Week 5

Question 1

Which is larger proximally? Radius or ulna?

Answer 1

Ulna

Question 2

Which is larger distally? Radius or ulna?

Answer 2

Radius

Question 3

Which bones serve as proximal attachments for muscles that flex and extend the elbow?

Answer 3

Scapula and humerus

Question 4

Which bones serve as distal attachments for muscles that flex and extend the elbow?

Answer 4

Radius and ulna

Question 5

Which bones serve as proximal attachments for muscles that pronate and supinate the radioulnar joints?

Answer 5

Scapula, humerus, and ulna

Question 6

on which bones are the distal attachments of radioulnar joint muscles?

Answer 6

radius

Question 7

Bony landmarks of the radioulnar joint

Answer 7

Medial condyloid ridge

olecranon process

coranoid process

radial tuberosity

Question 8

key bony landmarks for wrist and hand muscles

Answer 8

medial epicondyle

lateral epicondyle

lateral supracondylar ridge

Question 9

Elbow joint

Answer 9

hinge or ginglymus type

allows only flexion and extension

Question 10

2 interrelated joints in the elbow

Answer 10

humeroulnar

radiohumeral

Question 11

Elbow motions primarily involve movement between…

Answer 11

articular surfaces of humerus and ulna. Radial head has relatively small amount of contact with capitulum of humerus

Question 12

As elbow reaches full extension…

Answer 12

olecranon process is received by olecranon fossa. Increased joint stability when elbow is fully extended.

Question 13

as elbow is flexed 20 degrees or more…

Answer 13

its bony stability is unlocked, allowing for more side-to-side laxity.

stability in flexion is more dependent on the lateral (radial collateral ligament) and the medial (ulnar collateral ligament)

Question 14

Ulnar collateral ligament is critical in…

Answer 14

providing medial support to prevent elbow from abducting when stressed in physical activity.

Many contact sports and throwing activities place stress on medial aspect of joint, resulting in injury

Question 15

Ulnar Collateral Ligament (UCL)

Answer 15

particularly crucial to high-velocity sporting activities requiring optimal medial elbow stability like baseball pitching

compromise of this structure often requires surgery

TOMMY JOHN PROCEDURE- UCL reconstruction using a graft such as palmaris longus tendon

Question 16

Radial collateral ligament provides…

Answer 16

lateral stability and is rarely injured

Question 17

Annular ligament provides…

Answer 17

a sling effect around radial head for stability

Question 18

Elbow moves from 0 degrees at full extension to…

Answer 18

145 to 150 degrees of flexion

Question 19

Radioulnar joint

Answer 19

• Trochoid or pivot-type joint
• radial head rotates around at proximal ulna
• distal radius rotates around distal ulna

Annular ligament maintains radial head in its joint

Question 20

Radioulnar joint supinating and pronating capacity

Answer 20

supinate 80 to 90 degrees from neutral

pronate 70 to 90 degrees from neutral

Question 21

Radioulnar joint between shafts of radius and ulna held tightly together between proximal and distal articulations by…

Answer 21

an interosseus membrane (syndesmosis)

substantial rotary motion between the bones

Question 22

synergy between glenohumeral, elbow, and radioulnar joint muscles

Answer 22

-conversely, when loosening a tight screw with pronation, we tend to internally rotate and extend the elbow and glenohumeral joints, respectively

WE depend on both the agonists and antagonists in the surrounding joints to assist in an appropriate amount of stabilization and assistance with the required task

Question 23

Elbow flexors

Answer 23

Biceps brachii

brachialis

brachioradialis

weak assistance from pronator teres

Question 24

Elbow extensors

Answer 24

triceps brachii

Anconeus (provides assistance)

Question 25

Radioulnar pronators

Answer 25

pronator teres pronator quadratus brachioradialis

Question 26

Radioulnar supinators

Answer 26

biceps brachii supinator muscle brachioradialis

Question 27

Anterior muscles that take part in elbow movement

Answer 27

Primarily flexion and pronation Biceps brachii brachialis brachioradialis pronator teres pronator quadratus

Question 28

Posterior muscles that take part in elbow movement

Answer 28

primarily extension and supination triceps brachii anconeus supinator

Question 29

Biceps brachii

Answer 29

Origin- SH: coracoid process LH: supraglenoid tubercle Insertion: radial tuberosity Bicipical aponeurosis Location: anterior Movements: Elbow flexion, supination of the forearm, weak shoulder flexion

Question 30

Brachialis

Answer 30

Origin- Distal half of the anterior shaft of the humerus Insertion- coracoid process of the ulna location- anterior Movements- elbow flexion

Question 31

Brachioradialis

Answer 31

Origin- distal 2/3rds of lateral condyloid ridge of humerus Insertion- lateral surface of the distal end of the radius at styloid process Location- anterior Movements- elbow flexion (best in neutral position), pronation from supination to neutral, supination from pronated position to neutral

Question 32

Triceps Brachii

Answer 32

Origin: LH: infraglenoid tubercle of scapula LatH: Upper half of posterior surface of the humerus MH: distal 2/3rds of posterior surface of the humerus Insertion- Olecranon process of ulna Location- posterior Movements- Elbow extension Long head only: GH extension, GH horizontal abduction, GH adduction

Question 33

Anconeus

Answer 33

Origin- posterior surface of lateral condyle of the humerus Insertion- posterior surface of upper ulna and olecranon location- posterior Movements- elbow extension

Question 34

Pronator Teres

Answer 34

Origin- distal part of the medial condyloid ridge of humerus, medial side of the proximal ulna Insertion- middle third of lateral surface of the radius Location- anterior Movements- pronation, weak flexion of elbow

Question 35

Pronator Quadratus

Answer 35

Origin- Distal 1/4th of anterior side of ulna Insertion- Distal fourth of anterior side of radius Location- anterior Movements- pronation

Question 36

Supinator muscle

Answer 36

Origin- lateral epicondyle Insertion- lateral surface of proximal radius, just below head Location- lateral Movements- supination

Question 37

Elbow flexion agonists

Answer 37

Biceps brachii brachialis brachioradialis Ex: biceps curl

Question 38

Elbow extension agonists

Answer 38

Triceps brachii anconeus Ex: push-up

Question 39

Radioulnar pronation agonists

Answer 39

pronator teres pronator quadratus brachioradialis (from supination to neutral) Ex: loosening a screw

Question 40

Radioulnar supination agonists

Answer 40

biceps brachii supinator muscle brachioradialis (from pronation to neutral)