THE SHORT DESCRIPTION OF THE JOINTS 2. THE LOWER LIMB (Dr. Dóra Reglődi*, version 02-2007)

Pelvic joints Sacroiliac joint 1. Articulating surfaces -the auricular articular surfaces of the iliac bone and of the sacrum -the surfaces show reciprocal depressions and elevations, which add to the strength of the joint -surfaces are covered by fibrous cartilage (lot of friction) 2. capsule- very strong, and further strenthened by the ant. and post. ligaments 3. ligaments -interosseus sacroiliac ligaments- short strong fibers running between the tuberosities of both bones, these are not visible, because they are covered by: -dorsal sacroiliac ligaments- short and longer fibers running between the sacrum and iliac bone -ventral sacroiliac ligaments- further strengthen the capsule on the ant. side Pubic symphysis - between the two symphyseal surfaces of the pubic bones - interpubic disc between the surfaces, which may contain a cavity inside (therefore, the symphysis is considered a transition between synchondrosis and synovial joint) - there are accessory ligaments, strengthening the attachment: superior and arcuate pubic ligaments. - almost no movement, except for late pregnancy, when the ligaments become loose Accessory ligaments of the pelvis - sacrotuberal ligament - connects the sciatic tuberosity to the posterior iliac spines and lateral parts of sacrum - sacrospinous ligament- connects the sciatic spines to the sacrum and coccygeal bone. (with these 2 ligaments the greater and lesser sciatic notches are converted into foramina) -iliolumbar ligament- connects the L4-5 transverse processes to the post. side of the iliac crest, thus completing the post. wall of the pelvis - obturator membrane- covers the obturator foramen, except for the obturator sulcus, which is by this membrane closed to be the obturator canal for the obturator artery and nerve.

*Revised by Dr. Tibor Hollósy

Joints-2 - inguinal ligament – bw. the ant. sup. iliac spine and the pubic tubercle (the subinguinal hiatus is formed under the ligament) movements -no movements, the pelvis is held together very strongly to provide stability, the whole body weight acts on the promontorium, and then through the sacroiliac joints to the heads of femur -the force caused by the body weight has 2 components: -one would push the sacrum more downward, but because of the shape of the surfaces and the strong sacroiliac ligaments, the more the sacrum is pushed down, the more strongly is held between the iliac bones -the other direction of the force would push the promontorium down, and the caudal end of the sacrum up (see shape of sacrum), this is prevented by the strong sacrotuberal and sacrospinous ligaments -in sitting position the weight is conveyed to the sciatic tuberosities, and the symphysis is more stretched

Hip joint 1. Articulating surfaces -head of femur, which in the center has the fovea capitis femoris, where there is no hyaline cartilage, but a ligament: the ligament of the head of femur is attached. (This ligament is thought to be of special importance, because it contains an artery which supplies the head) - acetabulum of the hip bone, which is covered by hyaline cartilage in a C shaped surface: the lunate surface. The center is filled with fat. It has an acetabular notch, which is traversed by a ligament: the transverse ligament of the acetabulum, which completes the art. surface -the acetabulum is further deepened by the acetabular labrum, which is a fibrous cartilage ring - the head is included over its equatorian line in the acetabulum, so it is called enarthrosis 2. capsule -the neck is also included in the capsule, that is how blood vessels reach the joint, they can be injured at fractures, which can lead to necrosis of the head -very strong and further strenghtened by the ligaments which cover the whole capsule 3. ligaments -iliofemoral lig. (the strongest ligament of the body) origin: above the acetabulum,

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Joints-2 insertion: in a V shape on the intertrochanteric line -pubofemoral lig. -origin: sup. limb of pubic bone, insertion: above the lesser trochanter, it goes around the neck of femur in a spiral manner from anterior to post. -ischiofemoral lig.- origin: limb of sciatic bone, insertion: neck of femur medial to the greater trochanter, near the trochanteric fossa (the fibers also follow a spiral course) -all ligaments follow a spiral course, from ant. to inferior and post. to superior they are all streched in an extended position (180 degrees) and more loose in the flexed position that is why no/minimal retroflexion is possible in the hip joint -the deeper fibers of all 3 ligaments form the zona orbicularis, which slings around the neck, and helps keeping the femur in its position (internal ligaments: lig. of the head of femur, and transverse lig. of the acetabulum, see above) 4. movements type:ball and socket -around the sagittal axis (connecting the middle of the head to the greater trochanter): abduction- adduction (variable, but in abduction, the greater trochanter faces the margin of the acetabulum, and no further movement is possible) -around the transverse axis (going through the middle of the head): flexion -extension (no retroflexion is possible), the flexion is restricted by the post. thigh muscles (individually very variable) - around the axis of the femur (from the center of head to the intercondylar fossa) medial and lateral rotation - combination of all 3: circumduction (connecting the end-points of the movements) (traumatic dislocations happen rarely, but congenital luxation/dysplasia is more often, when the socket is too shallow)

Knee joint 1. Articulating surfaces -condyles of the femur and condyles of the tibia ( the fibula is not directly included in the joint, only by a ligament: the ligament of the head of fibula) femur condyles 1.- the circumference of the femur condyles is smaller in both sagittal and frontal planes than the flattened condyles of tibiaÎ there is an incongruence bw. them 2. - the femur condyles have a spiral shape, with the epicondyles in excentric, posterior positionÎso the anterior circumference is larger than the posteriorÎ in the flexed position the smaller, posterior part faces a more post. part of tibial condylesÎ the incongruence is even bigger 3. -the ant. margin of medial femur condyle has a lateral curve (Îsee later

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Joints-2 passive rotation), and the medial is longer than the lateral 4. -the condyles diverge posteriorlyÎ that is why the menisci slide apart in flexed position Menisci - there is a lateral and medial fibrous disc: the menisci to equalize the incongruence -both menisci are C shaped, the medial meniscus has a longer diameter in sagittal direction, than the lateral one, which is almost a closed ring - both ends of the lateral meniscus, and the post. end of the medial meniscus are attached to the intercondylar eminence of tibia - the ant. end of the medial men. is attached to the lateral one by a ligament: the ligamentum transversum genus - the whole medial meniscus, and part of the lateral meniscus are attached to the capsule - the lateral parts of the menisci are thicker, and have a better blood supply in many animals the knee is two separate joints divided by a septum, in human there is only a remnant of this septum: the plica synovialis infrapatellaris (from intercondylar fossa to the ant. side of the capsule) movements of the menisci: in every position they move in order to equalize the incongruence they can slide in- sagittal direction: forward-backward and- in transverse direction: slide apart and towards each other (by this the diameter of the menisci change) -they can also become flattened in flexed position in flexion: the menisci slide backward, apart from each other, and the sagittal diameter decreases, the shape is more flattened (the movements of the medial meniscus are more restricted due to the attachments to the medial collateral ligament and tot he capsule / injuries happen more often) - the meniscofemoral ligament plays an important role in the movements of the menisci 2. capsule posteriorly origin: above the femur condyles, attached to the menisci, and inserts to the margin of the tibia condyles. The capsule here is strong, further strengthened by ligaments, and prevents hyperextension on the sides: above the art. surfaces, on the medial side is attached to the meniscus, on the lateral side, attached only to the ant. margin of the meniscus. On the lateral post. side, the capsule is partly formed by a tendon: the tendon of the popliteal muscle. anteriorly: origin: patellar surface, but then turns upward: suprapatellar recess, which unites with the originally separate suprapatellar bursa, and the whole structure is called suprapatellar bursa after about 8 cm. under the extensor muscles it turnes downward, and is attached to the patella, partly goes downward on the sides of the patella (the patella is inserted in the capsule)

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Joints-2 under the patella the capsule becomes very thin and the infrapatellar adipose pad pushes it towards the art. cavity inserts on the ant. margins of the tibia condyles 3. ligaments collateral ligaments the medial coll. lig. : from the medial epicondyle to the medial condyle of tibia, attached to the capsule and the meniscus the lateral coll. lig. : from lateral epicondyle to the head of fibula, not attached to the capsule or to the meniscus. Under the ligament, the tendon of the popliteal muscle is runningÎhere it formes partly the capsule intracapsular ligaments: the cruciate ligaments anterior and posterior cruciate ligaments: from the condyles of the femur facing the intercondylar fossa. anterior lig: from the medial margin of the lateral condyle to the ant. intercondylar area of tibia (this is longer than the posterior one) post lig: from the lateral margin of medial condyle to the post. intercondylar area the 2 ligaments cross each other some fibers are streched in every position of the joint (the lig. transversum genus is also intracapsular, this connects the medial meniscus to the lateral-see above, and the meniscofemoral ligament is also intracapsular – see above) oblique popliteal ligament- in the post. part, is part of the inserting tendon of the semimembranosus muscle patellar ligament -is also a tendon- the tendon of the quadriceps muscle- connects the patella to the tuberosity of tibia, but there are other inserting parts of this muscle: the medial and lateral patellar retinaculum Bursae -besides the suprapatellar bursa, there are numerous others in front and behind the joint, wherever skin, muscle or tendon rubs against bone. (eg: prepatellar, infrapatellar, popliteal etc, these can be inflamed and filled with fluid) 4. mechanism type: trochogynglimus -around the transverse axis (bw. the two epicondyles) : flexion-extension (art. surfaces, and movements of the menisci see above) hyperextension is prevented by: the collateral ligaments, which are stretched in extension., the strong post. capsule., the stretching of certain fibers of the cruciate ligaments and the ant. edge of the menisci

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Joints-2

in flexion the patella comes out of the patellar fossa, and is moved to the intercondylar fossa. In the flexed position the infrapatellar adipose tissue has an important role in equalizing the incongruence - rotation: 2 types: passive and active active rotation: around a vertical axis through the medial tibial condyle only possible in flexed position, because the strong collateral ligaments become lax in flexed position and there are also no muscles which would do rotation in extended position (the flexors of the knee). passive rotation: around a vertical axis through the lateral condyle of tibia it is caused mainly by the lateral curve found in the medial condyle of femur (see above) and it occurs only at the very end of extension - a small lateral rotation and the very beginning of flexion - a small medial rotation.

Ankle joint (talocrural joint) 1. Articulating surfaces trochlea of talus and the inf. art. surface of tibia and medial and lateral malleolar surfaces of tibia and fibula - the trochlea is much wider in the anterior part (see mechanism) - the tibiofibular syndesmosis is an accessory part of the joint, it connects the two bones to each other, turning them into a very strong socket 2. capsule very thin ant. and post on the sides strengthened and covered by the ligaments 3. ligaments strong collateral ligaments which radiate from the malleoli to the talus, calcaneus and the navicular bone - medial collateral lig: the deltoid ligament has a triangular shape, from the medial malleolus it radiates to the navicular bone, the ant. and post. parts of talus and to the sustentaculum tali of the calcaneus - lateral collateral ligaments: - ant. talofibular, post. talofibular and calcaneofibular ligaments 4. mechanism type: hinge joint

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Joints-2 dorsalflexion (15 degrees) and plantarflexion (40 degr) around a transverse axis that connects the lateral malleolus to the tibia 1.5-2 cm. below the medial malleolus ( the tibia ends more proximally) the joint is more stabilized in dorsalflexion, because the trochlea tali is wider anteriorly. In plantarflexion, the joint is loose (see walking in high-heeled shoes). In normal walking when the foot leaves the ground it is in plantarflexion, when it arrives to the ground it is in dorsalflexion (more stability).

Talotarsal joint It is between the calcaneus, talus and the navicular bone, composed of two separate joints, which are separated by the sinus tarsi, but have common ligaments, and movements 1. Talocalcaneonavicular joint 1. Art surfaces: - mail part: head of talus, and the anterior and middle calcanear surfaces of talus. These 3 parts form a common spheroid art. surface. -female part: the proximal art. surface of the navicular bone, and the ant. and middle talar surfaces of calcaneus. The navicular bone and the calcaneus are not directly connected to each otherÎ there is a space bw. themÎ is filled with a ligament: the plantar calcaneonavicular ligament (spring ligament), the inner surface of which is covered by cartilageÎ so the female part is completed. (the ligament connects the sustentaculum tali and body of calcaneus to the navicular bone) The capsule of the joint surrounds the whole joint, and strong. 2. Subtalar joint between the post. calcanear surface of talus and post. talar surface of calcaneus. These surfaces add up to a hinge surface with an axis going from ant-medial to post-lateral. The ligaments and mechanism are common for the 2 joints: ligaments: - plantar calcaneonavicular lig (see above) - interosseous talocalcanear ligament - inside the sinus tarsi, it connects the walls of sulcus calcanei and sulcus tali. - Many other small ligaments connect the bones

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Joints-2 mechanism: the 1. joint would be a ball-and-socket joint, but of course it cannot move freely, there is a common movement of the 2 joints axis: from ant-medial-sup to post-lateral-inf around this axis: eversion (when sole faces laterally) and inversion (sole faces medially) on inversion the foot is: in plantarflexion, adduction and supination on eversion the foot is: in dorsalflexion, abduction and pronation

Other joints of the foot -calcaneocuboidal joint -saddle shaped surfaces, but its movement is very limited (is actually a plane joint), strengthened by very strong ligaments - Chopart joint - transverse intertarsal joint, not a separate joint, but bw. talus-calcaneus and navicular-cuboidal bones. It is more an articulation line, which has an S shape (was an important amputational line). - cuneonavicular joint: bw. navicular bone and cuneiform bones - tarsometatarsal joints bw. bases of metatarsal bones and tarsal bones, plane joints Lisfrank line connects the joints (amputation) - metatarsophalangeal joints / resemble those of the hand bw. metatarsal heads and the proximal phalanges of the toes restricted free joints with less movements than those of the hand ligaments (like those of the hand): plantar ligaments, collateral ligaments, deep metatarsal transverse ligaments movements: plantar and dorsalflexion, abduction and adduction (rotation is only passive) by flexed position, limited or no abduction is possible due to the stretching of the excentric collateral ligaments - interphalangeal joints hinge joints, like those in the hand Important ligaments of the foot - long plantar ligament- from calcaneus to cuboidal bone and to the II-V. metacarpal bases. - bifurcate ligament- connects the dorsal surface of calcaneus to the navicular and cuboidal bones in V-shape - plantar calcaneonavicular ligament - see above

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Joints-2

Arches of the foot only an arch-like structure can fulfill the functions of the foot, namely to support the body weight and to serve as a lever to propel the body in walking or running. Longitudinal arch From the tuber calcanei to the metatarsal bones Medial longitudinal arch: calcaneus, talus, navicular bone, the 3 cuneiform bones, and the first 3 metatarsal bones lateral longitudinal arch: calcaneus, cuboidal bone, and metatarsal bones IV and V. (actually we have 5 longitudinal arches, to the 5 metatarsal bones, starting from one point, the tuber calcanei and spreading like a fan) Transverse arch through the bases of the metatarsal bones and the cuboid and the 3 cuneiform bones assymmetrical, the highest point is the middle cuneiform bone, and the medial part is higher then the lateral end point. The metatarsi also form such a transverse arch, only the I. and V. metatarsi reach the ground These arches are held (and so the stability of the foot) by : -bones (shapes like wedges) -ligaments: plantar calcaneonavicular lig., long plantar lig., bifurcate lig., interosseous talocalcanear lig, plantar aponeurosis -muscles: the ant. tibial and long peroneal muscles pull the arches upward like a loop on the medial side: the ant. tibialis with the post. tibialis muscle on the lateral side: the extensor digitorum longus and the peroneus brevis muscle inferiorly: the small muscles of the foot When there is an overweight or overstress, first the muscular components get overstrain (pain), then the ligaments get loose, and so the arches get flattened (later the bones are also deformated).

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