Knee menisci
Updates to Article Attributes
Body
was changed:
The knee mensici menisci are fibrocartilaginous structures that sit within the knee joint, deepening the tibiofemoral articulation. They function to improve stability, shock absorption and load transmission of the knee.
Gross anatomy
There are two knee menisci in each joint - medial and lateral. They are semilunar or curved in shape. The menisci are described as having a central body with anterior and posterior horns. In cross-section they have a triangular (bow-tie) shape, being thicker peripherally and thinning to a free-edge centrally. Each meniscus has a differing shape, size and attachments:
-
medial meniscus
- larger
- more open and wider; semi-circular in shape
-
lateral meniscus
- smaller
- narrower and more C-shaped
Attachments
-
medial meniscus
- the anterior horn of the medial meniscus attaches immediately anterior to the tibial attachment of the anterior cruciate ligament (ACL) on the intercondylar area
- lateral aspect attached to the deep (third) layer of the medial collateral ligament
-
lateral meniscus
- the anterior horn of the lateral meniscus attaches immediately posterior to the tibial attachment of the ACL on the intercondylar area
- no attachment to the lateral collateral ligament
- meniscofemoral ligament: posterior horn to femur
- popliteus tendon laterally
-
common attachments
- posterior horns of both the medial and lateral menisci attach to the posterior intercondylar area of the tibial plateau
- transverse meniscal (or genual) ligament (of Winslow) attaches the anterior horns to each other
- joint capsule peripherally except the lateral meniscus at the site of the popliteus tendon hiatus
Blood supply
- outer one-third
- supply: supply from the peripheral meniscal plexus from medial, lateral and middlegeniculategenicular arteries 6, 8 - inner two-thirds
- no: no vascular supply; diffusion dependent 6
Nerve supply
- posterior articular branch of the posterior tibial nerve and terminal obturator and femoral nerve branches 8
Variant anatomy
- discoid meniscus 4-5
- congenital hypoplasia or absence 4
- aberrant insertion of the anterior horn of the medial menisci (2%)
- into the ACL or intercondylar notch 4
- anterior margin of the tibia in the midline 5
- no attachment
- stabilised: stabilised by the transverse meniscal ligament 5
- meniscal ossicle (rare; incidence <0.2%) 5
Related pathology
-<p>The <strong>knee mensici </strong>are fibrocartilaginous structures that sit within the <a href="/articles/knee-joint">knee joint</a>, deepening the tibiofemoral articulation. They function to improve stability, shock absorption and load transmission of the knee.</p><h4>Gross anatomy</h4><p>There are two knee menisci in each joint - <strong>medial </strong>and <strong>lateral</strong>. They are semilunar or curved in shape. The menisci are described as having a central body with anterior and posterior horns. In cross-section they have a triangular shape, being thicker peripherally and thinning to a free-edge centrally. Each meniscus has a differing shape, size and attachments:</p><ul>- +<p>The <strong>knee menisci </strong>are fibrocartilaginous structures that sit within the <a href="/articles/knee-joint-1">knee joint</a>, deepening the tibiofemoral articulation. They function to improve stability, shock absorption and load transmission of the knee.</p><h4>Gross anatomy</h4><p>There are two knee menisci in each joint - <strong>medial </strong>and <strong>lateral</strong>. They are semilunar or curved in shape. The menisci are described as having a central body with anterior and posterior horns. In cross-section they have a triangular (bow-tie) shape, being thicker peripherally and thinning to a free-edge centrally. Each meniscus has a differing shape, size and attachments:</p><ul>
-<li>the anterior horn of the medial meniscus attaches immediately anterior to the tibial attachment of the <a href="/articles/anterior-cruciate-ligament">anterior cruciate ligament (ACL)</a> on the <a title="Intercondylar area" href="/articles/intercondylar-area">intercondylar area</a>- +<li>the anterior horn of the medial meniscus attaches immediately anterior to the tibial attachment of the <a href="/articles/anterior-cruciate-ligament">anterior cruciate ligament (ACL)</a> on the <a href="/articles/intercondylar-area">intercondylar area</a>
-<li>lateral aspect attached to the deep (third) layer of the <a href="/articles/medial-collateral-ligament">medial collateral ligament</a>- +<li>lateral aspect attached to the deep (third) layer of the <a href="/articles/medial-collateral-ligament-of-the-knee">medial collateral ligament</a>
-<li>the anterior horn of the lateral meniscus attaches immediately posterior to the tibial attachment of the ACL on the <a title="Intercondylar area" href="/articles/intercondylar-area">intercondylar area</a>- +<li>the anterior horn of the lateral meniscus attaches immediately posterior to the tibial attachment of the ACL on the <a href="/articles/intercondylar-area">intercondylar area</a>
-<li>posterior horns of both the medial and lateral menisci attach to the posterior <a title="Intercondylar area" href="/articles/intercondylar-area">intercondylar area</a> of the <a href="/articles/tibial-plateau">tibial plateau</a>- +<li>posterior horns of both the medial and lateral menisci attach to the posterior <a href="/articles/intercondylar-area">intercondylar area</a> of the <a href="/articles/tibial-plateau">tibial plateau</a>
-<li>outer one-third - supply from the peripheral meniscal plexus from medial, lateral and middle geniculate arteries <sup>6, 8</sup>- +<li>outer one-third: supply from the peripheral meniscal plexus from medial, lateral and middle genicular arteries <sup>6, 8</sup>
-<li>inner two-thirds - no vascular supply; diffusion dependent <sup>6</sup>- +<li>inner two-thirds: no vascular supply; diffusion dependent <sup>6</sup>
-<a href="/articles/discoid_meniscus">discoid meniscus</a> <sup>4-5</sup>- +<a href="/articles/discoid-meniscus">discoid meniscus</a> <sup>4-5</sup>
-<li>aberrant insertion of the anterior horn of the medial menisci<ul>- +<li>aberrant insertion of the anterior horn of the medial menisci (2%)<ul>
-<li>no attachment - stabilised by the transverse meniscal ligament <sup>5</sup>- +<li>no attachment: stabilised by the transverse meniscal ligament <sup>5</sup>
-<li>buckle-handle tear<ul>- +<li>
- +<a title="Meniscal tear" href="/articles/meniscal-tear">meniscal tear</a><ul>
-<li><a href="/articles/meniscal_flounce">meniscal flounce</a></li>- +<li><a href="/articles/meniscal-flounce">meniscal flounce</a></li>
References changed:
- 9. Nguyen JC, De Smet AA, Graf BK et-al. MR imaging-based diagnosis and classification of meniscal tears. Radiographics. 2014;34 (4): 981-99. <a href="http://dx.doi.org/10.1148/rg.344125202">doi:10.1148/rg.344125202</a> - <a href="http://www.ncbi.nlm.nih.gov/pubmed/25019436">Pubmed citation</a><span class="auto"></span>