Download Anatomy of the Anterior Talofibular Ligament

Anatomy of the Anterior Talofibular Ligament
Bader Khawaji and Roger Soames
Centre for Anatomy and Human Identification, College of Life Sciences, University of Dundee, UK
Results & Discussion 2.
Introduction
Of the lateral collateral ligaments the anterior talofibular
ligament (ATFL) is the most frequently injured (van den
Bekerom et al., 2008), being seen in approximately two thirds
of ankle sprains (Kumai et al., 2002). The morphology of the
ATFL has been investigated previously (Burks & Morgan, 1994,
Milner & Soames, 1997), however there is disagreement about
the number of the ATFL bands (Golano et al., 2010). In addition,
the ATFL bands were not studied separately under different
positions of the ankle joint.
Aims
The aims of this study were: (1) study the anatomy and
morphology of the ATFL (attachments, orientation, length,
width and thickness); and (2) investigate the anatomical
variations of the ATFL.
Three
Bands,
12.9%
The superior band of the ATFL is the largest band widest band
and it is considered as the main component of the ATFL. It has
been suggested that the inferior and middle bands are the
additional bands.
One Band,
25.8%
The length of the superior band is maximum during
plantarflexion and minimum during dorsiflexion (Figure 5).
Two Bands,
61.3%
The inferior band becomes taut during plantarflexion and lax
in the neutral position of the ankle joint.
Figure 1: Number of the ATFL bands
Materials and Methods
The middle band is the smallest band of the ATFL: it is lax
during dorsiflexion becoming tense during plantarflexion.
Figure 4: Three band form of the ATFL
Band and Position
Range (mm)
Mean (mm)
Standard
Deviation
Superior (Neutral)
Superior (Dorsiflexion)
Superior (Plantarflexion)
Inferior (Neutral)
Inferior (Dorsiflexion)
Inferior (Plantarflexion)
Middle (Neutral)
Middle (Dorsiflexion)
Middle (Plantarflexion)
13.85 – 31.94
13.97 – 30.78
15.58 – 34.88
13.63 – 23.4
12.17 – 21.24
14.78 – 23.2
10.77 – 21.26
11.51 – 23.37
16.08 – 22.9
21.27
20.24
21.96
17.75
17.83
18.69
15.97
16.96
19.82
3.55
3.67
4.02
2.75
2.56
2.36
4.37
5
3.24
Conclusion
Table 1: The length of the ATFL bands under different
conditions
Thirty four feet were dissected from 17 European Caucasian
formaldehyde embalmed cadavers (11 female, 6 male; aged
68 to 98 years). The skin, fascia, muscles and tendons on the
posterior and lateral aspects of the ankle were removed and
the ATFL exposed. The number of the bands of the ATFL, their
attachments , orientation and thickness were assessed and
measured and photographs taken. Each band length was
measured using a digital calliper with the ankle positioned in
neutral, dorsiflexion and plantarflexion. The width of each
ATFL band was measured at three points: the middle and the
proximal and distal attachments.
ATFL Band
Level
Range (mm)
Mean
(mm)
Standar
d
Deviati
on
Superior band width
Proximal
Middle
Distal
Proximal
Middle
Distal
Proximal
Middle
Distal
2.38 – 8.01
1.52 – 8.89
1.07 – 7.08
2.33 – 7.6
2.21 – 6.97
1.14 – 6.85
1.76 – 2.71
1.22 – 2.82
1.46 – 2.87
0.36 – 2
0.37 – 1.98
0.49 – 1.69
4.88
4.71
3.98
4.33
4.23
3.29
2.04
2.1
1.99
1.25
0.89
0.93
1.41
1.46
1.02
1.35
1.2
1.2
0.45
0.66
0.61
0.48
0.4
0.55
Inferior band width
Middle band width
Figure 2: One band form of ATFL
Results & Discussion 1
Superior band thickness
Inferior band thickness
Middle band thickness
Table 2: Width and thickness of ATFL bands
The ATFL originates from the anterior border of the lateral
malleolus and runs anteromedially to attach to the talus. The
ligament is directed proximally during dorsiflexion and distally
during plantarflexion. One, two and three band forms of the
ATFL were observed (Figure 1).
An understanding of the anatomy and variations of the
anterior talofibular ligament will help in diagnosing and
treating ATFL injury, usually caused by ankle sprains.
A sound knowledge of ATFL variations is necessary to be able
to read MRI images in diagnosing injuries.
This study has highlighted the anatomical variation of the
ATFL, with some findings being inconsistent with previous
studies.
The bands of the ATFL were investigated separately under
different conditions (plantarflexion, neutral, dorsiflexion),
which will aid in the understanding ATFL function. The results
are encouraging: further investigation swill be conducted.
Reference:
Burks, R. T. & Morgan, J. 1994. Anatomy of the lateral ankle ligaments. The
American journal of sports medicine, 22, 72-7.
Golano, P., Vega, J., De Leeuw, P. A., Malagelada, F., Manzanares, M. C.,
Gotzens, V. & Van Dijk, C. N. 2010. Anatomy of the ankle ligaments: a
pictorial essay. Knee surgery, sports traumatology, arthroscopy : official
journal of the ESSKA, 18, 557-69.
Kumai, T., Takakura, Y., Rufai, A., Milz, S. & Benjamin, M. 2002. The
functional anatomy of the human anterior talofibular ligament in relation to
ankle sprains. Journal of anatomy, 200, 457-65.
Milner, C. E. & Soames, R. W. 1997. Anatomical variations of the anterior
talofibular ligament of the human ankle joint. Journal of anatomy, 191 ( Pt
3), 457-8.
Van Den Bekerom, M. P., Oostra, R. J., Alvarez, P. G. & Van Dijk, C. N. 2008.
The anatomy in relation to injury of the lateral collateral ligaments of the
ankle: a current concepts review. Clinical anatomy, 21, 619-26.
The one band form was seen in 25.8% of specimens (Figure 2),
with approximately two third being observed in the left foot :
all except one were unilateral. The two band form (Figure 3)
was observed in 61.3% of specimens, with approximately two
third being observed in the right foot: 47.4% were bilateral.
12.9% of the specimens were observed to have three bands
(Figure 4); 75% were associated with the right foot and were
present unilaterally.
The lengths, widths and thicknesses of the different bands of
the ATFL in all ankle positions are shown in Tables 1 and 2
respectively. The width of all bands at the proximal attachment
was larger than at the distal attachment.
The results of this study suggest that the bands of the anterior
talofibular ligament have important roles in limiting ankle
movement, particularly plantarflexion.
Figure 3: Two band form of the ATFL
Figure 5: Length of the ATFL bands under different
conditions