美国PT学校使用教材

O B J E C T I V E S After studying this chapter, the reader will be able to: 1 Identify important aspects of the structure and func- tion of the ankle and foot for review. 2 Establish a therapeutic exercise program to manage soft tissue and joint lesions in the ankle and foot re- lated to stages of recovery after an inflammatory in- sult to the tissues, recognizing unique circum- stances in the ankle and foot for their management. 3 Describe common indications and an overview of operative procedures for common soft tissue in- juries and late-stage joint disease of the ankle and foot. 4 Develop and progress therapeutic exercise interven- tions after surgical repair or reconstruction of soft tissues and joints of the ankle and foot. The joints, ligaments, and muscles of the ankle and foot are designed to provide stability as well as mobility in the terminal structures of the lower extremity. The foot must bear the body weight during standing with a minimum of muscle energy expenditure. The foot also must be able to adapt to absorb forces and accommodate to uneven surfaces, and then it must be able to become a rigid structural lever to propel the body forward during walking or running. The anatomy and kinesiology of the ankle and foot are complex, but it is important to understand and be able to apply this information to effectively treat impairments in this region of the body. The first section of this chapter reviews highlights of these areas that the reader should know and under- stand. Chapter 8 presents information on principles of management; the reader should be familiar with that material before proceeding with establishing a therapeutic exercise program for the ankle and foot. The Ankle and Foot • Review of the Structure and Function of the Ankle and Foot Bony Parts (see Figs. 6 -49 and 6-58) Leg The tibia and fibula make up the leg. These two bones are bound together by an interosseous mem- brane along the shafts of the bones, by strong ante- rior and posterior inferior tibiofibular ligaments that hold the distal tibiofibular articulation together, and by a strong capsule that encloses the proximal tibio- fibular articulation. These two bones do not rotate around each other as do the radius and ulna in the upper extremity, but there is slight movement be- tween the two bones that allows greater movement of the ankle joints. Foot The foot is divided into three segments: Hindfoot. The talus and calcaneus make up the pos- terior segment. Midfoot The navicular, cuboid, and three cunei- forms make up the middle segment. Forefoot Five metatarsals and 14 phalanges make up the anterior segment. Each toe has three pha- langes except for the large toe, which has two. Motions of the Foot and Ankle Primary Plane Motions Sagittal plane motion. Dorsiflexion is movement in a dorsal direction; plantarflexion is movement in a plantar direction around a frontal axis.11'12,55 Frontal plane motion. Inversion is turning inward and eversion is turning outward around a sagittal axis. Normally, an inward and outward motion is de- scribed by the terms abduction and adduction, but 563 5 6 4 PART II • Application of Therapeutic Exercise Techniques to Regions of the Body because the foot is at a right angle to the leg, ab- duction and adduction are not used here.11,12 Transverse plane motion. Abduction is movement away from the midline, and adduction is movement toward the midline. In the foot this motion occurs around a vertical axis.11,12'55 Triplanar Motions Occurring About Oblique Axes Triplanar motion occurs at each articulation of the ankle and foot. The definitions are descriptive of the movement of the distal bone on the proximal bone. When the proximal bone moves on the stabilized distal bone as occurs in closed-chain mechanics, the motion of the proximal bone is opposite, although the relative joint motion is the same as defined. Pronation. This is a combination of dorsiflexion, eversion, and abduction. Supination. This is a combination of plantarflexion, inversion, and adduction. Note: The terms inversion and supination, as well as ever- sion and pronation, are often interchanged.46 This text will use the terms as defined above. Joints and Their Characteristics The characteristics of each joint in the leg, ankle, and foot dictate how they contribute to their function.37'45'55'60 The Tibiofibular Joints Anatomically, the superior and inferior tibiofibular joints are separate from the ankle but provide acces- sory motions that allow greater movement at the an- kle; fusion or immobility in these joints will impair ankle function. Superior tibiofibular joint. This is a plane synovial joint made up of the fibular head and a facet on the posterolateral aspect of the rim of the tibial condyle; the facet faces posteriorly, inferiorly, and laterally. Inferior tibiofibular joint. This is a syndesmosis with fi- broadipose tissue between the two bony surfaces; it is supported by the crural tibiofibular interosseous ligament and the anterior and posterior tibiofibular ligaments. Accessory motions. With dorsiflexion and plantarflex- ion of the ankle, there are slight accessory move- ments of the fibula.25 • As the ankle plantarflexes, the lateral malleolus (fibula) rotates medially and is pulled inferiorly, and the two malleoli approximate. At the superior joint, the fibula slides inferiorly. The opposite oc- curs with dorsiflexion. • As the foot supinates, the head of the fibula slides distally and posteriorly (external rotation); with pronation, the head of the fibula slides proximally and anteriorly (internal rotation). The Ankle (Talocrural) Joint This is a synovial hinge joint supported by a struc- turally strong mortise, which is the distal articulat- ing surfaces of the tibia and tibial and fibular malle- oli. The tibia and fibula are held together by an interosseous membrane and by the anterior and pos- terior talofibular ligaments. The ankle, along with the subtalar joint, is supported medially by the del- toid ligament and laterally by the anterior and pos- terior talofibular and calcaneofibular ligaments. • The concave articulating surface is the mortise. The fibular malleolus extends farther distally and posteriorly than the tibial malleolus so that the mortise angles outward and downward. This causes the axis of motion to be rotated laterally 20 to 30 degrees and inclined downward 10 de- grees. The surface of the mortise is congruent with the articulating surface of the body of the talus. • The convex articulating surface is the body of the talus. The surface is wedge-shaped, being wider anteriorly, and is also cone-shaped, with the apex pointing medially. • As a result of the orientation of the axis and shape of the talus when the foot dorsiflexes, the talus also abducts and slightly everts (pronation); when the foot plantarflexes, the talus also adducts and slightly inverts (supination). With physiologic motions of the foot, the articulating surface of the talus slides in the opposite direc- tion (Box 14-1). Subtalar (Talocalcaneal) Joint This is a uniaxial joint with an oblique axis of mo- tion lying approximately 42 degrees from the trans- verse plane and 16 degrees from the sagittal plane, which allows the calcaneus to pronate and supinate in a triplanar motion on the talus. Frontal plane in- version (turning heel inward) and eversion (turning heel outward) can be isolated only with passive mo- tion. The subtalar joint is supported by the medial CHAPTER 14 • The Ankle and Foot 565 Box 14 -1 Arthrokinematics of the Ankle and Foot Joints Physiologic motion Roll Slide Talocrural joint: motion of talus Dorsiflexion Anterior Posterior Plantarflexion Posterior Anterior Subtalar joint: motion of calcaneus (posterior articulating surface) Supination with Medial Lateral inversion Pronation with Lateral Medial eversion Talonavicular joint: motion of navicular (open-chain) Supination Plantar and medial Plantar and medial Pronation Dorsal and lateral Dorsal and lateral Metatarsophalangeal and interphalangeal joints: motion of the phalanges Flexion Plantar Plantar Extension Dorsal Dorsal and lateral collateral ligaments, which also support the talocrural joint, by the interosseous talocalcaneal ligament in the tarsal canal, and by the posterior and lateral talocalcaneal ligaments. In closed-chain ac- tivities, the joint attenuates the rotatory forces be- tween the leg and foot so that, normally, excessive inward or outward turning of the foot does not occur. • There are three articulations between the talus and calcaneus; the posterior is separated from the anterior and middle by the tarsal canal. The canal divides the subtalar joint into two joint cavities. • The posterior articulation has its own capsule; the facet on the bottom of the talus is concave, whereas the opposing facet on the calcaneus is convex. • The anterior articulations are enclosed in the same capsule as the talonavicular articulation, forming the talocalcaneonavicular joint.37 Func- tionally, these articulations work together. The facets of the anterior and middle articulations on the talus are convex, whereas the opposing facets on the calcaneus are concave. • With physiologic motions of the subtalar joint, the convex posterior portion of the calcaneus slides opposite to the motion; the concave ante- rior and middle facets on the calcaneus slide in the same direction, similar to turning a doorknob. With eversion, as the calcaneus rolls laterally the posterior articulating surface slides medially, and with inversion, the posterior articulating surface slides laterally (see Box 14-1). Talonavicular Joint Anatomically and functionally part of the talocalca- neonavicular joint, this joint is supported by the spring, the deltoid, the bifurcate, and the dorsal talonavicular ligaments. The triplanar motions of the navicular on the talus function with the subtalar joint, resulting in pronation and supination. In the weight-bearing foot this occurs as the head of the talus drops plantarward and medially, resulting in a pliable foot and a decreased medial longitudinal arch. The opposite accessory motions occur with supination, resulting in a rigid foot and an increased medial longitudinal arch. • The head of the talus is convex; the proximal ar- ticulating surface of the navicular is concave. With physiological motions of the foot, the navic- ular slides in the same direction as the motion of the forefoot. In the open-chain motion of prona- tion, the navicular slides dorsally and laterally (abduction and eversion), and with supination it slides volarly and medially (adduction and inver- sion) (see Box 14-1). • In the weight-bearing foot (closed-chain), this ar- ticulation is influenced by what is happening in the subtalar joint.37 • During pronation, as the calcaneus everts, it can- not also dorsiflex and abduct with the foot on the ground, so the talus plantarflexes and inverts on the calcaneus. This downward and inward mo- tion of the talar head results in an upward and outward motion of the navicular and a flattening in the medial longitudinal arch (and pliable foot). • During supination, the opposite occurs. The cal- caneus inverts, and the talus dorsiflexes and everts, resulting in the navicular plantarflexing, inverting and adducting. The overall effect is an increase in the medial longitudinal arch and a structurally stable foot. Transverse Tarsal Joint This functionally compound joint between the hind- and midfoot includes the anatomically separate talonavicular and calcaneocuboid joints. • Talonavicular joint (described in the previous section). • The calcaneocuboid joint is saddle-shaped. The articulating surface of the calcaneus is convex in a dorsal-to-plantar direction and concave in a medial-to-lateral direction; the articulating sur- face of the cuboid is reciprocally concave and convex. 5 6 6 PARTII • Application of Therapeutic Exercise Techniques to Regions of the Body • The transverse tarsal joint participates in the tri- planar pronation/supination activities of the foot and makes compensatory movements to accom- modate variations in the ground. Passive acces- sory motions include abduction/adduction, inversion/eversion, and dorsal/plantar gliding. The Remaining Intertarsal and Tarsometatarsal Joints These are plane joints whose functions reinforce those of the hindfoot. The Metatarsophalangeal (MTP) and Interphalangeal (IP) Joints of the Toes These joints are the same as the metacarpopha- langeal and interphalangeal joints of the hand ex- cept that, in the toes, extension range of motion (ROM) is more important than is flexion (the oppo- site is true in the hand). Extension of the MTP joints is necessary for normal walking. Also, the large toe does not function separately as does the thumb. Functional Relationships of the Ankle and Foot Ankle. Normally, an external torsion exists in the tibia so that the ankle mortise faces approximately 15 degrees outward. With dorsiflexion, the foot moves up and slightly laterally; with plantarflexion, the foot moves down and medially.37 Dorsiflexion is the close-packed, stable position of the talocrural joint. Plantarflexion is the loose-packed position. This joint is more vulnerable to injury when walking in high heels because of the less stable plantarflexed position at the same time that the subtalar and transverse tarsal joints are in their close-packed (rigid) position. Supination. In the closed-chain, weight-bearing foot, supination of the subtalar and transverse tarsal joints with a pronation twist of the forefoot (plan- tarflexion of the first and dorsiflexion of the fifth metatarsals) increases the arch of the foot and is the close-packed or stable position of the joints of the foot. This is the position the foot assumes when a rigid lever is needed for propelling the body forward during the push-off phase of ambulation.37,55 Pronation. During weight bearing, pronation of the subtalar and transverse tarsal joints causes the arch of the foot to lower, and there is a relative supina- tion of the forefoot with dorsiflexion of the first and plantarflexion of the fifth metatarsals. This is the loose-packed or mobile position of the foot and is as- sumed when the foot absorbs the impact of weight bearing and rotational forces of the rest of the lower extremity and when the foot conforms to the ground.12 Interdependence of leg and foot motions. In the weight- bearing foot, subtalar motion and tibial rotation are interdependent. Supination of the subtalar joint re- sults in or is caused by lateral rotation of the tibia, and conversely, pronation of the subtalar joint re- sults in or is caused by medial rotation of the tibia.37'55 Arches. The arches of the foot are visualized as a twisted osteoligamentous plate, with the metatarsal heads being the horizontally placed anterior edge of the plate, and the calcaneus being the vertically placed posterior edge. The twist causes the longitu- dinal and transverse arches. When bearing weight, the plate tends to untwist and flatten the arches slightly.37 • Primary support of the arches comes from the spring ligament with additional support from the long plantar ligament, the plantar aponeurosis, and short plantar ligament. During push-off in gait, as the foot plantarflexes and supinates and the metatarsal phalangeal joints go into exten- sion, increased tension is placed on the plantar aponeurosis, which helps increase the arch. This is called the windlass effect. • In the normal static foot, muscles do little to sup- port the arches, yet without muscle tension the passive support stretches, and foot pronation in- creases under weight-bearing loads. Muscles con- tribute to support during ambulation. Abnormal foot postures. A person with a varus defor- mity of the calcaneus (observed nonweight-bearing) may compensate by standing with a pronated (or everted) calcaneus posture.11'13 Pes planus, pronated foot, and flat foot are terms often interchanged to mean a pronated posture of the hindfoot and de- creased medial longitudinal arch. Pes cavas and supinated foot describe a high-arched foot.46 Muscle Function in the Ankle and Foot Plantarflexors. Plantarflexion is primarily caused by the two-joint gastrocnemius muscle and the one- joint soleus muscle; they attach to the calcaneus via the Achilles tendon. Secondary plantarflexors. Other muscles passing pos- teriorly to the axis of motion of plantarflexion con- tribute little to that motion, but they do have other functions. CHAPTER 14 • The Ankle and Foot 5 6 7 • Tibialis posterior is a strong supinator and inver- tor that helps to control and reverse pronation during midstance of gait. • Flexor hallucis longus and flexor digitorum longus flex the toes and help support the medial longitudinal arch. To prevent clawing of the toes (MTP extension with IP flexion), intrinsic mus- cles must also function at the MTP joints. • Peroneus longus and brevis primarily evert the foot, and the longus gives support to the trans- verse and lateral longitudinal arches during weight-bearing activities. Dorsiflexors. Dorsiflexion of the ankle is caused by the tibialis anterior muscle (which also inverts the ankle), the extensor hallucis longus and extensor digitorum longus (which also extend the toes), and the peroneus tertius muscles. Intrinsic muscles. Intrinsic muscles of the foot are sim- ilar to the hand in their functioning of the toes (ex- cept there is no thumb-like function in the foot), and they also provide support to the arches during gait. Stability in standing. In normal standing, the gravita- tional line falls anteriorly to the axis of the ankle joint, creating a dorsiflexion moment. The soleus muscle contracts to counter the gravitational mo- ment through its pull on the tibia. Other extrinsic foot muscles help stabilize the foot during postural sway. The ankle and foot during gait.37'47 During the normal gait cycle, the ankle goes through a ROM of 35 de- grees: 15 degrees of dorsiflexion occurs at the end of midstance, and 20 degrees of plantarflexion occurs at the end of stance. Joint Function of the Ankle and Foot During Gait Shock-absorbing, terrain-conforming, and propul- sion functions of the ankle and foot. • During the loading response (heel strike to foot flat), the heel strikes the ground in neutral or slight supination. As the foot lowers to the ground it begins to pronate to its loose-packed po- sition.21 The entire lower extremity rotates in- ward, which reinforces the loose-packed position of the foot. With the joints in a lax position, they can conform to variations in the ground contour and absorb some of the impact forces as the foot is lowered. • Once the foot is fixed on the ground, dorsiflexion begins as the tibia comes up over the foot; the tibia continues to rotate internally, which rein- forces pronation of the subtalar joint and loose- packed position of the foot. • During midstance and continuing through termi- nal stance, the tibia begins to rotate externally, which initiates supination of the hindfoot and locking of the transverse tarsal joint. This brings the foot into its close-packed position, which is reinforced as the heel rises and the foot rocks up onto the toes causing toe extension and tighten- ing of the plantar aponeurosis (windlass effect). This stable position converts the foot into a rigid lever, ready to propel the body forward as the an- kle plantarflexes from the pull of the gastrocne- mius-soleus muscle group. Muscle Control of the Ankle During Gait • The ankle dorsiflex