Bones, Joints, Capsules and Ligaments of the Lower Limb Flashcards
The hip bone
The hip is formed by three bones, the ilium, the ischium and the pubis. At birth, these bones are held together by hyaline cartilage. The inferior rami of the ischium and pubis are incompletely ossified by the age of nine. At puberty, the intersection of the threebones at the acetabulum is separated y a Y shaped triradiated cartilage. The bons begin to fuse at age 15-17 years and completely fuse at about the age of 25.
The bony pelvis
The bony pelvis is comprised of two hip bones (also called pelvic, coxal or innominate bones), the sacrum, and the coccyx. The sacrum and coccyx are part of the vertebral column, which is part of the axial skeleton.
The acetubulum
The ilium, ischium and pubis contribute to it. It has a smooth lunate or articular surface and a rough depression extending from the acetubular notch called acetabular fossa. The fossa contains synovial membrane that provides lubrication to the joint, the transverse acetabular ligament and the ligament of the head of the femur.
The acetabular labrum
Fibrocartilaginous annular lip. It deepens the acetabular socket and adds to the area of contact between articulating bones. Some books say it may act as lubricant spreader.
The hip joint
Acetabulum and proximal femur. Synovial joint, ball and socket joint. It is one of the most mobile joins in the body. It combines stability and movility and is designef for weight bearing. It is enclosed by a fibrous membrane, the hip joint capsule.
Hip joint ligaments
Iliofemoral ligament, pubfemoral ligament and ischiofemoral ligrament.
Iliofemoral ligament
Strong triangular-shaped ligament anterior to the joint that extends from the ilium between A.I.I.S. and margin of acetabulum to the areas above and below the intertrochanteric line of femur. This results in an inverse Y-shaped appearance. Transverse part of this ligament limits lateral rotation and abduction and the descending part limits medial rotation. Together limit hip extension.
Pubofemoral ligament
Medially, it extends from iliopubic area of the acetabulum and superior pubic ramus. It blends inferior-medially with the fibrous capsule. Laterally, it attaches to the intertrochanteric line of the femur. Limits hip extension, abduction and external rotation.
Ischiofemoral ligament
Reinforces posterior aspect of the fibrous capsule. Medially, attaches to the ischium, posterior to the acetabulum. Laterally, attaches to the nech of the femur and greater trochanter, deep to the iliofemoral ligament. Limits extension, abduction and later rotation. The three ligaments are arranged in a spiral fashion around the hip joint. They become taught when hip joint is extended. Together they stabilise the joint and decrease the amount of energy required to maintain a standing posture.
The hip joint bursae
A bursa is a small fluid-filled sac lined by synovial membrane. Filled with synovial fluid and usually occurs in locations subject to friction. Allows free movement of surfaces. Bursae associated with the hip joint include iliopsoas, trochanteric, ischiogluteal and trochanteric bursae.
Hip joint movements
Flexion (120-130) Extension (20-30) Abduction (40-50) Adduction (20-30) Internal (medial) rotation (45) with hip and knee flexed to 90 External (lateral) rotation (45) with hip and knee flexed to 90 Circumduction
The knee joint
The knee joint is made out of the femur, tibia and patella bones. It is a modified synovial hinge joint: 1- femorotibial -bicondylar 2 - femoropatellar - plane. Note: proximal tibiofibular joint not part of the knee joint. The stability of the knee joint is dependent on ligaments and muscles, as there is almost no contribution from shape of bones and minisci.
Knee joint menisci
Disc of fibrocartilage and fibrous tissue. There is one medial meniscus and one lateral meniscus. Their wedge shape helps to distribute compressive forces across wider surface area. Movement accommodates for changes in bone shape through range of motion. Menisci are interconnected anteriorly by the transverse ligament. The medial meniscus attaches around its margins to the capsule via the coronary ligaments and also attaches to the tibial collateral ligament. The lateral meniscus does not attach to the capsule therefore it is more mobile than the medial. Posteriorly it is attached to the femur via the meniscofemoral ligament and also ttaches to the tendon of the popliteus muscle.
Ligaments of the knee
Intracaosular ligaments: anterior cruciate ligament (ACL), posterior cruciate ligament (PCL). Extracapsular ligaments: patellar ligament (tendon), tibial (medial) collateral ligament (MCL), lateral (fibular) collateral ligament (LCL).
Anterior cruciate ligament (ACL)
Attaches to tibia anteriorly and to the femur at the intercondylar fossa on the lateral side. Prevents anterior displacement of tibia relative to femur, and posterior displacement of femur relative to tibia, also prevents hyperextension.
Posterior cruciate ligament (PCL)
Attaches to tibia posteriorly and tto the fmur at the intercondylar fossa on the medial side. Prevents posterior displacement of tibia relative to femur, and anterior displacement of femur relative to tibia (e.g. when walking downhill).
Patellar ligament (tendon)
continuation of quadriceps tendon from patella to tibial tuberosity. Vastus medialis (oblique fibres) balance lateral forces of rest of quadriceps muscle. The patella improves line of pull of quads reduces wear and tear of quadriceps tendon on femur.
Tibial (medial) collateral ligament (MCL)
Broad ligament, atached to femur, tibia and medial meniscus. Receives fibres from adductor magnus. Prevents abduction of tibia (<5 of passive abduction normal) and hyperextension. More often injured ligament in the knee.
Lateral (fibular) collateral ligament (LCL)
Strong, cord-like ligament,m attached to femur, head of fibrula, but not lateral meniscus. Not often injured. Prevents adduction of tibia (<5 f passive adduction normal), hyperextension.
Synovial membrane
Attaches to the margins of the articular surfaces and menisci. Lines internal surfaces of capsule. ACL, PCL excluded from synovial cavity (intracapsular but extasynovial).
Knee joint bursae
Suprapaellar bursa. Subcutaneous and depp infrapatellar bursae. Pesanserinus bursa. Popliteal bursa. Medal and lateral collateral ligament bursae.
Blood supply around the knee
Ten blood vessels form the genicular anastomoses around tghe knee that provide blood supply. he genicular branches of the femoral, popliteal, and anterio and posterior recurrent branches of the anterior tibial recurrent and circumflex tibial arteries.
Tibiofibular joints
Proximal tibiofibular: synovial plane Distal tibiofibular: fibrous syndesmosis Tibiofibular: interosseous membrane, fibrous syndesmosis.
Movement at knee joint
Flexion (135) Extension (0) Hyperextension (5-10) Lateral rotation (30-40) Medial rotation (10)
The ankle (talocrural) joint
The ankle joint is made out of the talus (trochlea, dome), tibia and fibula. It is a synovial hinge joint. Movements at ankle joint are plantarflexion/dorsiflexion.
Subtalar joint
Also called talocalcaneal joint (anterior and posterior parts), is a synoial plane joint. ovements atsubtalar joint are inversion and eversion.
Transverse tarsal
(midtarsal, Chopart’s) joint
Talonavicular (talocalcaneonavicular) joint is a synovial plane (or ball and socket) joint. Calcaneocuboid joint is a synovial plane joint. Movement at transverse tarsal joint are inversion/eversion (supination/pronation).
Ligaments of the ankle
Medial collarteral (deltoid) ligament, lateral collateral ligament and interosseous talocalcaneal ligament.
Medial collateral (deltoid) ligament
Contributes to stability of ankle, subtalar and talonavicular joints. Prevents over-eversion. It has three parts: anterior and posterior tibiotalar, tibiocalcaneal, tibionavicular.
Lateral collateral ligament of the ankle
Contributes to stability of the ankle and subtalar joints. Preents over-inversion. It has three parts: anterior and posterior talofibular, calcaneofibular.
Interosseous talocalcaneal ligament
Contributes to the stability fo subtalar joint. Located within tarsal canal (not tunnel).
Other foot joints
Various intertarsal joints (synovial plane) Tarsometatarsal (Lisfranc’s) joints (synovial plane) Intermetatarsal joints (synovial plane) Metatarsophalangeal (MTP) joints: synoial condyloid: abduction/adduction, flexion/extension, plantar plates (ligaments) Interphalangeal (IP): synovial hinge, flexion/extension
