glenohumeral joint

Question 1

glenohumeral joint classifications

Answer 1

multiaxial ball-and-socket
enarthrodial

Question 2

glenohumeral joint components

Answer 2

joint cavity
fibrous capsule
synovial membrane

Question 3

glenoid labrum role

Answer 3

thickens cavity, deepens socket to improve articular fit (thick periphery, thin at center)

Question 4

problems with joint

Answer 4

little congruity between ball and socket
Shoulder joint is set up such that a ball is sitting on a plane that is angled forward and down
Like a golf ball sitting on a tee that is lying on is side -> Ball is constantly trying to roll/slide off the Glenoid

Question 5

glenoid labrum role

Answer 5

slightly enhances stability by deepening the concavity of the fossa
serves as buttress to excessive humeral head translation

Question 6

glenoid labrum injuries

Answer 6

injured with sudden overhead movements and with trauma

Question 7

supra-humeral space

Answer 7

Deep=Long-head of Biceps tucked up under fibrous capsule, Fibrous portion of Capsule, & Supraspinatus Tendon (Most easily & commonly injured rotator cuff)
Superficial=Subacromial/Subdeltoid Bursa and Coracoacromial Ligament

Question 8

glenohumeral ligaments

Answer 8

superior gh ligament
middle gh ligament
inferior gh ligament
coracohumeral ligament

Question 9

glenohumeral ligament roles

Answer 9

provide stability
usually blend together, cannot separate out to identify/not all people possess all of these ligaments

Question 10

superior gh ligament role

Answer 10

Thicken Anterior Capsule
Help to protect against anterior dislocations

Question 11

coracohumeral ligament role

Answer 11

Won’t allow humeral head to be displaced inferiorly (pulled downward)

Question 12

typical dislocations

Answer 12

usually inferior or anterior
posterior not usually seen (falling on outstretched arm)

Question 13

ligament tension

Answer 13

Ligaments are quite lax until extreme ranges of motion reached due to wide range of motion involved

Question 14

ROM for each motion

Answer 14

difficult to measure exactly due to accompanying shoulder girdle movement

Question 15

abduction ROM

Answer 15

180 degrees

Question 16

adduction ROM

Answer 16

0 degrees, 75 degrees anterior to trunk

Question 17

extension ROM

Answer 17

40 to 60 degrees

Question 18

flexion ROM

Answer 18

90 to 100 degrees

Question 19

flexion/extension limitations

Answer 19

must do motions in anatomical position
external rotation required to clear shoulder, internal rotation with movement has limit

Question 20

internal / external rotation ROM

Answer 20

70 to 90 degrees in both planes [horizontal and vertical]

Question 21

horizontal abduction ROM

Answer 21

45 degrees

Question 22

horizontal adduction ROM

Answer 22

135 degrees

Question 23

anatomical design components contributing to injury

Answer 23

shallowness of glenoid fossa
laxity of ligamentous structures
lack of strength & endurance in muscles

Question 24

dislocation types and frequency

Answer 24

anterior or anteroinferior glenohumeral subluxations & dislocations – common
posterior dislocations – rare
posterior instability problems somewhat common

Question 25

SITS muscles

Answer 25

subscapularis
supraspinatus
infraspinatus
teres minor

Question 26

SITS design and role

Answer 26

attach to the front, top & rear of humeral head
point of insertion enables humeral rotation
vital in maintaining humeral head in correct approximation within glenoid fossa while more powerful muscles move humerus through its wide range of motion

Question 27

Glenohumeral internal rotation deficit (G I R D)

Answer 27

difference in internal rotation range of motion between an individual’s throwing & nonthrowing shoulders
overhead athletes with a G I R D of greater than 20% had a higher risk of injury