The leg

The tibia, the second longest bone in the body and its companion, the fibula, are vertically oriented and articulate at both their upper and lower ends (Figs 14.1, 14.2).

Figure 14.1 Anterior aspect of the right tibia and fibula. Interosseous membrane offers stability while also allowing mobility between the two bones.

(Reproduced, with permission, from Gray’s anatomy for students, 2nd edn, 2010, Churchill Livingstone).

Figure 14.2 A: Anterior aspect of the right tibia and fibula. B: Posterior distal tibiofibular joint. C: Course of common fibular nerve, which is vulnerable at the head and neck of the fibula.

(Reproduced, with permission, from Gray’s anatomy for students, 2nd edn, 2010, Churchill Livingstone).

While the fibula has no articulation at the knee joint itself, it does indeed have a proximal articulation with the tibia on the inferior surface of the tibia’s lateral projection. Both bones are included in the ankle joint, their distal ends forming a mortise, which receives the head of the talus. The two leg bones are also connected through their entire length by the interosseous membrane, a tough, fibrous sheath that strengthens the tibiofibular syndesmosis, offers a broad surface for muscular attachment and provides separation of the anterior and posterior compartments of the leg.

The proximal tibia (described on p. 450) has (on the inferior surface of its lateral projection) a fibular facet, which faces distally and posterolaterally to receive the fibular head. This articulation comprises the proximal tibiofibular joint. While this joint does not provide a high degree of movement, dysfunctions within this joint are an important consideration when the ankle is being assessed due to the potential impact this may have on distal tibiofibular joint function, and, therefore, movements of the ankle joint.

The triangular shaft of the tibia has a medial, lateral and posterior surface, the borders of which are fairly sharply defined. The medial surface is immediately recognizable as the ‘shin’, while the interosseous border is the attachment site for the interosseous membrane. When compared to the proximal end, the distal end of the tibia, where its medial malleolus projects inferomedially, is noted to be rotated laterally (tibial torsion) about 30°, this being significantly more in Africans (Eckhoff et al 1994). The distal surface, which articulates with the talus, is concave sagittally, convex transversely and is continuous with the malleolar articular surface. The medial malleolus lies anterior and proximal to the lateral malleolus. Various ligaments (described below) and the joint capsule attach to it.

The fibula has a proximal head, a long, thin shaft and a distal projection, the lateral malleolus. The head offers a round facet, which articulates with the tibia. Like the tibia, the fibula has three borders and surfaces, the details of both being well described by Gray’s anatomy (2005). Its distal end articulates with the lateral talar surface and is joined to the tibia as a syndesmosis (fibrous union that does not directly contact) to form the ankle mortise.

Both the proximal and distal tibiofibular joints are stabilized by anterior and posterior tibiofibular ligaments. Additionally, the distal end also possesses an inferior transverse ligament and the crural tibiofibular interosseous ligament, which offer support to the distal joint, as does the interosseous membrane.

The proximal tibiofibular joint

The proximal tibiofibular joint is a synovial joint that is not directly connected with the knee joint. When the knee is flexed, this joint plays a part in rotation of the leg, allowing small degrees of supplementary abduction and adduction of the fibula (Lewit 1985) or, as Kuchera & Goodridge (1997) term it, ‘anterolateral and posteromedial glide of the fibular head’.

Greenman (1996) notes that the behavior of the fibular head is strongly influenced by the biceps femoris muscle, which attaches to it, suggesting that any dysfunction of the tibiofibular joint calls for assessment of this muscle, for length, strength and localized dysfunction (trigger points). Schiowitz (1991) notes that: ‘When evaluating or treating a fibular head dysfunction, the [practitioner] should completely examine the distal articulation as well, at the ankle joint’. Kuchera & Goodridge (1997) point out that functional movement of the distal tibiofibular joint is imperative as it allows the ankle mortise to accommodate the increased width of the posterior portion of the talus during dorsiflexion.

Proximal tibiofibular joint play

Lewit (1985) reports joint play at the proximal tibiofibular joint as involving an anteroposterior glide as well as some rotation potential of the fibular head on the tibia.

• When the tibia and ankle are externally rotated, the proximal fibular head elevates and glides (translates) anteriorly, to accommodate this movement (Kuchera & Goodridge 1997) (Fig. 14.3).

• Similarly, when the tibia and ankle are internally rotated, the proximal fibular head depresses and glides (translates) posteriorly, to accommodate this movement.

Figure 14.3 External rotation of the tibia (A) moves the distal fibula posteriorly (B) while the fibular head moves anteriorly (C). All these movements are reversed for internal rotation of the tibia (after Ward 1997).

The proximal tibiofibular joint’s role in ankle sprains

Details regarding ankle sprains are discussed on p. 512. In addition to those considerations, Kuchera & Goodridge (1997) suggest that in cases of recurrent ankle sprain, examination for fibular head dysfunction should be carried out, ‘because with trauma the physiologic, reciprocal motion [between the distal and proximal tibiofibular articulations] may not occur’.

Greenman (1996), discussing the problem of recurrent ankle sprain, suggests they ‘are difficult to treat’ and that ‘structural diagnostic findings in this population consistently show dysfunction at the proximal tibiofibular joint and dorsiflexion restrictions of the talus at the talotibial articulation’. Greenman further observes that common findings include loss of subtalar joint play, pronation of the cuboid, and weakness of the lateral compartment muscles and tibialis anterior.

• In cases involving a pronation sprain of the ankle joint, ‘the distal talofibular joint glides posteriorly and the head of the fibula glides anteriorly’.

• In cases of supination ankle sprain, ‘the distal fibula is often found to be anterior and the fibular head is posterior’ (Kuchera & Goodridge 1997).

Testing joint play and mobilizing the proximal tibiofibular joint

• The patient is supine with hip and knee flexed so that the sole of the foot is flat on the table.

• The practitioner sits so that her buttock rests on the patient’s toes, stabilizing the foot to the table.

• The head of the fibula is grasped between thumb and index finger of one hand as the other hand holds the tibia firmly, inferior to the patella.

• Care should be taken to avoid excessive pressure on the posterior aspect of the fibula head as well as its neck, as the common fibular nerve (relatively exposed) wraps around it and is vulnerable to compression (Kuchera & Goodridge 1997) (see Fig. 14.2C).

• The thumb resting on the anterior surface of the fibula should be reinforced by placing the thumb of the other hand over it.

• A movement that takes the fibular head firmly posteriorly and anteriorly, in a slightly curved manner (i.e. not quite a straight backward-and-forward movement, but more back and slightly curving inferiorly, followed by forward and slightly curving superiorly, at an angle of approximately 30° – see Fig. 14.3), determines whether there is freedom of joint glide in each direction.

• If restriction is noted in either direction, repetitive rhythmical springing of the fibula at the end of its range should restore normal joint play.

• It is worth noting that when the fibular head glides anteriorly there is automatic reciprocal movement posteriorly at the distal fibula (lateral malleolus), while posterior glide of the fibula head results in anterior movement of the distal fibula. Restrictions at the distal fibula are, therefore, likely to influence behavior proximally and vice versa.

• Petty (2006) utilizes a similar anteroposterior glide to that described above, but suggests a prone position for the posteroanterior assessment.

• The prone patient’s leg is supported proximal to the ankle on a cushion, so that the knee is in slight flexion.

• The practitioner’s thumbs are applied to the posterior aspect of the fibula head while avoiding the common fibular nerve, with fingers curved around the proximal leg to offer support for the hands as well as to stabilize the leg.

• On-and-off combined thumb pressure is applied to assess anterior glide potential of the head of the fibula.

Entrapment possibility

As observed above, care is required to avoid undue pressure on the posterior aspect of the fibula head due to neural structure proximity. Kuchera & Goodridge (1997) point out additionally that dysfunction that involves the fibular head being locked in a posteriorly translated direction ‘may cause symptoms related to entrapment neuropathy or compression of the common peroneal [fibular] nerve’ (see Box 14.9).

Box 14.9 Neural impingement and neurodynamic testing

Note: See Volume 1, Box 13.11 for additional information regarding the background to neural impingement.

Korr (1970, 1981) demonstrated that nerves transport vital biochemical substances throughout the body, constantly. The rate of axonal transport of such substances varies from 1 mm/day to several hundred mm/day, with ‘different cargoes being carried at different rates’. ‘The motor powers (for the waves of transportation) are provided by the axon itself’. Transportation is a two-way traffic, with retrograde transportation, ‘a fundamental means of communication between neurons and between neurons and non-neuronal cells’.

Korr (1981) believes this process to have an important role in maintenance of ‘the plasticity of the nervous system, serving to keep motor-neurons and muscle cells, or two synapsing neurons, mutually adapted to each other and responsive to each other’s changing circumstances’. The trophic influence of neural structures on the structural and functional characteristics of the soft tissues they supply can be shown to be vulnerable to disturbance. Korr (1981) explains:

Any factor which causes derangement of transport mechanisms in the axon, or that chronically alters the quality or quantity of the axonally transported substances, could cause the trophic influences to become detrimental. This alteration in turn would produce aberrations of structure, function, and metabolism, thereby contributing to dysfunction and disease.

Among the negative influences frequently operating on these transport mechanisms, Korr informs us, are deformations of nerves and roots, such as compression, stretching, angulation and torsion. Nerves are particularly vulnerable in their passage over highly mobile joints, through bony canals, intervertebral foramina, fascial layers and tonically contracted muscles (for example, posterior rami of spinal nerves and spinal extensor muscles).

Neurodynamic testing for and the treatment of ‘tensions’ in neural structures offer a means of dealing with some forms of pain and dysfunction.

Maitland (1986) suggested that assessment and treatment of ‘adverse mechanical tension’ (AMT) in the nervous system should be seen as a form of ‘mobilization’.

Any pathology in the mechanical interface (MI) between nerves and their surrounding tissues can produce abnormalities in nerve movement, resulting in tension on neural structures. Examples of MI dysfunction are nerve impingement by disc protrusion, osteophyte contact or carpal tunnel constriction. These problems may be regarded as mechanical in origin and symptoms will more easily be provoked by movement rather than passive testing.

Chemical or inflammatory causes of neural tension can also occur, resulting in ‘interneural fibrosis’, which leads to reduced elasticity and increased ‘tension’, which would become obvious with tension testing of these structures (see the discussion of Morton’s neuroma on p. 532). The pathophysiological changes resulting from inflammation, or from chemical damage (i.e. toxicity) lead to internal mechanical restrictions of neural structures, which are quite different from externally applied mechanical causes, such as would be produced by a disc lesion, for example.

When a neurodynamic test (see below) is positive (i.e. pain is produced by one or another element of the test – initial position alone or with ‘sensitizing’ additions) it indicates only that AMT exists somewhere in the nervous system and not that this is necessarily at the site of reported pain.

Petty (2006) suggests that in order to ‘ascertain the degree to which neural tissue is responsible for the production of the patient’s [ankle and foot] symptoms’ the tests that should be carried out are passive neck flexion, straight leg raising, passive knee flexion and slump. These tests are described below, with the exception of passive neck flexion, which is self-explanatory.

• A positive tension test is one in which the patient’s symptoms are reproduced by the test procedure and where these symptoms can be altered by variations in what are termed ‘sensitizing maneuvers’, which are used to ‘add weight to’, and confirm, the initial finding of AMT.

• Adding dorsiflexion during SLR is an example of a sensitizing maneuver.

• Precise symptom reproduction may not be possible, but the test is still possibly relevant if other abnormal symptoms are produced during the test and its accompanying sensitizing procedures. Comparison with the test findings on an opposite limb, for example, may indicate an abnormality worth exploring.

• Altered range of movement is another indicator of abnormality, whether this is noted during the initial test position or during sensitizing additions.

Variations of passive motion of the nervous system during examination and treatment

1. An increase in tension can be produced in the interneural component, where tension is being applied from both ends, so to speak, as in the ‘slump’ test (Fig. 14.45).

2. Increased tension can be produced in the extraneural component, which then produces the maximum movement of the nerve in relation to its mechanical interface (such as in straight leg raising) with the likelihood of restrictions showing up at ‘tension points’.

Figure 14.45 The slump test places the entire neural network, from pons to the feet, under tension. Note the movement pattern of nerve roots and dura mater as indicated by the arrows. Also note that as the knee moves from flexion to extension the tibial nerve moves in two directions in relation to the tibia and femur. The fibular tension point is at the head of the fibula. No neural movement occurs behind the knee or at levels C6, T6 or L4

(Butler 1994).

3. Movement of extraneural tissues in another plane can be engineered.

CAUTION: General precautions and contraindications

• Care should be taken of the spine during the ‘slump test’ if disc problems are involved or if the neck is sensitive (or the patient is prone to dizziness).

• If any area is sensitive, care should be taken not to aggravate existing conditions during performance of tests.

• If obvious neurological problems exist, special care should be taken to avoid exacerbation that vigorous or strong stretching might provoke.

• Similar precautions apply to diabetic, MS or recent surgical patients or where the area being tested is affected by circulatory deficit.

• Tests of the sort described below should be avoided if there has been recent onset or worsening of neurological signs or if there is any cauda equina or cord lesion.

Straight leg raising (SLR) test

Note: See text relating to hamstring tests (for shortness) in Chapters 10 and 12. See Figure 12.46 in particular. In Chapter 10 Box 10.5, see discussion under the subheading: Protocol for assessment of symptoms caused by nerve root or peripheral nerve dysfunction (p. 237).

The leg is raised in the sagittal plane, knee extended.

It is suggested that this test should be used in all vertebral disorders, all lower limb disorders (and some upper limb disorders) to establish the possibility of abnormal mechanical tension in the nervous system in the lower back or limb.

Sensitizing additions to SLR

• Ankle dorsiflexion (this stresses the tibial component of the sciatic nerve).

• Ankle plantarflexion plus inversion (this stresses the common fibular nerve, which may be useful with anterior shin and dorsal foot symptoms).

• Passive neck flexion.

• Increased medial hip rotation.

• Increased hip adduction.

• Altered spinal position (for example, left SLR may be ‘sensitized’ by lateral flexion to the right of the spine).

The SLR test should be performed with the addition, one at a time, of each sensitizing maneuver, in order to assess changes in symptoms, new symptoms, restrictions, etc.

The question being asked is: ‘Can the leg be raised as far, and as easily, without force, and without symptoms (new or old) appearing, when the sensitizing additions are incorporated?’

Notes on SLR test

• During the SLR test there is caudad movement of the lumbosacral nerve roots in relation to interfacing tissue (which is why there is a ‘positive’ indication of pain and limitation of leg-raising potential when SLR is performed in the presence of a prolapsed intervertebral disc).

• The tibial nerve, proximal to the knee, moves caudad (in relation to the mechanical interface) during SLR, whereas distal to the knee it moves cranially. There is no movement of the tibial nerve behind the knee itself, which is therefore known as a ‘tension point’.

• The common fibular nerve is attached firmly to the head of the fibula (another ‘tension point’).

Prone knee bend test (PKB)

• The patient is prone and the knee is flexed, taking the heel toward the buttock to assess reproduction of existing symptoms, or other abnormal symptoms, or altered range of movement (heel should approximate buttock easily). See Figure 12.18 for positioning in prone position.

• During the test, the knee of the prone patient is flexed while the hip and thigh are stabilized, which moves the nerves and roots from L2, L3, L4 and, particularly, the femoral nerve and its branches.

• If, however, the test is conducted with the patient sidelying, the hip should be maintained in extension during the test (this alternative position is thought more appropriate for identifying entrapped lateral femoral cutaneous nerve problems).

• It is obvious that the PKB test stretches rectus femoris and rotates the pelvis anteriorly, thus extending the lumbar spine, which can confuse interpretation of nerve impingement symptoms. Care should be taken to avoid this by stabilizing the pelvis or by placement of a pillow under the abdomen to support the lumbar spine. A bodyCushion™ would most ideally achieve this goal.

• Sensitizing maneuvers include (in either prone or sidelying use of the test):

• introduction of cervical flexion

• adopting the ‘slump’ position (below) – but only in the sidelying variation of the test

• hip abduction, adduction, or rotation.

The ‘slump test’

Butler (1994) regards this as the most important test in this series. It links neural and connective tissue components from the pons to the feet and requires care in performance and interpretation (Fig. 14.45). The slump test is suggested for all spinal disorders, most lower limb disorders and some upper limb disorders (those that seem to involve the nervous system).

The test involves the seated patient introducing the following sequence of movements:

• thoracic and then lumbar flexion, followed by

• cervical flexion

• knee extension

• ankle dorsiflexion

• sometimes also hip flexion (produced by either bringing the trunk forward on the hips or by increasing SLR).

Additional sensitizing movements during slump testing are achieved by changes in the terminal positions of joints. Butler (1994) gives examples.

• If the test reproduces (for example) lumbar and radiating thigh pain, a change in head position – say into slight extension – could result in total relief of these symptoms (desensitizing).

• A change in ankle and knee positions could significantly change cervical, thoracic or head pain produced by the test.

• In both instances this would confirm that AMT was operating, although the site would remain obscure.

• Trunk sidebending and rotation or even extension, hip adduction, abduction or rotation and varying neck positions are all sensitizing movements.

Cadaver studies demonstrate that neuromeningeal movement occurs in various directions, with C6, T6 and L4 intervertebral levels being regions of constant state (i.e. no movement, therefore ‘tension points’). Butler (1994) reports that many restrictions identified during the slump test may only be corrected by appropriate spinal manipulation.

It is possible for SLR to be positive (e.g. symptoms are reproduced) and the slump test negative (no symptom reproduction) and vice versa, so both should always be performed.

The following findings have been reported in research using the slump test. Mid-thoracic to T9 are painful on trunk and neck flexion in 50% of ‘normal’ individuals. The following are considered normal responses if they are symmetrical.

• Hamstring and posterior knee pain occurring with trunk and neck flexion, when the knees are extended and increasing further with ankle dorsiflexion.

• Restrictions in ankle dorsiflexion during trunk/neck flexion while the knee is in extension.

• There is a common decrease in pain noted on release of neck flexion and an increase in range of knee extension or ankle dorsiflexion on release of neck flexion.

If the patient’s symptoms are reproduced by the slump position, altered or aggravated by sensitizing movements and can be relieved by desensitizing maneuvers, the test is regarded as positive.

Butler (1994) suggests that in treating adverse mechanical tensions in the nervous system, initial stretching of the tissues associated with neural restrictions should commence well away from the site of pain in sensitive individuals and conditions. It is not within the scope of this text to detail methods for releasing abnormal tensions, except to suggest that the treatment positions are commonly a replication of the test positions (as in shortened musculature, where MET is used).

We suggest that when the protocols outlined throughout the clinical applications segments are diligently carried out, including identifying and releasing tense and shortened musculature, releasing tense, indurated, fibrotic myofascial structures using NMT or other deep tissue methods as well as deactivating trigger points, where appropriate, mobilizing joints, including those aspects of movement that are involuntary (joint play), there will almost always be an improvement in abnormal neural restrictions.

Retesting restricted tissues regularly during treatment is important, in order to see whether gains in range of motion or lessening of pain noted during AMT testing are being achieved.

The ankle joint and hindfoot

The ankle joint composes of the malleoli of the tibia and fibula, the distal surface of the tibia and the body of the talus (see Figs 14.1, 14.2, 14.4). The tibia is weight-bearing onto the head of the talus, while the fibula has very little weight-bearing responsibility, with ‘no more than 10% of the weight that comes through the femur being transmitted through the fibula’ (Levangie & Norkin 2005).

Figure 14.4 The (A) medial and (B) posterior aspects of the talus.

(Reproduced, with permission, from Gray’s anatomy for students, 2nd edn, 2010, Churchill Livingstone).

The tibiofibular component supplies three facets, which together form an almost continuously concave surface, resembling an adjustable mortise (similar to an adjustable wrench). Levangie & Norkin (2005) observe:

The proximal head of the talus is a wedge-shaped structure, wider anteriorly than posteriorly, that is held in an arch (mortise) created by the medial (tibial) and lateral (fibular) malleoli. Approximately one-third of the medial aspect of the talus is bounded by the tibial malleolus, while the lateral aspect of the talus is entirely bounded by the fibular malleolus, which is more posteriorly situated when compared to the tibial malleolus. The relative oblique axis between the malleoli results in ‘a toeing out (by about 15°) of the free foot…with dorsiflexion and toeing in, with plantarflexion’. We are reminded by Goodridge & Kuchera (1997) that this position of the free foot is important ‘when setting up manipulative techniques addressing this joint’.

The tibia rests on the proximal trochlear surface of the talus. The talus projects a long neck that ends in a rounded distal head for articulation with the navicular bone and the plantar calcaneonavicular ligament, and it offers a facet for each of the malleoli and three articulations with the calcaneus (Fig. 14.4).

The talus has no direct muscular attachments so its ligamentous structure is significant (see below). Its movements are influenced by muscular action on bones that lie above and below it (Greenman 1996). Because of the strong ligaments of the ankle, the shape of the crural concavity and the length of the lateral malleolus on the talus, joint dislocation is extremely unlikely unless accompanied by fracture.

The ankle mortise (also called talocrural, tibiotalar or talotibiofibular joint) is designed to handle enormous degrees of force. (Figs 14.5) Gray’s anatomy (1995) reports that: Compressive forces transmitted across the joint during gait reach five times body weight while tangential shear forces, the result of internally rotating muscle forces and externally rotating inertial forces associated with the body moving over the foot, may reach 80% body weight.

Figure 14.5 The ankle joint. A) The ankle joint functions as a mortise, with the tibia and fibula ‘grasping’ the talus. B) The tibia is weight-bearing while the fibula slides in relation to the tibia. C) The anterior aspect of the head of the talus ‘wedges’ between the tibia and fibula during dorsiflexion.

(Reproduced, with permission, from Gray’s anatomy for students, 2nd edn, 2010, Churchill Livingstone).

Gray’s anatomy (2005) describes the ankle joint as follows:

During dorsiflexion, the fibula and tibia spread away from each other (but only slightly) to accommodate the wider anterior aspects of the head of the talus. This malleolar gap is increased a minor amount by slight lateral rotation of the fibula and a small gliding movement at the proximal tibiofibular joint, which affects the distal joint as well. The close-packed position for this joint is full dorsiflexion where the joint is most congruent and the ligaments are taut. Its least stable position is plantarflexion, where the narrow portion of the talus fits loosely into the mortise.

Levangie & Norkin (2005) artfully describe the mortise:

Since movements of the fibula assist the foot in accommodating unstable surfaces, muscular control of the foot when it is not in full dorsiflexion is essential to stability of the structure.

The line of the joint is usually considered to be at the anterior margin of the tibia’s distal end. This can be palpated if the superficial tendons are relaxed. Along with those tendons will be found a variety of structures that are listed here in relation to the malleoli.

Anterior to the malleoli on the dorsum of the talocrural joint:

Posterior to the medial malleolus (Fig. 14.6):

Figure 14.6 The course of the neurovascular structures beneath the medial malleolus

(Reproduced, with permission, from Gray’s anatomy for students, 2nd edn, 2010, Churchill Livingstone).

Posterior to the lateral malleolus (in a groove):

The arterial blood supply to the joint is from the malleolar rami of the anterior tibial and fibular arteries. Nerve supply to the joint derives from the deep fibular and tibial nerves.

The ankle ligaments

The bones that make up the crural arch (the distal tibia and the medial and lateral malleoli) are connected to the talus by the joint capsule and powerful ligaments (Fig. 14.7ABC).

• Medial (deltoid)

• Anterior talofibular

• Posterior talofibular

• Calcaneofibular

Figure 14.7 The ligaments of the A) medial ankle B) lateral ankle and C) posterior aspect of the ankle joint

(Reproduced, with permission, from Gray’s anatomy for students, 2nd edn, 2010, Churchill Livingstone).

Medial (deltoid) ligament

This extremely powerful, medially located ligament is triangular in shape with its superior attachments on the apex as well as the anterior and posterior borders of the medial malleolus. Inferiorly it has a variety of fibers and attachments, as described by Gray’s anatomy (2005).

…the anterior (tibionavicular [fibers]) pass forwards to the navicular tuberosity and, behind this, blend with the medial margin of the plantar calcaneonavicular ligament; intermediate (tibiocalcaneal) fibers descend almost vertically to the whole length of the sustentaculum tali; posterior fibers (posterior tibiotalar) pass posterolaterally to the medial side of the talus and its medial tubercle. The deep fibers (anterior tibiotalar) pass from the tip of the medial malleolus to the non-articular part of the medial talar surface.

Anterior talofibular ligament

This ligament attaches to the anterior margin of the lateral (fibular) malleolus from which it runs inferiorly, anteriorly and medially to attach at both the lateral articular facet of the talus and the lateral aspect of its neck.

Posterior talofibular ligament

This attaches to the lower aspect of the lateral malleolus from where it runs virtually horizontally to the lateral tubercle of the posterior talar process. Gray’s anatomy (2005) reports that: ‘A “tibial slip” of fibres connects it to the medial malleolus’.

Calcaneofibular ligament

This is ‘a long cord, [that] runs from a depression anterior to the apex of the fibular malleolus [inferiorly] to a tubercle on the lateral calcaneal surface and is crossed by the tendons of peroneus [fibularis] longus and brevis’ (Gray’s anatomy 2005).

Movements of the ankle joint

Kuchera & Goodridge (1997) suggest that the ankle joint is in fact two joints, which should be considered together as a functional unit: the talocrural joint (ankle mortise) and the subtalar joint (described below). They point to the research of Inman (1976) who showed that during the gait cycle, as weight is taken on the foot, there is ‘visible medial rotation of the tibia [that] is greater than can be attributed to movement solely at the talocrural joint’. Inman demonstrated that the increased tibial rotation resulted from ‘relative calcaneal eversion about the subtalar axis’. As the stance phase progresses the tibia then externally (laterally) rotates, at the same time as calcaneal inversion occurs, again about the subtalar axis (see Box 14.1).

The motions of the ankle joint are as follows.

• Plantarflexion (up to 50°, if motion is not isolated and includes subtalar or transverse tarsal joint excursion) achieved by soleus and gastrocnemius, assisted by plantaris, fibularis (peroneus) longus and brevis, tibialis posterior, flexor digitorum longus and flexor hallucis longus.

• Dorsiflexion (10° with knee straight, 30° with knee flexed) achieved largely by tibialis anterior, extensor digitorum longus and fibularis (peroneus) tertius, assisted by extensor hallucis longus (Schiowitz 1991, Travell & Simons 1992).

• Accessory minor motions of anterior glide with plantar flexion and posterior glide with dorsiflexion (Goodridge & Kuchera 1997).

• Additionally, Kuchera & Goodridge (1997) note that: ‘Plantar flexion is accompanied by adduction and supination of the foot….[and]…the proximal fibular head glides posteriorly and inferiorly…[and]…the talus glides anteriorly, placing the narrow position of the talus in the ankle mortise, a less stable position’.

• Although it appears to be simply a hinge, during plantarflexion it is dynamic and can shift (Gray’s anatomy 2005). Platzer (2004) notes that in plantarflexion (open-packed position), some side-to-side movement is possible.

• Stability during symmetrical standing requires continuous action by soleus, which increases during forward leaning (often involving gastrocnemius) and decreases with backward sway. If a backward movement takes the center of gravity posterior to the transverse axes of the ankle joints, the plantarflexors relax and the dorsiflexors contract (Gray’s anatomy 2005).

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

Clinical reasoning: the core of clinical practice to clinical application chapters Contextual influences: nutrition, respirationand other factors Adaptation and sport Gait analysis The knee

Stay updated, free articles. Join our Telegram channel

Join