Elbow Myology

Question 1

Movements at the elbow and muscles acting on the elbow and forearm

Answer 1

FLEXORS
0-150˚
Biceps Brachii
Brachialis
Brachioradialis

EXTENSORS
0-10˚
Triceps Brachii
Anconeus

PRONATORS
0-90
Pronator Teres
Pronator Quadratus
Brachioradialis

Supinators
0-90
Biceps Brachii
Supinator

Question 2

Muscles that
flex the elbow

3 B’s

Answer 2

 BICEPS BRACHII –
supination and flexion –
palm up

 BRACHIALIS – flexion
only palm down

 BRACHIORADIALIS –
flexion and pronation –
thumb up

Question 3

Biceps Brachii

Answer 3

Origin
 Long head -supraglenoid tubercle
 Short head - apex of
coracoid process

Insertion
 Tuberosity of radius

Action
 flexion of shoulder joint
 flexes elbow joint
 forearm supination

Question 4

Brachialis

Answer 4

Brachialis
 Origin
 Humerus, distal one-
half of anterior surface

 Insertion
 Ulnar tuberosity and
coronoid process

 Action
 Flexes the elbow

Question 5

Brachioradialis

Answer 5

(works hardest in mid position)

Origin
 Humerus, proximal two-thirds of
lateral supracondylar ridge

Insertion
 Radius, lateral side of styloid
process

Action
 Flexes the elbow
 Pronates the forearm from
supination to mid position
 Supinates the forearm from
pronation to mid position

(strongest hammering nails)

Question 6

Muscle that extend the elbow

Answer 6

 TRICEPS BRACHII

 ANCONEUS – synergist
to Triceps Brachii

 Anchors Olecranon to
Lateral Epicondyle

Question 7

Triceps Brachii

Answer 7

Origin
 Long head - infraglenoid tubercle of scapula
 Medial head - distal 2/3 of medial and posterior surfaces of humerus below the radial groove and from medial intermuscular septum
 Lateral head - lateral and posterior surfaces of humerus of proximal 1/2 of body of humerus and lateral intermuscular septum

Insertion
▪ Posterior surface of olecranon process of ulna

Action
▪ Extends the elbow joint, in addition long head assists extension and adduction of
shoulder joint

Question 8

Anconeus

Answer 8

Origin:
 Humerus, posterior surface
of lateral epicondyle

Insertion:
 Proximal ulna
 Lateral aspect of olecranon process, and proximal posterior surface of body

Action:
 Extends elbow

Question 9

Forearm Pronation

Answer 9

 Pronator teres
 Pronator quadratus

Question 10

Pronator Teres

Answer 10

Origin
 Medial epicondyle of humerus
 Medial aspect of coronoid process

Insertion
 Middle one-third of lateral radius

Action
 Pronates the forearm
 Assists in flexing the elbow

(Use screwdriver powerful turning movements)

Question 11

Pronator Quadratus

Answer 11

Origin
 Most distal quarter of the anterior ulna

Insertion
 Distal quarter of the anterior radius.
 Only muscle that attaches only to the ulna at one end and the radius at the other end.

Action
 When pronator quadratus contracts, it pulls the lateral side of the radius towards the
ulna, thus pronating the hand.

Its deep fibres serve to keep the two bones in the forearm bound together

Question 12

Forearm Supination

Answer 12

Biceps Brachii
Supinator

Question 13

Supinator

Answer 13

Origin
 Lateral epicondyle of
Humerus
 Supinator crest on Ulna

Insertion
 Proximal one-third of
posterior, lateral, and
anterior surfaces of Radius

Action
 Supinates the forearm,
helps Biceps Brachii

Question 14

Common flexor origin

common extensor origin

Answer 14

medial epicondyle (attachment site for muscles which flex the wrist)

lateral epicondyle (attachment site for muscles which extend the wrist)

Question 15

FLEXORS CARPI RADIALIS

Answer 15

ORIGIN
 Humerus, medial epicondyle

INSERTION
 Metacarpals, base of 2nd and 3rd on palmar side

ACTION
 Flexes the wrist
 Radially deviates the wrist
 Slightly flexes the elbow
 Slightly pronates the forearm

(carrying a tray with arm supinated)

Question 16

FLEXORS CARPI ULNARIS

Answer 16

ORIGIN
 Humeral head: medial epicondyle
 Ulnar head: medial aspect of olecranon process and proximal two-thirds of posterior border

INSERTION
 Pisiform, hook of hamate, and base of 5th metacarpal on palmar side

ACTION
 Flexes the wrist
 Ulnar deviates (adducts) the wrist
 Slightly flexes the elbow

(hammering/ tennis backhand)

Question 17

Palmaris Longus

Answer 17

(purely wrist flexor)

ORIGIN
 Humerus: medial epicondyle

INSERTION
 Flexor retinaculum and palmar
aponeurosis

ACTION
 Tenses the palmar fascia
 Flexes the wrist
 Slightly flexes the elbow

Question 18

Extensor carpi radialis longus

Answer 18

(Posterior and medial to
Brachioradialis)

ORIGIN
 Humerus, distal one-third of lateral supracondylar ridge

INSERTION
 Base of 2nd metacarpal, dorsal side

ACTION
 Extends the wrist
 Radially deviates (abducts) the wrist
 Assists in flexing the elbow
 Slightly pronates the forearm

Question 19

Extensor carpi radialis brevis

Answer 19

ORIGIN
 Humerus, lateral epicondyle

INSERTION
 Base of 3rd metacarpal, dorsal
side

ACTION
 Extends the wrist
 Radially deviates (abducts) the
wrist
 Assists in flexing the elbow

(flick of wrist frisbee)

Question 20

Extensor Carpi Ulnaris

Answer 20

ORIGIN
 Humerus, lateral epicondyles and ulna, middle one-third of posterior border

INSERTION
 Base of 5th metacarpal, dorsal side

ACTION
 Extends the wrist
 Ulnar deviates (adducts) the wrist
 Slightly extends the elbow

(Helps with throwing and swing a
bat)