles/patella-alta">patella alta</a>: tendon longer than patella</li>- +<a href="/articles/patella-alta">patella alta</a>: tendon longer than patella</li>
-<a title="Patella baja" href="/articles/patella-baja">patella baja</a>: tendon shorter than patella</li>-</ul><h4>Radiographic features</h4><h5>Ultrasound</h5><p>Shows striated appearance with predominanty high echogenicity, similarly to any other tendon. Deep to it, the infrapatellar fat pad is homogeneously hyperechoic <sup>3</sup>.</p><h5>MRI</h5><p>Shows low homogeneous signal on all sequences <sup>4</sup>.</p><h4>Related pathology</h4><p><a href="/articles/patellar-tendon-rupture">Patellar tendon rupture</a></p><p><a href="/articles/paratenonitis">Paratenonitis</a></p><p><a href="/articles/osgood-schlatter-disease">Osgood-Schlatter disease</a></p><p><a href="/articles/sinding-larsen-johansson-disease">Sinding-Larsen-Johansson disease</a></p><p><a href="/articles/jumpers-knee-1">Jumper's knee</a></p><h4>Related articles</h4><p><a href="/articles/extensor-mechanism-of-the-knee">Extensor mechanism of the knee</a></p><p><a href="/articles/quadriceps-tendon">Quadriceps tendon</a></p>- +<a href="/articles/patella-baja">patella baja</a>: tendon shorter than patella</li>
- +</ul><h4>Radiographic features</h4><h5>Ultrasound</h5><p>Shows striated appearance with predominanty high echogenicity, similarly to any other tendon. Deep to it, the infrapatellar fat pad is homogeneously hyperechoic <sup>3</sup>.</p><h5>MRI</h5><p>Shows low homogeneous signal on all sequences <sup>4</sup>.</p><h4>Related pathology</h4><ul>
- +<li>
- +<a title="Patellar tendon rupture" href="/articles/patellar-tendon-rupture">p</a><a href="/articles/patellar-tendon-rupture">atellar tendon rupture</a>
- +</li>
- +<li>
- +<a title="paratenonitis" href="/articles/paratenonitis">p</a><a href="/articles/paratenonitis">aratenonitis</a>
- +</li>
- +<li><a href="/articles/osgood-schlatter-disease">Osgood-Schlatter disease</a></li>
- +<li><a href="/articles/sinding-larsen-johansson-disease">Sinding-Larsen-Johansson disease</a></li>
- +<li>
- +<a title="Jumper's knee" href="/articles/jumpers-knee-1">j</a><a href="/articles/jumpers-knee-1">umper's knee</a>
- +</li>
- +</ul><h4>Related articles</h4><ul>
- +<li>
- +<a title="Extensor mechanism of the knee" href="/articles/extensor-mechanism-of-the-knee">e</a><a href="/articles/extensor-mechanism-of-the-knee">xtensor mechanism of the knee</a>
- +</li>
- +<li>
- +<a title="Quadriceps tendon" href="/articles/quadriceps-tendon">q</a><a href="/articles/quadriceps-tendon">uadriceps tendon</a>
- +</li>
- +</ul>