Elbow joint/ forearm

Question 1

muscles flexing the elbow joint?

Answer 1

• biceps brachii
• brachialis
• brachioradialis
• pronator teres

Question 2

what is the action of biceps brachii?

Answer 2

• flexor of elbow joint
• powerful supinator of the forearm
• often both performed together with any unwanted actions being cancelled by antagonists
• also a flexor of the shoulder joint, and the fact that the long head crosses the superior part of the joint means that it has an important stabilising role

Question 3

what happens to biceps brachii if deltoid becomes paralysed and how is it achieved?

Answer 3

it can be re-educated to abduct the shoulder. achieved by laterally rotating the humerus at the shoulder joint in order to put the long head into a more appropriate position

Question 4

what is the functional activity of biceps brachii?

Answer 4

may use its supinatory and flexing actions sequentially in an activity such as pulling a cork out

Question 5

what is the action of brachialis?

Answer 5

main flexor of the elbow

Question 6

what is the functional activity of brachialis?

Answer 6

although it flexed it is also important in controlling extension produced by gravity, in this situation, the flexors of the elbow control the movement by eccentric contraction

Question 7

what is the action of brachioradialis?

Answer 7

• flexes the elbow joint, particularly when the forearm is midway between pronation and supination
• It also helps return the forearm to this mid position from the extremes of either pronation or supination, this can be confirmed by palpation

Question 8

What is the functional activity of brachioradialis?

Answer 8

• acts to maintain the integrity of the elbow joint since its fibres run more of less parallel to the radius
• it also works eccentrically as an extensor of the elbow joint in activities such as hammering

Question 9

muscles extending the elbow joint?

Answer 9

• anconeus

- triceps brachii

Question 10

Action of anconeus?

Answer 10

• assists in extension of the elbow joint

Question 11

action of triceps brachii?

Answer 11

• extensor of the elbow joint

- the long head can also adduct the arm and extend it from a flexed position

Question 12

functional activity of triceps brachii?

Answer 12

• only become active in this form of extension when gravity is pulling downwards and this muscle is working eccentrically to control the movement
• triceps work strongly in pushing and pulling activities (push ups)
• in the latter it is working concentrically in the upward movement and eccentrically in the downwards movement
• when using a wheel chair triceps brachii works strongly to push the wheel around and to propel the chair forward

Question 13

functional activity of anconeus?

Answer 13

• produces lateral movement and extension of the bones at its distal end
• these movements occur during pronation and are essential when a screwdriver is being used
• the movement of the ulna with respect to the radius allows the axis of pronation and supination to be altered so that the forearm rotates about a single axis and so does not describe an arc

Question 14

muscles supinating the forearm?

Answer 14

• supinator
• biceps brachii
• brachioradialis

Question 15

action of supinator?

Answer 15

• supinates the forearm, in which there is an anterolateral movement of the distal end of the radius around the ulna
• this causes the 2 bones to lie parallel to each other
• Usually the prime mover, biceps brachii helps

Question 16

When does biceps brachii come into play in relation to supination of the forearm?

Answer 16

if the elbow is fully extended

Question 17

when does powerful supinatory movements occur of the forearm?

Answer 17

with the elbow fixed to about 120’

Question 18

muscles pronating the forearm?

Answer 18

pronator teres
pronator quadratus
brachioradialis

Question 19

action of pronator teres?

Answer 19

• pronates the forearm by producing and anteromedial movement of the lower end of the radius across the ulna
• also a weak flexor of the elbow

Question 20

action of pronator quadratus?

Answer 20

• initiates pronation of the arm
• the transverse nature of its fibres allows the lower ends of the radius and ulna to be held together when upwards pressure is applied