Muscles Crossing Shoulder Joint

Question 1

Deltoid (Origin)

3 parts

Origin of anterior part -
Origin of posterior part
Origin of middle part

Answer 1

Anterior- Lateral one third of clavicle, middle- acromion
Posterior- scapular spine

Question 2

Deltoid (insertion)

Answer 2

Deltoid tuberosity on mid- lateral shaft of humerus

Question 3

Deltoid (action)
Anterior
Posterior
Middle

Answer 3

Anterior- flexes arm at shoulder and medially rotates

Posterior- extends and laterally rotates shoulder

Medially- Adducts arm at shoulder

Question 4

Triceps (Origin)

Long head
Lateral head
Medial head (deeper)

Answer 4

Long head origin- scapula inferior to the glenoid fossa

Lateral head- upper posterior shaft of humerus

Medial head-lower posterior shaft of humerus

Question 5

Tricep (insertion)

Answer 5

Olecranon process

Question 6

Triceps (action)

Answer 6

Extension of elbow (and also shoulder) press up

Question 7

Biceps brachii
(Origin)
Lu5 lies just radial to the tendon, and PC3 lies just ulnar to it
Lung, PC and Heart channels relate to the body of the muscle.
Lung- laterally
Heart- medially
PC runs in line with the gap between the two heads

Answer 7

Shoulder joint (two heads)

Question 8

Biceps brachii (insertion)

Answer 8

Radial tuberosity of the head of the radius

Question 9

Biceps brachii (Action)

Answer 9

Flexion of the elbow joint

Question 10

Brachialis (Origin)

Answer 10

Lower half of humerus

Question 11

Brachialis (insertion)

Answer 11

Coronoid process of ulna

Question 12

Brachialis (Action)

Answer 12

Flexes the elbow

Question 13

Brachioradialis (origin)

Answer 13

Lower lateral humerus

Question 14

Brachioradialis (Insertion)

Answer 14

Radial styloid at the wrist (lies very deep)

Question 15

Brachioradialis (Action)

Answer 15

Flexes the forearm