Surgical Science, 2012, 3, 484-488
http://dx.doi.org/10.4236/ss.2012.310096 Published Online October 2012 (http://www.SciRP.org/journal/ss)
Anatomical Reconsideration of the Lateral Collateral
Ligament in the Human Knee: Anatomical Observation
and Literature Review
Jun Yan1, Sanjuro Takeda2, Kotaro Fujino2, Goro Tajima2, Jiro Hitomi1
1Department of Anatomy, School of Medicine, Iwate Medical University, Morioka, Japan
2Department of Orthopaedic Surgery, School of Medicine, Iwate Medical University, Morioka, Japan
Received August 6, 2012; revised September 8, 2012; accepted September 17, 2012
ABSTRACT
In the published literature as well as in the most commonly used textbooks, the lateral collateral ligament (LCL) is de-
scribed as having 1 attachment at the lateral epicondyle of the femur and another at the head of the fibula. In this article,
we reconsider the attachments, the length of the LCL, and the tissues surrounding the LCL by presenting our anatomical
observations and by rev iewing the literature. Our results have shown th at the LCL is not only attached to the lower part
of the lateral epicondyle of the femur, but also extend s to the upp er part of the lateral epicondyle. The attachment of the
LCL on the fibula is enclosed by 2 insertion points of the biceps femoris tendon. The average length of the LCL in 71
knees was 51.4 mm. There is an “incomplete gap” on the LCL that is interrupted under the tendon of the biceps femoris.
Keywords: Knee Joint; Lateral Collateral Ligament; Morphological Feature; Incomplete Gap; Human
1. Introduction
Recently, varus instability has been reported as causing
injuries of the lateral collateral ligament (LCL) [1-5]; re-
construction of the injured LCL by semitendinosus
grafting has also been reported [6,7]. Since the deve-
lopment of clinical imaging modalities such as computed
tomography and magnetic resonance imaging, more
detailed morphological data relating to the LCL have
been acquired. However, the textbooks and published
literature remain unclear as to where the LCL attaches to
the femur and the fibula. We believe that for clinical ex-
amination and reconstruction of the LCL to be successful,
it is very necessary to reconsider the attachment of the
LCL on the femur and fibula, to determine the average
length of the LCL, and t o describe t he surrounding ti ssues.
This new data will be useful for further clinical
examinations. The objectives of the present observational
study were as follows: 1) to reconsider differences in
attachments on the femur and fibula; 2) to explain
differences in th e length of the LCL based on our present
observations and unpublished data; and 3) to describe the
surrounding tissue and nerve innervation of the LCL.
2. Materials and Methods
Eight cadavers (5 male, 3 female; 16 knees) were
examined to observe the LCL and surroundin g structur es.
The specimens were obtained from cadavers during the
2010 and 2011 courses of dissection at Iwate Medical
University School of Med icine (fixed with 10% formalin
through the radial artery and preserved in 50% alcohol
for 6 months). The superficial tissues of the lower limbs
were removed, and the LCL and structures surrounding
the LCL were dissected out carefully. Attachments on the
femur and fibula were carefully identified. As shown in
Figures 1 and 2, the length of the LCL was measured as
the distance between the central point of attachment on
the lateral epicondyle of the femur and the apex of the
head of fibula. The LCL and the surrounding structures
were photographed and sketched.
3. Results
We previously investigated the LCL in 55 knees [8].
Here, we report our unpublished data from that study as
well as our observations from the present investigation
(total 71 knees). As shown in Figure 2, an attachment on
the lateral epicondyle of the femur was observed on the
lower part of the LCL; however, a fiber bundle of the
LCL also extended to the upper part of the lateral
epicondyle of the femur. The attachment on the fibula
was observed on the anterolateral apex of the head of
fibula, and was overlapped by the tendon of the biceps
femoris. The tendon of the biceps femoris also extended
C
opyright © 2012 SciRes. SS

J. YAN ET AL. 485
Figure 1. The photo and sketch show the attachments of the
LCL and other structures surrounding the LCL. Note that
the insertion of the tendon of biceps femoris includes two
parts, the superficial (red small ball in photo and black
arrow in sketch) and deep parts. The “incomplete gap” on
the surface of the LCL also extends to the deep portions of
the LCL (red arrow in photo). The deep part of the tendon
of biceps femoris attaches to the apex under the LCL and
blends with the anterior ligament of the fibular head. AL:
anterior capitis fibular ligament; An: anterior; BF: biceps
femoris; Cr: cranial; CF: caput fibulae; EL: epicondylus
lateralis; LG; lateral caput of gastrocnemius; LP: patella
ligament; LS: lateral intermuscular septum; TQ: tendon of
quadriceps femori s.
Figure 2. The photo shows the attachments on the lateral
epicondyle of femur and the he ad of fibula. The attachment
on femur is not at lower part of lateral epicondyle only, but
also extended to the upper part of the lateral epicondyle. A:
The end of the attachment of the LCL on femur; B and C:
show the upper and lower ce ntral points of the attachments
of the LCL; D: the end of the attachment on fibula of the
LCL; BF: biceps femoris.
deep into the LCL, forming a “sandwich” structure (Fi-
gures 1 and 2). As shown in Figure 2, consideration of
the length of the LCL was possible using 2 criteria. One
was the distance between AD (the ends of the LCL on
the femur and fibula attachments) and the other that be-
tween BC (the central points of attachment on the femur
and the fibula). In this stud y, AD ranged from 65 .1 - 71.2
mm (the average value for 16 knees was 69.8 mm) and
BC ranged from 45.2 - 55.3 mm (the average value for
71 knees was 51 .4 mm).
In our previous study, an “incomplete gap” [8] be-
tween the surface of the LCL and the deep portion of the
tendon of the biceps femoris was observed (Figure 3). In
the present study, the gap was found to possibly extend
into the deep portion of the LCL, especially to the lower
part of the LCL (Fi gure 3).
4. Discussion
The lateral structures of the knee have been well reported.
The lateral patellofemoral ligament, popliteus tendon,

J. YAN ET AL. 486
Figure 3. The photos show the “incomplete gap” on the
surface of the LCL. Upon removal of the tendon of biceps
femoris, a soft tissue membrane superficial to the LCL was
clear (A). The “incomplete gap” also extended deep to the
lower edge of the LCL (red arrow in B). Asterisk: super-
ficial part of the tendon of biceps femoris. An: anterior; BF:
biceps femoris; Cr: cranial; LR: lateral retinaculum; LS:
lateral intermuscular septum.
popliteofibular ligament, and fabellofibular ligament have
all been described in detail [3,9-13], but to date descrip-
tions of the attachments of the LCL remain incomplete in
the published literature.
In textbooks, the LCL is described as a strong cord (or
a cord-like structure) attached to the lateral epicond yle of
the femur, proximal to the popliteal groove, and exten-
ding anteriorly to the apex of the head of fibula. It is
largely overlapped by the tendon of the biceps femoris,
which surround s and partly blends with it [14-18 ]. In the
newest version of Gray’s Anatomy (40th), the LCL is
reported as being attached to the lower part of the lateral
epicondyle of the femur [19]. Our findings show that the
LCL is not only attached to the lower part of the lateral
epicondyle of the femur, but also extends to the upper
part of the lateral epicondyle. We believe that this may
be the reason for the different reports of the length of the
LCL in the literature. The point of attachment on the
fibula is not consistent in current textbooks and in the
published literature. Gardner et al. [20], Hollinshead [21],
and Sugita [22] reported that the LCL is attached to the
head of the fibula. Clemente [23] and Eswpregueira and
Silva [24] stated that the attachment is on the ante-
rolateral side of the apex of the head of fibula. Meister et
al. [25] described the fibular attachment as being on the
lateral surface with a V-shaped plateau. In our study, we
found the fibular attachment of the LCL to be on the
anterolateral head of the fibula at its apex, similar to the
reports of Clemente [23] and Eswpregueira and Silva
[24]. On the other hand, our findings indicate that the
attachment fibers of the biceps femoris could be divided
into 2 layers, the superficial and profound layers. An
insertion of the LCL was enclosed between these layers
to form a “sandwich,” and this point has not been noted
in the literature. This finding also highlights the close
connection between the LCL and the tendon of the biceps
femoris.
The length of the LCL has been well reported. Meister
et al. reported that the length of the LCL ranges fro m 59
to 72 mm [25]. Gil et al. reported a length of 51.99 mm
[26], and Ishigooka et al. a length of 56.3 - 65.7 mm [27].
Otake et al. reported that the anterior length of the LCL
is 45.6 - 60.2 mm and the posterior length is 47.4 - 61.8
mm [28]. Jung et al. reported a mean length of 53.0 mm
[29], and LaPrade et al. indicated th at the average le ngth
of the LCL is 35.3 mm [30]. Kozanek et al. reported a
range of 45.5 to 57.7 mm [31], and in a review of the
literature, Lai et al. reported an LCL length of 59.0 - 72.0
mm [32]. We believe that 2 standards are used for the
measurement of the LCL: one is the distance from the
end of the attachments on the femur and fibula; the other
is the distance between the central points of attachment
on the 2 bones. As shown in Figure 2, when the mea-
surement point was between the central points of attach-
ment on the femur and fibula, the average length of the
LCL was 51.4 mm. This value is lower than that reported
by Lai et al., but the AD average value of the present
observation is 69.8 mm, which is similar to the results of
Lai et al. [32].
The lateral soft tissues of the knee are arranged in 3

J. YAN ET AL. 487
layers, and the LCL belongs to the second layer [33]. The
surface of the LCL is overlapped by the fabellofibular
ligament and the tendon of the biceps femoris [25,34].
However, Yan et al. reported that there is an “incomplete
gap” between the tendon of the biceps femoris and the
surface of the LCL [8]. Based on the present results, this
“gap” is not on the surface of LCL alone, but also
extends to the deep portions of the LCL near its fibular
attachment.
In textbooks, innervation of the LCL is not clearly
delineated [14,35,36]. The articular branches of the knee
joint in humans and cats may be supplied by branches of
the sciatic nerve, but no detailed routes and distribution
patterns of the nerve branches are described [37-39]. Yan
et al. [8] demonstrated that the nerves distributed to the
LCL could be classified into 3 types with 6 patterns. The
nerve innervating the LCL could be a single nerve branch
or multiple branches stemming from a common fibular
nerve. The main branching patterns are branch(es) ste-
mming from the innervating nerve of the breve caput of
the biceps femoris and/or branch(es) stemming directly
from the common fibular nerve. In about 25% of 55
cases, the nerve fibers coming from the tibial nerve en-
tered the branch(es) innervating the LCL.
5. Conclusion
The LCL is attached to the lower part of the lateral
epicondyle of the femur, but it also extends to the upper
part of the lateral condyle. The attachment of the LCL on
the fibula is overlapped by the tendon of the biceps
femoris both superficially and deeply. Different reports
of LCL length may be related to different considerations
of the points of attachment on the femur and fibula.
There is also an “incomplete gap” between the surface of
the LCL and the deep part of the tendon of the biceps
femoris.
6. Acknowledgments
We thank Mr. S. Takahashi and Mr. N. Sasaki (Iwate
Medical University) for their technical advice. This work
was supported financially by the Advanced Medical Sci-
ence Center of Iwate Medical University.
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