Hinge Joints

Question 1

What are hinge joints?

Answer 1

• uni-axial joints where movement only occurs in the Sagittal plane

Question 2

What are the movements of hinge joints ?

Answer 2

• flexion/extension

Question 3

What are the 2 hinge joints?

Answer 3

• elbow joint
• knee joint

Question 4

What is the classification of the elbow joint?

Answer 4

• structural = synovial
• functional = diarthrosis

Question 5

What are the 3 bones involved with the elbow joint?

Answer 5

• humerus
• ulna
• radius

Question 6

What are the 3 ligaments that support the elbow joint?

Answer 6

• ulnar collateral ligament (on the medial epicondyle of humerus, provides medial stability)
• radial collateral ligament (seen on the lateral epicondyle of humerus, provides lateral stability)
• annular ligament (seen on the radial head, connects the head of radius to humerus & ulna, & reduces friction during pronation/supination)

Question 7

What are the 3 flexor muscles of the anterior compartment that act on the elbow joint?

Answer 7

• brachialis
• brachioradialis
• biceps brachii (both heads)

Question 8

What are the 2 extensor muscles of the posterior compartment that act on the elbow joint?

Answer 8

• triceps brachii (all 3 heads)
• anconeus

Question 9

What are the 3 Pronator/supinator muscles that act on the elbow joint?

Answer 9

• Pronator teres/quadratus
• supinator

Question 10

What are functional movements of the elbow joint?

Answer 10

• 30-130 degrees of elbow flexion & 50 degrees of pronation to 50 degrees of supination is well established
• tasks such as cell phone use & keyboarding require greater elbow flexion & pronation than the functional motion arc

Question 11

What are clinical findings of the elbow joint?

Answer 11

• facilitates an arc of hand placement in space under fine motor control
• it is made up of a number of important bony & soft tissue structures that confer stability to the joint & facilitates Kinematics

Question 12

What is the classification of the knee joint?

Answer 12

• structural (synovial)
• functional (diarthrosis)

Question 13

What are the 3 bones involved with the knee joint?

Answer 13

• femur
• tibia
• patella

Question 14

What are the 6 ligaments that support the knee joint?

Answer 14

• medial/lateral meniscus
• medial (medial femoral condyle)/lateral collateral ligament (lateral femoral condyle)
• anterior Cruciate ligament (anterior portion of intercondylar eminence, runs posterior/superior direction, runs to external aspect of lateral femoral condyle, APEX)
• posterior Cruciate ligament (posterior aspect of intercondylar eminence, runs anterior direction to front of knee, runs inward to internal aspect of medial femoral condyle, PAIN)

Question 15

What are the 12 muscles that act on the knee joint?

Answer 15

• quadriceps group (Rectus femoris, Vastus lateralis/medialis/intermedialis)
• semimembranosus/semitendinosus
• gracilis
• sartorius
• popliteus
• tensor fascia latae
• gastrocnemius
• biceps femoris

Question 16

What are 3 functional movements of the knee joint?

Answer 16

• screw home mechanism
• open chain/non-weight bearing
• closed chain/non-weight bearing

Question 17

What is the screw home mechanism?

Answer 17

• during knee extension, the femoral condyles roll on the tibia & the lateral articular surface is the first to be used
• the femur then medially rotates on the lateral condyle as the rolling action of the femur continues on the medial condyle

Question 18

What is open chain/closed chain non-weight bearing?

Answer 18

• open chain (tibia rotates laterally & medially to unlock & start to flex the knee)
• closed chain (femur rotates medially & laterally to unlock & start to flex the knee)

Question 19

What are clinical findings of the knee joint?

Answer 19

• the unhappy triad is a complete tear of the ACL, MCL, & meniscus