Patellar tendon

Changed by Yaïr Glick, 9 Jul 2018

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The patellar tendon, also referred to as the patellar ligament,~~) is attached~~ attaches the patella to the ~~inferior aspect~~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 ~~tibial tuberosity. Superior to patella~~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

Patellar tendon rupture

Paratenonitis

Osgood-Schlatter disease

Sinding-Larsen-Johansson disease

Jumper's knee

Extensor mechanism of the knee

Quadriceps tendon

-<p>The <strong>patellar tendon </strong>(sometimes called the <strong>patellar ligament</strong>) is attached to the inferior aspect of the patella and tibial tuberosity. Superior to patella is the <a href="/articles/quadriceps-femoris">quadriceps femoris</a> tendon. </p>
+<p>The <strong>patellar tendon</strong>, also referred to as the <strong>patellar ligament,</strong> attaches the patella to the tibia and is part of the <a href="/articles/extensor-mechanism-of-the-knee">extensor mechanism of the knee</a>.</p><h4>Summary</h4><ul>
+<li>
+<strong>origin:</strong> <a title="Patella" href="/articles/patella">patellar</a> apex</li>
+<li>
+<strong>insertion:</strong> tibial tuberosity</li>
+<li>
+<strong>action:</strong> aids in knee extension, as the distal part of the extensor mechanism of the knee</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>
+<li>descending genicular artery, a branch of the <a href="/articles/profunda-femoris-artery">deep femoral artery</a>
+</li>
+<li>inferior medial genicular artery, a branch of the <a href="/articles/popliteal-artery">popliteal artery</a>
+</li>
+<li>superior and inferior lateral genicular arteries, branches of the popliteal artery</li>
+<li>anterior tibial recurrent artery, a branch of the <a href="/articles/anterior-tibial-artery">anterior tibial artery</a>
+</li>
+</ul><h4>Action</h4><p>Assists in proper patellar alignment and knee extension.</p><h4>Variant anatomy</h4><p>Variation of >20% between the patellar tendon length and patellar height will result in either <sup>4</sup></p><ul>
+<li>
+<a title="Patella alta" href="/articles/patella-alta">patella alta</a>: tendon longer than patella</li>
+<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>

References changed:

2. Patrik Danielson. Innervation patterns and locally produced signal substances in the human patellar tendon. Umeå University Medical Dissertations, New Series No. 1103 (2007)<a href="http://books.google.com/books?vid=ISBN9789172643192">Read it at Google Books</a><span class="auto"></span>
2. Patrik Danielson. Innervation patterns and locally produced signal substances in the human patellar tendon. Umeå University Medical Dissertations, New Series No. 1103 (2007)<a href="http://books.google.com/books?vid=ISBN9789172643192">Read it at Google Books</a><span class="auto"></span>
3. Eugene G McNally. Practical Musculoskeletal Ultrasound, second edition (2014). Churchill-Livingstone<a href="http://books.google.com/books?vid=ISBN9781455774043">Read it at Google Books</a><span class="auto"></span>
3. Eugene G McNally. Practical Musculoskeletal Ultrasound, second edition (2014). Churchill-Livingstone<a href="http://books.google.com/books?vid=ISBN9781455774043">Read it at Google Books</a><span class="auto"></span>
3. Eugene G McNally. Practical Musculoskeletal Ultrasound, second edition (2014). Churchill-Livingstone<a href="http://books.google.com/books?vid=ISBN9781455774043">Read it at Google Books</a><span class="auto"></span>
4. Diagnostic and Surgical Imaging Anatomy: Musculoskeletal. Amirsys Inc. (2006) <a href="http://books.google.com/books?vid=ISBN9781931884327">ISBN 9781931884327</a><span class="auto"></span>
2. Gray's anatomy for students. Churchill Livingstone. ISBN:0702051314. <a href="http://books.google.com/books?vid=ISBN0702051314">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/0702051314">Find it at Amazon</a><span class="auto"></span>
2.
3.
3. Eugene G McNally. Practical Musculoskeletal Ultrasound, second edition. Churchill-Livingstone, 2014<a href="http://books.google.com/books?vid=ISBN9781455774043">Read it at Google Books</a><span class="auto"></span>