Shoulder and elbow joints

Question 1

What are the 3 joints in the shoulder involved in movement and what type of joint are tehy

Answer 1

• acromiclavicular joint ( saddle )
• glenohumeral joint (ball and socket)
• sternoclavicular joint (planar)

Question 2

why are anterior dislocations of the shoulder more common

Answer 2

• muscular and ligamentous support anterior to the humeral head is much less robust than the substantial muscular and bony support afforded posteriorly by the rotator cuff and scapular

Question 3

different between posterior and anterior shoulder dislocation seen on xray is?

Answer 3

posterior = looks laterally displaced to the glenoid cavity

anterior = moves down and medially to the glenoid cavity

Question 4

which ligament provides the strongest resistance to anterior dislocation of the humerus from the glenoid cavity and why

Answer 4

• inferior glenohumeral ligament
• this ligament is thicker than the rest of the joint capsule

Question 5

what is the role of synovial membrane found around joints

Answer 5

• protects the joints by reducing friction between bones

Question 6

what are the 4 rotator cuff muscles

Answer 6

• supraspinatous
• infraspinatous
• teres minor
• subscapularis

Question 7

what are the 3 bursae found in the shoulder

Answer 7

• subcutaneous acromial (sits on top of acromion)
• subacromial (sits on the lateral aspect of the supraspinatous muscle)
• sub deltoid (sits on lateral head of humerus)

Question 8

how can you differentiate the position of the long head and short head of biceps

Answer 8

short head of biceps = sits on inner side of arm, close to chest

long head of biceps = sits on outer side of arm

Question 9

what rotator cuff muscle(s) allows for abduction movement

Answer 9

supraspinatus

Question 10

what rotator cuff muscle(s) allows for internal rotation of arm

Answer 10

subscapularis

Question 11

what rotator cuff muscle(s) allows for external rotation

Answer 11

infraspinatus and teres minor

Question 12

why do all of the rotator cuff muscles work to compress and decompress the humeral head on elevation

Answer 12

• helps humeral head maintain contact with the glenoid fossa during movements supporting the joint

Question 13

what muscle aids in flexion of the arm

Answer 13

biceps brachii

Question 14

what structure would help reduce the risk of damage to the supraspinatous muscle and how

Answer 14

subacromial bursae

• reduces rubbing of supraspinatus against the acromion

Question 15

all rotator cuff injuries involves the supraspinatous muscle, keeping this in mind, how is the severity of rotator cuff injuries graded

Answer 15

• the severity of injury is graded by the number of additional rotator cuff muscles involved to the supraspinatus

Question 16

what is a hill-sachs lesion

Answer 16

a dent in the bone on the head of your humerus when it’s pressed against the lip of its socket as you experience an anterior glenohumeral dislocation

(notch taken out of head of humerus by glenoid fossa due to anterior displacement of humerus)

Question 17

what are the 4 main muscles in the anterior aspect of the forearm that allow flexion

Answer 17

• pronator teres
• flexor carpi radialis
• palmaris longus
• flexor carpi ulnaris

Question 18

where is the origin attachment of the anterior flexor muscles

Answer 18

medical epicondyle of the humerus

Question 19

what are the 4 main muscles in the posterior aspect of the forearm that allow extension

Answer 19

• extensor carpi radialis longus and brevis
• extensor digitorium
• extensor digit minimi
• extensors carpi ulnaris

Question 20

where is the origin attachment of the posterior extensor mucles

Answer 20

lateral epicondyle of humerus

Question 21

just know due to the it being the origin of attachment, if the lateral or medial epicondyle of the humerus is damages,

wrist and finger flexion or extension can be affected

Question 22

what are 6 ossification centres found in the elbow

Answer 22

• capitellum
• radial head
• internal epicondyle
• trochlea
• olecranon
• lateral epicondyle

Question 23

which one ossifies taste the trochlea or the medial epicondyle

Answer 23

medial epicondyle

Question 24

know that the radial nerve, medial (turning into ulnar nerve) go along the shaft of the humerus down to the wrist on either side,

• a fracture in the arm can damage these nerves

Question 25

find a diagram and label all the ligaments, bones, muscle and bursae of the shoulder

Question 26

define the arteries that supply the arm

Answer 26

• subclavian artery (by clavicle) down into
• axillary artery (by armpit)
• then forms brachial artery by the distal shaft of humerus
• then splits into the radial and ulnar artery by the radius and ulnar

Question 27

basilic vein sits on the medial side of the forearm

cephalic vein sits on the lateral side of the forearm

Question 28

what artery supplies the hand

Answer 28

deep and superficial palmar artery