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Joints of the Lower ExtremityI. Joints and Ligamentsa. A joint, arthrosis, or articulation is the union of two or more bones.b. Movement between the bones varies depending on the type of joint.c. The traditional classification of joints divides them according to the amount of movement permittedi. Synarthrosis: 1. Permits very little to no movement at all2. Consist of bones intimatelu joined together by fibrous tissue3. Four subtypes are distinguished: Suture, Gomphosis, Achyndylesis, and Syndesmosisii. Amphiarthrosis: 1. Permits greater flexibility between bones but they are closely connected by cartilage or fibrocartilage.2. Two subtypes are distinguished: Symphisis and Synchondrosisiii. Diarthrosis:1. Permits free movement between bones; the same as a synovial jointd. More recently, this classification has been modified inot a simpler one that is based on the type of connection between bones rather than the amount of movement involved. II. This is essentially the same classification but with a simpler terminology:a. Fibrous jointsi. Bones are strongly connected by fibrous tissue or ligamentii. Occurs mainly between bones of the skull during growth and between the teeth and their alveolar socketsiii. Most fibrous joints have no movement or flexibility1. EXCEPT for the tibiofibular syndesmosis, the only regularly occurring fibrous joint in the LEb. Cartilaginous jointsi. Primary (synchondrosis) type1. Bones are united by a segment of hyaline cartilage with no movement permitted between them (ribs to sternum by way of costal cartilage and epiphysis to diaphysis by way of growth plate)ii. Secondary (symphysis ) type1. Bones are united by a plate of fibrocartilage with slight movement or flexibility permitted between them (intervertebral joints and pubic symphysis). 2. The pubic symphysis of the pelvis is an example of a cartilagenout joint.c. Synovial jointi. Articular facets of the bones are smooth and unconnected. 1. There is therefore a SPACE between the bones and the facets are free to move against each otherii. A fibrous capsule surrounds the joint, creating an internal joint sac or cavityiii. Internal side of the capsule (as well as the non-articular surfaces of the bone in the joint cavity) is lined with synovial membraneiv. Synovial membrane produces synovial fluid which lubricates the articular facets to reduce friction during movement (synovial membrane does not cover the articular facets, but synovial FLUID does).v. A layer of cartilage (avascular and having no nerves) covers the articular facets. vi. Ligaments, holding the bones together, are situated around the capsulevii. Most ligaments occur externally to the capsule and are partially blended with it; however, ligaments, discs of fibrocartilage, tendons and fat pads may also occur inside the joint cavity (the knee joint contains all of these). viii. Blood supply to synovial joints is from anastomosing branches of local arteries- they supply the capsule, epiphysis, and the highly vascularized synovial membrane. ix. Nerves to the joint (sensory and vasomotor) supply the capsule, ligaments, synovial membrane, and periosteum and are usually derived from the nerves which innervate the muscles acting on the joint. x. The kind of movement occurring at a sunovial joint depends mainly on the shaoe fo the facets and on the ligaments (which limit movement) around the joint; synovial joints may be loosely grouped into the following functional types:III. Review of Cardinal Body Planes, Directions, and Axes of Motiona. Cardinal Body Planes: references for defining foot and leg motioni. Frontal- divide body into Front and Rear halvesii. TV- Top and Bottomiii. Sagittal- Left and Rightb. Motions: i. Abduction: in the TV plane; the distal segments move away from the midline ii. Adduction: in TV plane; distal segments move toward the midlineiii. Eversion: in the frontal plane; plantar surface of the foot faces away from midlineiv. Inversion: in the frontal plane; plantar surface of the foot faces towards the midlinev. Dorsiflexion: in the sagittal plane, distal segments of the foot move toward the anterior surface of the legvi. Plantarflexion: in the sagittal plane, where distal segments of the foot move away from the anterior surface of the legc. Triplanar Motion: a motion taking place consisting of three components and where the axis of the motion makes an angle to all three body planesi. Supination: Plantarflexion, Adduction, and Inversionii. Pronation: Dorsiflexion, Abduction, and EversionIV. Types of Synovial Jointsa. Plane joint (arthrodial, gliding):i. The facets are flat and movement between them produces only a sliding or gliding movementii. One axis of motioniii. In the lower extremity: most intertarsal jointsb. Pivot (trochoidal, ring):i. Rotation, one axis of motionii. In LE: nonec. Hinge (ginglymus):i. Mainly flexion/extensionii. One axis of motioniii. Have collateral ligaments on each sideiv. Associated with trochlear articular shapesv. In LE: IP joints, ankle and knee are modified hinge jointsd. Ellipsoid (condyloid):i. The concave facet is an oval head which has a much greater length than widthii. Two axes of motion- flexion/extension on long axis and adduction/abduction on short axisiii. In LE: MP joints, and the knee is sometimes described as this typee. Saddle (sellar):i. The facets have a saddle shape, whereby one side of the faced is turned downii. Two axes of motioniii. In LE: calcaneocuboid jointf. Ball and Socket (enarthrodial):i. Three axes of motion; allows for the actions of all other synovial joints, as well as circumductionii. In LE: hip joint and talonavicular jointV. Sacroiliac Jointa. Bony Structurei. Sacrum- auricular facetii. Ilium- auricular facet1. Both of these facets are ruggose rather than smooth in surface texture. 2. This surface roughness helps to resist slippage at this important joint which transmits body weight from the trunk to the pelvis.iii. Type of joint1. Synovial (partial)2. This joint has a joint space surrounded by ligaments, with some cartilage covering on the auricular surface of the ilium, however, cartilaginous adhesions occur between the facets with ageb. Ligamentsi. Capsule: is attached closely around the articular facets, its fibrous part is continuous wit three ligaments1. Anterior (ventral) sacroiliac ligament: attached to anterior surfaces of the ilium and sacrum2. Interosseosu sacroiliac ligament: short and deep transverse fibers connecting the sacrum and the ilium3. Posterior (dorsal) sacroiliac ligament: has short and long parts, both attached to the posterior superior iliac spine fanning inferiorly onto the posterior aspect of the sacrum. c. Movements:i. Although the shape of the facets make this a PLANE type of synovial joint, the rugosity of the surfaces, internal fibrosing and density of surrounding ligaments greatly restricts movement. ii. Very slight rotational movement normally occurs here when the pelvis receives body weight upon rising from a reclining position. iii. The joint is somewhat flexible in females particularly during pregnancy in preparation for passage of the fetus through the birth canal. Eventually the joint becomes immobile. VI. Hip Jointa. Bony structurei. Acetabulum- the socket of the joint formed by the fusion (at completion of growth) of the original three pelvic bones: the ilium, the ischium, and the pubis. 1. Lunate surface- the part of the socket which actually articulates with the head of the femur; it is a smooth C-shaped facet and is the only part of the acetabulum covered with articular cartilage. 2. Acetabular fossa- the non-articular center of the C, contains a fat pad3. Acetabular notch- inferior indentation between the two ends of the lunate surfaceii. Femur1. Head- spheroidal in shape and covered with articular cartilage except for on the pit2. Fovea capitis femoris (pit of the head of the femur)- non-articular depression located superomedially on the head, attachment for the ligament of the head of the femur. 3. Neck- non-articular, covered with synovial membrane which forms ridges, or retinacula within which are located main blood vessels to the jointb. Type of Joint- synovial of the enarthrodial or ball and socket typec. Ligamentsi. Intracapsular1. Acetabular labrum (glenoid labrum)a. A ring of fibrocartilage attached to the rim of the acetabulumb. Triangular in cross section with its base at the bony attachmentc. Internally it is continuous with the cartilage of the joint capsuled. Its presence deeps the socket resisting dislocation of the head2. Transverse Acetabular ligamenta. Fibrous inferior continuation of the labrumb. Attached to the edges of the C-shaped lunate surface, thus converting the Acetabular notch into an Acetabular foramen3. Ligament of the head of the femur (round ligament)a. Narrow end attached to the pit of the head of the femur superiorly and its wide end to the transverse ligament and Acetabular notch inferiorlyii. Extracapsular1. Capsule (and intracapsular synovial membrane)a. Attached to the rim of the acetabulum and external edge of the Acetabular labrum and transverse ligament on the femur, it is anteriorly attached to the intertrochanteric line, posteriorly it is attached to the neck about 1 cm above the intertrochanteric crestb. The capsule does not attach to the trochantersc. Synovial membrane covers the capsule internally- at the neck it is reflected from the capsular wall onto the neck where, with some reflecting capsular fibers, it forms the retinacula within which main vessels of the joint are locatedd. The synovial membrane is also attached to the Acetabular labrum and margin of the femoral heade. It lines the fat pad and surrounds the ligamentum teres (round ligament)2. Zona orbicularisa. A circular bundle of capsular fibers within the capsule distal to the femoral headb. No attachment to bone3. Iliofemoral ligament (Y Ligament of Bigelow)a. Strongest ligament of the body, arranged in two bands forming an overall Y or triplanar shapeb. On the pelvis it is attached to the ASIS and on the femur along the intertrochanteric line blending with the joint capsulec. It is thinner in the center, thus the thicker lateral (known separately as the iliotrochanteric ligament) and inferior fibers give the impression of two bands. 4. Pubofemoral ligamenta. Situated medially and inferiorly to the iliofemoral ligamentb. Attached on the pelvis to the iliopectineal eminence and pubic part of obturator margin and on the femur to the inferomedial margin o the intertrochanteric line and the joint capsule 5. Ischiofemoral ligamenta. Spiral shaped, situated posteriorly o the capsule, attached to the body of the ischium and courses superolaterally to attach on the femoral neckd. Blood Supply and Innervationi. Branches from the trochanteric anastomosis around the neck of the femur:1. Medial Femoral Circumflex (ascending branch)2. Lateral Femoral Circumflex (ascending branch)3. Superior Gluteal4. Inferior Glutealii. Through the Acetabular foramen to the ligament of the head of the femur and Acetabular fossa, one or both of these branches may be absent but even when present they contribute little ot the blood supply of the joint: 1. MFC (Acetabular branch)2. Obturator (Acetabular branch from the posterior division)iii. Nerves1. Femoral, from the branch to the rectus femoris2. Obturator3. Nerve to quadrates femoris4. Sciatic5. Accessory Obturator (when present)6. Superior gluteale. Functioni. Range of motion1. As a ball and socket joint the hip joint permits multiaxial movement:a. Flexion and extension in the sagittal planeb. Adduction and abduction in the frontal planec. Superoinferior axis- medial and lateral rotationd. Combine axes- circumductionii. Ligament function1. The role of the three extracapsular ligaments is important in limiting certain movements at this joint. 2. All three ligaments are tight around the joint in extension and loose in flexion!3. The iliofemoral ligament is especially important in standing when it resist backward rotation of the trunk on the femur, thus, it maintains the upright posture at the hip joint without enlisting muscle activity for this function4. The strength and position of the iliofemoral ligament anteriorly to the hip joint resists dislocation, thus dislocation of the hip is more likely to occur posteriorly than anteriorly5. The iliofemoral ligament also limits medial rotation, while the ischiofemoral ligament limits medial rotation and the pubofemoral ligament limits abduction. 6. Internally, the ligament of the head of the demur is extended in adduction but not enough to affect motion of the joint. VII. Knee Joint:a. Skeletal Structurei. Femur1. Media and lateral Condylesa. Anteroposterior ellipsoid (condyloid)b. Medial more elongated, Lateral more roundedc. Smooth surface covered by articular cartilage2. Patellar Surfacea. Articularb. Cartilage coveredc. Connects the Femoral Condyles anterosuperiorlyd. The patellar surface is BROADER, HIGHER, AND PROJECTS MORE ANTERIORLY ON THE LATERAL SIDEi. Functions in resisting the dislocation of the patella3. Intercondylar notch (fossa)a. Nonarticular and very deep inferoposterior indentation between the femoral condylesii. Patella1. Articulates with only the Femur2. Attachment for Quadriceps Tendon/Patellar tendon3. Posterior surface has smooth articular faceta. LATERAL SIDE GREATER THAN MEDIAL SIDEiii. Tibia1. Medial and Lateral condylesa. Forms a plateau with M and L Facetsi. MEDIAL FACET IS LARGER AND MORE OVAL2. Intercondylar areaa. Intercondylar Eminencei. Anterior and Posterior Intercondylar Tuberclesb. Type of Jointi. Synovialii. Ginglymus (Hinge)iii. Modified Condylar (Second axis in addition to hinge motion)iv. 3 Compartments1. Sellar (patellofemoral)a. Plane/Arthrodial (gliding)2. Mediala. Condylar3. Laterala. Condylarc. Ligamentsi. Extracapsular1. Capsulea. Attaches to articular margins of the Femoral and Tibial Condylesb. Capsule is ABSENT anteriorly2. Quadriceps Tendon/Patellar Tendona. Posterior surface forms part of the anterior wall of the Knee Jointb. The tendon fibers combine with the joint capsule and insert into the Tibial Tuberosity3. Medial and Lateral Patellar Retinaculaa. Oblique tendinous fibers from the V. Medialis and Lateralis which course toward the patellar tendon and form part of the anterior wall of the knee joint4. Oblique Popliteal Ligamenta. Formed by superolaterally reflected part of the SEMIMEMBRANOSUS in the popliteal fossai. Attached to:1. Posterior part of the lateral femoral condyle2. Origin of the lateral head of the Gastroc3. Femoral Intercondylar Fossa5. Arcuate Popliteal Ligamenta. Y shaped ligament:i. Stem attached to the fibular headii. Medial band arches over the Popliteus M.iii. Lateral band continues superiorly as the Short Lateral Ligament to blend with the origin of the Lateral head of the Gastroc6. Tibial Collateral Ligament (Medial Collateral)a. Connects Femur and Tibia mediallyi. Superior attachment: Medial epicondyle of the Femurii. Inferior Attachment: Superomedial side of the Tibiab. Has superficial and deep parts:i. Superficial is visible UNDER the pes anserine tendons and goes as far inferiorly as the tibial tuberosityii. Deep is attached to the tibial condyle, joint capsule, and medial mensicus7. Fibular Collateral Ligament (Lateral Collateral)a. Round, cord like ligament connecting the Femur and Fibula laterallyi. Superior attachment is to the lateral epicondyle of the Femurii. Inferior attachment is to the head of the Fibulab. Does NOT attach to the joint capsule or to the lateral meniscusc. Near its inferior end it goes THROUGH the tendon of the Biceps femoris, which ALSO INSERTS on the head of the Fibula8. External Bursaea. Prepatellari. Between the skin and the patellab. Superficial Infrapatellari. Between the skin and the tibial tuberosity, superficial to the patellar tendonc. Deep Infrapatellari. Deep to patellar tendon, between the patellar tendon and the tibial tuberosityd. Anserinei. Between the tibial collateral ligament and the overlying tendons of Sartorius, Gracilis, and Semitendinosusii. Intracapsular1. Cruciate Ligaments- 2 ligaments connecting the Tibia and the Femur in the middle of the joint, cross each other. Distinguished by their attachments on the TIBIAa. Anterior Cruciatei. Distal attachment is on the anterior part of the tibial intercondylar areaii. Proximal attachment is on the medial side of the Lateral Femoral Condyle (within intercondylar fossa)b. Posterior Cruciatei. Distal attachment is on the posterior part of the tibial intercondylar area1. Smooth depressionii. Proximal attachment is the lateral side of the Medial Femoral Condyle (within intercondylar fossa)2. Menisci- FIBROcartilagenous C shaped (semilunar) cartilage discs interposed between the tibial and femoral condylesa. Triangular in cross sectionb. Thicker at outer edges where they attach to the tibia and narrower at their inner edge which is free and faces the center of each tibial condylei. The two free edges of each meniscus are attached to the intercodylar eminencec. Medial Meniscusi. Oval shaped ii. Anterior horn is attached to the anterior intercondylar area of the tibiaiii. Posterior horn is attached to the posterior intercondylar area of the tibiaiv. On its medial side it is attached to the capsule and the deep part of the Tibial Collateral Ligamentd. Lateral Meniscusi. Circularii. Smaller than the Medial Meniscus but covers more area of the lateral tibial facetiii. Anterior and Posterior horns are closer in their attachment of the intercondylar area1. Anterior horn is attached just behind the anterior cruciate ligament2. Posterior horn is attached to the intercondylar eminence3. Meniscofemoral Ligaments- two ligaments attached to the posterior horn of the LATERAL MENSICUS and pass SUPERIORLY to JOIN the attachment of the Posterior Cruciate Ligamenta. Posterior Meniscofemoral- passes POSTERIOR to the Posterior Cruciate Ligamentb. Anterior Meniscofemoral- smaller and more variable, passes ANTERIOR to the Posterior Cruciate Ligament4. Coronary Ligamenta. part of the joint capsule which attaches the OUTER edges of the menisci to the Tibia5. Transverse Ligament of the Kneea. Connects the ANTERIOR edge of the LATERAL meniscus to the ANTERIOR horn of the MEDIAL meniscus6. Tendon of Popliteus Musclea. Popliteus originates on the Lateral Femoral Condyle inside the joint capsule and passes posteriorly THROUGH the joint capsule in the popliteal fossab. On its way to the posterior wall of the joint capsule it passes the LATERAL meniscus and PASSES A MUSCULAR SLIP TO ITc. This muscular slip is thus able to exert a posterior pull on the lateral meniscus and its position inside the joint prevents the attachment of the lateral meniscus to the capsule7. Infrapatellar Fat Pada. FILLS the space in anteroposteriorly between the patellar tendon and the intercondylar fossa of the femur, covered by synovial membrane8. Synovial Membranea. Attached around the borders of the articular facets on the tibia, femur, and patella and in the center surrounds the cruciate ligamentsb. Inferiorly covers the infratpatellar fat pad and from this forms a partition, the INFRAPATELLAR FOLD, attached to the intercondylar fossa of the femuri. On either side of this fold, on the fat pad, there are two small synovial flaps, the ALAR foldsii. Intracapsular BUT EXTRASYNOVIAL:1. CruciateLigaments2. Meniscofemoral Ligaments3. Infrapatellar Fat Pad4. Tendon of Popliteus9. Internal Bursaea. Suprapatellari. Superior to the patella in the joint space between the quadriceps tendon and the femurii. Lgest of the bursae of the knee jointb. Popliteali. May also communicate with the interior of the knee jointii. Between Popliteus tendon inside the joint and the lateral condyle of the tibiac. Gastrocnemius (Semimembranosus)i. Extension of the synovial cavity between the medial head of the Gastrocnemius, the Semimembranosus tendon and the Medial femoral condyled. Blood Supplyi. Geniculate Anastomosis1. From Popliteal Arterya. Superior Medial Genicularb. Superior Lateral Genicularc. Inferior Medial Geniculard. Inferior Lateral Geniculare. NOTE: Middle Genicular artery pierces the posterior wall of the capsule directly into the joint and DOES NOT JOIN THE ANASTOMOSIS2. From the Femoral Arterya. Descending Genicularb. Lateral Femoral Circumflexi. Descending branch3. From Anterior Tibial Arterya. Posterior Tibial Recurrentb. Anterior Tibial Recurrent4. From the Posterior Tibial Arterya. Circumflex Flibulare. Innervationi. Femoral Nerve1. From the muscular branches to the Quadriceps femorisii. Obturator Nerve1. From a small genicular branch which enters the Popliteal regioniii. Tibial Nerve1. Superior Medial Genicular branch2. Inferior Medial Genicular branch3. Middle Genicular branchiv. Common Peroneal Nerve1. Superior Lateral Genicular2. Inferior Lateral Genicularf. Functioni. Basic actions: Flexion and Extension1. Rolling, sliding, and rotating can occurii. Movement is different on the two femoral condyles1. Medial condyle is more Anteroposteriorly ELONGATED2. Lateral is more Globulariii. Femur SLIDES AS IT ROLLSiv. Locking Mechanism1. In extension of the knee, the femoral condyles ROLL FORWARD and SLIDE BACKWARD on the tibial condylesa. In the last 15 degrees of this process ROTATING OCCURS, and the joint is LOCKEDi. All ligaments are taut at this timeb. In order to UNLOCK, the joint must unscrew, therefore the femoral condyles must turn LATERALLY against the tibiac. Performed by contraction of the Popliteus Muscle which rotates the Femur LATERALLY and the tibia MEDIALLY2. Therefore:a. Standing up (EXTENSION)i. Tibia is WEIGHT BEARING, and therefore FIXED and DOESNT MOVEii. Femur rotates MEDIALLYb. Sitting Down (FLEXION)i. Tibia is WEIGHT BEARING, and therefore FIXED and DOESNT MOVEii. Femur rotates LATERALLYc. If the Tibia is NOT WEIGHT BEARINGi. Extension: the Femur is fixed and the Tibia rotates LATERALLYii. Flexion: the Femur is fixed and the Tibia rotates MEDIALLYv. Patella- moves against the Lateral Condyle of the femur1. Moves UP in extension 2. Moves DOWN in flexion3. Only in EXTREME FLEXION does the patella articulate with the medial condyle of the femur and for this contact both the patella and the medial condyle of the Femur have small medial facets4. Pull of Quadriceps Tendon is stronger on the Lateral side due to the Vastus Lateralisa. Therefore the patella tends to displace toward the lateral sideb. Resisted by the action of the Vastus Medialis, but mostly by the projecting lateral lip (or lateral condylar part) of the patellar surfaceg. Functions of the PARTS of the Knee Jointi. Menisci1. Increase the depth of the tibial articular facets, increasing congruence between the femoral and tibial condyles2. Shift slightly anteriorly in extension, posteriorly in flexion3. The medial meniscus is less mobile due to having more attachments, and therefore the medial meniscus often gets trapped and crushed between the bones during fast, twisting movement of the legii. Cruciate Ligaments1. Restrict excessive sliding of the femoral condyles, both are TAUT in full extension2. Anterior Cruciate Ligament- fully taut in extension, RESISTS HYPEREXTENSION and pulling away of the Tibia anteriorly (or Femur posteriorly)3. Posterior Cruciate Ligament- more taut in FLEXION, therefore RESISTS HYPERFLEXION and pulling away of the Femur anteriorly (or Tibia posteriorly)iii. ALL LIGAMENTS OF THE KNEE JOINT (including extracapsular ligaments and intracapsular cruciate ligaments) are TAUT DURING EXTENSIONiv. The collateral ligaments specifically confine overall movement to flexion/extension by resisting abduction/adductionv. Iliotibial band also stabilizes the joint on the lateral sidevi. Quadriceps femoris muscle group moves the patella and forms (through the patella tendon) the anterior wall of the joint, provides the patellar retinacula (to strengthen the joint capsule and control patellar movement) and provides stability during FLEXION by RESISTING this motion and therefore controlling it (prevents excessive flexion)VIII. Tibiofibular Jointsa. Superior (Proximal) Tibiofibular Jointi. Bony structure1. Tibiaa. Oval shaped facet on the postero lateral aspect of the lateral tibial condyle2. Fibulaa. Oval shaped facet on the anteromedial aspect of the fibular headii. Type of Joint1. Synovial2. Plane iii. Ligaments1. Capsulea. Closely following the outline of the articular facetsb. SOMETIMES this joint is open to the knee joint through the Subpopliteal recess (bursa)2. Anterior Tibiofibular Ligamenta. Obliquely situated across the front of the jointb. Superomedially attached to the lateral tibial condylec. Inferolaterally attached to the head of the fibula3. Posterior Tibiofibular Ligamenta. Obliquely situated across the BACK of the jointb. Superomedially attached to the lateral tibial condylec. Inferolaterally attached to the head of the fibulad. COVERED BY THE TENDON OF THE POPLITEUSiv. Blood Supply1. Anterior Tibial Arterya. Anterior Recurrentb. Posterior Recurrentv. Innervation1. Common Peroneal 2. Nerve to Popliteus (Tibial)b. Interosseous Membranei. Bony Structure1. Tibiaa. Interosseous (lateral) border2. Fibulaa. Interosseous borderii. Type of Joint1. DOES NOT have an arthrological designationiii. Ligaments1. The interosseous membrane forms the link between the two shafts and does not include any additional ligaments (although it is continuous inferiorly with the interosseous ligament of the distal (inferior) Tibiofibular joint).2. Separates the ANTERIOR AND POSTERIOR CRURAL COMPARTMENTS3. Has an opening SUPERIORLY for the ANTERIOR TIBIAL VESSELS4. Has another INFERIORLY for the perforating branch of the PERONEAL ARTERY5. Most of the fibers of the shaft run INFEROLATERALLY from tibia to fibula, providing a slight shift upward of the fibular shaft in DORSIFLEXION OF THE ANKLEc. Inferior (Distal) Tibiofibular Jointi. Bony Structure1. Tibiaa. Fibular notch on the lateral inferior aspect, this is a ROUGH CONCAVE AREA2. Fibulaa. A ROUGH, CONVEX area on the inferomedial triangular areaii. Type of Joint1. Fibrous2. Syndesmosisa. This is the ONLY regularly occurring syndesmosis in the lower extremity3. While this is not a synovial joint, the capsule, synovial, and articular cartilage from the synovial ankle joint MAT INCLUDE the lowermost millimeter or so of this jointiii. Ligaments1. Interosseous Tibiofibular Ligamenta. Strong and thick, attached to the two bones in the middle of the jointb. This ligament is the main feature of the joint2. Anterior Inferior Tibiofibular Ligmamenta. Situated anterior to the joint, running INFEROLATERALLY from the Medial to the Lateral Malleolus3. Posterior Inferior Tibiofibular Ligamenta. Stronger than the anterior ligament b. Runs posteriorly and INFEROLATERALLY from the BASE OF THE TIBIA to the Lateral Malleolus4. Inferior Transverse Ligamenta. The deepest fibers of the Posterior Inferior Tibiofibular Ligamentb. Extends beyond the inferior border of the tibia where it forms part of the posterior wall of the ankle joint and articulates with the Talusiv. Blood Supply1. Perforating Branch of the Peroneal Artery2. Lateral Malleolar Branches of the Posterior and Anterior Tibial Arteriesv. Innervation1. Deep Peroneal Nerve2. Tibial Nerved. Function of the Tibiofibular Joints:i. DORSIFLEXION at the ankle pushes the Fibula UP and slightly rotates it LATERALLY (as does eversion of the foot at the subtalar joint)ii. Therefore, some SLIDING at the PROXIMAL Tibiofibular Joint occurs during Dorsiflexion iii. It is possible to rupture or tear both the Interosseous Ligament and Membrane is sudden and extreme EversionIX. Ankle (Talocrural) Jointa. Bony Structurei. Tibia1. Inferior Surface2. Lateral surface of the medial malleolusa. These two articulating surfaces (or facets) are CONTINUOUS, forming the top and medial side of the joint Mortiseii. Fibula1. Facet on the medial side of the Medial side of the Lateral Malleolusiii. Talus1. Trochleaa. The SUPERIOR surface of the body of the Talus, wider ANTERIORLY than posteriorly and having a shallow anteroposterior indentation (spool shaped) b. Articulates with the INGERIOR SURFACE OF THE TIBIA2. Medial side of the Talar Bodya. Small tear drop or comma shaped facetb. Continuous with the Trochlea abovec. Articulates with the MEDIAL MALLEOLUS OF THE TIBIA3. Lateral side of the Talar Bodya. Large, somewhat INFEROLATERALLY projecting triangular facet b. Continuous with the Trochlea abovec. Articulates with the LATERAL MALLEOLUS OF THE FIBULAb. Type of Jointi. Synovialii. Ginglymus (hinge)1. Articular surfaces are covered with articular cartilageiii. The articular facets of the Crural (Tibia and Fibula) part of the joint form, laterally-superiorly- medially, the Mortise1. A box like container for the Talus2. The two rigid sides of this mortise restrict Talar movement to ONLY the up and down dorsiflexion and plantarflexionc. Ligamentsi. Capsule and Synovial Membrane1. Articular Capsulea. Closely attached to the articular margins of the Talus (except on the anterosuperior surface where part of the neck of the fibula is enclosed within the joint cavityb. ANTERIORLY WEAK, LATERALLY STRONG- where reinforced by collateral ligamentsc. SUPERIORLY the capsule projects slightly INTO the tibiofibular syndesmosisi. POSTERIORLY the joint wall is reinforced by the fibrocartilagenous Inferior Transverse Ligament between the Tibia and the Fibula ii. Collateral Ligaments1. Lateral (Fibular External) Collateral Ligamentsa. Anterior Talofibulari. FROM the anterior border of the Lateral Malleolusii. TO the NECK of the Talus JUST IN FRONT of the lateral triangular facetiii. Shortest of the Lateral ligaments and the most commonly injured b. Calcaneo Talofibulari. FROM the APEX of the Lateral Malleolusii. TO a TUBERCLE on the Lateral surface of the Calcaneousiii. Cord-like in shapec. Posterior Talofibulari. FROM the Lateral Malleolar fossaii. TO the Lateral Tubercle of the Posterior process of the Talusiii. Its course is almost horizontal iv. Strongest of the Lateral Ligaments2. Medail (Tibial Internal) Collateral Ligaments AKA the Deltoid Ligament a. Stronger of the two sets of collateralsb. Three ligaments are superficial and one is deep (Anterior Tibiotalar)c. Made up of four ligaments:i. Anterior Tibiotalar1. FROM the anterior border of the medial malleolus2. TO the medial side of the Talar body3. DEEP part of the Deltoid Ligamentii. Posterior Tibiotalar1. FROM the posterior border of the Medial Malleolus2. TO the Medial Tubercle of the Talusiii. Tibiocalcaneal1. FROM the apex of the Medial Malleolus 2. TO the medial edge of the Sustantaculum Tali3. There, its fibers blend with those of the PLANTAR CALCANEONAVICULAR LIGAMENT (which is not part of the deltoid ligament)iv. Tibionavicular1. FROM the anterior border of the Medial Malleolus2. TO the Navicular Tuberosity3. Overlies the Tibiotalar Ligament4. Its inferior fibers BLEND with the PLANTAR CALCANEONAVICULAR LIGAMENTd. Blood Supplyi. Tibial Artery1. Malleolar Branchesii. Peroneal Artery1. Malleolar Branchese. Innervationi. Local innervations from:1. Tibial Nerve2. Deep Peroneal Nervef. Functioni. The main function is dorsiflexion/plantarflexion of the foot against the legii. The Mortise of the joint does NOT allow motion in more than one plane (sagittal)iii. DORSIFLEXION1. Toes point UP2. 10-20 degrees ROM from neutral position3. Sometimes considered to be a Flexion because angle is decreased between two surfaces BUT ANATOMICALLY THIS IS EXTENSION!!!!a. The movement is caused by EXTENSOR muscles and is innervated by the POSTERIOR DIVISIONS of the lumbosacral plexus, located on the DORSAL surfaces of the relevant body partsiv. PLANTAR FLEXION1. Toes point DOWN2. 20-40 degrees ROM from neutral position3. ANATOMICALLY THIS IS FLEXION!!!!4. Movement caused by Flexor muscles, innervated by Anterior Division of the Lumbosacral plxus and brings together two VENTRAL surfaces (the soles and the calves)!!!!!v. The GREATER WIDTH of the Trochlea ANTERIORLY creates a more snug fit and maximum congruence of the Talus during DORSIFLEXION (toes pointed UP)vi. The function of the Collateral Ligaments are to stabilize the bones of the leg on the talusvii. RELATIONSHIP!!--> Note that the Calcaneofibular and the Tibiocalcaneal ligaments cross both the ankle and the subtalar joints1. These two ligaments help to control inversion/eversion movements (which occur at the subtalar joint)Intrinsic Anatomical Joints of the FootX. Introductiona. Anatomical vs. Functional jointsi. All regular (normally present) joints in the foot are synovial. ii. An anatomical synovial joint is one in which two or more facets share a joint capsule and joint cavity, thus forming a natural anatomical unitiii. However, in the many boned hand and foot they include the subtalar, midtarsal and lisframcks jointsiv. These three functional joints will be described in the last section- but it is essential to first understand the arrangement of the anatomical joints.b. Intrinsic joints of the foot are those which include only footbones, thus, the ankle joint is not an intrinsic pedal joint since two of the participating bones are cruralc. In the foot itself the anatomical joints include:i. 6 tarsal (intertarsal and tarsometatarsal)ii. 5 metatarsophalangeal (MPJ, MTPJ)iii. 9 interphalangeal (IPJ)d. Overall Tarsal functioni. Apart from the dorsiflexion/plantarflexion movements of the whole foot at the ankle, the most important overall actions occur at the functional subtalar joint (which includes the anatomical subtalar joint) and midtarsal (which combines two anatomical) joints.ii. These two joint complexes work synchronously to produce pronation and supinationiii. Although these movements are complicated, most of the synovial tarsal articulations are of the PLANE type. iv. This means that action between any two tarsal bones (or tarsal with a metatarsal base) is basically gliding. v. It is the different arrangements of bone-to-bone that creates differences in axes of motion.vi. Also making foot movement complicated is the fact that many bones are packet close together.vii. Because of this, no movement of the foot can be completely confined in one joint, instead, all of the joints accommodate each other in greater or lesser degree. e. Blood supply and Innervationi. Vessels and nerves supplying the tarsal bones and joint are derived from local articular branches of the dorsalis pedis, medial and lateral plantar arteries, and from deep peroneal, medal and lateral plantar nerves. f. Ligamentsi. Most ligaments are simply named according to the bones they connect. Some functionally distinct or clinically important ligaments have other names as well (such as the deltoid, spring, and cervical ligaments). ii. Because there are many bones in the foot, there musct be many more ligaments to keep them firmly in place. iii. As a result, most of the ligaments, especially in the distal tarsal row, are interconnected and it is not possible to neatly classify them according to the joints they serve.iv. That is why, further on in this section, a number of ligaments of little individual importance will be listed but not discussed. v. Finally, notice that ligaments of the same name (connecting the same bones) usually occur both on plantar as well as dorsal sides. XI. Subtalar joint (Posterior subtalar, posterior talocalcaneal)a. Bony structurei. Concave posterior facet of the talusii. Convex posterior facet of the calcaneusb. Ligamentsi. Capsule1. Closely follows the articular facet margins 2. Anteriorly it is attached along the sinus tarsi and helps to form the interosseous talocalcaneal ligamentii. Posterior talocalcaneal ligament1. Attached behind the posterior calcaneal facet and to the lateral tubercle of the talus. 2. The medial part of this ligament covers (and straps in) the tendon of the flexor hallucis longus in its groove.iii. Lateral talocalcaneal ligament1. Attached to the lateral process of the talus and the lateral surface of the calcaneus, deep to the calcaneofibular ligament2. Usually present as an indistinct part of the capsuleiv. Medial talocalcaneal ligament1. Attached to the medial tubercle of the talus and to the posterior aspect of the sustentaculum tali2. The fibers may blend with those of the spring ligament and with the interosseous talocalcaneal ligamentv. Interosseous talocalcaneal ligament1. Formed buy the joining of two anatomical joint capsules (the subtalar joint posteriorly and the talocalcaneonavicular joint anteriorly) at the sinus tarsi2. Usually described as the strongest of the subtalar ligaments3. Limits EVERSION!!vi. Cervical Interosseous talocalcaneal ligament (anterior talocalcaneal)1. A lateral extension of the Interosseous talocalcaneal ligament2. Attached to the neck of the talus and to the superior surface of the calcaneus3. Closely situated to the attachment of the stem of the inferior extensor retinaculum and to the origin of the extensor digitorum brevis muscle4. Limits INVERSION!!XII. Talocalcaneonavicular jointa. Bony structurei. Head of the talus, including anterior and middle calcaneal facetsii. Anterior and middle talar facets of the calcaneusiii. Posterior (or proximal) surface of the naviculariv. The navicular forms a shallow socket for the front of the talar head. This socket is made much deeper by the anterior and middle talocalcaneal facets posteriorly, and by the plantar calcaneonavicular (spring) ligament medially. v. The resulting arrangement resembles a ball and socket joint (enarthrodial) although it has also been described as a condylar type joint.vi. It may also be described as having two parts: the talonavicular is part of the functional midtarsal joint and the anterior subtalar is part of the functional subtalar joint. b. Ligamentsi. Capsule1. Weak and incomplete, particularly on the anteromedial side, the surrounding ligaments are therefore especially important in reinforcing capsular walls2. Posterior wall of the capsule is located in the sinus tarsi where it fuses with the anterior capsular wall of the subtalar joint to form the Interosseous talocalcaneal ligamentii. Plantar calcaneonavicular (SPRING) ligament1. Attached to the anterior border of the sustentaculum tali and to the navicular tuberosity2. Its medial fibers blend with the tibiocalcaneal part of the deltoid ligament3. Forms the inferomedial part of the wall of the socket of the joint and contains a flat, fibrocartilagenous disc which supports the head of the talus4. In supporting the talar head, this ligament receives help from the tendon of the tibialis posterior muscle which is directly beneath (plantar to) it5. The only ligament in the foot having elastic fibers!!iii. Dorsal talonavicular ligament1. Attached to the dorsal aspect of the talar neck and to the dorsal surface of the naviculariv. Bifurcate ligament- dorsal calcaneonavicular part1. Attached to the dorsal aspect of the calcaneus near the sinus tarsi and cervical ligament2. Then divides, one part going to the cuboid (calcaneocuboid ligament) and one going to the dorsal aspect of the navicular (calcaneonavicular ligament)XIII. Calcaneocuboid jointa. Bony surfacei. Anterior (cuboidal) facet of the calcaneusii. Posterior (calcaneal) facet of the cuboidiii. The shape of these facets creates a saddle-type joint (although sometimes also described as a PLANE joint). b. Ligamentsi. Capsuleii. Dorsal calcaneocuboid ligament1. Connects the dorsolateral surface of the calcaneus and cuboidiii. Bifurcate ligament- calcaneocuboid part1. This is the lateral portion of the bifurcate ligament attached to the dorsomedial margin of the cuboid. iv. Long plantar ligament1. Longest ligament of the foot2. Attached distally to the promontory (peroneal ridge) of the cuboid and bases of MT II, III, IV, and sometimes V3. Between its cuboidal and metatarsal attachments, the ligament covers the peroneal groove of the cuboid, forming a tunnel or canal for the tendon of peroneus longus muscle.v. Plantar calcaneocuboid (short plantar) ligament1. Situated deep to the long plantar ligament and lateral to plantar calcaneonavicular ligament2. Attached proximally to the anterior tubercle of the calcaneus and distally to the plantar surface of the cuboidXIV. Cubometatarsal joint (lateral tarsometatarsal)a. Bony structurei. Cuboid1. Metatarsal facet on distal surface, divided by a vertical ridge into two articular surfaces of MT IV and Vii. Base of metatarsal IV1. Has a rectangular shape unlike other metatarsal basesiii. Base of metatarsal V1. Has a triangular shape with the apex directed laterally and the base against MT IV2. Both MT bases have a facet on the side for articulation with each other (MT IV on the lateral side of the base and MY V on the medial side of the base)XV. Medial Tarsaometatarsal jointa. Bony structurei. Medial cuneiform1. Distal, kidney shaped articular facet (medially convex in outline)ii. Base of MT I1. Kidney shaped articular facetiii. There may be a fibrous articulation between the bases of MT I and II. In that case, it may be included within the joint cavity of the first tarsometatarsal joint or instead, in the freat tarsal synovial cavityXVI. Great tarsal synovial cavitya. The remaining, centrally grouped intertarsal tarsometatarsal articulations are all enclosed within one synovial capsule and share a single synovial joint cavityb. Many articulations are involved:i. Cuneonavicular1. Anterior (distal) facet of navicular2. Posterior (proximal) facets of the three cuneiformsii. Intercuneiform1. Medial cuneiforma. Two facets on the lateral side, one oval shaped anteriorly and one L shaped posteriorly2. Middle cuneiforma. Two facets on the medial side (oval shaped and L shaped corresponding to those on the lateral side of the medial cuneiform) and one oval shaped facet on the lateral side.3. Lateral cuneiforma. An oval shaped facet on the medial side (corresponding to the one on the lateral side of the middle cuneiform) and two demifacets (half facets), one over the other, on the distal edge (for articulation with the base of MT II)iii. Cuneocuboid1. Lateral cuneiforma. An oval shaped facet for the lateral side (there may also be a small oval facet in the anterior edge for the base of MT IV)2. Cuboida. An oval shaped facet on the medial surface corresponding to the facet on the lateral side of the lateral cuneiform. iv. Cuboidonavicular1. This is a highly variable articulation. Usually, there is a fibrous joint at the posterodorsal corner of the navicular and cuboid bones with an Interosseous ligament in between.2. This is not included in any synovial joint3. Sometimes two smooth facets (one on each bone) occur here and are incorporated into the synovial joint cavityv. Remaining tarsometatarsal articulations1. Bases of MT II and III with anterior (distal) facets of middle and lateral cuneiforms2. Anteromedial corner of lateral cuneiform (having two demi-facets) with the lateral side of the base of MT II (having two corresponding facets)3. Medial side of the base of MT II with anterolateral corner of medial cuneiform each having an oval facetvi. Remaining intertarsal articulations1. Between MT bases II and IIIa. One facet on the lateral side of the base of MT II and a corresponding facet on medial side of base MT III (this side has a total of three facets- the other two articulating with the third cuneiform). b. Between bases III and IVi. One facet is situated superiorly on the lateral side of the base of MT III and a corresponding facet is on the medial side of the base of MT IVc. There is usually no articulation between the bases of MT I and II. Basal articulation between MT IV and V is part of the anatomically separate cubo-metatarsal joint.c. The ligaments discussed so far have almost all involved the bones of the hindfoot: talus and calcaneus; the following is a list of the remaining intertarsal, the tarsometatarsal, and proximal intermetatarsal ligaments:i. Dorsal cuboideonavicularii. Plantar cuboideonaviculariii. Interosseous cuboideonavicular1. This ligament is sometimes absent and the two bones instead bear smooth facets for synovial articulation and are included in the great synovial joint cavityiv. Dorsal cuneonavicular1. Three ligaments, from the navicular to each of the three cuneiformsv. Plantar cuneonavicular1. Also three ligaments, but less distinct since they merge with the fibers of the expansion of the tendon of tibialis posterior2. The strongest of these ligaments is between the navicular and the medial cuneiformvi. Dorsal intercuneiform and cuneocuboid1. Three transverse ligaments between adjacent cuneiforms and cuboidvii. Plantar intercuneiform and cuneocuboid1. Similarly arranged to the dorsal set except that the cuneocuboid ligament is oblique rather than transverse in positionviii. Interosseous intercuneiform and cuneocuboid1. Again, three ligaments but these occurring between the sides of adjacent bones close to the plantar surfaced. Tarsometatarsal ligamentsi. Dorsal tarsometatarsal1. Eight ligaments, one between each tarsal and its adjacent metatarsal base and three additional: between the bases of MT II and medial cuneiform, base of MT II and lateral cuneiform and base of MT IV and lateral cuneiformii. Plantar tarsometatarsal1. Nine ligaments; variable in arrangement and not as strong overall as the dorsal set. 2. Fibers merge with the long plantar ligament and tendon of tibialis posterior3. Strongest of the ligaments are those to MT I and MT II, while the weakest are the ligaments to MT IV and MT Viii. Interosseous tarsometatarsal1. Three ligamentsa. LISFRANCS- between the lateral side of the medial cuneiform and the medial side of the base of MT II; strongest of the three; forms part of the capsular wall between the medial tarsometatarsal joint and the general tarsal jointb. Another ligament between the medial side of the lateral cuneiform and the lateral side of the base of MT II; weakest of the threec. Another between the lateral side of the lateral cuneiform and the medial side of the base of MT IVe. Intermetatarsal ligamentsi. Dorsal intermetatarsal1. Transverse fibers connecting adjacent bases of metatarsalsii. Plantar intermetatarsaliii. Interosseous intermetatarsal1. Attached to adjacent sides of the metatarsal basesXVII. Metatarsophalangeal jointsa. The five metatarsophalangeal joints (MPJ or MTPJs) are synovial of the condyloi (ellipsoid) type. b. The main movements are flexion (toes turn down or curl under toward ventral or plantar surface) and extension (toe straightens out or lifts upwards dorsally).c. Slight additional movement is possible: adduction/abductiond. All the joints are built with the same featurese. The first MTP joint, however, has some unique additional features as a result of the presence of two sesamoid bones on the plantar aspecti. This joint will be describes separately following the description of the othersf. Bony Structurei. Metatarsal head1. Articular surface convex and elongate dorsoventrally (in the sagittal plane) 2. The plantar articular end is more extensive than the dorsal end3. Flattened, non-0articular sides each having a tubercleii. Base of proximal phalanx1. Circular or oval and concaveg. Ligamentsi. Capsule1. On the phalanx is closely attached to articular margin2. On the metatarsal head, is closely attached to dorsal articular margin, but more proximally on the sides (where it is attached to the tubercles) and farthest away from the edge of the facet on the plantar side. 3. The capsule is loose on the plantar aspect to allow for movement4. Dorsally, the capsule itself is thin but is reinforced by the expansion of the extensor tendonsii. Collateral ligaments1. Reinforce the capsule medially and laterally2. Attached proximally to the medial and lateral tubercles of the metatarsal head and distally to the sides of the base of the phalanxiii. Plantar ligaments1. Also known as the plantar pad, plantar plate, glenoid ligament, and plantar metatarsaophalangeal ligament2. Fibrocartilagenous disc or pad which thickens the plantar aspect of the capsule3. More firmly attached to the phalanx than to the metatarsal head and moves with the phalanx4. Four other structures are attached to each side of this disc:a. Flexor sheathb. Sling of the extensor expansionc. DTMLd. Collateral ligamentsiv. Deep transverse metatarsal ligament (DTML)1. Connects the capsules of the five metatarsal heads2. Attached closer to the plantar than dorsal sides and blends with the joint capsules, flexor sheaths and deep fascicles of the plantar fascia XVIII. First MTPJa. Bony structurei. Articular base of proximal phalanx as in the other MPJsii. Metatarsal I head1. Condyloid as in other metatarsals but having a central ridge, or crista on the plantar aspect which separates two slightly concave articular areas for the tibial (medial) and fibular (lateral) sesamoids2. The sesamoids are embedded in the dual tendons of FHB with their depp (superior, dorsal) aspects fixed in the capsular wall and internally articulating (by cartilage covered facets) with the metatarsal head3. The plantar pad is attached between them and binds them firmly together4. These three structures form a deep groove for the flexor hallucis longus tendon externally to the joint5. Internally, the two sesamoids are part of the joint (both functionally and anatomically) sharing a joint capsule, joint cavity and synovial with the articular facets of the head and the phalanx6. Thus, the four bones (instead of two at the other MPJs) form the first MTPJiii. Ligaments1. Capsulea. As in other MPJs except in having the sesamoids in it and the DTML attached to the lateral side of the joint onlyb. The dorsal aspect of the capsule does not always have the typical extensor expansion and therefore slings of this structure are not usually attached to the plantar pad2. Sesamoids ligamentsa. Tibial and fibular proximal sesamoidal ligamentsi. From the head (distal to the tubercle) to each sesamoidsb. Tibial and fibular sesamoids ligamentsi. From each of the sesamoids to the side of the phalanxc. Intersesamoid ligamenti. Between the two sesamoidsXIX. Interphalangeal Joitnsa. Bony structurei. Proximal and middle phalangeal heads have articular trochlear shape (sagittaly grooved) and tubercles on the sidesii. Middle and distal phalangeal bases have shallow sagittal ridges (or crests) fitting the corresponding trochlear headsb. Ligamentsi. Capsule1. More closely fitting than MPJ capsulesii. plantar pad and collateral ligaments as in MPJsiii. absence of a transverse ligament and lateral extensor expansion