Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Ligament

3,078 views

Published on

overview of ligaments

Published in: Education
  • Be the first to comment

Ligament

  1. 1. LIGAMENT PRASHANTH 1st YR PG
  2. 2. DEFINITION: a short band of tough, flexible fibrous connective tissue which connects two bones or cartilages at a joint or supporting an organ.
  3. 3. • HISTOLOGY: • At the microscopic level, ligaments are much more complex, being composed of cells called fibroblasts which are surrounded by matrix. • The cells are responsible for matrix synthesis and they are relatively few in number and represent a small percentage of the total ligament volume. • Although these cells may appear physically and functionally isolated, recent studies have indicated that normal ligament cells may communicate by means of prominent cytoplasmic extensions that extend for long distances and connect to cytoplasmic extensions from adjacent cells, thus forming an elaborate 3-dimensional architecture.
  4. 4. • Gap junctions have also been detected in association with these cell connections raising the possibility of cell-to-cell communication and the potential to coordinate cellular and metabolic responses throughout the tissue. • Ligament microstructure can be visualized using polarized light that reveals collagen bundles aligned along the long axis of the ligament and displaying an underlying "waviness" or crimp along the length. • Crimp is thought to play a biomechanical role, possibly relating to the ligaments loading state with increased loading likely resulting in some areas of the ligament uncrimping, allowing the ligament to elongate without sustaining damage
  5. 5. STRUCTURE: Extracellular components consist of: water Type I collagen (70% of dry weight) elastin higher elastin content than tendons lipids proteoglycans epiligament coat present in some ligaments, not all analogous to epitenon of tendons Cellular component the main cell type in both tendons and ligaments is the fibroblast both tendons and ligaments have low vascularity and cellularity
  6. 6. the crimped structure of the collagen fibre bundles permits stretching by 10–15% before failure. This combination of strength and extensibility enables ligaments to absorb more strain energy per unit weight than any other biological material, and makes them very effective shock absorbers .
  7. 7. • Ligaments vs. tendons – composition • compared to tendons, ligaments have –lower percentage of collagen –higher percentage of proteoglycans and water –less organized collagen fibers –rounder fibroblasts
  8. 8.  An important mechanical difference between tendons and ligaments is that ligaments often contain bundles of collagen fibres orientated in a range of directions, presumably because bones can be moved apart in a range of directions, whereas the fibres in a tendon are aligned only in the direction in which the muscle pulls on the tendon.
  9. 9. • Two types of ligament bone insertion – indirect (fibrous insertion): • most common form of bone insertion • superficial fibers insert into the periosteum • deep fibers insert directly into bone via perforating collagen fibers called Sharpey fibers • at insertion, endotenon becomes continuous with periosteum • examples –MCL inserting into proximal tibia
  10. 10. –direct (fibrocartilaginous insertion): • has both deep and superficial fiber insertion • deep fibers –have four transitional zones of increasing stiffness that allow for force dissipation and reduce stress concentration »Zone 1 (tendon or ligament proper) • consists of well aligned type I collagen fibers with small amounts of proteoglycan decorin
  11. 11.  Zone 2 (fibrocartilage)  consists of types II and III collagen, with small amoutns of type I, IX and X collagen, and proteoglycans aggrecan and decorin  Zone 3 (mineralized fibrocartilage)  consists of type II collagen, with significant amounts of type X collagen and aggrecan  Zone 4 (bone)  is made up of type I collagen, with high mineral content  examples supraspinatus insertion
  12. 12. • FUNCTIONS: a)STABILITY: • One of the main functions of ligaments is mechanical as they passively stabilize joints and help in guiding those joints through their normal range of motion when a tensile load is applied. • Ligaments exhibit nonlinear anisotropic mechanical behaviour and under low loading conditions they are relatively compliant, perhaps due to recruitment of "crimped" collagen fibres as well as to viscoelastic behaviours and interactions of collagen and other matrix materials.
  13. 13. • Continued ligament-loading results in increasing stiffness until a stage is reached where they exhibit nearly linear stiffness and beyond this, then, ligaments continue to absorb energy until tensile failure (disruption).
  14. 14. • b)VISCOELASTIC BEHAVIOUR: • Another ligament function relates to its viscoelastic behaviour in helping to provide joint homeostasis. • Ligaments "load relax" which means that loads/stresses decrease within the ligament if they are pulled to constant deformations. • Ligaments also "creep" which is defined as the deformation (or elongation) under a constant or cyclically repetitive load. • Creep is particularly important when considering joint injury or reconstructive surgery as excessive creep could result in laxity of the joint thus predisposing it to further injury
  15. 15. • C)PROPRIOCEPTION: • A third function of ligaments is their role in joint proprioception, which is referred to as the conscious perception of limb posi tion in space. • In joints such as the knee, proprioception is provided principally by joint, muscle and cutaneous receptors. • When ligaments are strained, they invoke neurological feedback signals that then activate muscular contraction and this appears to play a role in joint position sense. • Although progress continues to be made to elucidate the role of proprioception in normal ligament function and during injury, more precise quantification is the subject of ongoing analysis.
  16. 16. •ATTACHMENTS
  17. 17. • Anterior sternoclavicular ligament: • The anterior sternoclavicular ligament is broad and attached above to the anterosuperior aspect of the sternal end of the clavicle. • It passes inferomedially to the upper anterior aspect of the manubrium, spreading onto the first costal cartilage. • Posterior sternoclavicular ligament : • The posterior sternoclavicular ligament is a weaker band posterior to the joint. • It descends inferomedially from the back of the sternal end of the clavicle to the back of the upper manubrium
  18. 18. • Interclavicular ligament : • The interclavicular ligament is continuous above with deep cervical fascia, and unites the superior aspect of the sternal ends of both clavicles; some fibres are attached to the superior manubrial margin.
  19. 19. • Acromioclavicular ligament: • The acromioclavicular ligament is quadrilateral. • It extends between the upper aspects of the lateral end of the clavicle and the adjoining acromion. • Its parallel fibres interlace with the aponeuroses of trapezius and deltoid
  20. 20. • Coracoclavicular ligament : • The coracoclavicular ligament connects the clavicle and the coracoid process of the scapula . • Though separate from the acromioclavicular joint, it is a most efficient accessory ligament, and maintains the apposition of the clavicle to the acromion.
  21. 21. • Coracohumeral ligament : • The coracohumeral ligament is attached to the dorsolateral base of the coracoid process and extends as two bands, which blend with the capsule, to the greater and lesser tubercles . Portions of the coracohumeral ligament form a tunnel for the biceps tendon on the anterior side of the joint. • The rotator interval is reinforced by the coracohumeral ligament. • It also blends inferiorly with the superior glenohumeral ligament.
  22. 22. • Anular ligament : • This is a strong band, which encircles the radial head,holding it against the radial notch of the ulna. • Forming about four-fifths of the ring, it is attached to the anterior margin of the notch, broadens posteriorly and may divide into several bands. • It is attached to a rough ridge at or behind the posterior margin of the notch; diverging bands may also reach the lateral margin of the trochlear notch above and proximal end of the supinator crest below. • The proximal anular border blends with the elbow joint capsule, except posteriorly where the capsule passes deep to the ligament to reach the posterior and inferior margins of the radial notch.
  23. 23. • From the distal ANULAR border a few fibres pass over reflected synovial membrane to attach loosely on the radial neck. • The external surface of the anular ligament blends with the radial collateral ligament and provides an attachment for part of supinator. • Subluxation of the radial head through the anular ligament arising from a sudden jerk on the arm is a relatively common injury in young children (known as ‘pulled elbow’).
  24. 24. • This is because the anular ligament has vertical sides in children compared with more funnel-shaped sides in adults.
  25. 25. • Triangular fibrocartilage complex (TFCC) and distal radio-ulnar ligaments: • The triangular fi brocartilage complex (TFCC) is a ligamentous and cartilaginous structure which suspends the distal radius and ulnar carpus from the distal ulna. • The TFCC stabilizes the ulnocarpal and radio-ulnar joints, transmits and distributes load from the carpus to the ulna, and facilitates complex movements at the wrist . • By definition,it is made up of the cartilaginous disc, the meniscus homologue (an embryological remnant of the ‘ulnar’ wrist that is only occasionally present), volar and dorsal distal radio-ulnar ligaments, ulnar collateral ligament, floor of extensor carpi ulnaris subsheath, ulnolunate and ulnotriquetral ligaments.
  26. 26. • FUNCTION: a. The triangular fibrocartilage complex stabilizes the wrist at the distal radioulnar joint. b. It also acts as a focal point for force transmitted across the wrist to the ulnar side. • Traumatic injury or a fall onto an outstretched hand is the most common mechanism of injury. The hand is usually in a pronated or palm down position. • Tearing or rupture of the TFCC occurs when there is enough force through the ulnar side of the hyperextended wrist to overcome the tensile strength of this structure.
  27. 27. • superficial and deep components of the distal radio-ulnar ligaments which act as a functional couple stabilizing the rotation of the ulnar head on the sigmoid notch of the radius
  28. 28. • ligamenta flava : ligaments of the spine. • They connect the laminae of adjacent vertebrae, all the way from the second vertebra, axis, to the first segment of the sacrum.
  29. 29. • Function: • Their marked elasticity serves to preserve the upright posture, and to assist the vertebral column in resuming it after flexion. • The elastin prevents buckling of the ligament into the spinal canal during extension, which would cause canal compression. • Clinical relevance: • Hypertrophy of this ligament may cause spina stenosis, particularly in patients with diffuse idiopathic skeletal hyperostosis,]because it lies in the posterior portion of the vertebral canal.
  30. 30. • Iliofemoral ligament: • The iliofemoral ligament is very strong and shaped like an inverted Y, lying anteriorly and intimately blended with the capsule. Its apex is attached between the anterior inferior iliac spine and acetabular rim, its base to the intertrochanteric line.
  31. 31. • FUNCTION: • In a standing posture, when the pelvis is tilted posteriorly, the ligament is twisted and tense, which prevents the trunk from falling backwards and the posture is maintained without the need for muscular activity. • In this position the ligament also keeps the femoral head pressed into the acetabulum. • As the hip flexes, the tension in the ligament is reduced and the amount of possible rotations in the hip joint is increased, which permits the pelvis to tilt backwards into its sitting angle. Lateral rotation and adduction in the hip joint is controlled by the strong transversal part, while the descending part limits medial rotation.
  32. 32. • Ischiofemoral ligament: • The ischiofemoral ligament thickens the back of the capsule and consists of three distinct parts. The central part, the superior ischiofemoral ligament, spirals superolaterally from the ischium, where it is attached posteroinferior to the acetabulum, behind the femoral neck to attach to the greater trochanter deep to the ilio-
  33. 33. • Pubofemoral ligament: • The pubofemoral ligament is triangular, its base attaching to the iliopubic eminence, superior pubic ramus, obturator crest and obturator membrane. • It blends distally with the capsule and deep surface of the medial iliofemoral ligament.
  34. 34. • FUNCTION: • The pubofemoral ligament stabilizes the hip joint. • It prevents the joint from moving beyond its normal range of motion, front-to-back and side-to-side. • It also limits external rotation of the joint. • The pubofemoral ligament is considered to be a supporting element of the joint capsule. • It reinforces the inferior and anterior capsule.
  35. 35. • Anterior cruciate ligament: • The anterior cruciate ligament is attached to the anterior intercondylar area of the tibia, just anterior and slightly lateral to the medial tibial eminence, partly blending with the anterior horn of the lateral meniscus. • It ascends posterolaterally, twisting on itself and fanning out to attach high on the posteromedial aspect of the lateral femoral condyle .
  36. 36. • FUNCTION: • it resist anterior translation & medial rotation of the tibia,in relation to the femur. • Congenital absence of the anterior cruciate ligament is rare. The condition is usually associated with lower limb dysplasia and may be a cause of instability of the knee
  37. 37. • Posterior cruciate ligament: • The posterior cruciate ligament is thicker and stronger than the anterior cruciate ligament . • It is attached to the lateral surface of the medial femoral condyle and extends up onto the anterior part of the roof of the intercondylar notch, where its attachment is extensive in the anteroposterior direction. • They pass distally and posteriorly to a fairly compact attachment posteriorly in the intercondylar region and in a depression on the adjacent posterior tibia. • This gives a fan-like structure in which fibre orientation is variable
  38. 38. • FUNCTION:it prevent the femur from sliding of the anterior edge of tibia & to prevent the tibia from displacing posterior to the tibia.
  39. 39. • Medial collateral ligament (deltoid ligament): • The medial collateral ligament (deltoid ligament) is a strong, triangular band, attached to the apex and the anterior and posterior borders of the medial malleolus • Of its superficial fibres, the anterior (tibionavicular) pass forwards to the navicular tuberosity, behind which they blend with the medial margin of the plantar calcaneonavicular ligament. • intermediate (tibiocalcaneal) fibres descend almost vertically to the entire length of the sustentaculum tali. • posterior fibres (posterior tibiotalar) pass posterolaterally to the medial side of the talus and its medial tubercle. • The deep fi bres (anterior tibiotalar) pass from the tip of the medial malleolus to the non-articular part of the medial talar surface.
  40. 40. • FUNCTION: a) Superficial deltiod primarily resist eversion of foot. b) Tibionavicular portion suspends spring lig & prevents inward displacement of head talus ,while tibiocalcaneal portion prevents valgus displacement. c) Deep deltiod lig extends the function of medial malleolus& lateral displacement of talus &prevents external rotation of talus.
  41. 41. • Lateral ligament : • The lateral ligament has three discrete parts. a) The anterior talofibular ligament extends anteromedially from the anterior margin of the fibular malleolus to the talus, attached in front of its lateral articular facet and to the lateral aspect of its neck . FUNCTION: a) Primary restraint to inversion in plantar flexion b) Resists anterolateral translation of talus in he mortise  Weakest of the lateral lig ,so mst cmnly injured in sprains.
  42. 42. B) The posterior talofibular ligament runs almost horizontally from the distal part of the lateral malleolar fossa to the lateral tubercle of the posterior talar process a ‘tibial slip’ of fibres connects it to the medial malleolus. FUNCTION: a. Plays only a supplementary role in ankle stabilty when the lateral lig is intact. b. Limits posterior talar displacement within the mortise as well as talar external rotation. c. if ATFL and CFL are incompetent then – short fibres of PTFL restrict internal and external rotation, talar tilt, and dorsiflexion; – long fibres inhibit only external rotation, talar tilt, and dorsiflexion
  43. 43. C) The calcaneofibular ligament, a long cord, runs from a depression anterior to the apex of the fibular malleolus to a tubercle on the lateral calcaneal surface and is crossed by the tendons of fibularis longus and brevis . • FUNCTION: a. primary restrain to inversion in neutral or dorsiflexed position b. restrains subtalar inversion, thereby limiting talar tilt within mortise
  44. 44. • Calcaneonavicular Ligament (Spring Ligament): – attaches from the sustentaculum tali to the inferior aspect of the navicular • Function – static stabilizer of the medial longitudinal arch and head of the talus

×