MSK - Arm And Forearm Anatomy

Question 1

What is the membrane called between the radius and ulna?

Answer 1

Interosseus membrane

Question 2

What are the three joints of the elbow?

Answer 2

1) ulnohumeral (hinge joint)
2) radiohumeral (ball and socket)
3) upper radioulnar joint (trochoid)

Question 3

Is the elbow joint a synovial hinge joint?

Answer 3

Yes

Question 4

What is the difference between cubitus varus and cubitus valgus?

Answer 4

Cubitus varus is when the arm is held inwards at an angle from the elbow. This is a cosmetic problem only. Cubitus valgus is when the arm is held outwards at the elbow. This is a functional problem as it stretches the ulnar nerve and may prevent movement of the hand

Question 5

How is the elbow joint stabilised?

Answer 5

It has a capsule, ligaments and muscles to stabilise it

Question 6

What are the three ligaments found at the elbow?

Answer 6

• medial collateral ligament (posterior, anterior and transverse parts)
• lateral collateral ligament (with radial and ulnar parts)
• annular ligament

Question 7

What is the ‘fat pad sign’?

Answer 7

This is when the fat pad (usually pressed against the olecranon fossa by the triceps tendon) is moved out of place due to inflammation and therefore visible on an X-ray. It suggests a fracture of the humerus or the radial head

Question 8

Which movement is the upper radioulnar joint involved with?

Answer 8

Pronation and supination

Question 9

Which movement is the ulnohumeral joint mainly involved with?

Answer 9

Flexion and extension

Question 10

What are the three main nerve supplies to the forearm?

Answer 10

Median nerve, ulnar nerve, radial nerve

Question 11

What is compartment syndrome?

Answer 11

Increased pressure within a muscle compartment of the arm of leg. Usually due to injury such as a fracture. Treatment is fasciotomy

Question 12

What is a synovial bursa?

Answer 12

A small fluid-filled sac lined by synovial membrane with an inner capillary later of viscous fluid