BMS Anatomy Lecture 13 Hip and Knee Joints Fall 2023 PDF

BMS Anatomy Lecture 13 Hip and Knee Joints (In-Person Class) Presented By: Dr. K. Lumsden; [email protected] (Toronto Campus) Dr. M. Doroudi; [email protected] Boucher Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II Ph.D. FAAA (Author), Anne M. R. Agur BSc (OT) MSc Ph.D. FAAA (Au...

BMS Anatomy Lecture 13 Hip and Knee Joints (In-Person Class) Presented By: Dr. K. Lumsden; [email protected] (Toronto Campus) Dr. M. Doroudi; [email protected] Boucher Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II Ph.D. FAAA (Author), Anne M. R. Agur BSc (OT) MSc Ph.D. FAAA (Author), 9th ed. Upper Limb Chapter; Pages: 795 – 811 The hip is of ball and socket synovial variety with spherical articular surfaces. There are 3 axes in the joint: horizontal, vertical, and anteroposterior. The hip has 3 DOF; flexion/extension; abduction/adduction; and medial/lateral rotation. Circumduction, the combination of these three movements, occurs in the hip joint. Hip Joint 2 Joints of the Lower Limb Movement of the Hip joint: JOINT CLASSIFICATION ANGULAR MOVEMENTS Iliofemoral Ball and Socket = head of femur with acetabulum Flexion Extension Abduction Adduction Internal Rotation External Rotation Hip Joint The femoral head (1) forms about 2/3 of a sphere of diameter 4-5 Cm. The head is supported by the neck of femur, the axis of which runs superiorly, medially and anteriorly. The head of the femur in the adult forms an angle of ~125 (Angle of Inclination) with the femoral shaft to place the knee under the weight-bearing line of the head of the femur. There is an impression on the head for the attachment of the round ligament of the head, called the fovea. 4 Femur The head of the femur in the adult forms an acute angle of 10-30 with the femoral plane (angle of anteversion). Femoral anteversion can be determined by measuring the angle formed between the long axis of the femoral neck and a line parallel to the dorsal aspect of the femoral condyles 5 Femur An increase in this angle is called anteversion and is one factor that is considered to cause in-toeing, or pigeon toes, as well as genu valgum. A decrease in the angle is called retroversion, which may lead to out-toeing (external rotation) during standing and walking as well as genu varum during standing. The angle of anteversion normally decreases with growth and development of the child, causing orthopedists to be conservative in treatment of children who walk with intoeing. 6 Angle of Anteversion Anteversion Retroversion 7 ❑ Hip Joint (Articular Surfaces), Acetabulum (2) is hemispherical and is bounded by the acetabular rim. Only the lunate surface of the acetabulum is lined by a horseshoe-shaped articular cartilage, which is interrupted inferiorly by the deep acetabular notch. The central part of the cavity (acetabular fossa) is deeper and is non-articular. The acetabulum is directed laterally, inferiorly, and anteriorly. o The acetabular fossa permits movement of the ligamentum teres and importantly serves as a reservoir for synovial fluid when the hip is heavily loaded. o When joint forces are decreased, synovial fluid once again returns to the joint space to provide lubrication and nutrition to the articular cartilages. 8 Acetabular Labrum & Transverse Acetabular Ligament The acetabular labrum is a fibrocartilaginous ring inserted into the acetabular rim(2). It deepens the acetabulum and fills out the various gaps of the acetabular rim. Transverse acetabular lig (TAL) is attached to either side of the acetabular notch and to the labrum. 9 Round Ligament of the head of the femur The ligamentum teres (LT) of the head of the femur (ligamentum capitis femoris) (4) is a flattened fibrous band, which arises from the acetabular notch and runs at the floor of the acetabular fossa before its insertion into the fovea femoris capitis. It is embedded in fibroadipose tissue within the acetabular fossa and is lined by the synovial membrane. This ligament is extremely strong (breaking force equivalent to 45 Kg. weight) and its primary function is to carry the vascular supply to the head of the femur. 10 Hip Joint Capsule and Ligaments The capsule is like a cylindrical sleeve running from the hip bone to the upper end of the femur. Medially it is inserted into the acetabular rim and laterally into a line which runs along the intertrochanteric line and at the junction of the lateral and middle thirds of the femoral neck. The capsule of the hip is strengthened by powerful ligaments anteriorly and posteriorly. 1. The iliofemoral ligament: is a Y-shaped ligament that has two thick borders known as superior and inferior bands. It covers the hip joint anteriorly and superiorly. 2. The pubofemoral ligament is anterior and inferior to the hip, limiting lateral rotation & abduction. 3. The ischiofemoral ligament: is posterior and inferior, limiting medial rotation. 11 The fibrous layer of the joint capsule ❖ Parallel fibres linking two discs resemble those making up the tube-like fibrous layer of the hip joint capsule. ❖ When one disc (the femur) rotates relative to the other (the acetabulum), the fibers become increasingly oblique and draw the two discs together. ❖ Similarly, the extension of the hip joint winds (increases the obliquity of) the fibers of the fibrous layer, pulling the head and neck of the femur tightly into the acetabulum, increasing the stability of the joint. ❖ Flexion unwinds the fibers of the capsule. 12 Hip joint Flex.-Ext. Axis of Motion and ROM In standing, a horizontal axis running in a side-to-side direction is used for flexion and extension. The common hip axis represents a line connecting the centers of the two femoral heads, with movement occurring about this axis when, for example, the pelvis rocks forward and backward in standing, or when both knees are pulled up to the chest from a supine lying position. Active hip flexion with the knee flexed can be reached to 120. With the knee extended, flexion is limited to 7090 by the hamstrings. Passive hip flexion with knee flexed exceeds 145, but with knee extended would be less, due to hamstring stretching. Hyperextension of the hip is limited to 10-20 by the iliofemoral ligament. (further motion is usually perceived when one attempts this movement, however, it is extension of the lumbar vertebrae which gives a misleading impression). Hyperextension of the hip joint is less when knee joint is flexed due to the fact that the hamstrings lose some of their efficiency as extensors of the hip because their contraction has largely been utilized in flexing the knee. 1 2 3 4 5 Movement Hip Active Flexion (with knee extended) Hip Active Flexion (with knee flexed) Hip Passive Flexion (with knee flexed) Hip Hyperextension Hip Passive Hyperextension Degrees 70 - 90 120 145 10 - 20 30 13 Hip J. Abduction – Adduction Axis of Motion and ROM The axis for abduction and adduction in the standing position is in a front-to-back direction. Either the limb may move in relation to the pelvis (lifting the limb laterally), or the pelvis may move in relation to the limb (inclining the trunk to the side of the stance leg). In either case, either abduction or adduction of the hip is the correct term to use to describe these movements. Hip abduction is  45 and is usually accompanied by elevation of the pelvis. Hip adduction is frequently described as contact between the two thighs, or 0. However, with the legs crossed  30 - 40 of adduction is possible. 1 2 Movement Degrees Hip Abduction Hip Adduction 45 30 - 40 14 Hip J. Rotations Axis of Motion and ROM The axis for medial and lateral rotation in standing is vertical, and identical to the mechanical axis of the femur. Hip rotation is easier to observe when the knee is flexed to 90 and the motion of the tibia from the neutral position is measured. 1 2 Movement Hip Medial Rotation Hip Lateral Rotation Degrees 30 60 15 ❑ Flexor Muscles of the Hip These muscles lie anterior to the frontal plane, which passes through the center of the joint (a). There are many flexor muscles of the hip joint and the most important of which are the following (b): 1. Psoas major 2. Iliacus 3. Sartorius 4. Rectus femoris 5. Tensor fascia latae 6. Pectineus 7. Adductor longus 8. Gracilis 9. Anterior fibers of glutei medius and minimus These muscles may be classified in to 2 groups: o The first group (9,5) produce flexion, abduction, and medial rotation (Image A). o The second group (1,2,6,7) produce flexion, adduction, and lateral rotation (Image B). 16 Extensor Muscles of the Hip These muscles lie behind the frontal plane that passes through the center of the joint (a). There are two main groups (b): the one group is inserted into the femur and the other in the vicinity of the knee joint. The first group consists of the following muscles: 1. Gluteus maximus 2. Posterior fibers of gluteus medius 3. Posterior fibers of gluteus minimus The second group consists of the following muscles: 4. Biceps femoris 5. Semitendinosus 6. Semimembranosus 7. Adductor magnus 17 Abductor Muscles of the Hip These muscles generally lie lateral to the sagittal plane which traverses the center of the joint (a) and include the following: 1. Anterior fibers of gluteus medius 2. Gluteus minimus 3. Tensor fascia lata 4. Gluteus maximus (upper fibers) 5. Piriformis In certain positions, other muscles also contribute to the force of abduction: the Sartorius, Obturators, Gemelli. 18 Adductor Muscles of the Hip These lie generally medial to the sagittal plane, which traverses the center of the joint. 1. 2. 3. 4. 5. 6. 7. 8. 9. 11. 12. Adductor magnus Gracilis Semimembranosus Semitendinosus Biceps femoris Gluteus maximus Quadratus femoris Pectineus Obturator externus Adductor longus Adductor brevis 19 Rotator Muscles of the Hip The lateral rotators of the hip are: 1. Piriformis 2. Obturator internus 3. Obturator externus 4. Quadratus femoris 7. Gluteus maximus 8. Gluteus medius (Posterior fibers) 9. Gemelli (Not Shown) The medial rotator group consists of: 1. Tensor fascia lata 2. Gluteus minimus (Anterior fibers) 3. Gluteus medius (Anterior fibers) 20 Knee Joint ❑ Knee Joint: Introduction The knee joint, a synovial modified hinge joint, is a complex joint, consisting of three bones, 2 DOF, and three articulating surfaces: Medial tibio-femoral Lateral tibio-femoral Patello-femoral ❖ All of which are enclosed by a common joint capsule. The multiple functions of the knee include: Withstanding large forces Providing great stability Enabling a large ROM. ✓ Mobility is primarily provided by the knee bony structure, while the soft tissues, including ligaments, muscles, and cartilage, provide stability. ✓ Of these supports, the muscles are the most important; therefore, many sport injuries are preventable through appropriate conditioning and training. 21 Joints of the Lower Limb Movement of the Knee Joint: JOINT CLASSIFICATION ANGULAR MOVEMENTS Flexion Extension Tibiofemoral = distal femur on condyles of tibia Modified Hinge Internal rotation External rotation Patellofemoral = Patella on femur Planar Slide / Glide Articular Surfaces of the Knee Joint The articular surfaces of the femur represent a segment of a pulley (1), which recalls the twin undercarriage of an aeroplane (2). The two femoral condyles, convex in both planes, form the two lips of the pulley, and they are extended anteriorly (3) by the pulley-shaped patellar surface. The tibial surfaces are reciprocally curved and comprise two curved and concaved parallel gutters which are separated by a blunt eminence running antero-posteriorly (4). This eminence lodges the two intercondylar tubercles, and if we prolong this eminence, it coincides with the vertical ridge on the deep surface of the patella (P) To allow axial rotation, the tibial surface (5) must be so modified as to shorten the intercondylar eminence. This is achieved by planning the two ends of the eminence (6) and leaving its middle part to act as a pivot, which, by lodging in the intercondylar notch, allows the tibia to rotate around it (axis R). 23 ❑ Joint Capsule The knee joint capsule comprises complex passive and active connections among the menisci, ligaments, retinacula, bones, muscles, and the capsule itself. The joint capsule forms a sleeve around the joint, attaching just above the femoral condyles and below the tibial condyles. Retinacula and ligaments reinforce and become integral parts of the capsule. ❑ Joint Capsule The complexity of the capsule includes: o The proximal tendon of the popliteus muscle pierces the capsule to attach to the lateral femoral condyle o The semimembranosus muscle forms part of the oblique popliteal ligament and gives off fibres to the MCL and its large bony attachment. It reinforces the joint capsule posteriorly. The arcuate popliteal ligament also strengthens the joint capsule postero-laterally. It arises from the posterior aspect of the fibular head, passes supero-medially over the tendon of the popliteus, and spreads over the posterior surface of the knee joint. ❑ The Collateral Ligaments of the Knee Collateral ligaments strengthen the articular capsule on its medial and lateral aspects. They are, therefore, responsible for the transverse stability of the knee during extension. 26 ❑ The Collateral Ligaments of the Knee The medial (tibial) collateral ligament (1) runs from the medial epicondyle of the femur to the upper end of the tibia just posterior to the pes anserine tendon. So it runs inferiorly and anteriorly. The lateral (fibular) collateral ligament (2) runs from the lateral epicondyle of the femur to the head of the fibula. The collateral ligaments are stretched during extension (4,5) and slackened (relaxed) during flexion (3,6). 27 Cruciate Ligaments of the Knee In the anterior view of the knee joint, the cruciate ligaments are seen in the center of the joint, being largely contained within the intercondylar notch and fossa. The anterior cruciate ligament (ACL), the weaker of the two cruciate ligaments, is attached to the anterior intercondylar area of the tibia. It runs superiorly, posteriorly and laterally and is attached to the internal aspect of the lateral condyle of the femur. The posterior cruciate ligament (PCL) is attached to the posterior intercondylar area of the tibia. The ligament runs obliquely medially, anteriorly, and superiorly to be inserted into the edge of the lateral surface of the medial femoral condyle. These ligaments stabilize the knee in the antero-posterior direction and allow the joint to work as a hinge while keeping the articular surfaces in contact. 28 Cruciate Ligaments & Synovial Membrane of the Knee Cruciate ligaments are intracapsular but extra synovial! Menisci The interposition of the menisci (semi-lunar fibrocartilages) corrected the lack of congruency in the articular surfaces. These rings are incomplete in the region of the intercondylar tubercles of the tibia so that they are crescent-shaped with an anterior and a posterior horn. The horns of the lateral meniscus come closer to each other so that the meniscus is almost a complete circle. Whereas the medial meniscus is C-shaped. These menisci have important attachments from a functional point of view. Each horn is anchored to the tibial condyle in the anterior and posterior intercondylar areas respectively. The important ligament attachments of the menisci are: 1. The two anterior horns are linked by the transverse ligament of the knee (8). 2. The medial collateral ligament of the knee is attached to the medial meniscus. 3. The lateral collateral ligament of the knee is separate from its corresponding meniscus by the tendon of popliteus, which sends a fibrous expansion to the posterior border of the lateral meniscus. 30 ❑ Menisci Attachments 31 Movements of the Knee Joint & ROMs The knee joint possesses two DOF: flexion-extension and axial rotation Flexion ranges from 120 to 150 depending on the size of the muscle mass in the calf and posterior thigh as they make contact Hyperextension of the knee is minimal, and usually will not exceed 15 1 2 Movement Knee Flexion Knee Hyperextension Degrees 135 - 150 5 - 15 32 ❑ Axial Rotation It occurs in the transverse plane when the knee is flexed. With the knee fully extended, the collateral ligaments are tense and contribute to joint stability. With the knee flexed to 90 the ligaments are slackened, allowing for a considerable amount of rotation to occur. Motion is limited by capsular and ligamentous structures, including the collateral, cruciate, and oblique popliteal ligaments as well as the retinacula and the Iliotibial tract Movement Knee Active Lateral Rotation Knee Active Medial Rotation Degrees 30-40 20-30 33 There is also a type of automatic axial rotation called Screw-Home Mechanism because it is inevitably and involuntarily linked to movements of flexion and extension. It occurs especially at the end of extension or the start of flexion. When the knee is extended the foot is laterally (EXTernally) rotated; hence the mnemonic EXTension and EXTernal rotation. Conversely, when the knee is flexed the leg is medially rotated. When the knee is fully extended with the foot on the ground, the knee passively “locks” because of lateral rotation of the tibia on the femoral condyles. 34 Extensor & Flexor Muscles of the knee The quadriceps (A) femoris is the extensor muscle of the knee. It is composed of four heads known as: 1. Vastus intermedius 2. Vastus lateralis 3. Vastus medialis 4. Rectus femoris The patella which is embeded in the tendon of this muscle increases the efficiency of the muscle up to 33%. The flexor muscles (B) of the knee are the hamstrings and some other muscles which consist of: 1. Biceps femoris 2. semitendinosus 3. Semimembranosus 4. Gracilis 5. Sartorius 6. Gastrocnemius 35 Rotator Muscles of the knee Muscles Biceps Femoris Semimembranosus Semitendinosus Gastrocnemius Plantaris Popliteus Sartorius Gracilis Rectus Femoris Vastus Lateralis Vastus Medialis Vastus Intermedius Tensor Fascia Latae Flexion Extension PM PM PM X X X X X Lateral Rotation PM Medial Rotation PM PM PM X X PM PM PM PM X X PM = Prime Mover X = Synergist 36