Popliteomeniscal Fascicles: Anatomic Considerations Using MR ...

Peduto et al. 

MR Arthrography of Popliteomeniscal Fascicles 

Musculoskeletal Imaging 

Original Research 

Anthony J. Peduto 1,2 

Alison Nguyen 1 

Debra J. Trudell 1 

Donald L. Resnick 1 

Peduto AJ, Nguyen A, Trudell DJ, Resnick DL 

Keywords: anatomy, fascicles, knee, MRI, 

popliteomeniscal 

DOI:10.2214/AJR.07.2643 

Received May 29, 2007; accepted after revision 

July 10, 2007. 

1 

Department of Radiology, Veterans Affairs Healthcare 

System, San Diego, CA. 

2 Department of Radiology, Westmead Hospital, Darcy 

Rd., Westmead, Sydney, New South Wales, Australia 

2145. Address correspondence to A. J. Peduto. 

AJR 2008; 190:442–448 

0361–803X/08/1902–442 

© American Roentgen Ray Society 

Musculoskeletal Imaging • Original Research 

Popliteomeniscal Fascicles: 

Anatomic Considerations Using 

MR Arthrography in Cadavers 

OBJECTIVE. This study was performed to examine the normal MR arthrographic anatomy 

of the popliteomeniscal fascicles with specific reference to the number of popliteomeniscal 

fascicles, thickness and course of the fascicles, and presence of other posterior attachments 

from the medial aponeurosis of the popliteus musculotendinous region. 

MaTERIals and METhOds. Multiplanar 1.5-T MR arthrography of 10 cadaveric 

knees was performed using a quadrature knee coil. Specimens were frozen and sectioned in 

the sagittal (n = 4), axial (n = 3), and coronal (n = 3) planes. MR images and anatomic specimens 

were correlated by two musculoskeletal radiologists. 

REsUlTs. Three popliteomeniscal fascicles were identified on MR arthrography: anteroinferior 

and posterosuperior fascicles in all 10 knees and posteroinferior fascicles in four 

of the knees. The posterosuperior popliteomeniscal fascicle was uniform in thickness, and the 

anteroinferior popliteomeniscal fascicle was variable in thickness. The anteroinferior popliteomeniscal 

fascicle formed a conjoined fibular attachment with the popliteofibular ligament. 

A medial aponeurotic extension from the popliteus musculotendinous region gave rise to the 

posteroinferior popliteomeniscal fascicle, which extended upward and attached to the inferomedial 

aspect of the posterior horn of the lateral meniscus. Additional attachments from the 

medial aponeurosis of the popliteus musculotendinous region to the posterior cruciate ligament, 

posterior capsule, oblique popliteal ligament, and posterior meniscofemoral ligament 

of Wrisberg were seen. 

COnClUsIOn. Three popliteomeniscal fascicles were identified on MR arthrographic images. 

The popliteus muscle–tendon unit forms robust attachments in the superior, inferior, medial, 

and lateral oblique aspects, highlighting its importance in posterolateral stability of the knee. 

B 

etter understanding of the clinical 

significance of injuries to the 

posterolateral corner of the knee 

has led to an increasing focus on 

clinical evaluation, treatment, and MRI of 

this region. Unrecognized injuries to the 

posterolateral corner have been cited as an 

important factor in postsurgical failure after 

cruciate ligament reconstruction and in chronic 

instability and degenerative changes after 

knee trauma [1, 2]. Within the posterolateral 

corner of the knee, the functional and structural 

relations among the lateral meniscus, 

popliteus muscle and tendon attachments, and 

the popliteomeniscal fascicles have received 

considerable emphasis [3–7]. 

The proximal intraarticular insertion of the 

popliteus tendon is situated within a shallow 

concavity in the lateral aspect of the femur 

designated the popliteal sulcus. The tendon 

descends in an inferoposterior helicoid man- 

ner to the posterolateral corner of the knee. As 

it passes the posterior horn of the lateral meniscus, 

the popliteus tendon becomes extraarticular. 

The popliteomeniscal fascicles are 

posterolateral meniscocapsular extensions 

that blend inferiorly into the popliteus musculotendinous 

region and allow the tendon to 

pass from an intraarticular to an extraarticular 

compartment while maintaining the compartmental 

integrity of the knee joint. The popliteomeniscal 

fascicles are considered functionally 

important stabilizers of the lateral meniscus, 

working in conjunction with the popliteus 

musculotendinous unit to prevent excessive 

lateral meniscal movement and possible entrapment 

[8–10]. Injuries to the popliteomeniscal 

fascicles are commonly underrecognized 

both clinically and on imaging studies 

and are reported [3, 9] to occur in association 

with acute anterior cruciate ligament tears in 

as many as 25% of patients. Isolated tears of 

442 AJR:190, February 2008

Fig. 1—Drawing shows superolateral view 

of posterolateral corner of knee with femur 

and superficial fibular attachments removed. 

Arrangement between popliteus muscle (8) 

and tendon (9) (cut proximally and reflected) 

and anteroinferior (11) and posterosuperior (10) 

popliteomeniscal fascicles is apparent. Inferolateral 

portion of anteroinferior popliteomeniscal fascicle 

(11) forms common fibular styloid attachment 

with anterior arm of popliteofibular ligament 

(6). 1 = anterior cruciate ligament, 2 = posterior 

cruciate ligament, 3 = lateral meniscus, 4 = anterior 

meniscofemoral ligament of Humphry, 5 = posterior 

meniscofemoral ligament of Wrisberg, 7 = posterior 

arm of popliteofibular ligament, 12 = fibula. (Reprinted 

with permission from Stäubli HU, Birrer S. The 

popliteus tendon and its fascicles at the popliteal 

hiatus: gross anatomy and functional arthroscopic 

evaluation with and without anterior cruciate 

ligament deficiency. Arthroscopy 1990; 6:209–220 [3]) 

the popliteomeniscal fascicles can be symptomatic 

and manifest as localized posterolateral 

pain and locking of the knee joint [8, 10, 

11]. Some authors [11] have referred to this 

disorder as hypermobile lateral meniscus and 

describe specific clinical examination techniques 

that can help in the diagnosis. 

Although there is debate about the number 

of popliteomeniscal fascicles, most studies 

have described at least two: an anteroinferior 

fascicle and a posterosuperior fascicle [3, 7, 

12, 13]. The anteroinferior popliteomeniscal 

fascicle originates from the lateral aspect of 

the body of the lateral meniscus, courses in 

an inferoposterior direction to form the floor 

of the popliteal hiatus, and then blends with 

the musculotendinous portion of the popli- 


teus muscle. The lateral portion of the anteroinferior 

popliteomeniscal fascicle takes 

an inferoposterior course and fuses with the 

popliteofibular ligament to form a conjoined 

attachment at the fibular styloid process. The 

origin of the posterosuperior popliteomeniscal 

fascicle is the posterosuperior margin of 

the posterior horn of the lateral meniscus 

medial to the popliteus tendon. This fascicle 

forms the roof of the popliteal hiatus. 

The posterosuperior popliteomeniscal fascicle 

has a posterior course and attaches to the 

posterior joint capsule, which fuses with the 

musculotendinous portion of the popliteus 

tendon (Fig. 1). 

The presence of a third popliteomeniscal 

fascicle, known as the posteroinferior popliteomeniscal 

fascicle, is controversial. This 

fascicle is reported to be located medial to 

the popliteal hiatus [11, 14–16]. Last [17] in 

1950 described a broad and robust aponeurotic 

extension from the medial aspect of the 

musculotendinous region of the popliteus 

muscle that had a prominent attachment to 

the inferior margin of the posterior horn of 

the lateral meniscus. Terry and LaPrade [15] 

and Ullrich et al. [16] also described the medial 

aponeurotic extension and designated 

the attachment to the inferior margin of the 

posterior horn of the lateral meniscus the 

posteroinferior popliteomeniscal fascicle. 

This fascicle passes upward from the medial 

aponeurosis of the popliteus muscle and inserts 

on the inferior margin of the posterior 

horn of the lateral meniscus near the origin 

of the posterior meniscofemoral ligament of 

Wrisberg. Feipel et al. [14] found the posteroinferior 

popliteomeniscal fascicle present in 

17% of 42 dissections of embalmed knee 

specimens. Most other reports of the posteroinferior 

popliteomeniscal fascicle do not 

state its frequency. 

The medial aponeurosis of the popliteus 

musculotendinous region has been reported 

to have additional medial attachments to the 

inferolateral aspect of the posterior cruciate 

ligament, the posterior capsule, and an 

infero lateral connection with the oblique 

popliteal ligament [14, 16]. A variant of the 

posterior meniscofemoral ligament of Wrisberg 

has been reported in which the origin is 

the medial aponeurosis of the popliteus musculotendinous 

region rather than the posterior 

horn of the lateral meniscus [14]. 

This study was performed to examine the 

normal MR arthrographic imaging anatomy 

of the popliteomeniscal fascicles with specific 

reference to the number of popliteomeniscal 

fascicles, the thickness and course of the fascicles, 

and the presence of other posterior attachments 

from the medial aponeurosis of the 

popliteus musculotendinous region. 

Materials and Methods 

After institutional review board approval was 

obtained, 10 fresh unembalmed frozen cadaveric 

knee specimens were obtained from the 

department of anatomy donor program at our 

institution. Specimens were from five men and 

five women whose average age at death was 85 

years (range, 73–93 years). 

MR Arthrography 

Before MRI, specimens were allowed to thaw 

to room temperature for 24 hours, after which 

arthrography was performed under fluoroscopic 

guidance. Approximately 55–60 mL of a solution 

containing 1 mL of gadopentetate dimeglumine 

(Magnevist, Bayer Schering Pharma) diluted in 

250 mL of equal parts saline solution and iohexol 

(Omnipaque 350, GE Healthcare) was injected 

into each knee joint via a lateral suprapatellar 

approach with an 18-gauge needle. T1-weighted 

spin-echo imaging was performed on a 1.5-T 

MRI system (Signa LX Horizon, software version 

8.3, GE Healthcare) with a quadrature knee coil 

in the orthogonal sagittal, axial, and coronal 

planes. The following MRI parameters were used: 

TR/TE, 900/22; bandwidth, 16 kHz; matrix size, 

512 × 256; field of view, 12 × 12 cm; slice 

thickness, 2.5-mm; interslice gap, 0.5 mm; single 

acquisition; imaging time, approximately 5 

minutes for each sequence. 

Specimen Sectioning and Photography 

After MRI, the knee specimens were placed in a 

freezer (Forma Bio-Freezer, Forma Scientific) and 

deep frozen to −40°C. The frozen knee specimens 

were sectioned with a band saw into 3-mm slices 

in the sagittal (n = 4), axial (n = 3), and coronal 

(n = 3) planes. After debris was rinsed from the 

surface of the specimens, the sections were 

thawed, floodlit, and photographed with a digital 

camera (Coolpix 990, Nikon). 

Image Interpretation 

MR arthrographic images and specimen 

photographs were simultaneously reviewed by two 

musculoskeletal radiologists working in consensus. 

Identification and location of the anteroinferior, 

posterosuperior, and postero inferior popliteomeniscal 

fascicles and the medial aponeurosis with 

its medial attachments were based on gross 

anatomic descriptions obtained from the literature 

[3, 12, 14–16]. The number of popliteomeniscal 

fascicles visualized and their location on MR 

AJR:190, February 2008 443

arthrographic images were recorded for each 

specimen. The reviewers inspected MR arthrographic 

images obtained through the popliteal 

hiatus, with the anteroinferior popliteomeniscal 

fascicle originating from the lateral surface of the 

body of the lateral meniscus and forming the floor 

and lateral wall of the hiatus, and the posterosuperior 

A 

Peduto et al. 

popliteomeniscal fascicle originating from the 

superior edge of the posterior horn of the lateral 

meniscus and forming the roof and medial wall of 

the hiatus. MR arthrographic images obtained 

medial to the popliteal hiatus were inspected for the 

presence of a medial aponeurotic extension from the 

musculotendinous junction of the popliteus muscle, 

C 

d 

Fig. 2—Anteroinferior popliteomeniscal fascicle and popliteofibular ligament of cadaver specimens. A and B 

are matching MRI and anatomic sections from one cadaver; C and D are matching MRI and anatomic sections 

from another cadaver. 

A–D, Sagittal T1-weighted MR arthrographic images with corresponding cadaveric sections show 

anteroinferior popliteomeniscal fascicle extending in posteroinferior course from lateral aspect of lateral 

meniscus (LM) and to blend with popliteus tendon. Conjoined attachment of anteroinferior popliteomeniscal 

fascicle and popliteofibular ligament (asterisk) at styloid process of fibula (f) is evident. Variable appearance 

of anteroinferior popliteomeniscal fascicle (arrows) is thin and membrane-like in A and B and thick in C and D. 

POP = popliteus tendon. 

which has been reported [15–17] to send an 

attachment to the inferior edge of the posterior horn 

of the lateral meniscus. This attachment is designated 

the posteroinferior popliteomeniscal fascicle and is 

immediately beneath the origin of the meniscofemoral 

ligament of Wrisberg. 

Electronic calipers were used to measure the 

thickness of each popliteomeniscal fascicle on 

MR arthrographic images. The fascicles were 

categorized as thin (≤ 1 mm), intermediate (1–2 

mm), or thick (≥ 2 mm). The following anatomic 

features were recorded: presence of a popliteofibular 

ligament and its relation to the anteroinferior 

popliteomeniscal fascicle, presence of a medial 

aponeurotic extension from the popliteus 

musculotendinous unit, and presence of medial 

attachments from the medial aponeurosis to the 

posterior cruciate ligament, posterior joint capsule, 

oblique popliteal ligament, and the posterior 

meniscofemoral ligament of Wrisberg. 

Results 

The anteroinferior and posterosuperior popli- 

teomeniscal fascicles were identified with MR 

arthrography in all 10 specimens. Together 

the anteroinferior and posterosuperior popliteomeniscal 

fascicles formed a meniscocapsular 

sheath enveloping the popliteal tendon as it 

passed through the popliteal hiatus and became 

extraarticular in location (Fig. 1). 

The anteroinferior popliteomeniscal fascicle 

(Fig. 2) extended in an inferoposterior direction 

from its attachment at the lateral aspect 

of the body of the lateral meniscus and formed 

the lateral wall and floor of the popliteal hiatus. 

The thickness of the anteroinferior popliteomeniscal 

fascicle was variable. In five of 

10 specimens, this fascicle was categorized 

as thick, in three as intermediate, and in two 

as thin. The anteroinferior popliteomeniscal 

fascicle curved in the inferior direction adjacent 

to the posteromedial aspect of the fibular 

styloid process and blended with the popliteofibular 

ligament to form a conjoined fibular 

attachment, which was found in eight of 10 

specimens (Fig. 2). In the more medial aspect 

the anteroinferior popliteomeniscal fascicle 

formed the floor of the popliteal hiatus and 

fused with the deep musculotendinous portion 

of the popliteus complex. The popliteofibular 

ligament was seen on MR arthro graphic 

images of nine of 10 specimens and had a robust 

attachment to the posteromedial aspect 

of the fibular styloid process (Fig. 2). Only a 

single attachment site of the popliteofibular 

ligament was discernible. 

The posterosuperior popliteomeniscal fascicle 

was in a medial position in relation to 

444 AJR:190, February 2008 

B


A B 

C 

d E F 

G 

Fig. 3—Popliteomeniscal fascicular attachments of cadaver specimen. 

A–G, Series of sagittal T1-weighted MR arthrographic images of lateral meniscus extending from lateral to 

medial shows three popliteomeniscal fascicular attachments. Anteroinferior popliteomeniscal fascicle (AI- 

PMF) is thinner than posterosuperior popliteomeniscal fascicle (PS-PMF) in this knee. The posteroinferior 

popliteomeniscal fascicle (PI-PMF) extends upward and in medial direction from medial aponeurotic extension 

(arrowheads, F and G) of popliteus musculotendinous region and attaches to inferior margin of posterior horn of 

lateral meniscus immediately below posterior meniscofemoral ligament of Wrisberg (curved arrow in G). 


the popliteus tendon at the level of the 

popliteal hiatus and extended in a posterior 

direction from the posterosuperior corner of 

the posterior horn of the lateral meniscus 

(Fig. 3) to the posterior joint capsule imme- 

Peduto et al. 

diately above the diverging popliteus tendon. 

In this region the popliteus tendon widened 

and formed a broad aponeurotic attachment 

with the posterior capsule, anchoring the 

posterior horn of the lateral meniscus to the 

popliteus muscle via the posterosuperior 

popliteomeniscal fascicle and capsule. The 

posterosuperior popliteomeniscal fascicle 

A B 

Fig. 4—Attachment of medial aponeurosis to posterior cruciate ligament. 

A, Axial T1-weighted MR arthrographic image shows inferomedial extension from medial aponeurosis to 

inferolateral aspect (arrows) of posterior cruciate ligament (PCL). 

B, Axial section of different specimen from A with traction on medial aponeurotic extension of popliteus 

muscle–tendon unit shows attachment to posterior cruciate ligament (arrows). POP = popliteus tendon. 

A 

C 

was uniform in thickness in all 10 of the 

specimens and was categorized as thick. 

A broad medial aponeurotic expansion from 

the medial aspect of the musculotendinous 

region of the popliteus tendon was identified 

in all 10 specimens (Fig. 3). From the medial 

aponeurosis an attachment to the inferior margin 

of the posterior horn of lateral meniscus 

was seen that corresponded to the anatomic 

descriptions by Terry and LaPrade [15] of 

the third, or posteroinferior, popliteomeniscal 

fascicle. The posteroinferior popliteomeniscal 

fascicle was seen on MR arthrographic images 

of four of 10 knee specimens (Fig. 3). 

All four posteroinferior popliteomeniscal 

fascicles identified were categorized as thick 

on measurement. 

Additional attachments of the medial 

aponeurosis were seen. An attachment to the 

posterior joint capsule was seen on MR arthrographic 

images of eight of the 10 knees. 

A deeper extension to the inferolateral aspect 

of the posterior cruciate ligament was found 

in seven of the 10 specimens (Fig. 4). A focal 

thickening of the medial aponeurosis coursed 

upward, where it joined the oblique popliteal 

ligament to form an inferior connection between 

the medial aponeurosis and the oblique 

popliteal ligament in seven of the 10 specimens 

(Fig. 5). In one knee in which both the 

anterior and posterior meniscofemoral ligaments 

were present, the medial aponeurotic 

extension from the popliteus musculotendinous 

region extended medially to form the 

posterior meniscofemoral ligament of Wrisberg 

(Fig. 5). In this knee, the anterior meniscofemoral 

ligament of Humphry had a 

normal attachment to the posterior horn of 

the lateral meniscus. 

discussion 

There has been increasing interest in the 

meniscocapsular attachments of the popliteus 

Fig. 5—Medial aponeurosis attachments of 

cadaver specimen. Series of axial T1-weighted MR 

arthrographic images from inferior (A) to superior (D) 

aspects. PCL = posterior cruciate ligament. 

A, MR arthrographic image shows relation between 

popliteus tendon (POP) and medial aponeurosis 

(arrowheads). Medial attachments to posterior 

capsule (large arrow) and ligament of Wrisberg (small 

arrow) extend from medial aponeurosis. LM = lateral 

meniscus. 

B–D, Successive superior MR arthrographic images 

show Wrisberg extension (short arrows) of medial 

aponeurosis can be followed upward. Upward 

extension of medial aponeurosis (arrowheads) 

forms inferior connection with oblique popliteal 

ligament (long arrows, D). Asterisk (B and C) indicates 

meniscofemoral ligament of Humphry. 

446 AJR:190, February 2008 

B 

d

muscle–tendon complex. These attachments 

not only are important in allowing the tendon 

to pass through the joint capsule to assume an 

extraarticular location but also act in concert 

with the popliteus complex to retract the lateral 

meniscus from the joint during knee flexion 

to prevent excessive meniscal shearing 

forces and entrapment [8–10]. A number of 

studies [3, 9] have shown a relatively high 

prevalence of disruption of the popliteomeniscal 

fascicle at arthroscopic surgery on patients 

with anterior cruciate ligament tears. 

In this series, the anteroinferior and posterosuperior 

popliteomeniscal fascicles were 

seen on all MR arthrographic studies. In comparison, 

Feipel et al. [14] found the anteroinferior 

popliteomeniscal fascicle in 83% and the 

posterosuperior popliteomeniscal fascicle in 

90% of dissections of 42 embalmed knee 

specimens. Terry and LaPrade [15] and Stäubli 

and Birrer [3] described the presence of 

these fascicles in their studies of 30 and 14 

fresh cadavers, but they did not discuss how 

frequently the fascicles were seen in the specimens. 

In arthroscopic studies [3, 15, 18], the 

anteroinferior and posterosuperior popliteomeniscal 

fascicles have been reported to be 

present in nearly all patients examined. Tria et 

al. [19], unlike most other investigators, found 

fascicular attachments to the lateral meniscus 

in only 22 of 40 knee dissections. 

In our study, unlike the posterosuperior 

popliteomeniscal fascicle, which had uniform 

thickness, the anteroinferior popliteomeniscal 

fascicle had variable thickness, ranging from a 

thin membrane-like structure to a much more 

robust structure. Bozkurt et al. [20] described 

a lateral meniscofibular ligament that appeared 

to correspond to the anatomic description of 

the anteroinferior popliteomeniscal fascicle in 

all 50 specimens examined by microdissection 

and transillumination. We found the lateral 

portion of the anteroinferior popliteomeniscal 

fascicle passed downward and in a lateral 

direction to form a conjoined attachment 

with the popliteofibular ligament at the fibular 

styloid process, resulting in a connection between 

the lateral aspect of the body of the lateral 

meniscus and the styloid process of the 

fibula that matched the description of a meniscofibular 

ligament by Bozkurt et al. 

Terry and LaPrade [15] described a third 

popliteomeniscal fascicle designated the 

posteroinferior popliteomeniscal fascicle, 

which extended from the medial aponeurotic 

extension of the popliteus tendon to attach to 

the inferior margin of the posterior horn of 

the lateral meniscus. The posteroinferior 


popliteomeniscal fascicle was seen in 40% 

of the knees in our study compared with 17% 

of those studied by Feipel et al. [14]. Ullrich 

et al. [16] found a third popliteomeniscal fascicle 

in their dissections of 13 fresh knees, 

but the frequency of the finding of a posteroinferior 

popliteomeniscal fascicle was not 

stated. Inconsistencies in descriptions of the 

third popliteomeniscal fascicle and doubts 

about its existence may relate to studies concentrated 

solely on the popliteal hiatus region 

without consideration of the more medially 

located capsular aponeurotic extension from 

the popliteus tendon and its complex posteromedial 

attachments. Last [17], in a report 

on the popliteus complex in 1950, described 

the broad medial aponeurotic extension from 

the medial portion of the popliteus muscle 

with a prominent attachment to the inferior 

margin of the posterior horn of the lateral 

meniscus. This description corresponds to 

other descriptions of the posteroinferior 

popliteomeniscal fascicle. 

The medial aponeurotic extension of the 

popliteus muscle appears to be an important 

structural element of the popliteus complex. In 

addition to blending with the posterior capsule, 

this extension forms an inferior connection 

with the popliteal oblique ligament, sends attachments 

to the posterior cruciate ligament 

and posterior horn of the lateral meniscus 

(posteroinferior popliteomeniscal fascicle), 

and in some individuals gives origin to a variant 

of the ligament of Wrisberg. Thus the popliteus 

muscle–tendon complex has attachments 

that form a robust-appearing cruciate arrangement: 

a superior attachment to the femur at the 

popliteal sulcus, an inferior triangular attachment 

of the main muscle bulk to the posterior 

aspect of the tibia, a robust inferolateral attachment 

to the fibular styloid process via the 

popliteofibular ligament, and several complex 

superomedial attachments to the joint capsule, 

lateral meniscus, oblique popliteal ligament, 

and ligament of Wrisberg. The importance of 

the popliteus muscle–tendon unit is highlighted 

by these robust-appearing attachments and 

by study findings [16, 21, 22] of dynamic and 

static functions that include balancing and 

controlling neutral tibial rotation, acting as a 

principal dorsolateral knee stabilizer, and preventing 

lateral meniscal entrapment during 

knee flexion by retraction of the meniscus 

via popliteomeniscal fascicle attachments. 

Limitations of this study included the relatively 

small number of specimens, allowing 

only limited comment on the frequency of 

variations in the attachments of the popliteus 

complex. In addition, the cadavers were those 

of elderly persons (average age at death, 85 

years). In most specimens, moderate degenerative 

joint disease was present, with variable 

areas of articular surface wear and meniscal 

degeneration or tearing. These changes might 

have affected visualization of structures on 

MR arthrographic images. Ligament, capsular, 

and fascicular degenerative changes might 

also have contributed to variability in the appearance 

of these structures with resultant 

adaptive thickening or attenuation. No history 

of knee injury or surgery was evident in any of 

the knee specimens, but untreated or unreported 

injury cannot be excluded. 

Arthrographic fluid in the joints provided 

excellent joint distention and optimized visualization 

of the popliteomeniscal fascicles, 

but this technique is not part of routine MRI 

of the knee. In the absence of substantial 

joint effusion or hemarthrosis, it is unlikely 

that visualization of the popliteomeniscal 

fascicles will be as optimal in nonarthrographic 

studies of the knee. Hemarthrosis is 

a common finding in patients with acute tear 

of the anterior cruciate ligament, who have 

been found to be at particular risk of popliteomeniscal 

fascicle tears [3, 9]. Sakai et al. 

[7] used an optimized oblique coronal plane 

in combination with nonarthrographic MRI 

and found the anteroinferior popliteomeniscal 

fascicle in 94.1% and the posterosuperior 

popliteomeniscal fascicle in 88.2% of subjects. 

We used all three orthogonal MR arthrographic 

imaging planes in analysis and 

did not assess the visibility of the popliteomeniscal 

fascicles in individual imaging 

planes. Our impression, however, was that 

the popliteomeniscal fascicles were best seen 

on sagittal MR arthrographic images. 

We studied the normal MRI anatomic features 

of the popliteomeniscal fascicles and 

found three fascicles. The third, or posteroinferior, 

popliteomeniscal fascicle was located 

medial in relation to the popliteal hiatus and 

arose from a medial aponeurotic extension of 

the popliteus musculotendinous region, which 

had additional capsular, oblique popliteal ligament, 

posterior cruciate, and ligament of 

Wrisberg attachments. These extensive attachments, 

combined with femoral, tibial, and 

fibular attachments, highlight the important 

role of the popliteus muscle–tendon unit in the 

posterolateral corner of the knee. 

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