7.5: Anatomy of Selected Synovial Joints

By the end of this section, you will be able to:

• Describe the bones that articulate together to form selected synovial joints
• Discuss the movements available at each joint
• Describe the structures that support and prevent excess movements at each joint

Each synovial joint of the body is specialized to perform certain movements. The movements that are allowed are determined by the structural classification for each joint. For example, a multiaxial ball-and-socket joint has much more mobility than a uniaxial hinge joint. However, the ligaments and muscles that support a joint may place restrictions on the total range of motion available. Thus, the ball-and-socket joint of the shoulder has little in the way of ligament support, which gives the shoulder a very large range of motion. In contrast, movements at the hip joint are restricted by strong ligaments, which reduce its range of motion but confer stability during standing and weight bearing.

This section will examine the anatomy of selected synovial joints of the body. Anatomical names for most joints are derived from the names of the bones that articulate at that joint, although some joints, such as the elbow, hip, and knee joints are exceptions to this general naming scheme.

Articulations of the Vertebral Column

In addition to being held together by the intervertebral discs, adjacent vertebrae also articulate with each other at synovial joints formed between the superior and inferior articular processes called facet joints (zygapophysial joints). These are plane joints that provide for only limited motions between the vertebrae. The orientation of the articular processes at these joints varies in different regions of the vertebral column and serves to determine the types of motions available in each vertebral region. The cervical and lumbar regions have the greatest ranges of motions.

In the neck, the articular processes of cervical vertebrae are flattened and generally face upward or downward. This orientation provides the cervical vertebral column with extensive ranges of motion for flexion, extension, lateral flexion, and rotation. In the thoracic region, the downward projecting and overlapping spinous processes, along with the attached thoracic cage, greatly limit flexion, extension, and lateral flexion. However, the flattened and vertically positioned thoracic articular processes allow for the greatest range of rotation within the vertebral column. The lumbar region allows for considerable extension, flexion, and lateral flexion, but the orientation of the articular processes largely prohibits rotation.

The articulations formed between the skull, the atlas (C1 vertebra), and the axis (C2 vertebra) differ from the articulations in other vertebral areas and play important roles in movement of the head. The atlanto-occipital joint is formed by the articulations between the superior articular processes of the atlas and the occipital condyles on the base of the skull. This articulation has a pronounced U-shaped curvature, oriented along the anterior-posterior axis. This allows the skull to rock forward and backward, producing flexion and extension of the head. This moves the head up and down, as when shaking your head “yes.”

The atlantoaxial joint, between the atlas and axis, consists of three articulations. The paired superior articular processes of the axis articulate with the inferior articular processes of the atlas. These articulating surfaces are relatively flat and oriented horizontally. The third articulation is the pivot joint formed between the dens, which projects upward from the body of the axis, and the inner aspect of the anterior arch of the atlas (Figure \(\PageIndex{1}\)). The strong transverse ligament passes posterior to the dens to hold it in position against the anterior arch. These articulations allow the atlas to rotate on top of the axis, moving the head toward the right or left, as when shaking your head “no.”

Figure \(\PageIndex{1}\): Atlantoaxial Joint. The atlantoaxial joint is a pivot type of joint between the dens portion of the axis (C2 vertebra) and the anterior arch of the atlas (C1 vertebra), with the dens held in place by a ligament. (Image Credit: "Atlantoaxial Joint" by Jennifer Lange is licensed under CC BY-NC-SA 4.0, modification of image from Anatomy Standard.

Pivot Joint Biomechanics

 

The modified structure of the atlas and axis, as well as the position of the transverse ligament, allow for a higher degree of rotation at the atlantoaxial joint than at other intervertebral joints.  The pivot joint allows for the neck/head to rotate almost 90^o to both the right and left sides.

Temporomandibular Joint

The temporomandibular joint (TMJ) is the joint that allows for opening (mandibular depression) and closing (mandibular elevation) of the mouth, as well as lateral/medial excursion and protraction/retraction motions of the lower jaw. This joint involves the articulation between the mandibular fossa and articular tubercle of the temporal bone, with the condyle (head) of the mandible. Located between these bony structures within the joint cavity, filling the gap between the skull and mandible, is a flexible articular disc (Figure \(\PageIndex{2}\)) . This disc serves to smooth the movements between the temporal bone and mandibular condyle.

Movement at the TMJ during opening and closing of the mouth involves both gliding and hinge motions of the mandible. With the mouth closed, the mandibular condyle and articular disc are located within the mandibular fossa of the temporal bone. During opening of the mouth, the mandible hinges downward and at the same time is pulled anteriorly, causing both the condyle and the articular disc to glide forward from the mandibular fossa onto the downward projecting articular tubercle. The net result is a forward and downward motion of the condyle and mandibular depression. The temporomandibular joint is supported by an extrinsic ligament that anchors the mandible to the skull. This ligament spans the distance between the base of the skull and the lingula on the medial side of the mandibular ramus.

Dislocation of the TMJ may occur when opening the mouth too wide (such as when taking a large bite) or following a blow to the jaw, resulting in the mandibular condyle moving beyond (anterior to) the articular tubercle. In this case, the individual would not be able to close their mouth. Temporomandibular joint disorder is a painful condition that may arise due to arthritis, wearing of the articular cartilage covering the bony surfaces of the joint, muscle fatigue from overuse or grinding of the teeth, damage to the articular disc within the joint, or jaw injury. Temporomandibular joint disorders can also cause headache, difficulty chewing, or even the inability to move the jaw (lock jaw). Pharmacologic agents for pain or other therapies, including bite guards, are used as treatments.

Figure \(\PageIndex{2}\): Temporomandibular Joint. The temporomandibular joint is the articulation between the temporal bone of the skull and the condyle of the mandible, with an articular disc located between these bones. (Image credit: "Temporomandibular Joint" by Jennifer Lange and Justin Greene is licensed under CC BY-NC-SA 4.0, modification of image from Anatomy Standard.)

Shoulder Joint

The shoulder joint is called the glenohumeral joint. This is a ball-and-socket joint formed by the articulation between the head of the humerus and the glenoid cavity of the scapula (Figure \(\PageIndex{3}\)) . This joint has the largest range of motion of any joint in the body. However, this freedom of movement is due to the lack of structural support and thus the enhanced mobility is offset by a loss of stability.

Figure \(\PageIndex{3}\): Glenohumeral Joint. The glenohumeral (shoulder) joint is a ball-and-socket joint that provides the widest range of motions. It has a loose articular capsule and is supported by ligaments and the rotator cuff muscles. (Image credit: "Shoulder Joint Ligaments" by Justin Greene is licensed under CC BY-NC-SA 4.0, modification of image from Anatomy Standard.)

The large range of motions at the shoulder joint is provided by the articulation of the large, rounded humeral head with the small and shallow glenoid cavity, which is only about one third of the size of the humeral head. Both of these structures are lined with articular cartilage. The socket formed by the glenoid cavity is deepened slightly by a small lip of fibrocartilage called the glenoid labrum, which extends around the outer margin of the cavity. The articular capsule that surrounds the glenohumeral joint is composed of a synovial membrane lined by a fibrous membrane and is relatively thin and loose to allow for large motions of the upper limb. Some structural support for the joint is provided by thickenings of the articular capsule wall that form weak intrinsic ligaments. These include the coracohumeral ligament, running from the coracoid process of the scapula to the anterior humerus, and three ligaments, each called a glenohumeral ligament, located on the anterior side of the articular capsule. These ligaments help to strengthen the superior and anterior capsule walls. An accessory ligament to the joint is the coracoacromial ligament, which attaches the coracoid process of the scapula to the acromion, and serves to prevent the head of the humerus from being displaced superiorly.

However, the primary support for the shoulder joint is provided by muscles crossing the joint, particularly the four rotator cuff muscles. These muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) arise from the scapula and attach to the greater or lesser tubercles of the humerus. As these muscles cross the shoulder joint, their tendons encircle the head of the humerus and become fused to the anterior, superior, and posterior walls of the articular capsule. The thickening of the capsule formed by the fusion of these four muscle tendons is called the rotator cuff. Another muscle associated with the shoulder joint is the biceps brachii muscle. While it is not part of the rotator cuff, the tendon of the long head of the biceps brachii muscle, which is surrounded by a tendon sheath for protection within the joint, attaches to the glenoid labrum. Because of this association, any damage to the glenoid labrum typically results in damage or tearing of the biceps brachii tendon.

Two bursae, the subacromial bursa and the subscapular bursa, help to prevent friction between the rotator cuff muscle tendons and the scapula as these tendons cross the glenohumeral joint. In addition to their individual actions of moving the upper limb, the rotator cuff muscles also serve to hold the head of the humerus in position within the glenoid cavity. By constantly adjusting their strength of contraction to resist forces acting on the shoulder, these muscles serve as “dynamic ligaments” and thus provide the primary structural support for the glenohumeral joint.

Injuries to the shoulder joint are common. Repetitive use of the upper limb, particularly in abduction such as during throwing, swimming, or racquet sports, may lead to acute or chronic inflammation of the bursa or muscle tendons, a tear of the glenoid labrum, or degeneration or tears of the rotator cuff. Because the humeral head is strongly supported by muscles and ligaments around its anterior, superior, and posterior aspects, most dislocations of the humerus occur in an inferior direction. This can occur when force is applied to the humerus when the upper limb is fully abducted, as when diving to catch a baseball and landing on your hand or elbow. Inflammatory responses to any shoulder injury can lead to the formation of scar tissue between the articular capsule and surrounding structures, thus reducing shoulder mobility, a condition called adhesive capsulitis (“frozen shoulder”).

Interactive Link

Shoulder Joint

Query \(\PageIndex{1}\)

Elbow Joint

The elbow joint is a uniaxial hinge joint formed by the humeroulnar joint, the articulation between the trochlea of the humerus and the trochlear notch of the ulna. Also associated with the elbow are the humeroradial joint and the proximal radioulnar joint. All three of these joints are enclosed within a single articular capsule (Figure \(\PageIndex{4}\)) .

The articular capsule of the elbow is thin on its anterior and posterior aspects, but is thickened along its outside margins by strong intrinsic ligaments. These ligaments prevent side-to-side movements and hyperextension. On the medial side is the triangular ulnar collateral ligament. This arises from the medial epicondyle of the humerus and attaches to the coronoid process on the medial side of the proximal ulna. The strongest part of this ligament is the anterior portion, which resists hyperextension of the elbow. The ulnar collateral ligament may be injured by frequent, forceful extensions of the forearm, as is seen in baseball pitchers. Reconstructive surgical repair of this ligament is referred to as Tommy John surgery, named for the former major league pitcher who was the first person to have this treatment.

The lateral side of the elbow is supported by the radial collateral ligament. This arises from the lateral epicondyle of the humerus and then blends into the lateral side of the annular ligament. The annular ligament encircles the head of the radius. This ligament supports the head of the radius as it articulates with the radial notch of the ulna at the proximal radioulnar joint. This is a pivot joint that allows for rotation of the radius during supination and pronation of the forearm.

Figure \(\PageIndex{4}\): Elbow Joint. The elbow is a hinge joint that allows only for flexion and extension of the forearm, it is supported by the ulnar and radial collateral ligaments. The annular ligament supports the head of the radius at the proximal radioulnar joint, the pivot joint that allows for rotation of the radius. (Image credit: "Elbow Joint Ligaments" by Justin Greene is licensed under CC BY-NC-SA 4.0.)

Hip Joint

The hip joint, or the coxofemoral joint, is a multiaxial ball-and-socket joint between the head of the femur and the acetabulum of the hip bone (Figure \(\PageIndex{5}\)). The hip carries the weight of the body and thus requires strength and stability during standing and walking. For these reasons, its range of motion is more limited than that of the shoulder joint.

The acetabulum is the socket portion of the hip joint. This space is deep and has a large articulation area for the femoral head, thus giving stability and weight bearing ability to the joint. The acetabulum is further deepened by the acetabular labrum, a fibrocartilage lip attached to the outer margin of the acetabulum. The surrounding articular capsule is strong, with several thickened areas forming intrinsic ligaments. These ligaments arise from the hip bone, at the margins of the acetabulum, and attach to the femur at the base of the neck. The ligaments are the iliofemoral ligament, pubofemoral ligament, and ischiofemoral ligament, all of which spiral around the head and neck of the femur. The ligaments are tightened by extension at the hip, thus pulling the head of the femur tightly into the acetabulum when in the upright, standing position. Very little additional extension of the thigh is permitted beyond this vertical position. These ligaments thus stabilize the hip joint and allow you to maintain an upright standing position with only minimal muscle contraction. Inside of the articular capsule, the ligament of the head of the femur (ligamentum teres) spans between the acetabulum and femoral head. This intracapsular ligament is normally slack and does not provide any significant joint support, but it does provide a pathway for an important artery that supplies the head of the femur.

The hip is prone to osteoarthritis, and thus was the first joint for which a replacement prosthesis was developed. A common injury in elderly individuals, particularly those with weakened bones due to osteoporosis, is a “broken hip,” which is actually a fracture of the femoral neck. This may result from a fall, or it may cause the fall. This can happen as one lower limb is taking a step and all of the body weight is placed on the other limb, causing the femoral neck to break and producing a fall. Any accompanying disruption of the blood supply to the femoral neck or head can lead to necrosis of these areas, resulting in bone and cartilage death. Femoral fractures usually require surgical treatment, after which the patient will need mobility assistance for a prolonged period, either from family members or in a long-term care facility. Consequentially, the associated health care costs of “broken hips” are substantial. In addition, hip fractures are associated with increased rates of morbidity (incidences of disease) and mortality (death). Surgery for a hip fracture followed by prolonged bed rest may lead to life-threatening complications, including pneumonia, infection of pressure ulcers (bedsores), and thrombophlebitis (deep vein thrombosis; blood clot formation) that can result in a pulmonary embolism (blood clot within the lung).

Figure \(\PageIndex{5}\): Hip Joint. Stability is added to the hip joint by three strong ligaments: the iliofemoral ligament, the ischiofemoral ligament, and the pubofemoral ligament.  Additional stability comes from the acetabular labrum, a fibrocartilage pad that deepens the socket.  (Image credit: "Hip Joint" by Justin Greene is licensed under CC BY-NC-SA 4.0, modification of image from Anatomy Standard.)

Interactive Link

Hip Joint Motion

Query \(\PageIndex{2}\)

Knee Joint

The knee joint is the largest joint of the body (Figure \(\PageIndex{6}\)) . It actually consists of two articulations: the patellofemoral joint is found between the patella and the distal femur and the tibiofemoral joint is located between the medial and lateral condyles of the femur and the medial and lateral condyles of the tibia. All of these articulations are enclosed within a single articular capsule. The knee functions as a hinge joint, allowing flexion and extension of the leg. This action is generated by both rolling and gliding motions of the femur on the tibia. In addition, some rotation of the leg is available when the knee is flexed (locking the knee), but not when extended. The knee is well constructed for weight bearing in its extended position, but is vulnerable to injuries associated with hyperextension, twisting, or blows to the medial or lateral side of the joint, particularly while weight bearing.

Figure \(\PageIndex{6}\): The Knee Joint. The knee joint has two articulations within a single capsule: the patellofemoral (gliding) and the tibiofemoral (hinge) joints. (Image credit: "The Knee Joint" by Jennifer Lange is licensed under CC BY-NC-SA 4.0, modification of image from Anatomy Standard under CC BY-NC 4.0.)

At the patellofemoral joint, the patella slides vertically within a groove on the distal femur. The patella is a sesamoid bone incorporated into the tendon of the quadriceps femoris muscle, the large muscle group of the anterior thigh. Continuing from the patella to the tibial tuberosity is the patellar ligament. The patella serves to protect the knee joint from anterior damage and to increase the force generated by the quads during knee extension.

The tibiofemoral joint is the articulation between the rounded condyles of the femur and the relatively flat condyles of the tibia. During flexion and extension motions, the condyles of the femur both roll and glide over the surfaces of the tibia. The rolling action produces flexion or extension, while the gliding action serves to maintain the femoral condyles centered over the tibial condyles, thus ensuring maximal bony, weight-bearing support for the femur in all knee positions. As the knee comes into full extension, the femur undergoes a slight medial rotation in relation to tibia. The rotation results because the lateral condyle of the femur is slightly smaller than the medial condyle. Thus, the lateral condyle finishes its rolling motion first, followed by the medial condyle. The resulting small medial rotation of the femur serves to “lock” the knee into its fully extended and most stable position. Flexion of the knee is initiated by a slight lateral rotation of the femur on the tibia, which “unlocks” the knee. This lateral rotation motion is produced by the popliteus muscle of the posterior leg.

Located between the articulating surfaces of the femur and tibia are two articular discs, the medial meniscus and lateral meniscus (Figure \(\PageIndex{7}\)) . Each is a C-shaped fibrocartilage structure that is thin along its inside margin and thick along the outer margin. They are attached to their tibial condyles, but do not attach to the femur. While both menisci are free to move during knee motions, the medial meniscus shows less movement because it is anchored at its outer margin to the articular capsule and tibial collateral ligament. The menisci provide padding between the bones and help to fill the gap between the round femoral condyles and flattened tibial condyles. Some areas of each meniscus lack an arterial blood supply and thus these areas heal poorly if damaged.

Figure \(\PageIndex{7}\): Knee Joint Menisci. The superior surface of the tibia has two fibrocartilage pads - the (A) lateral meniscus and the (B) medial meniscus - that are thicker along their outer edges than on their inner edges. This creates a slight indentation to help keep the femoral condyles from slipping out of place. (Image credit: "Knee Joint Menisci" by Jennifer Lange is licensed under CC BY-NC-SA 4.0, modification of images from Scientific Animations and from Anatomy Standard.)

The knee joint has multiple ligaments that provide support, particularly in the extended position (Figure \(\PageIndex{8}\)) . Outside of the articular capsule, located at the sides of the knee, are two extrinsic ligaments. The fibular collateral ligament (lateral collateral ligament) is on the lateral side and spans from the lateral epicondyle of the femur to the head of the fibula. The tibial collateral ligament (medial collateral ligament) of the medial knee runs from the medial epicondyle of the femur to the medial tibia. As it crosses the knee, the tibial collateral ligament is firmly attached on its deep side to the articular capsule and to the medial meniscus, an important factor when considering knee injuries. In the fully extended knee position, both collateral ligaments are taut (tight), thus serving to stabilize and support the extended knee and preventing side-to-side or rotational motions between the femur and tibia.

Figure \(\PageIndex{8}\): Knee Joint Ligaments. The knee joint is supported by four strong ligaments: A. the anterior cruciate ligament, B. the posterior cruciate ligament, C. the lateral (fibular) collateral ligament, and D. the medial (tibial) collateral ligament. (Image credit: "Knee Joint Ligaments" by Jennifer Lange is licensed under CC BY-NC-SA 4.0, modification of original by Scientific Animations.)

The articular capsule of the posterior knee is thickened by intrinsic ligaments that help to resist knee hyperextension. Inside the knee are two intracapsular ligaments, the anterior cruciate ligament and posterior cruciate ligament. These ligaments are anchored distally to the tibia at the intercondylar eminence, the roughened area between the tibial condyles, and proximally to the distal femur. The cruciate ligaments are named for whether they are attached anteriorly or posteriorly to this tibial region. Each ligament runs diagonally upward to attach to the inner aspect of a femoral condyle. The cruciate ligaments are named for the X-shape formed as they pass each other (cruciate means “cross”). The posterior cruciate ligament is the stronger ligament. It serves to support the knee when it is flexed and weight bearing, as when walking downhill. In this position, the posterior cruciate ligament prevents the femur from sliding anteriorly off the top of the tibia. The anterior cruciate ligament becomes tight when the knee is extended, and thus resists hyperextension.

Knee Biomechanics

Query \(\PageIndex{3}\)

Ankle and Foot Joints

The ankle is formed by the talocrural joint (Figure \(\PageIndex{9}\)) . It consists of the articulations between the talus bone of the foot and the distal ends of the tibia and fibula of the leg (crural = “leg”). The superior aspect of the talus bone is square-shaped and has three areas of articulation. The top of the talus articulates with the inferior tibia. This is the portion of the ankle joint that carries the body weight between the leg and foot. The sides of the talus are firmly held in position by the articulations with the medial malleolus of the tibia and the lateral malleolus of the fibula, which prevent any side-to-side motion of the talus. The ankle is thus a uniaxial hinge joint that allows only for dorsiflexion and plantar flexion of the foot.

Additional joints between the tarsal bones of the posterior foot allow for the movements of foot inversion and eversion. Most important for these movements is the subtalar joint, located between the talus and calcaneus bones. The joints between the talus and navicular bones and the calcaneus and cuboid bones are also important contributors to these movements. All of the joints between tarsal bones are plane joints. Together, the small motions that take place at these joints all contribute to the production of inversion and eversion foot motions and are helpful for maintaining balance.

Like the hinge joints of the elbow and knee, the talocrural joint of the ankle is supported by several strong ligaments located on the sides of the joint. These ligaments extend from the medial malleolus of the tibia or lateral malleolus of the fibula and anchor to the talus and calcaneus bones. Since they are located on the sides of the ankle joint, they allow for dorsiflexion and plantar flexion of the foot. They also prevent abnormal side-to-side and twisting movements of the talus and calcaneus bones during eversion and inversion of the foot. On the medial side is the broad deltoid ligament, named for its triangular shape. The deltoid ligament supports the ankle joint and also resists excessive eversion of the foot. The lateral side of the ankle has several smaller ligaments. These include the anterior talofibular ligament and the posterior talofibular ligament, both of which span between the talus bone and the lateral malleolus of the fibula, and the calcaneofibular ligament, located between the calcaneus bone and fibula. These ligaments support the ankle and also resist excess inversion of the foot.

Figure \(\PageIndex{9}\): Ankle Joint. The talocrural (ankle) joint is a uniaxial hinge joint that only allows for dorsiflexion or plantar flexion of the foot. Ligaments that unite the medial or lateral malleolus with the talus and calcaneus bones serve to support the talocrural joint and to resist excess eversion or inversion of the foot. (Image credit: "Ankle Joint Ligaments" by Justin Greene is licensed under CC BY-NC-SA 4.0.)

Interactive Link

Ankle Joint Ligaments

Query \(\PageIndex{4}\)

DISORDERS OF THE...

Joints

The ankle is the most frequently injured joint in the body, with the most common injury being an inversion ankle sprain. A sprain is the stretching or tearing of the supporting ligaments. Excess inversion causes the talus bone to tilt laterally, thus damaging the ligaments on the lateral side of the ankle. The anterior talofibular ligament is most commonly injured, followed by the calcaneofibular ligament. In severe inversion injuries, the forceful lateral movement of the talus not only ruptures the lateral ankle ligaments, but also fractures the distal fibula.

Figure \(\PageIndex{10}\): "Ankle Sprains" by Jennifer Lange is licensed under CC BY-NC-SA 4.0, modification of original by Laboratoires Servier via Wikimedia Commons.

Less common are eversion sprains of the ankle, which involve stretching of the deltoid ligament on the medial side of the ankle. Forcible eversion of the foot, for example, with an awkward landing from a jump or when a football player has a foot planted and is hit on the lateral ankle, can result in a Pott’s fracture and dislocation of the ankle joint. In this injury, the very strong deltoid ligament does not tear, but instead shears off the medial malleolus of the tibia. This frees the talus, which moves laterally and fractures the distal fibula. In extreme cases, the posterior margin of the tibia may also be sheared off.

Above the ankle, the distal ends of the tibia and fibula are united by a strong syndesmosis formed by the interosseous membrane and ligaments at the distal tibiofibular joint. These connections prevent separation between the distal ends of the tibia and fibula and maintain the talus locked into position between the medial malleolus and lateral malleolus. Injuries that produce a lateral twisting of the leg on top of the planted foot can result in stretching or tearing of the tibiofibular ligaments, producing a syndesmotic ankle sprain or “high ankle sprain.”

Most ankle sprains can be treated using the RICE technique: Rest, Ice, Compression, and Elevation. Reducing joint mobility using a brace or cast may be required for a period of time. More severe injuries involving ligament tears or bone fractures may require surgery.

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Concept Review

Although synovial joints share many common features, each joint of the body is specialized for certain movements and activities. The joints of the upper limb provide for large ranges of motion, which give the upper limb great mobility, thus enabling actions such as the throwing of a ball or typing on a keyboard. The joints of the lower limb are more robust, giving them greater strength and the stability needed to support the body weight during running, jumping, or kicking activities.  The joints described in this section are summarized in Table \(\PageIndex{1}\).

Table \(\PageIndex{1}\): Movements at Select Joints

Joint	Skeletal Structures	Classification	Movements	Key Supporting Structures
Intervertebral	Intervertebral discs between adjacent vertebra bodies	Symphysis; amphiarthrosis	flexion, extension, hyperextension lateral flexion (right/left)  rotation (right/left)
Intervertebral	Superior and inferior articular processes of adjacent vertebrae	Planar; diarthrosis	flexion, extension, hyperextension lateral flexion (right/left)  rotation (right/left)
Atlanto-occipital	Superior articular processes of C1 and occipital condyles	Condyloid; diarthrosis	flexion, extension,  lateral flexion (right/left) - slight
Atlantoaxial	Dens of C2 and anterior arch of C1	Pivot; diarthrosis	rotation (right/left)	transverse ligament
Temporomandibular	Head of mandible and mandibular fossa of temporal bone; head of mandible and articular tubercle of temporal bone	Hinge and planar; diarthrosis	elevation, depression protraction, retraction side-to-side (lateral displacement)
Glenohumeral (shoulder)	Head of humerus and glenoid fossa of scapula	Ball and socket; diarthrosis	flexion, extension, hyperextension adduction, abduction rotation (medial/lateral) circumduction	glenoid labrum ligaments: coracohumeral, glenohumeral tendons of rotator cuff and biceps brachii
Humeroulnar (elbow)	Trochlea of humerus and trochlear notch of radius	Hinge; diarthrosis	flexion, extension	ligaments: ulnar collateral, radial collateral
Proximal radioulnar	Head of radius and radial notch	Pivot; diarthrosis	supination, pronation	annular ligament
Hip	Head of femur and acetabulum of os coxa	Ball and socket; diarthrosis	flexion, extension, hyperextension adduction, abduction rotation (medial/lateral) circumduction	acetabular labrum ligaments: iliofemoral, pubofemoral, ischiofemoral
Tibiofemoral (knee)	Femoral condyles and tibial condyles	Hinge; diarthrosis	flexion, extension	menisci: medial and lateral ligaments: anterior cruciate, posterior cruciate, medial collateral, lateral collateral
Talocrural (ankle)	Distal tibia, medial malleolus, lateral malleolus and talus	Hinge; diarthrosis	plantarflexion, dorsiflexion	ligaments: deltoid, talofibular, calcaneofibular

 

Sprains are graded on a scale of 1 - 3, with grade 1 being the least severe (stretched) and grade 3 being the most severe (completely torn).  The most commonly sprained joint is the ankle.

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Review Questions

Query \(\PageIndex{5}\)

Query \(\PageIndex{6}\)

 

Critical Thinking Questions

Query \(\PageIndex{7}\)

Query \(\PageIndex{8}\)

 

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Glossary

Query \(\PageIndex{9}\)

Contributors and Attributions

• OpenStax Anatomy & Physiology (CC BY 4.0). Access for free at https://openstax.org/books/anatomy-and-physiology