Scapular region & arm

Question 1

Bony features of scapula

Answer 1

acromion process
spine of scapula 
supra scapular notch
supraspinous fossa
infraspinous fossa

Question 2

Bony features of anterior humerus

Answer 2

head of humerus
anatomical neck (distal to head)
greater tubercle (lat)
lesser tubercle (med)
intertubercular sulcus/bicipital groove
surgical neck (*fracture site)
deltoid tuberosity

Question 3

Bony features of posterior humerus

Answer 3

anatomical neck
greater tubercle
surgical neck
deltoid tuberosity
radial (spiral) groove

Question 4

scapular movements

Answer 4

elevation/depression
protraction/retraction
upward/downward rotation

Question 5

scapulohumeral rythm

Answer 5

during 180 abduction, motion at scapulothoracic and glenohumeral joints

(1:2 ratio scapulothoracic/glenohumeral, 60 degrees at scapulothoracic, 120 at glenohumeral)

Question 6

glenohumeral joint

Answer 6

most mobile joint in body (lgr surface area of humeral head than glenoid fossa), but less stability (non-weight bearing)

ball and socket joint

motions: flexion, extension, internal rotation, external rotation, adduction, abduction, circumduction

Question 7

glenoid labrum

Answer 7

fibrocartilaginous ring surrounding glenoid fossa

biceps tendon attached to superior edge

Question 8

glenohumeral joint capsule

Answer 8

• fibrous capsule (medial attach: to glenoid cavity, lateral attach: to anatomical neck of humerus)
• synovial membrane

reinforced on anterior/superior/posterior surfaces

Question 9

What prevents anterior displacement of humeral head from glenoid cavity?

Answer 9

STATIC structures

1. superior glenohumeral ligament (SGL)
2. middle glenohumeral ligament (MGL)
3. inferior glenohumeral ligament (IGL)

Question 10

What prevents superior displacement of humeral head from glenoid cavity?

Answer 10

STATIC structures

1. coracoacromial ligament (CAL)*
2. coracohumeral ligament (CHL)

*pt of coraco-acromial arch

Question 11

What can lead to glenohumeral dislocation?

Answer 11

GH is not reinforced inferiorly, so if arm is in ABduction + lateral rotation (joint capsule stretched) and ANTERIOR force is added –> xs extension –> head of humerus comes out inferiorly

Question 12

What stabilizes the glenohumeral joint?

Answer 12

Rotator cuff muscles (dynamic structures)

1. supraspinatus
2. infraspinatus
3. teres minor
4. subscapularis

SItS

Provide compressive forces medially and inferiorly across GH joint

Question 13

Of the rotator cuff muscles, which is the only one that inserts onto the lesser tubercle of humerus rather than greater tubercle?

Answer 13

Subscapularis

Question 14

subacromial (subdeltoid) bursa

Answer 14

between the acromion process, coracoacoromial ligament, deltoid muscle, and supraspinatus tendon

Question 15

bursae of shoulder

Answer 15

subacromial bursa
subdeltoid bursa
subscapular bursa
synovial sheath

Question 16

3 causes of rotator cuff - subacromial impingement

Answer 16

1. weak rotator cuff
2. type of acromion
3. AC joint OA

–> repeated abduction and flexion of arm –> humeral head and rotator cuff tendons (*supraspinatus) impinge on coracoacromial arch

Question 17

Weak rotator cuff muscles can lead to

Answer 17

superior displacement of humeral head

Question 18

Which muscle overrides rotator cuff muscle actions?

Answer 18

Deltoid (elevates humerus)

Question 19

Which “type” of acromion process can lead to subacromial impingement?

Answer 19

a “hooked” acromion –> dips into where supraspinatus will be traveling and will start to fray the supraspinatous tendon as it runs underneath

Question 20

What is the body’s reaction to stabilize the joint after loss of cartilage?

Answer 20

ostephyte formation

Question 21

posterior axioappendicular (extrinsic shoulder muscles)

Answer 21

trapezius
latissimus dorsi
^superficial

levator scapulae
rhomboid major
rhomboid minor
^deep

Question 22

scapulohumeral (intrinsic shoulder muscles)

Answer 22

deltoid
teres major
teres minor
supraspinatous
infraspinatus
subscapularis

Question 23

Which muscle initiates ABduction of the humerus?

Answer 23

supraspinatus

Question 24

Scapular anastomosis key players

Answer 24

dorsal scapular a.
suprascapular a.
circumflex scapular branch of subscapular a.

Question 25

anterior arm

Answer 25

3 m. innervated by 1 n. and supplied by 1 a.

biceps brachii
coracobracialis
brachialis

musculocutaneous n.

brachial a.

Question 26

posterior arm

Answer 26

1 m. (3 heads) innervated by 1 n. and supplied by 1 a.

triceps brachii

radial n.

deep brachial a.

Question 27

How to distinguish suprascapular a. and n.

Answer 27

suprascapular a. –> above superior transverse scapular ligament

suprascapular n. –> below superior transverse scapular ligament

• superior transverse scapular ligament attaches from coracoid process to scapular notch

Question 28

Spaces of the scapular region/arm

Answer 28

quadrangular space

• axillary n.
• posterior circumflex humeral a.

medial triangular space
- circumflex scapular a.

lateral triangular space

• radial n.
• deep brachial a.

Question 29

Erb Duchenne Palsy

Answer 29

superior brachial plexus injury

present w/ medially rotated and Adducted arm, and extended forearm

injury to C5 and C6

Question 30

Pt w/ hand flexed behind back …

Answer 30

impaired radial n. (supplies posterior forearm m. (extend hand @ wrist))

Question 31

Surgical neck fracture

Answer 31

injury to axillary n. and posterior circumflex humeral n.

• inability to ABduct arm (deltoid)
• loss of sensation over lateral side of shoulder and proximal arm

Question 32

Spiral groove fracture

Answer 32

injury to radial n. and deep brachial a.

• inability to extend forearm and hand
• wrist drop