T2 l3: anatomy of the shoulder region

Question 1

what does the pectoral girdle consist of

Answer 1

Clavicle and scapula

Question 2

what 2 joints are in the pectoral girdle

Answer 2

• glenohumeral

- acromioclavicular

Question 3

function of ligaments

Answer 3

Stabilize the shoulder region

Question 4

what are the 4 ligaments of the shoulder region

Answer 4

coracoclavicular

acromioclavicular

coracoacromial

glenohumeral:

• Superior
• middle
• inferior

Question 5

describe the coracoclavicular ligament

Answer 5

• 2 parts

- major stabilizing ligament

Question 6

describe the coracoacromial ligament

Answer 6

• Forms arch
• Provides support for head of humerus
• prevents superior dislocation

Question 7

Glenohumeral joint:
describe type of joint

describe its function:

Answer 7

ball and socket joint

• Abduction/Adduction
• Flexion/Extension
• Lateral/Medial rotation
• Circumduction

Question 8

Deltoid muscle

Answer 8

Spine of scapula+clavicle + acromion

deltoid tuberosity

post fibres: -extension + lateral rotation

anterior fibres: -flexion and medial rotation

supplied by axillary nerve

overall: arm abduction

Question 9

what 2 muscles help the arm adduct

Answer 9

Latissimus dorsi, pec major

Question 10

what are the 2 structural components that allows the arm to abduct/adduct

Answer 10

• glenohumeral joint

- the scapula

Question 11

what muscles act on the scapula and in what direction n

Answer 11

Abduction : Upper fibres trapezius

serratus anterior

lower fibres trapezius

Adduction :

levator scapulae

rhomboids

Question 12

what muscles perform arm flexion

Answer 12

Coracobrachialis

biceps brachii

Question 13

what muscles perform arm extension

Answer 13

Triceps brachii

post fibres deltoid

latissimus dorsi

Question 14

what contributes to glenohumeral joint stability

Answer 14

large humeral head

shallow glenoid fossa

Question 15

what is most common type of dislocation of the glenohumeral joint

Answer 15

anterior dislocation common

Question 16

what are the 5 factors that increase stability of glenohumeral joint

Answer 16

Coracoacromial arch

2. Glenohumeral ligaments
3. Deepening of glenoid fossa by glenoid labrum
4. Long heads of biceps (above) and triceps (below)
5. Tendons of rotator cuff muscles

Question 17

what is the function of the coracoacromial arch

Answer 17

prevents superior dislocation

Question 18

whay is the function of the glenohumeral ligaments

Answer 18

• Supports anterior of joint (sup mid and inferior )

Question 19

what is the function of the glenoid labrum

Answer 19

deepens the glenoid fossa

Question 20

what is the structural function of the long head of the biceps and triceps

Answer 20

Splint joint- passes through its origin-jo capsule- transverse humeral ligament- intertubercular sulcus

triceps- origin helps stabilise it

Question 21

what are the structural function of the rotator cuff muscles

Answer 21

4 muscles - insert close to glenohumeral joint- fuse with the capsule and forms a cuff around the joint

Question 22

what are the rotator cuff muscles

Answer 22

Supraspinatous

infraspinatous

teres minor

subscapularis

Question 23

where do the SIT muscles insert

Answer 23

Greater tubercle

Question 24

where does the subscapular muscle insert

Answer 24

lesser tubercle

Question 25

describe the action of the teres major and why it can be considered a rotator cuff muscle

Answer 25

Performs medial rotation

Stabilises the humerus during
abduction - Eccentric contraction

Question 26

describe an injury to the rotator cuff muscles

Answer 26

Supraspinatus impingement
:Supraspinatus most commonly injured

Limited space for tendon under coracoacromial arch

• Impingement due to repetitive overhead activities
• Common in athletes (throwers)

Question 27

what is the blood supply to the shoulder

Answer 27

Scapula anastomosis- via subclavian and axillary arteries

Question 28

describe scapula anastomosis

Answer 28

From subclavian :
upwards- thyrocervical trunk- suprascapular

downwards- dorsal scapula r- subscapular

Question 29

describe the nerve supply to the shoulder

Answer 29

superior trunk-suprascapular nerve- infr and supraspinatous muscles

posterior cord:

• axilla-teres minor & deltoid
• radial- triceps brachii
• upper/lower subscapular nerves- subscapularis, teres major

Thoracodorsal nerve- latissimus dorsi

lateral cord:
- musculocutaneous - arm flexors

lateral pectoral nerve - pectoralis major

Medial cord: medial pectoral nerve - pectoralis major/minor

and to cutaneous nerves to arm and forearm

Question 30

what is the quadrangular space and its importance

Answer 30

made up of teres major and minor as well as the humerus and the long head of the biceps

axllary nerve & post circumflex humeral artery passes through trough to supply deltoid and teres minor and badge area

fracture of surgical neck can damage nerve and vessel