0198-0211/91/1106-0354$03.00/0 FOOT& ANKLE Copyright 0 1991 by the American Orthopaedic Foot and Ankle Society, Inc.
The Lateral Ligamentous Support of the Subtalar Joint Marion C. Harper,* M.D. Nashville, Tennessee
LITERATURE REVIEW
ABSTRACT A review of the ligamentous structures spanning the subtalar joint laterally, as well as within the sinus and canalis tarsi, is presented based on previous descriptions and a series of anatomic dissections. Defined supporting structures are categorized into superficial, intermediate, and deep layers. Of these, the inferior extensor retinaculum is seen to be a discrete, substantial structure readily accessible for ligament reconstructions involving both the ankle and subtalar joints.
In 1944 Wood JonesJ2 provided the first detailed description in this century of the anatomy of the contents of the tarsal sinus and canal. This author emphasized the difference between the sinus tarsi and canalis tarsi and felt that the ligamentous tissue that occupied this region was derived from the lateral stem of the inferior extensor retinaculum. This stem was termed the “ligamentum frondiforme” by French anatomists, with British texts converting this to “ligamentum fundiforme.” In addition, a “discrete powerful bond” extending from the neck of the calcaneus to the neck of the talus was designated the “ligamentum cervicis” rather than the anterior interosseous ligament as had previously been done. J.W. Smith” in 1958 found three ligamentous structures within the sinus and canalis tarsi. The first was the inferior extensor retinaculum which was felt to originate from three roots. A lateral root was noted to blend into the deep fascia on the lateral aspect of the foot; a larger intermediate root descended to the calcaneal floor of the sinus tarsi with a slender medial root inclining into the canalis tarsi before being attached to the calcaneus. The second constant structure in the anterior sinus tarsi was the cervical ligament described as a broad flattened band lying anterior to the intermediate root of the retinaculum. A third ligament consistently present was termed the ligament of the canalis tarsi. This was noted to be a broad band, flattened in the coronal plane extending downwards and laterally from the sulcus tali to the sulcus calcanei, intervening between the talocalcaneal and talocalcaneonavicular joints. Last’ in 1952 observed that the cervical ligament appeared to be the strongest bond between the talus and calcaneus, and that the ligament of the tarsal canal was composed of two bands diverging upward from the calcaneus to the talus. Cahil13 in 1965 again noted the presence of three lateral roots for the inferior extensor retinaculum and emphasized that the retinaculum consisted of two layers, one superficial and one deep to the extensor
INTRODUCTION
Lateral instability of the subtalar joint has come under increasing scrutiny as a cause of disability following inversion injuries of the lower e ~ t r e m i t y .There ’ ~ ~ ~ has ~ also been increasing support for using local ligamentous tissue in the surgical repair of lateral instability syndromes involving both the foot and ankle. Brostrom2 reported using a flap of the lateral talocalcaneal ligament to reconstruct the anterior talofibular ligament in the treatment of chronic ankle instability. Gould’ advocated resuturing the freshened ends of chronically torn calcaneofibular and anterior talofibular ligaments. This repair was augmented by suturing the proximal end of the torn lateral talocalcaneal ligament as well as the arching fibers of the inferior extensor retinaculum to the lateral malleolus. Although the anatomy of the ligamentous support in the sinus tarsi and canalis tarsi has been studied well, the orientation of the ligaments spanning the subtalar joint laterally is often obscure to the clinician. This may relate to the complexity of these structures as well as to some variability in the diagrammatic depictions and descriptions in the literature. It was thus elected to combine a literature review with a series of anatomic dissections in an effort to clarify the anatomy in this region. Address correspondence and requests for reprints to Marion C. Harper, M.D., Department of Orthopaedics and Rehabilitation, Vanderbilt University Medical Center, Nashville, TN 37232-2550. 354
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LIGAMENTOUS SUPPORT
foot & Ank/e/Vol. 1 7 , No. 6/June 1991
OF THE SUBTALAR JOINT
355
peripheral were the lateral and posterior talocalcaneal which were felt to be weak and function as reinforcements for the stronger ankle ligaments. The central ligaments were the retinacular and cervical in the sinus tarsi and the ligament of the tarsal canal which was divided into anterior and posterior parts.
Talus
ANATOMIC DISSECTIONS
1
Calcaneus
1
Ten fresh or fresh frozen lower extremities were dissected as regards the lateral ankle and hindfoot. Germane to this discussion is the understanding that the inferior extensor retinaculum dorsally consists of two layers, one superficial and one deep to the extensor tendons (Fig. 1). The superficial layer of the inferior extensor retinaculum was seen as a condensation of the fascia enveloping the foot and ankle. This layer was noted to insert on the lateral aspect of the anteriorsuperior process of the calcaneus (Fig. 2) as the lateral root of the extensor retinaculum. Removal of the peroneal retinaculum and peroneal tendons revealed the obliquely oriented calcaneofibular ligament crossing the posterior facet of the subtalar joint (Fig. 2). At this same level of dissection, a structure consistent with the lateral talocalcaneal ligament was usually found although significant variability was noted in its appearance. This appearance varied from that of a discrete ligament several millimeters in width to no definite ligament per se being identifiable. In the latter instance, an anterior portion of the fibers of the calcaneofibular ligament was noted to attach to the talus rather than the fibula (Fig. 2). In general, the lateral talocalcaneal ligament was found to be relatively narrow, thin, parallel with, and slightly anterior to the larger calcaneofibular ligament (Fig. 3). Its anterior fibers were noted to consistently insert onto the talus adjacent to the inferior fibers of
Fig. 1. A, Ligaments of the sinus and canalis tarsi: a, lateral retinacular root. b, intermediate retinacular root. c, medial retinacular root. d, cervical ligament. e, ligament of tarsal canal. (after Schmidt’). 6, Calcaneal attachments of ligaments depicted in 1A. (after Schmidt’).
tendons. The intermediate and medial roots were derived from the deep layer and the medial root was noted to commonly insert into both the talus and calcaneus in common with the ligament of the tarsal canal. The cervical ligament was also felt to be significantly larger in cross-sectional area than the ligament of the tarsal canal. Schmidtg in 1978 clearly defined five distinct ligaments within the sinus and canalis tarsi. These were the lateral, intermediate, and medial roots of the inferior extensor retinaculum, the cervical ligament, and the ligament of the tarsal canal (Fig. 1). Finally, Viladot et al.” in 1984 divided the ligaments of the subtalar joint into peripheral and central. The
Fig. 2. Superficiallayer of inferior extensor retinaculum(large arrow) and calcaneofibular ligament (small arrow). Note attachment of anterior fibers of calcaneofibular ligament to talus.
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Fig. 3. Calcaneofibular ligament (large arrow), lateral talocalcaneal ligament (intermediatearrow), and anterior talofibular ligament (small arrow).
the anterior talofibular ligament. This group of three ligaments, i.e., the lateral root of the extensor retinaculum, the calcaneofibular ligament, and the lateral talocalcaneal ligament, appeared to constitute the most superficial lateral ligamentous support for the subtalar joint. The superficial layer of the inferior extensor retinaculum was divided dorsally over the tendons of the extensor digitorum longus and reflected laterally, following which two additional ligamentous structures became apparent slightly depper in the sinus tarsi. The first encountered was one root of the deep layer of the inferior extensor retinaculum as it continued laterally from beneath the extensor tendons (Fig. 4). This layer, which has been termed the intermediate root Of the retinaculum, although of moderate thickness and width, usually appeared less strong than the previously described lateral root of the superficial retinaculum. Slightly anterior to the intermediate root was the relatively thick cervical ligament passing from the neck of the calcaneus to the neck of the talus (Fig. 5). These two ligaments appeared to make up an intermediate layer of ligamentous support. Deeper within the sinus tarsi, another more medial root of the deep layer of the retinaculum (Fig. 6) was noted to course into the canalis tarsi. In the majority of specimens it appeared to attach to both talus and calcaneus in conjunction with the ligament of the canalis tarsi or, as commonly termed, the talocalcaneal interosseous ligament. The lateral extent of the talocalcaneal interosseous ligament is visible at the mouth of the canalis tarsi (Fig. 7), although the bulk of its fiber cross the midline deep within the medial aspect of the canal between the talocakaneal and talocalcaneonavicular joints. The full extent of these fibers, which are
Fig. 4. Intermediateroot (large arrow) ot interior extensor retinaculum as an extension of deep retinacular layer following reflection of superficial retinaculum (small arrow).
Fig. 5. Cervical ligament (large arrow). Both superficial and deep retinacular layers (small arrows) have been reflected.
Fig. 6. Medial root (large arrow) and intermediate root (small arrow) of inferior extensor retinaculum.
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Foot & Ankle/Vol. 1 1, No. 6/June 199 1
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TABLE 1 Lateral Ligamentous Support of the Subtalar Joint
Superficial layer Lateral root of inferior extensor retinaculum Lateral talocalcaneal ligament Calcaneofibular ligament Intermediatelayer Intermediateroot of inferior extensor retinaculum Cervical ligament Deep layer Medial root of inferior extensor retinaculum lnterosseous talocalcaneal liqament
I Fig. 7. Ligament of the tarsal canal or interosseous talocalcaneal ligament (large arrow). Deep layer of inferior extensor retinaculum (small arrow) reflected anteriorly.
oriented obliquely, is only seen following removal of the posterior talus or in association with progressive division of this ligament and dislocation of the subtalar joint. These two final structures can be considered to compose the deep layer of ligamentous tissue within the sinus and canalis tarsi supporting the subtalar joint.
nterior Talofibular
Calcaneof ibular
DISCUSSION
The subtalar joint appears complex in its osseous configuration, ligamentous support, and motion. As a prelude to better understanding both normal and abnormal function, the anatomy in this region should be appreciated well. A consensus regarding the discrete ligaments spanning the subtalar joint lateral, as well as within the sinus and canalis tarsi, emerges from a review of the literature. This consensus appears to have been largely confirmed by this anatomic study. In addition, these structures have been categorized into three groups (superficial,intermediate, and deep) (Table 1) in an effort to make their orientation more clear. As regards the feasibility of using these local structures in the surgical stabilization of ankle and subtalar instability, several observations are pertinent. First, the superficial layer of the inferior extensor retinaculum consistentcly appeared to be a thick, strong, welldefined layer readily accessible for repairs in this area. This structure may be mobilized superiorly as described by G ~ u l dor . ~partially detached dorsally and reoriented as a flap with suture of the proximal end of this flap to the ligamentous tissue adjacent to the fibula (Fig. 8) or to the fibula itself. This reconstruction would thus attempt to fashion a second calcaneofibular ligament oriented so as to oppose inversion of the hindfoot particularly with the ankle in plantarflexion. Such a reconstruction would appear to be potentially valuable
3 Lateral Talocalcaneal
Fig. 8. Ligament reconstruction using flap of superficial layer of inferior extensor retinaculum.
in treating lateral instability syndromes involving either the ankle or subtalar joint or both. A second observation is that the lateral talocalcaneal ligament in these dissections often appeared relatively small and ill-defined and thus poorly suited for an ankle or subtalar reconstruction. The retinaculum with its multiple stout lateral roots would appear to be a better choice.
REFERENCES
1. Brantigan, J.W., Pedegana, L.R., and Lippert, F.G.: Instability of the subtalar joint: Diagnosis by stress tomography in three cases. J. Bone Joint Surg., 59A:321-324, 1977. 2. Brostrom, L.: Sprained ankles. VI. Surgical treatment of "chronic" ligament ruptures. Acta Chir. Scand., 132:551-565, 1966. 3. Cahill, D.R.: The anatomy and function of the contents of the human tarsal sinus and canal. Anat. Rec., 153:l-17. 1965. 4. Clanton, T.O.: Instability of the subtalar joint. Orthop. Clin. North Am., 20(4):583-592, 1989. 5. Gould, N.: Repair of lateral ligament of ankle. Foot Ankle, 8(1):55-58, 1987.
Downloaded from fai.sagepub.com at CARLETON UNIV on June 15, 2015
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HARPER
6. Gould, N., Seligson, D., and Gassman, J.: Early and late repair of lateral ligament of the ankle. Foot Ankle, 1:84-89, 1980. 7. Last, R.J.: Specimens from the Hunterian Collections. 7. The subtalar joint (specimens S 100 1 and S 100 2). J. Bone Joint Surg., 349:116-119, 1952. 8. Meyer, J.M., Garcia, J., Hoffmeyer, P., et al.: The subtalar sprain. A roentgenographic study. Clin. Orthop., 226:169-173, 1988.
9. Schmidt, H.M.: Shape and fixation of band systems in human sinus and canalis tarsi. Acta Anat., 102:184-194, 1978. 10. Smith, J.W.: The ligamentous structures in the canalis and sinus tarsi. J. Anat., 92:616-620, 1958. 11. Viladot, A., Lorenro, J.C., Salarar, J., et al.: The subtalar joint: embryology and morphology. Foot Ankle, 554-66, 1984. 12. Wood Jones, F.: The talocalcaneal articulation. Lancet, 24:241242.1944.
Downloaded from fai.sagepub.com at CARLETON UNIV on June 15, 2015
The Lateral Ligamentous Support of the Subtalar Joint Marion C. Harper,* M.D. Nashville, Tennessee
LITERATURE REVIEW
ABSTRACT A review of the ligamentous structures spanning the subtalar joint laterally, as well as within the sinus and canalis tarsi, is presented based on previous descriptions and a series of anatomic dissections. Defined supporting structures are categorized into superficial, intermediate, and deep layers. Of these, the inferior extensor retinaculum is seen to be a discrete, substantial structure readily accessible for ligament reconstructions involving both the ankle and subtalar joints.
In 1944 Wood JonesJ2 provided the first detailed description in this century of the anatomy of the contents of the tarsal sinus and canal. This author emphasized the difference between the sinus tarsi and canalis tarsi and felt that the ligamentous tissue that occupied this region was derived from the lateral stem of the inferior extensor retinaculum. This stem was termed the “ligamentum frondiforme” by French anatomists, with British texts converting this to “ligamentum fundiforme.” In addition, a “discrete powerful bond” extending from the neck of the calcaneus to the neck of the talus was designated the “ligamentum cervicis” rather than the anterior interosseous ligament as had previously been done. J.W. Smith” in 1958 found three ligamentous structures within the sinus and canalis tarsi. The first was the inferior extensor retinaculum which was felt to originate from three roots. A lateral root was noted to blend into the deep fascia on the lateral aspect of the foot; a larger intermediate root descended to the calcaneal floor of the sinus tarsi with a slender medial root inclining into the canalis tarsi before being attached to the calcaneus. The second constant structure in the anterior sinus tarsi was the cervical ligament described as a broad flattened band lying anterior to the intermediate root of the retinaculum. A third ligament consistently present was termed the ligament of the canalis tarsi. This was noted to be a broad band, flattened in the coronal plane extending downwards and laterally from the sulcus tali to the sulcus calcanei, intervening between the talocalcaneal and talocalcaneonavicular joints. Last’ in 1952 observed that the cervical ligament appeared to be the strongest bond between the talus and calcaneus, and that the ligament of the tarsal canal was composed of two bands diverging upward from the calcaneus to the talus. Cahil13 in 1965 again noted the presence of three lateral roots for the inferior extensor retinaculum and emphasized that the retinaculum consisted of two layers, one superficial and one deep to the extensor
INTRODUCTION
Lateral instability of the subtalar joint has come under increasing scrutiny as a cause of disability following inversion injuries of the lower e ~ t r e m i t y .There ’ ~ ~ ~ has ~ also been increasing support for using local ligamentous tissue in the surgical repair of lateral instability syndromes involving both the foot and ankle. Brostrom2 reported using a flap of the lateral talocalcaneal ligament to reconstruct the anterior talofibular ligament in the treatment of chronic ankle instability. Gould’ advocated resuturing the freshened ends of chronically torn calcaneofibular and anterior talofibular ligaments. This repair was augmented by suturing the proximal end of the torn lateral talocalcaneal ligament as well as the arching fibers of the inferior extensor retinaculum to the lateral malleolus. Although the anatomy of the ligamentous support in the sinus tarsi and canalis tarsi has been studied well, the orientation of the ligaments spanning the subtalar joint laterally is often obscure to the clinician. This may relate to the complexity of these structures as well as to some variability in the diagrammatic depictions and descriptions in the literature. It was thus elected to combine a literature review with a series of anatomic dissections in an effort to clarify the anatomy in this region. Address correspondence and requests for reprints to Marion C. Harper, M.D., Department of Orthopaedics and Rehabilitation, Vanderbilt University Medical Center, Nashville, TN 37232-2550. 354
Downloaded from fai.sagepub.com at CARLETON UNIV on June 15, 2015
LIGAMENTOUS SUPPORT
foot & Ank/e/Vol. 1 7 , No. 6/June 1991
OF THE SUBTALAR JOINT
355
peripheral were the lateral and posterior talocalcaneal which were felt to be weak and function as reinforcements for the stronger ankle ligaments. The central ligaments were the retinacular and cervical in the sinus tarsi and the ligament of the tarsal canal which was divided into anterior and posterior parts.
Talus
ANATOMIC DISSECTIONS
1
Calcaneus
1
Ten fresh or fresh frozen lower extremities were dissected as regards the lateral ankle and hindfoot. Germane to this discussion is the understanding that the inferior extensor retinaculum dorsally consists of two layers, one superficial and one deep to the extensor tendons (Fig. 1). The superficial layer of the inferior extensor retinaculum was seen as a condensation of the fascia enveloping the foot and ankle. This layer was noted to insert on the lateral aspect of the anteriorsuperior process of the calcaneus (Fig. 2) as the lateral root of the extensor retinaculum. Removal of the peroneal retinaculum and peroneal tendons revealed the obliquely oriented calcaneofibular ligament crossing the posterior facet of the subtalar joint (Fig. 2). At this same level of dissection, a structure consistent with the lateral talocalcaneal ligament was usually found although significant variability was noted in its appearance. This appearance varied from that of a discrete ligament several millimeters in width to no definite ligament per se being identifiable. In the latter instance, an anterior portion of the fibers of the calcaneofibular ligament was noted to attach to the talus rather than the fibula (Fig. 2). In general, the lateral talocalcaneal ligament was found to be relatively narrow, thin, parallel with, and slightly anterior to the larger calcaneofibular ligament (Fig. 3). Its anterior fibers were noted to consistently insert onto the talus adjacent to the inferior fibers of
Fig. 1. A, Ligaments of the sinus and canalis tarsi: a, lateral retinacular root. b, intermediate retinacular root. c, medial retinacular root. d, cervical ligament. e, ligament of tarsal canal. (after Schmidt’). 6, Calcaneal attachments of ligaments depicted in 1A. (after Schmidt’).
tendons. The intermediate and medial roots were derived from the deep layer and the medial root was noted to commonly insert into both the talus and calcaneus in common with the ligament of the tarsal canal. The cervical ligament was also felt to be significantly larger in cross-sectional area than the ligament of the tarsal canal. Schmidtg in 1978 clearly defined five distinct ligaments within the sinus and canalis tarsi. These were the lateral, intermediate, and medial roots of the inferior extensor retinaculum, the cervical ligament, and the ligament of the tarsal canal (Fig. 1). Finally, Viladot et al.” in 1984 divided the ligaments of the subtalar joint into peripheral and central. The
Fig. 2. Superficiallayer of inferior extensor retinaculum(large arrow) and calcaneofibular ligament (small arrow). Note attachment of anterior fibers of calcaneofibular ligament to talus.
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Fig. 3. Calcaneofibular ligament (large arrow), lateral talocalcaneal ligament (intermediatearrow), and anterior talofibular ligament (small arrow).
the anterior talofibular ligament. This group of three ligaments, i.e., the lateral root of the extensor retinaculum, the calcaneofibular ligament, and the lateral talocalcaneal ligament, appeared to constitute the most superficial lateral ligamentous support for the subtalar joint. The superficial layer of the inferior extensor retinaculum was divided dorsally over the tendons of the extensor digitorum longus and reflected laterally, following which two additional ligamentous structures became apparent slightly depper in the sinus tarsi. The first encountered was one root of the deep layer of the inferior extensor retinaculum as it continued laterally from beneath the extensor tendons (Fig. 4). This layer, which has been termed the intermediate root Of the retinaculum, although of moderate thickness and width, usually appeared less strong than the previously described lateral root of the superficial retinaculum. Slightly anterior to the intermediate root was the relatively thick cervical ligament passing from the neck of the calcaneus to the neck of the talus (Fig. 5). These two ligaments appeared to make up an intermediate layer of ligamentous support. Deeper within the sinus tarsi, another more medial root of the deep layer of the retinaculum (Fig. 6) was noted to course into the canalis tarsi. In the majority of specimens it appeared to attach to both talus and calcaneus in conjunction with the ligament of the canalis tarsi or, as commonly termed, the talocalcaneal interosseous ligament. The lateral extent of the talocalcaneal interosseous ligament is visible at the mouth of the canalis tarsi (Fig. 7), although the bulk of its fiber cross the midline deep within the medial aspect of the canal between the talocakaneal and talocalcaneonavicular joints. The full extent of these fibers, which are
Fig. 4. Intermediateroot (large arrow) ot interior extensor retinaculum as an extension of deep retinacular layer following reflection of superficial retinaculum (small arrow).
Fig. 5. Cervical ligament (large arrow). Both superficial and deep retinacular layers (small arrows) have been reflected.
Fig. 6. Medial root (large arrow) and intermediate root (small arrow) of inferior extensor retinaculum.
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Foot & Ankle/Vol. 1 1, No. 6/June 199 1
LIGAMENTOUS SUPPORT OF THE SUBTALAR JOINT
357
TABLE 1 Lateral Ligamentous Support of the Subtalar Joint
Superficial layer Lateral root of inferior extensor retinaculum Lateral talocalcaneal ligament Calcaneofibular ligament Intermediatelayer Intermediateroot of inferior extensor retinaculum Cervical ligament Deep layer Medial root of inferior extensor retinaculum lnterosseous talocalcaneal liqament
I Fig. 7. Ligament of the tarsal canal or interosseous talocalcaneal ligament (large arrow). Deep layer of inferior extensor retinaculum (small arrow) reflected anteriorly.
oriented obliquely, is only seen following removal of the posterior talus or in association with progressive division of this ligament and dislocation of the subtalar joint. These two final structures can be considered to compose the deep layer of ligamentous tissue within the sinus and canalis tarsi supporting the subtalar joint.
nterior Talofibular
Calcaneof ibular
DISCUSSION
The subtalar joint appears complex in its osseous configuration, ligamentous support, and motion. As a prelude to better understanding both normal and abnormal function, the anatomy in this region should be appreciated well. A consensus regarding the discrete ligaments spanning the subtalar joint lateral, as well as within the sinus and canalis tarsi, emerges from a review of the literature. This consensus appears to have been largely confirmed by this anatomic study. In addition, these structures have been categorized into three groups (superficial,intermediate, and deep) (Table 1) in an effort to make their orientation more clear. As regards the feasibility of using these local structures in the surgical stabilization of ankle and subtalar instability, several observations are pertinent. First, the superficial layer of the inferior extensor retinaculum consistentcly appeared to be a thick, strong, welldefined layer readily accessible for repairs in this area. This structure may be mobilized superiorly as described by G ~ u l dor . ~partially detached dorsally and reoriented as a flap with suture of the proximal end of this flap to the ligamentous tissue adjacent to the fibula (Fig. 8) or to the fibula itself. This reconstruction would thus attempt to fashion a second calcaneofibular ligament oriented so as to oppose inversion of the hindfoot particularly with the ankle in plantarflexion. Such a reconstruction would appear to be potentially valuable
3 Lateral Talocalcaneal
Fig. 8. Ligament reconstruction using flap of superficial layer of inferior extensor retinaculum.
in treating lateral instability syndromes involving either the ankle or subtalar joint or both. A second observation is that the lateral talocalcaneal ligament in these dissections often appeared relatively small and ill-defined and thus poorly suited for an ankle or subtalar reconstruction. The retinaculum with its multiple stout lateral roots would appear to be a better choice.
REFERENCES
1. Brantigan, J.W., Pedegana, L.R., and Lippert, F.G.: Instability of the subtalar joint: Diagnosis by stress tomography in three cases. J. Bone Joint Surg., 59A:321-324, 1977. 2. Brostrom, L.: Sprained ankles. VI. Surgical treatment of "chronic" ligament ruptures. Acta Chir. Scand., 132:551-565, 1966. 3. Cahill, D.R.: The anatomy and function of the contents of the human tarsal sinus and canal. Anat. Rec., 153:l-17. 1965. 4. Clanton, T.O.: Instability of the subtalar joint. Orthop. Clin. North Am., 20(4):583-592, 1989. 5. Gould, N.: Repair of lateral ligament of ankle. Foot Ankle, 8(1):55-58, 1987.
Downloaded from fai.sagepub.com at CARLETON UNIV on June 15, 2015
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Foot & Ankle/Vol. 11, No. 6/June 1991
HARPER
6. Gould, N., Seligson, D., and Gassman, J.: Early and late repair of lateral ligament of the ankle. Foot Ankle, 1:84-89, 1980. 7. Last, R.J.: Specimens from the Hunterian Collections. 7. The subtalar joint (specimens S 100 1 and S 100 2). J. Bone Joint Surg., 349:116-119, 1952. 8. Meyer, J.M., Garcia, J., Hoffmeyer, P., et al.: The subtalar sprain. A roentgenographic study. Clin. Orthop., 226:169-173, 1988.
9. Schmidt, H.M.: Shape and fixation of band systems in human sinus and canalis tarsi. Acta Anat., 102:184-194, 1978. 10. Smith, J.W.: The ligamentous structures in the canalis and sinus tarsi. J. Anat., 92:616-620, 1958. 11. Viladot, A., Lorenro, J.C., Salarar, J., et al.: The subtalar joint: embryology and morphology. Foot Ankle, 554-66, 1984. 12. Wood Jones, F.: The talocalcaneal articulation. Lancet, 24:241242.1944.
Downloaded from fai.sagepub.com at CARLETON UNIV on June 15, 2015
