Femoral Attachments of Ligaments

For Medical Students

Structure and Location

There are two groups. Inside the notch are the cruciates. Outside, on the epicondyles and the supracondylar areas, is everything else.

Inside the notch: the anterior cruciate ligament attaches to the medial surface of the lateral condyle, and the posterior cruciate ligament to the lateral surface of the medial condyle. Each is on the wall facing the other condyle.

Outside, medially: adductor magnus to the adductor tubercle, the medial patellofemoral ligament between the tubercle and the epicondyle, the superficial medial collateral ligament from the epicondyle, and the medial head of gastrocnemius from the supracondylar area behind.

Outside, laterally: the lateral collateral ligament from the lateral epicondyle, popliteus from its sulcus anterior and distal to that, and the lateral head of gastrocnemius from the supracondylar area behind.

Relations

The capsule divides the two groups. The cruciate attachments are intracapsular; the collateral and muscular attachments are not.

On the lateral side the popliteus origin is intracapsular even though the collateral origin just above it is not, because the capsule attaches between them.

The two gastrocnemius origins lie behind everything else and separate the bone from the popliteal contents.

Function

The attachment positions determine when each structure is tight. A ligament attaching far from the axis of flexion changes length a great deal through the range; one attaching close to it changes little.

That is why the collateral ligaments, which attach near the epicondyles, stay relatively isometric, while the cruciates, attaching in the notch, change tension markedly with flexion.

Clinical Relevance

Reconstructing a ligament means reproducing its attachment, and every attachment on this page can be found from the epicondyle and the adductor tubercle.

Getting an attachment wrong does not merely weaken a reconstruction. It changes the length pattern through range, so the graft is tight at one angle and slack at another.

MRCS Level

Structure and Location

Work round the bone in a fixed order and nothing gets missed.

Intercondylar notch, lateral wall: anterior cruciate ligament, on the posterior part of the wall near the articular margin, with the anteromedial bundle fibres proximal and the posterolateral bundle fibres distal when the knee is extended. The footprint is conventionally described as an oval of the order of 17 mm along its long axis and 9 mm across. 2.7.6 owns it in detail.

Intercondylar notch, medial wall: posterior cruciate ligament, broader than the anterior cruciate's attachment and extending further anteriorly along the roof of the notch, with the anterolateral and posteromedial bundles.

Medial epicondylar region: the superficial medial collateral ligament from a depression on the epicondyle; the medial patellofemoral ligament from the saddle between epicondyle and adductor tubercle; adductor magnus on the tubercle itself; the medial head of gastrocnemius posteriorly above the condyle.

Lateral epicondylar region: the lateral collateral ligament from a depression on the epicondyle; popliteus from the popliteal sulcus, anterior and distal to the collateral; the lateral head of gastrocnemius posteriorly; the lateral intermuscular septum along the shaft above.

Relations

The capsular line is the organising relation. It runs around the articular margin, passes between the lateral collateral and popliteus origins, and leaves the notch contents inside while excluding everything on the epicondyles.

The meniscofemoral ligaments also attach in the notch, on the medial wall near the posterior cruciate, and 2.6.3 owns them.

The oblique popliteal ligament reinforces the posterior capsule and takes origin in part from the supracondylar region through the semimembranosus expansion rather than from the bone directly.

Blood Supply and Innervation

The notch attachments are supplied by the middle genicular artery, which is why both cruciates share a single main source and why their healing capacity is limited.

The epicondylar attachments are supplied from the superior and inferior genicular arteries through the surrounding soft tissue rather than through the bone, so a collateral ligament retains a blood supply after injury that a cruciate does not.

Mechanoreceptors and free nerve endings are present at the ligament insertions, supplied from the articular branches of the tibial and common peroneal nerves posteriorly. 2.7.5 and 2.7.10 own the innervation and proprioception of the anterior cruciate.

Function

Because the collaterals attach near the epicondyles, close to the flexion axis, their length changes little through the range and they restrain varus and valgus throughout.

Because the cruciates attach inside the notch, away from that axis, their fibres change length as the knee moves, and different fibre bundles are tight at different angles. That is the anatomical basis of bundle behaviour.

The medial patellofemoral ligament attaches close to the axis as well, which is why it restrains the patella with roughly constant tension over the first part of flexion rather than only at one angle.

Clinical Relevance

The femoral attachment is the part of a reconstruction most sensitive to position, because it is the end further from the flexion axis for a cruciate and the end determining isometry for a collateral or the medial patellofemoral ligament.

A single blood supply to both cruciates explains why intra-articular ligament healing is poor and extra-articular ligament healing is not.

In a growing knee several of these attachments lie close to the distal femoral physis, and the physis crosses the bone just above the condyles. Section 10 owns the consequences.

A collateral ligament avulsing from the epicondyle takes a fragment of extracapsular bone; a cruciate failing at the femur usually does not avulse bone in an adult, because the attachment is broad and the ligament fails within its substance.

FRCS Level

Relations

In revision work the attachments have to be located without the landmarks that normally find them, because previous tunnels, hardware and scar have altered the surface. The epicondyles and the adductor tubercle survive most of that and remain the reference of last resort.

Where a previous femoral tunnel sits relative to the native attachment determines whether a new tunnel can be placed in one stage, and the question is geometric rather than technical.

Function

Attachment position governs graft length change through range, and length change governs whether a graft is loaded or spared at a given angle.

This is why anatomical placement is argued for on mechanical grounds rather than aesthetic ones: a non-anatomical femoral attachment produces a graft that is tight somewhere in the range, and the knee either loses that part of the range or loses the graft.

The same reasoning applies to the medial patellofemoral ligament, where a femoral attachment placed too proximally produces a reconstruction that tightens with flexion.

Clinical Relevance

Three decisions turn on this anatomy. Whether a revision cruciate reconstruction is single or two stage. Whether a posterolateral reconstruction restores the collateral and popliteus origins separately or as one. Whether a medial patellofemoral ligament reconstruction will be isometric over the range that matters.

All three are answered by where the attachments are, and all three are discussed in Section 7 with the technique attached. What this page supplies is the map.

The map carries no coordinates. Every published description of these attachments gives distances from landmarks, and none of those distances could be verified here. Decision 005 records why they are absent, and a reviewer with sources should add them.