Anatomy- Elbow and Forearm

Question 1

What type of joint is the elbow joint?

Answer 1

-Hinge synovial joint

Question 2

What 3 joints share the same synovial cavity and make up the elbow joint?

Answer 2

• Humeroulnar joint
• Humeroradial joint
• Proximal radioulnar joint

Question 3

What movements can the elbow joint do?

Answer 3

• Flexion/extension

- Proximal radioulnar joint also allows movement of hand through supination and pronation of the forearm.

Question 4

What provides main stability of elbow joint?

Answer 4

-Main stability from bony articulations of the trochlea (humerus) and olecranon (ulna).

Question 5

What does the humerus articulate with?

Answer 5

• 2 forearm bones
• Laterally: radius: rounded at capitulum
• Medially: ulna: trochlea

Question 6

Where are the medial and lateral epicondyles of the humerus and what are they there for?

Answer 6

• Proximal to trochlea and capitulum

- Also sites of muscle attatchment

Question 7

Is the ulna medial or lateral and is it smaller or larger than the radius?

Answer 7

• Medial

- Larger than the radius

Question 8

What is found proximally on the ulna?

Answer 8

• Trochlear notch
• 2 processes:
• larger; olecranon; posterior; elbow prominence
• smaller; coronoid process; anterior

Question 9

Where does the humerus articulate with the ulna and how is this area created?

Answer 9

• Trochlear notch

- The 2 processes (olecranon and coronoid) form the trochlear notch to articulate with the trochlea of the humerus.

Question 10

What is found distally on the ulna?

Answer 10

• Head; anterior, articulates with radius

- Styloid processes; posterior/medial, wrist ligaments

Question 11

Is the ulna part of the wrist joint?

Answer 11

Not strictly:

• articulates with radius at distal radioulnar joint
• prevented from articulating with the carpal bones by a fibrocartilaginous ligament = articular disc

Question 12

Is the radius medial or lateral?

Answer 12

Lateral

Question 13

What can be found proximally on the radius?

Answer 13

• Head; articulates with capitulum of humerus and radial notch of ulna
• Radial tuberosity; medially, biceps attatch here

Question 14

What can be found distally on the radius?

Answer 14

• broad
• articulates with ulna and proximal carpal bones
• Styloid processes alterally; wrist ligaments attatch
• Ulnar notch; medially

Question 15

What forms the humeroulnar joint?

Answer 15

• Trochlea of humerus AND

- Trochlear notch of ulna

Question 16

Where is humeroulnar joint ?

Answer 16

Medially

Question 17

What is the main joint of the elbow?

Answer 17

-Humeroulnar joint

Question 18

What reinforces the humeroulnar joint?

Answer 18

Ulnar collateral ligament

Question 19

What movements does the humeroulnar joint allow?

Answer 19

• Flexion and extension
• Ulnar processes limit range of movement
• No pronation or supination

Question 20

What makes up the humeroradial joint?

Answer 20

• Capitulum of humerus AND

- Head of radius

Question 21

Where is humeroradial joint located?

Answer 21

-Lateral

Question 22

What reinforces humeroradial joint?

Answer 22

-Reinforced by radial collateral ligament.

Question 23

What movements does the humeroradial joint allow?

Answer 23

-Supination and pronation

Question 24

What does the annular ligament do?

Answer 24

-Stabilises both humeroradial and humeroulnar joint

Question 25

What are the flexors of the arm?

Answer 25

- Biceps brachii - Coracobrachialis - Brachialis

Question 26

What are the extensors of the arm?

Answer 26

Triceps | Anconeus

Question 27

Which areas move to allow forearm rotation?

Answer 27

- Movements between forearm bones at radioulnar joints. - Around radius head to ulna styloid process. - Radius rotates, proximal ulna stays in place

Question 28

Where does forearm rotation occur?

Answer 28

- Occurs below and independant of shoulder and elbow. | - Even though superior radioulnar joint cavity continous with elbow.

Question 29

Is supination or pronation more powerful?

Answer 29

Supination

Question 30

What gives forearm rotation the apparent range of 360 degrees?

Answer 30

- Rotation of humerus | - Pectoral girdle movements

Question 31

What happens in pronation and where are the radius and ulna located in pronation?

Answer 31

- Palm turned posteriorly - Proximal radius lateral to ulna - Distal radius medial to ulna

Question 32

What happens in supination and where are the radius and ulna located in pronation?

Answer 32

- Palm turned anteriorly - Movement reversed - Radius lateral and paralell with ulna.

Question 33

What type of joint is the superior radioulnar joint and what is it a joint between?

Answer 33

- Pivot joint | - Between head of radius and osseofibrous ring (radial notch of ulna and annular ligament).

Question 34

What does the radial annular ligament do?

Answer 34

-Consists of string fibres, encircles head of radius.

Question 35

What type of joint is inferior radioulnar joint and what make it up?

Answer 35

- Pivot synovial joint - Between head of ulna AND - ulnar notch of radius

Question 36

What holds the inferior radioulnar joint together?

Answer 36

- Articular disc | - Interosseous membrane

Question 37

What is the interosseous membrane?

Answer 37

- Is a broad thin fibrous tissue separating bones. - Fibrous sheet connecting radius and ulna to form radio ulnar syndesmosis (fibrous joint between radius and ulna). - Divides forearm into anterior and posterior. - Site of attatchment for muscles of forearm.

Question 38

What happens to the interosseous membrane fibres going from pronation to supination?

Answer 38

-Fibres change from relaxed to tense in the neutral position, relax again as forearm supinates.

Question 39

What may cause disloaction/subluxation of radial head and what group of people are at high risk?

Answer 39

- Pre school kids - If jerked by UL while forearm pronated - Tears distal attatchment of annular ligament - Radial head moves distally out.

Question 40

What is the treatment for disloaction/subluxation of radial head?

Answer 40

-Manipulating forearm into supination whilst elbow flexed-radial head back in place.

Question 41

What are the supinator muscles?

Answer 41

- Biceps brachii | - Supinator

Question 42

What are the pronator muscles?

Answer 42

- Pronator teres | - Pronator quadratus

Question 43

What is the cubital fossa important for?

Answer 43

-Important transition between arm and forearm.

Question 44

What is the triangular depression of the cubital fossa bound by?

Answer 44

- Brachioradialis laterally | - Pronator teres medially

Question 45

What artery enters cubital fossa and what does it leave as?

Answer 45

- Brachial artery | - Leaves as radial and ulnar arteries

Question 46

What nerves found in the cubital fossa?

Answer 46

- Median nerve runs through | - Radial nerve laterally if brachioradialis retracted.

Question 47

How can the muscles of the forearm be categorised?

Answer 47

- 2 layers: - Superficial: long muscles; humerus to hands (act on elbow and wrist), humerus to digits (act on elbow, wrist, digits) - Deep: arise from forearm bones and pass to digits. Crossing and acting on wrist joints and digit joints.