Elbow & wrist

Question 1

Muscles involved in extension of the elbow

Answer 1

Triceps brachii and anconeus

Question 2

Muscles involved in flexion

Answer 2

Brachialis, biceps brachii, brachioradialis

Question 3

What is a bursa? What is its function?

Answer 3

A bursa (plural bursae) is simply a membranous sac, filled with synovial fluid. It acts to cushion the moving parts of a joint, preventing degenerative damage.

Question 4

Outline the stability of the elbow joint inc. joint type & ligaments

Answer 4

1. Like all synovial joints, the elbow joint has a fibrous capsule enclosing the joint.
2. The joint capsule is thickened medially and laterally to form collateral ligaments, which stablise the flexing and extending motion of the arm.
3. The radial collateral ligament is found on the lateral side of the joint, extending from the lateral epicondyle, and blending with the anular ligament of the radius (a ligament from the proximal radioulnar joint).
4. The ulnar collateral ligament originates from the medial epicondyle, and attaches to the coronoid process and olecrannon of the ulna.
5. Anular ligament (blends with radial collateral)
6. Shape of the bones - the humerus and ulna interlock

Question 5

Name and describe three bursae of the elbow

Answer 5

Intratendinosus: Formed within the tendon of the triceps brachii.

Subtendinosus: Found between the olecrannon and the tendon of the triceps brachii, reducing friction between the two structures during extension and flexion of the arm.

Subcutaneous: Found between the olecrannon and the overlying connective tissue.

Question 6

Why are bursae clinically important?

Answer 6

Can become irritated and inflamed, producing pain.

Question 7

What blood vessels supply the wrist?

Answer 7

The wrist joint receives blood from branches of the dorsal and palmar carpal arches, which are derived from the ulnar and radial arteries

Question 8

Name the articulating surfaces of the wrist

Answer 8

o Distally – The proximal row of the carpal bones (except the pisiform).

o Proximally – The distal end of the radius, and the articular disk (see below).

The ulna is not part of the wrist joint – it articulates with the radius, just proximal to the wrist joint, at the distal radioulnar joint. It is prevented from articulating with the carpal bones by a fibrocartilginous ligament, called the articular disk, which lies over the superior surface of the ulna.

Question 9

Name three nerves that innervate the wrist

Answer 9

Median nerve – Anterior interosseous branch.
Radial nerve – Posterior interosseous branch.
Ulnar nerve – deep and dorsal branches.

Question 10

Stability of the wrist is due to its (synovial) joint capsule and ligaments. Name the ligaments of the wrist and where they are found

Answer 10

Palmar radiocarpal - It is found on the palmar (anterior) side of the hand. It passes from the radius to both rows of carpal bones. Its function, apart from increasing stability, is to ensure that the hand follows the forearm during supination.

Dorsal radiocarpal - It is found on the dorsum (posterior) side of the hand. It passes from the radius to both rows of carpal bones. It contributes to the stability of the wrist, but also ensures that the hand follows the forearm during pronation.

Ulnar collateral - Runs from the ulnar styloid process to the triquetrum and pisiform. Works in union with the other collateral ligament to prevent excessive lateral joint displacement.

Radial collateral - Runs from the radial styloid process to the scaphoid and trapezium. Works in union with the other collateral ligament to prevent excessive lateral joint displacement.

Question 11

The wrist is what kind of joint? What movements does this allow for?

Answer 11

Ellipsoid type synovial joint, allowing for movement along two axes. This means that flexion, extension, adduction and abduction can all occur at the wrist joint.

Question 12

Boundaries of the anatomical snuff box

Answer 12

Ulnar (medial) border: Tendon of the extensor pollicis longus.
Radial (lateral) border: Tendons of the abductor pollicis longus and extensor pollicis brevis.
Proximal border: Styloid process of the radius.
Floor: Carpal bones; scaphoid and trapezium.
Roof: Skin.

Question 13

What’s the other name for the wrist? what kind of joint is it

Answer 13

Radiocarpal joint - condyloid type synovial joint

& midcarpal joint

Question 14

What tissue lies between the ulna and radius

Answer 14

interosseus membrane

Question 15

How many radio-ulnar joints are there?

Answer 15

two - one distal, one proximal

Question 16

What is the most proximal end of the ulnar and what attaches here?

Answer 16

Olecranon - triceps tendon

Question 17

What is the prominence opposite the olecranon of the ulna?

Answer 17

Coronoid process

Question 18

Where does the brachioradialis tendon insert?

Answer 18

Lateral part of styloid process of the radius

Question 19

Where does the radius articulate with the ulnar?

Answer 19

Radial notch

Question 20

Where does the head of the radius articulate with?

Answer 20

Capitulum of the humerus

Question 21

What inserts on the radial tuberosity?

Answer 21

Biceps tendon

Question 22

Why are the elbow and proximal radioulnar joint considered to be one joint?

Answer 22

They are enclosed within one continuous space

Unlike the wrist and distal radioulnar joint - which are physically separate

Question 23

What bony features are at the distal end of the ulnar?

Answer 23

Head and ulnar styloid process

Question 24

What bony features are at the distal end of the radius?

Answer 24

Radial styloid process & ulnar notch

Question 25

How many distal articulating surfaces does the radius have?

Answer 25

Two - one with the ulnar, one with the proximal metacarpal bones

Question 26

Name the two pronator muscles of the foream and two supinator muscles

Which action is more powerful and why?

Answer 26

Pronator teres & pronator quadratus

Supinator & biceps brachii

Question 27

Which action is more powerful; supination or pronation and why?

Answer 27

Supination - because of the powerful action biceps provides

Question 28

Name the wrist flexors

Answer 28

Flexor carpi radialis, flexor carpi ulnaris, palmaris longus

Question 29

Name the wrist extensors

Answer 29

Extensor carpi radialis longus & brevis, extensor carpi ulnaris

Question 30

What do the wrist extensors pass under? What action does this tissue have?

Answer 30

Extensor retinaculum acts as a pulley

Question 31

What veins drain from the upper limb

Answer 31

Basilic & cephalic –> brachial veins (two) –> brachial vein –> axillary vein

Question 32

What is the name of the vein that joins the basilic and cephalic vein anterior to the elbow?

Answer 32

Antecubital vein

Question 33

Describe the arterial blood supply to the upper limb

Answer 33

Subclavian artery - axillary - brachial artery [- deep brachial (profunda brachii)] - ulnar & radial arteries

Question 34

Which nerve runs closely to the brachial artery and passes over it?

Answer 34

Median nerve

Question 35

What does the radial nerve branch into?

Answer 35

In the forearm the radial nerve divides into a deep (motor) branch and a superficial (Sensory) branch

Question 36

Describe the two articulating surfaces of the elbow?

Answer 36

Trochlear notch of the ulna and the trochlea of the humerus

Head of the radius and the capitulum of the humerus

(nb: The proximal radioulnar joint is found within same joint capsule of the elbow, but most literature considers it as a separate articulation)