9/19 Joints II_knee_ankle_foot Flashcards
Innervation of the Synovium
The synovial fibers are of two types?
- postganglionic sympathetic adrenergic fibers located around blood vessels are responsible for the control of articular blood flow
- unmyelinated C fibers responsible for pain transmission, typically fire only when there is trauma and are therefore termed nociceptive
- Prostaglandin E2 associated with inflammation can induce signaling in the nociceptive fibers causing pain in the normal range of movement.
- Substantial disruption to synovial nerves in the rheumatoid condition may effect joint homeostasis.
Anterior Cruciate Ligament (ACL)
- Attachments: – anterior part of intercondylar area of tibia – fibers oriented superiorly, posteriorly, and laterally – medial side of lateral condyle of femur
- Taut when leg is extended:
– prevents ______ displacement of femur
– prevents ______ displacement of tibia
posterior
anterior
Posterior Cruciate Ligament (PCL)
- Attachments: – posterior part of intercondylar area of tibia – fibers directed superiorly, anteriorly, and medially – lateral surface of medial condyle of femur
- Taut when leg is flexed:
– prevents _____ displacement of femur
– prevents _____ displacement of TIBIA
anterior
posterior
Clinical note: anterior drawer sign (ACL)
The Lachman test is a clinical test used to diagnose injury of the anterior cruciate ligament (ACL). It is recognized as reliable, sensitive, and usually superior to the anterior drawer test.[1]
Pivot-shift test is one of the three major tests for assessing anterior cruciate injury or laxity, the other two being the anterior drawer and Lachman test
Clinical note: posterior drawer sign (PCL)
Quads active test
To assess for integrity of the PCL.
Menisci (g., crescent)
• C-shaped plates of fibrocartilage on medial and lateral articular surfaces of tibia:
– deepens articular surface & absorb shock
- External margins: – thick – attached to joint capsule (coronary ligaments)
- Internal margins: – thin – not attached to joint capsule
Menisci: anterior edges
transverse ligament connects both menisci
Medial Meniscus
- Broader posteriorly
- Anterior horn: – may attach anteriorly to ACL
- Posterior horn: – attaches anterior to PCL
- Adherent to deep surface of tibial collateral ligament
Lateral Meniscus
- Nearly circular – anterior and posterior ends close together
- Smaller & more mobile than medial meniscus
- Posterior meniscofemoral ligament – joins it to posterior cruciate ligament
- Popliteus tendon passes between it and fibular collateral ligament
Clinical Note: Meniscal Tears
- Commonly involve medial meniscus
- Lateral meniscus usually does not tear because of mobility
- Peripheral meniscal tears can often be repaired or will heal because of blood supply
- Meniscal tears that do not heal or cannot be repaired are removed (arthroscopic surgery)
Testing for Meniscal Tears
Assessing a possible meniscal tear is usually done by locating pain and crepitus along the joint line. This palpation for these symptoms must be done while simultaneously adducting or abducting the leg.
Clinical anatomy: “unhappy triad of injuries”
tore which three ligaments?
ACL
tibial collecteral ligament
medial meniscus
foot arches
- Consists of dynamic and passive support
- Dynamic includes tibialis anterior and posterior, flexor hallucis longus and intrinsic plantar muscles
- Passive is by plantar aponeurosis, short and long plantar ligaments, and the plantar calcaneonavicular ligaments (spring ligaments)
- Passive fallen arch is primarily due to a laxity in the spring ligament
Stabalizers of Transverse Arch
• Note: The arch of the forefoot has only passive stabilizers, whereas the arches of the metatrsus and tarsus have only active/dynamic stabalizers
Passive Longitudinal Stabalizers
plantar vault
Clinical note: pes planus (flatfeet)
• In adolescents and adults result from “fallen arches:”
– usually medial parts of longitudinal arch
– plantar ligaments and plantar aponeurosis become abnormally stretched
– plantar calcaneonavicular ligament (spring ligament) can no longer support talus head:
• talar head displaces inferomedially and becomes prominent
Clinical notes: hallux valgus, bunion, & corns
• Hallux valgus is a foot deformity characterized by lateral deviation of great toe:
– surrounding tissues swell and resultant pressure and friction against shoe cause a bursa to form
– tender and inflamed bursa is called a bunion – corns (inflamed areas of thick skin) over proximal interphalangeal joints
Toe Deformities
- Referring to lateral four toes in first three cases below.
- If flexion in the distal IP joint, it is called a mallet toe
- If extension at the MP joint and flexion at the proximal IP joint, it is called a hammer toe
- If extension at the MP joint and flexion at both the proximal and distal IP joint, the deformity is referred to as a claw toe
- If the deformity occurs in the large toe (extend MP, flex IP, it is known as a trigger toe
- All appear a consequence, in part, of shortened flexor muscles which can override lumbrical function
Clinical note: hammer toe
• “Hammerlike” deformity (usually of 2nd digit) in which:
– proximal phalanx is permanently hyperextended at metatarsophalangeal joint – middle phalanx is plantarflexed at the proximal interphalangeal joint – distal phalanx is extended
Clinical note: claw toes
• Characterized by:
– hyperextension of metatarso-phalangeal joints
– flexion of the distal and proximal interphalangeal joints
