Synovial, diarthrodial, ball and socket, spheroid, multiaxial
Components
head of the humerus and the glenoid fossa of the scapula, most freely moveable joint in the body. BUT: to get that kind of mobility, stability had to be sacrificed. The joint is pretected on 3 sides, but not inferiorly, therefore this is the most often dislocated joint in the body, usually inferiorly and anteriorly.
3. Ligaments
coracohumeral ligament - coracoid process to greater tubercle of humerus
superior and inferior glenohumeral ligaments - thickenings of joint capsule around the neck of the scapula to the anatomic neck of the humerus
transverse humeral retinaculum - retaining band of CT- from greater tubercle to lesser tubercle of humerus
( across intertubercular groove) , holds bicipital tendon in place, tendon attaches to supraglenoid tubercle.
Glenoid labrium - increases the surface area of the glenoid fossa.
4. Protected from trauma from above by:
acromion & coracoid process of the scapula, lateral aspect of the clavicle, BUT: no protection inferior, therefore most dislocations inferiroly.
5. Bursae
Serve to cushion and decrease friction
subdeltoid bursa - between deltoid m and joint capsule \ sometimes these 2
subacromial bursa - between acromion and joint capsule / can be just 1
6. Rotator cuff muscles - musculotendinous cuff – rotators of the shoulder, medial and lateral N 396
Supraspinatus m. - support from above – small lateral abductor – most commonly torn rotator cuff muscle
Infraspinatus m. - support from posterior – lateral rotator
Teres minor m. - support from posterior – lateral rotator
Subscapularis m. - support from anterior – medial rotator ( Dr. G’s wife tore this falling down the stairs )
The Elbow Joint N 408
AKA Humeroulnar and Humeroradial joint or
Cubital joint - trochlea of humerus and trochlear notch of ulna and the capitulum of the humerus and the head of the radius ( primary between humerus and ulna)
Synovial, diarthrodial, hinge, uniaxial
Ligaments
Radial (lateral) collateral ligament – most often involved in “tennis elbow”
Ulnar (medial) collateral ligament
Anular ligament - encircles the head of the radius – provides circle for pivot joint
Olecranon bursa - on posterior side of elbow – if this bursa becomes inflammed, usually by trauma, it forms a hygroma.
Proximal Radioulnar Joint N 408
Formed by the head of the radius and the radial notch of the ulna, allows for supination and pronation
Synovial
Diarthrodial
Trochoid or pivot
Uniaxial
Anular Ligament – encircles head of radius and holds it tight into the radial notch
Metacarpophalangeal Joints N 427
AKA knuckle
Synovial, diarthrodial, biaxial
Condyloid – because of the shape of the surface
Interphalangeal Joints
Synovial, diarthrodial, uniaxial
Hinge
The Coxal (Hip) Joint N 454
Formed by the head of the femur and the acetabulum of the os coxae
Bears weight of the body - stable
Synovial, diarthrodial, spheroid, multiaxial
Acetabular labrum – fibrocartilage - rim
Ligaments of the hip
Iliofemoral ligament - “Y” ligament of Bigelow - anterior
AIIS to intertrochanteric line, prevents hyperextension
Pubofemoral ligament – triangular in shape
pubis to intertrochanteric line, limits hyperextension and abduction
Ischiofemoral ligament – spiral in shape
ischium to greater trochanter, limits hyperextension
Round ligament - ligamentum teres - intrinsic ligament ( w/I joint capsule), from fovea capitis of femur to transverse acetabular ligament, bridges the gap formed by the acetabular notch
Transverse acetabular ligament - crosses the acetabular notch, connects joint capsule to ligamentum capitis femoris
There is a small artery, the acetabular branch of the obturator artery that goes into the head of the femur. When this little artery ruptures, it leads to avascular necrosis of the head of the femur, and a hip replacement may be necessary ( Bo Jackson ).
Tibiofemoral - Stifle Joint N 458, 476
Largest and most complex joint of body
Synovial, diarthrodial, “modified hinge”- but also biaxial ( there is some rotation )
Classified as a double condyloid joint, capable of flexion, extension and medial and lateral rotation
Hyperextension of knee - foot firmly on the ground, locking of the knee medial rotation of femur
Foot in the air like in kicking lateral rotation of the tibia
Ligaments
Primary function ( keep femur and tibia together and aligned, allow for bending of the knee
control excessive knee extension
control abduction and adduction stresses
control anterior and posterior displacement of tibia on femur, so that the tibia doesn’t slide
control medial and lateral rotation of tibia beneath femur, so the tibia doesn’t twist off
give rotatory stabilization to the knee
Lateral and medial patellar retinacula – broad, flat band, tendinous insertion of quadriceps femoris m. Gives anterior stability. Attaches to patella and tibial tuberosity, gives anterior stability to the knee, this reinforces the joint since there is no anterior joint capsule.
Oblique popliteal ligament - posterior aspect of joint capsule, provides posterior stability and limits hyperextension.
Arcuate popliteal ligament – Extends from the head of fibula over tendon of popliteus muscle to insert to intercondylar area of tibia and lateral epicondyle of femur. Since this is on the posterior aspect of the knee, it limits hyperextension of knee.
Collateral Ligaments - provide medial and lateral stability N 473
Medial (tibial) collateral ligament – attaches to tibia
Lateral (fibular) collateral ligament – attaches to fibula
Anterior cruciate ligament ( ACL )
Anterior tibia to posterior medial aspect of the lateral condyle of the femur (support post. lateral)
Prevents anterior displacement of the tibia on the femur
During extension of the knee the ACL is pulled taut, PCL is lax most ACL injuries occur when the knee is extended
Torn ACL = Anterior drawer sign ( flex knee knee will slide anteriorly)
Posterior cruciate ligament ( PCL )
Posterior tibia to lateral aspect of medial condyle of femur, prevents posterior displacement of the tibia with relationship to the femur.
Shorter and less oblique than ACL – more straight up and down
During flexion of the knee the PCL is pulled taut, the ACL is lax most PCL injuries occur when the knee is flexed.
Torn PCL = Posterior drawer sign ( push tibia posteriorly )
Injuries to the ACL or PCL heal very slowly.
Bursa
Popliteal bursa - between tendon of popliteus m. and lateral condyle of femur
Prepatellar bursa - between patella and skin, more commonly damaged. This is why carpet layers etc. wear knee pads.
Suprapatellar bursa - between quadriceps tendon and anterior femur
Menisci
Medial meniscus – 2 fibrocartilaginous pads, semicircular, attached to medial collateral ligament and to semimembranosus muscle’s tendon of insertion. The anterior horn of this meniscus is the most commonly injured since it is thinner. Firm attachment.
Lateral meniscus - 4/5’s of a circle, attached to posterior cruciate lig. And popliteus muscle via coronary lig. And posterior joint capsule. This meniscus is thicker, has more give, loose attachment. Its function is to distribute and absorb the weight of the femur of the tibia. The compressive forces are 5-6 times the body weight when walking. The lateral meniscus is C shaped, thick in the periphery, thin centrally, forms a cup. The horns attach to the intercondylar tubercles of the intercondylar eminence.
Talocrural (ankle) Joint ( not on tests ) N 491
Synovial, diarthrodial, hinge, uniaxial – no rotation – straight hinge
Ligaments
posterior tibiotalar ligament
tibiocalcaneal ligament
tibionavicular ligament
anterior tibiotalar ligament
Lateral collateral ligaments
anterior and posterior talofibular ligament
calcenofibular ligament
Terms Related to Joint Pathology
1. Strain - stretched or pulled tendon or ligament
Sprain - hyperextension, with tearing of tendons or lig. Luxation - derangement of the articulating bones that compose a joint
Subluxation - partial dislocation of a joint
Bursitis - inflammation of a bursa
Tendonitis - inflammation of a tendon
Osteoarthritis - degenerative joint disease
Rheumatoid arthritis - autoimmune disease
Gouty arthritis - abnormal accumulation of uric acid
Marie Paas Page Anatomy TRI 1
4/22/2018
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