Dynamics of the Foot in Locomotion

Transcription

1 Continuing Dynamics of the Foot in Locomotion A new way of looking at functional dynamics. ORTHOTICS & BIOMECHANICS Objectives After reading this article, the podiatric physician should be able to: 1) Review functional anatomy. 2) Identify the functional compartments of the foot. 3) Describe the compartments function in the process of locomotion. 4) Describe the stabilizing effect of fibrous connective tissue. 5) Identify areas of possible desmopathy. 6) Introduce a method to quantify sagittal plane desmopathy. Welcome to Podiatry Management s CME Instructional program. Our journal has been approved as a sponsor of Continuing by the Council on Podiatric. You may enroll: 1) on a per issue basis (at $15 per topic) or 2) per year, for the special introductory rate of $99 (you save $51). You may submit the answer sheet, along with the other information requested, via mail, fax, or phone. In the near future, you may be able to submit via the Internet. If you correctly answer seventy (70%) of the questions correctly, you will receive a certificate attesting to your earned credits. You will also receive a record of any incorrectly answered questions. If you score less than 70%, you can retake the test at no additional cost. A list of states currently honoring CPME approved credits is listed on pg Other than those entities currently accepting CPME-approved credit, Podiatry Management cannot guarantee that these CME credits will be acceptable by any state licensing agency, hospital, managed care organization or other entity. PM will, however, use its best efforts to ensure the widest acceptance of this program possible. This instructional CME program is designed to supplement, NOT replace, existing CME seminars. The goal of this program is to advance the knowledge of practicing podiatrists. We will endeavor to publish high quality manuscripts by noted authors and researchers. If you have any questions or comments about this program, you can write or call us at: Podiatry Management, P.O. Box 490, East Islip, NY 11730, (631) or us at bblock@prodigy.net. Following this article, an answer sheet and full set of instructions are provided (p. 136). Editor By Jack B. Glick, D.P.M., M.S. Introduction This monograph presents a new dimension in the functional foot. Anatomists, biomechanists, physiologists, kinesiologists and podiatrists have well documented the normal and abnormal joint motions in the frontal plane. Combining what has been written with personal observation, deductive logic, and reverse engineering, we will describe normal and abnormal motions in the sagittal plane. We will begin with some definitions to ensure we are speaking with the same terminology. We will propose a new paradigm for the functional rela- Continued on page 96 SEPTEMBER 2001 PODIATRY MANAGEMENT 95

2 Locomotion... bones in the distal row. The metatarsus is the five metatarsal bones in front of the tarsus. The transverse arch or metatarsal arch is composed of the navicular, the cuboid, the three cuneiforms and the five metatarsals. Ligaments bind the osseous structures together to form a semi-rigid articulating complex for a functional foot. The upper ankle ligaments (the anterior, posterior and interosseus tibiofibular ligaments) form a movable articulation by embracing the talar body. The lower ankle joint (subtalar, talocalca- Continued on page 97 tionships in the foot. We will conclude with an introduction to sagittal plane foot pathology. Continuing Functional Anatomy Overview By definition, the longitudinal arch of the foot is comprised of the medial part and the lateral part. The pars medialis is composed of the calcaneus, talus, navicular, the three cuneiforms, and the three medial metatarsals. The lateral part is made up of the calcaneus, cuboid and the lateral two metatarsals. The bony tarsus consists of the talus, calcaneus and Ligaments bind the osseous structures together to form a semi-rigid articulating complex for a functional foot. navicular in the proximal row; and the cuboid and lateral, intermediate and medial cuneiform DEFINITIONS From Dorland s Medical Dictionary; 27th Edition TERM dynamic dynamics mechanics static statics tarsus osseus metaenergy force arch arcus pedis longitudinalis arcus pedis transversalis pars DEFINITION (di-nam ik) [Gr. dynamispower] pertaining to or manifesting force (di-nam iks) that phase of mechanics which deals with the motions of material bodies taking place under different specific conditions. (me-kan iks) the science dealing with the motions of material bodies, including kinematics, dynamics and statics. (stat ik) [Gr. staticoscausing to stand, from histanai to cause to stand] 1. at rest; in equilibrium; not in motion. 2. not dynamic. 3. a word termination, meaning inhibiting, or denoting an agent that inhibits. (stat iks) that phase of mechanics which deals with the action of forces and systems of forces on bodies at rest. the seven bones constituting the articulation between the foot and the leg; the talus, calcaneus and navicular in the proximal row; and the cuboid and lateral, intermediate and medial cuneiform bones in the distal row. Also called bony tarsus. [Gr. meta after, beyond, over] a prefix indicating after or next. (en er-je) [Gr. energeia] the capacity to operate or work; the power to produce motion, to overcome resistance, and to effect physical changes. (fors) [L. fortisstrong] energy, or power; that which originates or arrests motion. (arch) [L. arcus bow] a structure with a curved or bowlike outline; also arcus. [NA] the longitudinal arch of the foot, comprising the pars medialis {medial arch} and the pars lateralis {lateral arch}. [NA] transverse arch of the foot; the metatarsal arch of the foot, formed by the navicular, cuneiforms, cuboid and the five metatarsals. (parz) pl. par tes[l.] a division or part; a general term for a particular portion of a larger area, organ or structure 96 PODIATRY MANAGEMENT SEPTEMBER

3 Locomotion... neonavicular) is firmly joined to the tibiofibular complex (upper ankle joint). The talus is tied to the fibula anteriorly and posteriorly and to the tibia medially. The calcaneus is secured to the fibula laterally and to the tibia medially. The anterior anchoring of the tibia to the talus and navicular is of lesser extent than the medial and lateral ligaments. The talocalcaneonavicular ligaments bind this complex as a functional unit moving around the talus. The extracapsular ligaments of the sinus tarsi and the tarsal canal are the major elements guiding the movement of the calcaneonavicular structure around the talus. Of the three calcaneocuboid ligaments, the inferior is probably the most important. The inferior calcaneocuboid ligament is thick, powerful, and longitudinally oriented. After it passes over the calcaneocuboid joint it divides into two sets of fibers, deep and superficial. The deep or short plantar ligament inserts on the cuboid and the superficial or long plantar ligament divides into four slips and inserts on the bases of the lesser metatarsals (2-5). There are three cuneocuboid ligaments: dorsal, plantar and interosseus. There are two dorsal, two interosseus and one plantar intercuneiform ligaments. The tarsometatarsal joint (Lisfranc s joint) is linked with seven dorsal ligaments and three sets of interosseus ligaments corresponding to the first, second, and third cuneometatarsal spaces. The first interosseus cuneometatarsal ligament (Lisfranc s ligament) is the strongest. The plantar cuneometatarsal ligaments emanating from cuneiform 1 are always present. There is no cuneiform2- metatarsal2 plantar ligament. Plantar ligaments on the lateral aspect of Lisfranc s joint (cuneiform3, cuboid, metatarsals3,4,5) are present only about 50% of the time. The intermetatarsal ligaments are dorsal, plantar and interosseus. The dorsal ligaments are small and weak and between metatarsals 2,3 and 3,4 and 4,5. The plantar ligaments have the same distribution, but are a little stronger. The three interosseus liga- The three interosseus ligaments are very short and strong for intermetatarsal stability. Continuing ments are very short and strong for intermetatarsal stability. The phalangeal apparatus and the associated ligaments and articulations of the ball of the foot will not be addressed. The muscles are the motors controlling the movement of a joint or joints and the speed of those movements. The action of a muscle is determined by the position of the tendon relative to the axis of the joint motion. The motor unit may act from either end, proximal or distal. If the distal end is fixed, the proximal lever arm is displaced. If the proximal end is fixed the distal segment is displaced. In a multisegmented system, all the joints crossed by a tendon are subjected to its action. At the ankle, the plantar flexors are the triceps surae, flexor hallucis longus, flexor digitorum longus, tibialis posterior, peroneus longus, and the peroneus brevis. When the foot is planted on the ground, these motors rotate the leg posteriorly. The dorsiflexors at the ankle are the tibialis anterior, extensor digitorum longus, extensor hallucis longus and the peroneus tertius. With the foot fixed on a surface these muscles ro- Continued on page 98 Circle #10 SEPTEMBER 2001 PODIATRY MANAGEMENT 97

4 tate the leg anteriorly. At the subtalar and midtarsal joints, the invertors are the triceps surae, tibialis posterior, flexor digitorum longus, flexor hallucis longus and tibialis anterior. Continuing Locomotion... Raw nerve endings that respond to pain are found in the connective tissues of joints (ligaments), muscles and fascia. When the foot is fixed on the ground, these muscles rotate the leg externally. The evertors, peroneus brevis, extensor digitorum longus, peroneus tertius, extensor hallucis longus and tibialis anterior, will rotate the leg internally when the foot is firmly on the ground. The muscles of the sole of the foot, the intrinsic muscles, are usually classified in four layers; however, grouping by compartment is functionally more useful. In the medial compartment for the great toe: abductor hallucis, flexor hallucis brevis, adductor hallucis. In the central compartment for the second to fifth toes: flexor digitorum brevis, flexor accessorius, the lumbricals and the interossei. In the lateral compartment for the fifth toe: abductor digiti minimi and flexor digiti minimi brevis. These muscles assist the toes to firmly purchase the ground and relieve the tension on the plantar aponeurosis and the inferior calcaneocuboid (short and long plantar) ligament. Proprioception provides the means by which the muscles vary contractions relative to the moments of force developed in the joints. Of the two classes of proprioceptors, the enteroceptors respond to internal or deep stimuli and the exteroceptors respond to external stimuli, such as sensation and/or movement. The enteroceptors are nerve end organs located in the muscles, joints, tendons and ligaments. There are five different types and each seem to play a specific role. Muscle spindles are found in the muscle and tendons and seem to receive and send signals to quickly alter the muscle contraction strength in response to the changing moments of force, apparently bypassing the reflex arc through the spinal column. Golgi corpuscles are found in tendons and are stimulated by the stretching of the tendon. Pacinian corpuscles are found in tendons, periosteum, joint capsules, fascia and connective tissue and respond to both pressure and tension. Flower spray nerve endings are found in joint capsules and respond to stretching. Raw nerve endings that respond to pain are found in the connective tissues of joints (ligaments), muscles and fascia. The pressure and tension proprioceptors seem to adapt to a persistent stimulus by shutting down, not inducing muscle contraction. The pain receptors seem to cause a constant muscle contraction or spasm in response to constant or chronic pain stimuli. Aging, trauma and/or disease affect the cellular structure and create various levels of sensory loss which becomes evident as arthropathy, loss of muscle tone and contractility, and arthrochalaisis. Walking Cycle Speed Swing Phase Speed Stance Phase Speed Heel Strike to Foot Flat Foot Flat to Heel Rise Heel Rise to Toe Off Functional Relationships To understand the functional behavior of the foot in normal and pathologic states, we need to differentiate the functional regions and their anatomical relationships. The regions are the rearfoot or posterior and the three forefoot or anterior compartments which are joined at the midfoot. This is a skeletal depiction of the functional segments. It should be understood that the regions are conjoined by ligaments and controlled by the related neuromuscular system. The ligaments are responsible for the stability of the structure and the neuromuscular portions control the tension of the ligaments. Each functional segment may work independently in a nonweight-bearing status. When the foot is bearing the weight of the body, the regions work collectively to maintain a stable interface between the body and the surface. In static bipedal stance minimal motion is exhibited. In walking mode, the body will use all the resources available to maintain balance and ground contact. In the walking cycle, from heel strike to heel strike on the same foot and leg, the weight-bearing or stance phase constitutes 60% of the time involved and the non-weightbearing or swing phase utilizes 40%. Studies have shown the average step rate (full cycle) to be 110 cycles per minute. Calculation, then, would set the average cycle speed at second. Mining the cycle speed, we can conclude the following: Seconds Seconds Seconds Seconds Seconds Seconds The need for more or less speed will affect the average as will stride length and limb length. Physiologic disease, trauma and sensory loss will slow the cycle more significantly than the average daily conditions. The stance phase begins when the adipose heel cushion strikes the ground (heel strike). The foot descends rapidly for the ball of the foot to contact the ground Continued on page PODIATRY MANAGEMENT SEPTEMBER

5 Locomotion... (foot flat). The tibia has reached its maximum internal rotation at heel strike and begins external rotation, forcing the talocalcaneonavicular complex to pronate from a slightly supinated position. This action also moves the forefoot from its slightly inverted position to a contact position parallel to the surface or ground. As the weight of the body continues to shift from one foot to the other, the joints compact to a more rigid configuration and the ball of the foot and the toes increase their surface contact. The foot is plantigrade or in foot flat position. As the leg continues to move anteriorly and rotate externally toward the midstance position, the rearfoot is forced to pronate further. The pronation is primarily limited by the ligaments that hold the rearfoot to the leg. Stability is added through the truss mechanism of the lateral longitudinal arch. It acquires rigidity from the ground reaction compression of its convexity and the tension of the long and short plantar ligaments maintaining its concavity. The muscles of the anterolateral and anterocentral compartments relieve the tension on the truss tie, the inferior calcaneocuboid ligament, the long and short plantar ligaments. At mid stance the leg is perpendicular to the foot. The posterior functional segment has pronated to its weight-bearing neutral position, in line with the leg and perpendicular to the surface. The forefoot compartments have twisted, supinated, to accept the weight of the body and resist the forces that lower the longitudinal arch and pronate the rearfoot. The plantar aponeurosis is maximally tensed to maintain the multisegmented longitudinal arch. The long and short plantar ligaments are at maximum WEIGHT BEARING STANCE PHASE OF GAIT As the weight of the body continues to shift from one foot to the other, the joints compact to a more rigid configuration and the ball of the foot and the toes increase their surface contact. tension to maintain the arc of the tarsus. The intrinsic muscles contract to relieve the tension and the weight of the body is equally dispersed between the ball and heel of the foot. As the leg continues forward, the heel comes off the ground initiating the push off phase. The external rotation of the leg inverts the rearfoot which forces a relative increase in the forefoot s pronation twist. As the posterior component inverts, it becomes closer to the first metatarsophalangeal joint, relaxing the plantar aponeurosis. The windlass mechanism restores and increases the tension of the plantar aponeurosis to maintain the convexity of the medial longitudinal arch. The push off phase begins along t h e oblique axis of the distal end of the lateral HEEL STRIKE FOOT FLAT HEEL RISE PUSH OFF TOE OFF Continuing and central compartments (metatarsal heads 5 to 2) and as the leg continues forward, externally rotating, the push off moves to the transverse axis of the distal end of the central and medial compartments (metatarsal heads 1 to 2). In a slow gait, walking uphill or carrying a heavy load, push off seems to stay longer or primarily in the oblique axis of the ball of the foot. In sprinting or accelerated activities, push off is primarily in the transverse axis of the heads of the anteromedial and anterolateral segments and less time is spent in the oblique axis. As the torso and leg continue forward, the first metatarsophalangeal joint reaches maximum dorsiflexion and then begins to extend back to 0 at toe off. Toe off initiates the swing phase of the gait cycle. In swing phase the leg moves the foot forward to strike the ground with the heel and while it transitions to foot flat, the contralateral or weightbearing foot is moving from push off to toe off. Functional Stability The stability of a joint is directly affected by the integrity of the collateral, capsular ligaments. The stability of the complex, vault shaped foot mechanism depends on the integrity of the long and short plantar ligaments and the supporting plantar aponeurosis which provide the tension on the tarsus and the longitudinal arch. The stability of the cuneiform cantilever depends on the integrity of the intercuneiform and intermetatarsal ligaments. Stability of the posterior segment is achieved by the talocalcaneal interosseus and the ankle ligaments. Injury to any of these components disrupts the efficient flow of energy, force, power as the body attempts to move from place to place. Any sprain or rupture of the multiligament foot and ankle stabilizing structure allows more motion. The increased range allows the forces to accelerate and acquire more strength, predisposing Continued on page SEPTEMBER 2001 PODIATRY MANAGEMENT 99

6 Continuing Locomotion... that segment to further repetitive injury. The upper ankle, talocrural, talotibial joint is the first affected by the transition from nonweight-bearing, swing phase to weight-bearing stance phase. The talofibular mortise is holding the talus at about its neutral position near the center of the talar dome. This configuration allows some inversion/eversion movement which will increase as the foot plantar flexes toward foot flat. Heel strike compresses the talotibial, talocalcaneal, subtalar, lower ankle joint to form a semirigid tibiotalocalcaneal complex that can plantarflex and evert to a position directly under the tibia. As the talocalcaneal complex plantarflexes, the tibia is supported by the narrower portion of the talar dome which relatively increases the range of inversion/eversion of the posterior functional segment. The talar twist on the calcaneus is limited by the talocalcaneal interosseus ligament. The sole of the foot is planted on the ground as the leg continues forward and rotates externally. This forces the posterior segment to evert and plantarflex. The distal portion of the posterior segment and the proximal portion of the conjoined anterolateral segment are forced plantarward to a plantigrade or planus position. The truss mechanism, evidenced by the cuboid height from the surface, is maintained by the tension of the inferior calcaneocuboid ligament, short and long plantar ligaments. If the force creating the plantarward digression is strong enough, the plantar ligaments will strain, sprain or rupture, releasing the tension, allowing the lateral arch to collapse. If the plantar collater- al ligaments cannot resist the force, the cuboid will partially (subluxation) or completely dislocate. The plantarward digression of the posterior compartment, the cuboid and the anterolateral compartment increases the length of the lateral arch. Premidstance the posterior compartment is fixed by the gravitational forces and the extension occurs in the anterolateral compartment. Postmidstance the anterior compartments are firmly planted and the As the leg continues to move anteriorly and rotate externally toward the midstance position, the rearfoot is forced to pronate further. extension will occur in the posterior segment. At midstance, the leg is perpendicular to the foot, which is parallel to the surface. As the step continues, the leg moves anteriorly while rotating externally developing more inversion or supination of the posterior functional segment. The weight of the torso starts to shift medially in preparation for the contralateral foot and leg to transition to weight-bearing and forward progress. The heel begins to leave the surface and the gravitational or vertical forces are transmitted through the segmented cantilever arc of the cuneiforms and the corres p o n d i n g metatarsals. The stress is on the dorsal ligaments of the cuneiforms and especially Lisfranc s ligament. The ligaments may sprain as the horizontal torque combines with vertical force to rotate the anteromedial compartment, functional segment to an everted position for push off and toe off. The leg continues to rotate externally and anteriorly it raises the heel and moves the vertical The increased range allows the forces to accelerate and acquire more strength, predisposing that segment to further repetitive injury. and horizontal forces toward the ball of the foot and dorsiflexes the toes. The digital dorsiflexion creates a windlass effect on the plantar aponeurosis, increasing the tension on the longitudinal arch configuration and maintaining the transverse arch cantilever. The weight of the torso continues to shift toward the contralateral foot. All of these motions occur in less time than you can say thousand and the constant repetition intensifies the probability of recurring injury to the stabilizing ligaments and the tension relieving muscles. Ligaments are plastic, not elastic. Fibrous connective tissue will stretch as small tears appear in the fibers. The healing process does not shrink the fibers. A torn connective fiber heals in its new elongated shape. The lengthening of the ligament allows arthrochalaisis, joint hypermobility. Constant abnormal signals to the joint position and tissue stretch proprioceptors cause diminished or spasmodic muscular responses. As the motions causing the injury repeat, the lengths of the ligaments are increased and the muscle/tendon complex adjusts to the new joint position until the damage is exhibited in the resting functional relationships. The static, resting relationship of one segment to another will be the relationship position when the foot makes contact with the surface or the insole of a shoe. The amount of abnormal positioning and the functional relationships can be measured and documented. The measurements are the number of degrees a regional functional segment inclines from the transverse or horizontal plane, the plane of the surface the foot will contact. Measurement of the forefoot varus or Continued on page PODIATRY MANAGEMENT SEPTEMBER

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8 valgus positioning is in the frontal plane, with the posterior segment perpendicular to the surface. This may indicate the extent the foot will pronate to bring Continuing Locomotion... the ball of the foot in contact with the insole of the shoe. The inclination measurement of the posterior segment and the medial and lateral anterior segments is in the sagittal plane, with the vertex and one arm of the protractor in the transverse horizontal plane. The inclination of the posterior, anterolateral and anteromedial compartment segments is the amount of equinus or planus de- Measurement of the forefoot varus or valgus positioning is in the frontal plane, with the posterior segment perpendicular to the surface. formity of the rearfoot and/or the forefoot. The degree of plantigrade inclination, planus, will indicate the amount of extracapsular ligament damage, which ligaments are damaged and the amount of correction needed to straighten the functional relationships. Suggested Reading Gowitzke, B.A. and Milner, M. (1980) Understanding the Scientific Bases of Human Movement (second edition) Baltimore/London: Williams & Wilkins Inman, V.T. (1976) the Joints of the Ankle Baltimore: Williams & Wilkins Company Inman, V.T., Ralston, H.J. and Todd, F. (1981) Human Walking Baltimore/London: Williams & Wilkins Lehmkuhl, L.D. and Smith, L.K. (1983) Brunnstorm s Clinical Kinesiology (revised fourth edition) Philadelphia: F.A. Davis Company McMinn, R.M.H., Hutchings, R.T. and Logan, B.M. (1982) Color Atlas of Foot and Ankle Anatomy London: Wolfe Medical Publications, Ltd. Root, M.L., Orien, W.P. and Weed, J.H. (1977) Normal and Abnormal Function of the Foot Clinical Biomechanics-Vol. 2 Los Angeles: Clinical Biomechanics Corp. Sarrafian, S.K. (1983) Anatomy of the Foot and Ankle, Descriptive, Topographic, Functional Philadelphia: J.B. Lippincott Co. Dr. Glick is currently owner and chief researcher, AFO LAB, Beaumont, Texas. His address is jglick@afolab.com. Circle # PODIATRY MANAGEMENT SEPTEMBER

9 Continuing E X A M I N A T I O N See instructions and answer sheet on pages ) Anatomically, which of the following bones constitute the tarsus? A) Talus and Calcaneus B) Navicular and Cuboid C) Lateral, Intermediate and Medial Cuneiforms D) All of the above 2) The lower ankle joint is also known as which of the following? A) The subtalar joint B) The tibiotalar joint C) The tibiofibular joint D) None of the above 3) Which of the following is the thickest, most powerful extracapsular ligament in the foot? A) Plantar Fascia B) Lisfranc s ligament C) Inferior calcaneocuboid ligament D) Medial collateral ligaments 4) The muscles of the foot and leg contract to control the movement of a part in which direction? A) When the distal segment is fixed, the proximal lever arm is displaced B) When the proximal segment is fixed, the distal portion is displaced C) A & B D) Flexion and extension 5) The proprioceptive system triggers a response in which of the following organs? A) Brain B) Skin C) Ligaments D) Muscles 6) Septae divide the foot into how many longitudinal compartments? A) One B) Two C) Three D) Four 7) The transverse (metatarsal) arch is composed of which of the following bones? A) Navicular and cuboid B) Medial, intermediate and lateral cuneiforms C) The five metatarsals D) All of the above 8) Force is an equivalent term to which of the following? A) Energy B) Pressure C) Push D) Contraction 9) In a typical walking cycle of second duration, the push off (propulsion) phase should be how many seconds? A) 1.0 B) C) D) ) In the heel strike to foot flat portion of the gait cycle stance phase, the talocalcaneonavicular complex pronates to do which of the following? A) Create a rigid lever B) Bring the forefoot in contact with the surface C) Create a calcaneal valgus D) Create a calcaneal varus 11) In the foot flat portion of the gait cycle, which of the following limits pronation? A) Arch support B) The talonavicular ligaments C) The upper ankle ligaments D) The lower ankle ligaments 12) At mid stance, which of the following supports the weight of the body? A) Longitudinal arch B) Metatarsal arch C) Medial longitudinal arch D) Lateral longitudinal arch 13) The arc of the tarsus is maintained by which of the following? A) Navicular B) First metatarsal C) Calcaneal inclination D) Long and short plantar ligaments 14) At midstance, the weight of the body is at which of the following? A) On the heel B) On the medial arch C) Equally divided between the ball of the foot and the rearfoot D) On the first metatarsophalangeal joint 15) Push off (propulsion) phase begins right after midstance when which of the following occurs? A) Foot pronation B) Hallux hyperextension C) Calcaneal valgus D) Heel Rise (heel off) Continued on page SEPTEMBER 2001 PODIATRY MANAGEMENT 103

10 E X A M I N A T I O N (cont d) 16) Push off begins along which of the following? A) Sagittal plane of the cuboid B) Transverse plane of the calcaneocuboid C) Oblique axis of the metatarsophalangeal joints D) Transverse axis of the metatarsophalangeal joints 17) Stability of a joint is directly affected by which of the following? A) Fascia B) Muscle C) Collateral ligaments D) Nerves 18) At heel strike, which of the following restrict motion in the lower ankle joint? A) Compaction of the joint by surface reaction forces B) Intrinsic muscles C) Interosseus talocalcaneal ligament D) A & C 19) During push off, when the forefoot is fixed on the surface, the stress on the fibrous connective tissue is on which of the following? A) Anterior attachments B) Posterior attachments C) Lateral attachments D) Medial attachments 20) The static (relaxed) non-weight bearing positions of the parts of the foot may be which of the following? A) Neutral position B) The position the foot will assume in preparation for weight bearing C) Indicative of extracapsular desmopathy D) All of the above Circle #35 SEE INSTRUCTIONS AND ANSWER SHEET ON PAGES PODIATRY MANAGEMENT SEPTEMBER