Temporomandibular Joint (TMJ)

• Combination of a hinge and gliding joint

• Reinforced by 3 major extrinsic ligaments

• Only synovial joint in skull• Depression/elevation• Protraction/retraction• Lateral movements

The temporomandibular joint is formed by the mandibular condyle and the mandibular fossa of the temporal bone. It is supported by ligaments.

An articular disc separates the bones within the joint capsule. The movement of this disc may create clicking or popping sounds.

The TMJ allows depression/elevation, protraction/retraction, and lateral rotary movements.

Mouth splints can prevent teeth grinding which can lead to TMJ syndrome

Close-up of mouth splint used to prevent TMJ syndrome

ACCORDING TO THE CLINICAL VIEW IN YOUR TEXT, TMJ DISORDER CAN CAUSE WIDESPREAD DISTRIBUTION OF PAIN IN THE HEAD. WHY?

A SPREAD OF INFLAMMATORY CHEMICALS VIA THE LYMPHATIC SYSTEM

B AVASCULAR NECROSIS

C AUTOIMMUNE DISEASE

D PSYCHOSOMATIC PAIN FROM OCCIPITAL LOBE OF THE CEREBRUM

E IRRITATION OF THE TRIGEMINAL NERVE

The intervertebral discs form an amphiarthrotic symphysis between one vertebral body and the next.

The articulation between the articular processes form amphiarthotic synovial gliding (planar) joints.

The combined effect of slight movement between all the gliding joints is considerable movement of the spine.

Palpation of the ligamentum nuchae

The sternoclavicular joint is formed where the clavicle articulates with the manubrium. Depending on the reference source it is a either a diarthrotic synovial gliding joint OR a diarthrotic synovial saddle joint.

Sternoclavicular joint has an articular disc.

Mike Bond putting great stress on his sternoclavicular joints

Dislocation of the sternoclavicular joint

Partial dislocation of both sternoclavicular joints with bleeding

X ray of acromioclavicular separation

Glenohumeral Joint

The glenohumeral joint is formed by the head of the humerus articulating with the glenoid cavity of the scapula

Master Long preparing to dislocate an opponent’s glenohumeral joint

Read clinical view in the text

U. S. soldier learning how to dislocate opponent’s shoulder

Green arrow shows direction of force

Dislocation (luxation) of the right shoulder (glenohumeral joint) with subsequent anterior displacement of the head of the humerus.

Glenohumeral dislocation

Doctor’s foot

The glenoid labrum deepens the concavity of the shoulder joint

Lateral view of scapula

Rotator cuff (musculotendinous cuff) is formed by tendons of the infraspinatus, subscapularis, supraspinatus, and teres major. It is weak inferiorly.

The coracohumeral ligament, glenohumeral ligaments, and the transverse humeral ligament all help stabilize the glenohumeral joint.

There are numerous bursae and tendon sheaths associated with the shoulder (glenohumeral) joint.

WHICH OF THE FOLLOWING IS A CORRECT STATEMENT?

A GLENOHUMERAL DISLOCATIONS (LUXATIONS) INITIALLY OCCUR SUPERIORLY AND THEN THE HUMERAL HEAD SHIFTS POSTERIORLY.

B THE LIGAMENTUM NUCHAE CONNECTS TO THE VERTEBRA PROMINENS

C THE FIBROCARTILAGE PADS BETWEEN VERTEBRAL BODIES FORM SYNCHONDROSES

D THE ARTICULATION BETWEEN VERTEBRAL ARTICULAR PROCESSES ARE BIAXIAL SYMPHYSES

E. THE MUSCULOTENDINOUS CUFF IS FORMED BY INTEROSSEOUS MEMBRANE

Elbow joint

The humeroulnar joint (between trochlea and trochlear notch) is a hinge joint. The humeroradial joint (between capitulum and radial head) is considered by some to be a gliding joint.

Anterior view

Elbow joint

The elbow joint is supported by its articular capsule and by multiple strong ligaments: the radial (lateral) collateral ligament, the ulnar (medial) collateral ligament, and the annular ligament.

Elbow joint: note radial (lateral) collateral ligament and anular ligament

Elbow joint: note the ulnar (medial) collateral ligament and the anular ligament.

Read clinical view about subluxation of the head of the radius in your text

Subluxation of the head of the radius

Dislocation (luxation) of the elbow can damage the associated ligaments

The radiocarpal (wrist) articulation does NOT include the distal end of the ulna because the ulna is separated from the carpal bones by an articular disc.

Metacarpophalangeal and interphalangeal joints

Hinge joints

Condyloid joint

No ligamentous support posteriorly!

Posterior dislocation of interphalangeal joint

Open dislocation of interphalangeal joint of finger #1

Coxal (hip, acetabulofemoral) joints

A fibrocartilage acetabular labrum deepens the concavity of the acetabulum and helps stabilize the coxal (acetabulofemoral) joint

Strong ligaments, a strong joint capsule, and powerful muscles help to stabilize the acetabulofemoral joint

The retinacular fibers support the joint capsule and contain arteries that supply most of the blood to the neck and head of the femur

The ligament of the head of the femur (ligamentum teres) contains a small artery that supplies some of the blood to the head of the femur.

Fracture of the neck of the femur

Read about fracture of the femoral neck in the clinical view in the text

The knee joint is composed of two separate articulations: the tibiofemoral joint and the patellofemoral joint.

Patellofemoral joint of left knee

of femur

The quadriceps femoris tendon inserts onto the patella, which is embedded in this tendon

The patellar ligament extends inferiorly from the patella and attaches to the tibial tuberosity

The tibiofemoral joint is stabilized by the lateral (fibular) collateral ligament and by the medial (tibial) collateral ligament. The LCL is NOT attached to the meniscus.

Right knee, anterior view

In varus displacement of the knee (hyperadduction of the lower leg), the distal segment (lower leg) is abnormally deviated medially. This is normally prevented by the lateral (fibular) collateral ligament.

The tibiofemoral joint is stabilized by the lateral (fibular) collateral ligament and by the medial (tibial) collateral ligament.

Right knee, anterior view

In valgus displacement of the knee (hyperabduction of the lower leg), the knee is driven medially while the lower leg is deviated laterally. This is normally prevented by the medial (tibial) collateral ligament.

attached

The medial collateral ligament is attached to the medial meniscus. This means if the MCL tears the medical meniscus also tears.

Right knee, anterior view

The medial meniscus and the lateral meniscus are made of fibrocartilage and help stabilize the knee and act as cushions. Note the MCL is attached to the medial meniscus.

attached

Right knee, anterior view

The menisci help to pad and stabilize the knee

More deeply the tibiofemoral joint is stabilized by the posterior cruciate ligament and by the anterior cruciate ligament.

Note that the posterior cruciate ligament is tight (taut) when the tibiofemoral joint is flexed while the anterior cruciate ligament is tight (taut) when the tibiofemoral joint is extended. Most knee injuries occur when the knee is extended (anterior cruciate ligament is tight) so it is commonly ruptured (ruptured ACL) by hyperextension or lateral displacement when leg is extended.

ACL tight PCL tight

Humans are bipedal animals. An important aspect in walking and standing is the ability to “lock” the knees. This is possible because at full extension the tibia rotates laterally so as to tighten the ACL and squeeze the meniscus between the tibia and femur. This mechanism permits a person to stand for long periods without using or tiring the muscles of the leg.

The tibiofemoral joint (knee) is very vulnerable to injury. Read the clinical view in the text.

Valgus deviation of the knee (hyperabduction of lower leg))

Valgus stress to the knee (hyperabduction of the lower leg) can rupture the MCL, the medial meniscus, and, if enough displacement occurs, the ACL and the PCL.

(medial)

An allograft replacement of the ACL uses materials from another person (cadaver)

An autograft replacement uses your own tissues, such as the middle portion of the patellar ligament

An autograft replacement can also use a portion of your hamstring tendons. They are removed, braided, and used to replace the ACL.

There are numerous bursae associated with the knee. Two of them are shown here.

WHICH OF THE FOLLOWING WOULD BE INJURED IN THE KNEE BY HYPERABDUCTION OF THE LOWER LEG (VALGUS DEVIATION)?

A MENISCUS

B LATERAL COLLATERAL LIGAMENT

C PATELLAR LIGAMENT

D RUPTURED RETINACULAR FIBERS

E ALL OF THE ABOVE

The talocrural (ankle) joint is a hinge joint formed by the medial and lateral malleoli and the talus

The talocrural (ankle) joint is surrounded by an articular capsule

Medial view

Lateral view

The most common sprain of the ankle is excessive inversion that ruptures the anterior talofibular ligament and the calcaneofibular ligament

Excessive inversion of the ankle in rugby

Dislocated right ankle

Dislocated ankle joint

Excessive eversion, which is less common, can damage the deltoid ligament on the medial side of the ankle

High top athletic shoes have been statistically shown to reduce the incidence of ankle sprains, most likely by making the person more aware of the position of the ankle when leaping or jumping.

Results: The high-top shoes were more effective in reducing the amount and rate of inversion than the low-top shoes

Sprains are often accompanied by bleeding and inflammation of the joint capsule (synovitis). Read about ankle sprains and Pott fractures in the clinical view in the text.

Intertarsal joints (and tarsometatarsal joints) are planar (gliding) joints

Metatarsophalangeal joints are condyloid joints

Interphalangeal joints are hinge joints

Active joints develop larger and thicker capsules and the supporting ligaments increase in size.

Moderate exercise is good for the joints and all parts of the human body.

Dorothy Hamill, an Olympic figure skater now suffers from osteoarthritis.

Modern fiberoptic arthroscopy

Knee replacement

Hip replacement

Read about the different types of arthritis in the clinical view in your text.

WHICH OF THE FOLLOWING IS ASSOCIATED WITH RHEUMATOID ARTHRITIS?

A SUPPRESSION BY DIFFERENT HLA PROTEINS

B URIC ACID CRYSTALS ACCUMULATING IN SYNOVIAL FLUID

C OVEREXERCISE OR ADVANCING AGE

D MOST COMMON TYPE OF ARTHRITIS

E COMMONLY TREATED WITH SYNGENETIC GRAFTS OR XENOGRAFTS