Shoulder Flashcards
What are the joints/articulations that makeup the shoulder?
Glenohumeral joint, sternoclavicular joint, acromioclavicular joint, & scapulothoracic joint
On the manubrium, the ___ facets articulate with the clavicles
clavicular
The costal facets articulate with the ____
ribs
The first two costal facets articulate with what two things?
rib #1 and rib #2
The ____ notch is between the clavicular facets
jugular
The shaft of the clavicle is curved with the anterior surface generally (convex/concave) medially and (concave/convex) laterally
convex; concave
The anatomic position of the shaft of the clavicle is nearly in the (horizontal/frontal) plane
horizontal
The ___ tuberosity is the attachment of the costoclavicular ligament
costal
The ___ forms a shelf above the glenoid fossa
acromion
The glenoid fossa of the scapula is slightly (concave/convex)
concave
The angle of inclination of the scapula varies. It can be - ___ degrees pointing downward a little bit or way up in the air at + ___degrees. The + ___ degrees of upward slope for the glenoid is about where most people are about.
7; 16; 4
At rest with the scapula resting on the posterior-lateral surface of the thorax, the Glenoid Fossa faces approximately 30-40 degrees anterior to the Frontal Plane. This position is known as the “___ _____” – the position the humerus and arm follow naturally when raising the arm overhead
scapular plane
What is the proximal attachment of the longhead of the biceps?
The supraglenoid tubercle
What is the proximal attachment of the triceps brachii?
The infraglenoid tubercle
The head of the humerus faces (medially/laterally) and (superiorly/inferiorly) and forms a 135 degree angle of inclination with the long axis of the humeral shaft
medially and superiorly; 135
Retroversion is a backwards twist of the humerus which makes it so the head of the humerus does not point straight above. Retroversion aligns the humeral head within the scapular plane for articulation with the ___ _____
glenoid fossa
At birth there is (more/less) degrees of retroversion and it naturally (increases/de-rotates) to 30 degrees between 16 and 20 years old.
More; derotates
Mechanical stress can change the amount of retroversion you end up with in your humerus. Repetitive torsional stress causes adaptation to the humerus. It either causes greater retroversion or inhibits derotation. Either way the end result is the same which is 10 to 15 degrees of (more/less) humeral retroversion
More
If I was somebody who pitched in my younger days then I would typically have (more/less) retroversion.
more
The shaft of the humerus is separated from the head of the humerus by the (anatomical/surgical) neck of the humerus
anotomical
What is the inferior attachment site for the subscapularis?
The lesser tubercle of the humerus
What is the inferior attachment site for the supraspinatus, infraspinatus, & teres minor?
The greater tubercle of the humerus
The posterior shaft of the humerus contains the radial groove which lies between the lateral and medial heads of the _____
triceps
The ___ nerve lies in the radial groove
radial
What joint firmly attaches the clavicle to the scapula?
The A/C joint
What is the most distal and most mobile shoulder joint?
The glenohumeral joint
Which shoulder joint is not a true joint?
Scapulothoracic joint
What are the three movements of the scapula discussed in lecture?
Elevation/Depression,
Upward/Downward rotation,
Protraction/Retraction
What joint links the appendicular skeleton with the axial skeleton?
Sternoclavicular joint
Clavicle: (convex/concave) longitudinal diameter, (concave/convex) transverse diameter
convex; concave
Sternum: (concave/convex) longitudinally , (convex/concave) transversely
concave; convex
In the SC joint, which ligament connects the medial ends of each clavicle ?
The interclavicular ligament
In the SC joint, which ligament runs from the first rib to the clavicle and stabilizes the joint through all motions except depression?
Costoclavicular ligament
In the SC joint the articular disc (increases/decreases) congruity and (increases/decreases) shock absorption
increases; increases
What muscles provide the SC joint with stability anteriorly, posteriorly, and inferiorly?
Anteriorly: SCM, posteriorly: sternothyroid & sternohyoid, Inferiorly: sublavius
The glenohumeral joint is an articulation formed between the relatively large convex head of the ____ and shallow concavity of the ____ _____
humerus; glenoid fossa
The glenohumeral joint moves in conjunction with the moving ___ to produce an extensive range of motion of the shoulder
scapula
The orientation of the glenoid faces (upward/downward) and (anterior/posterior). It is almost as if the ball was able to rest a little bit on the socket at the bottom increasing a little bit of stability.
upward; anterior
There is a (cartilaginous/fibrous) ring that goes all the way around the glenoid and it deepens that concavity in order to create some stability. We don’t want deep bony sockets because that does not have as much give. We would rather have a shallow bony socket with a cartilage ring around the edge to hold it stable to some extent to allow more motion.
cartilaginous
The space within the capsule in the glenohumeral joint is twice the size of the humeral head so that tells us that the (passive/active) subsystem is pretty lax and allows a lot of freedom in movement.
passive
The capsular ligaments of the GH joint get taught at (different/same) degrees of “twist” or rotation of the humerus. This allows for specified stability depending on the position of the arm.
different
Name the capsular ligaments of the glenohumeral joint
Superior glenohumeral ligament, middle glenohumeral ligament, & the inferior glenohumeral ligament complex
How many parts are there in the inferior glenohumeral ligament complex? Name them.
3; anterior band, axillary pouch, & posterior band
What is the name of the ligament that is not a capsular ligament but is similar in function to the superior glenohumeral ligament?
Coracohumeral ligament
When is the superior glenohumeral ligament taught & what motions does it resist?
Taught in anatomical position and resists external rotation and anterior/inferior translations of the humeral head
When is the coracohumeral ligament taught and what motions does it resist?
Taught in anatomical position and resists external rotation and inferior translations of the humeral head
When is the middle glenohumeral ligament taught and what motions does it resist?
Taught at approximately 45 degrees of abduction and resists external rotation and anterior translation in this position
When is the anterior band of the inferior glenohumeral ligament complex taught and what motions does it resist?
Taught at 90 degrees of abduction and full external rotation and prevents anterior translation
When is the axillary pouch of the inferior glenohummeral ligament complex taught and what motions does it resist?
Taught at 90 degrees of abduction and prevents inferior translation
When is the posterior band of the inferior glenohumeral ligament complex taught and what motions does it resist?
Taught at 90 degrees of abduction and full internal rotation and prevents posterior translation
The glenohumeral joint gets significant structural support from which muscle group?
The rotator cuff muscles
Just by the rotator cuff muscles being present and playing a role in the structural support of the GH joint, the subscapularis muscle gives you anterior stability from the front preventing (anterior/posterior) translation, the supraspinatus muscle gives you support from the humeral head translating (superiorly/inferiorly), so it gives you a little support to keep the ball in socket, or the head of the humerus down. The infraspinatus and teres minor give you support (posteriorly/anteriorly). Remember that these muscles blend with the capsule so they kind of mimic the capsule as well as providing contractile stability as well.
anteriorly; superiorly; posteriorly
The glenoid labrum (increases/decreases) contact with the humeral head which (increases/decreases) stability
increases; increases
What is the name of the space between the roof of the glenohumeral joint and the humeral head ?
The subacromial space
What is located in the subacromial space?
The subacromial bursa, supraspinatus tendon, superior portion of the glenohumeral joint capsule, & the tendon of the longhead of the biceps
What are the kinematics that occur in the glenohumeral joint?
Flexion/extension, abduction/adduction, & internal/external rotation
Kinematics of abduction at the glenohumeral joint:
The scapula is going to (upwardly/downwardly) rotate, the ball in socket is going to move about 120 degrees relative to each other, and then the socket, IE the scapula is going to move another 60 degrees because of (upward/downward) rotation and that is how we get abduction all the way near to 180 degrees.
Upwardly; upward
Kinematics of abduction at the glenohumeral joint:
As the supraspinatus is performing its contraction it is actually (tightening/loosening) the capsule which we think helps with the slide and it helps keep this from having excess tissue which could get trapped overhead in the subacromial space.
tightening
Remember we talked about the (humerus/scapula) not moving a whole lot in the first 60 degrees of shoulder abduction? It does not move too much in this range and as that happens you are going to close down on that subacromial space and there is a relative ratio of 2 to 1 (2 degrees for every one degree of glenohumeral abduction accompanied with scapular upward rotation) that starts to catch up and create (inaudible). At 90 degrees we have reached the minimal amount of space in the subacromial space. (Abduction/ upward rotation) doesn’t significantly start moving until after 60 degrees of abduction so what happens here is as we abduct our glenohumeral joint and it decreases decreases decreases, and then the scapula starts to accommodate the upward rotation and it is going to move the acromion away from the proximal humeral head.
Scapula; upward rotation
During shoulder abduction, there is a (superior/inferior) roll and (inferior/superior) slide.
superior; inferior
When you go into straight flexion, in order to create room between the greater tubercle and the acromion process you have to have (posterior/anterior) tilting of the shoulder blade and (upward/downward) rotation throughout this motion.
posterior; upward
In flexion the shoulder blade moves backward which would be a (posterior/anterior) tilt. In extension the shoulder blade moves forward which means that this would be an (anterior/posterior) tilt.
posterior; anterior
What is the arthrokinematic motion of flexion/extension of the shoulder joint?
A spin
External rotation of the shoulder = (posterior/anterior) roll and (anterior/posterior) slide
posterior; anterior
Internal rotation of the shoulder joint = (anterior/posterior) roll and (posterior /anterior) slide
anterior; posterior
When you abduct the humerus to 90 degrees, it is now facing into the glenoid in the socket and the arthrokinematics becomes a __ .
spin
Definition:
The idea that the scapula and humerus move with certain principles through its range of motion.
Scapulohumeral rhythm
Scapulohumeral Rhythm Principals:
1) After about 30 degrees of abduction this rhythm remained constant with a ratio of 2:1, for every __ degrees of abduction, there is __ degrees of GH motion to __ degree of scapular upward rotation
3; 2; 1
Scapulohumeral Rhythm Principals:
2) For full scapular upward rotation to occur (60 degrees) there must be elevation at the ___ joint and upward rotation at the __ joint
SC; AC
Scapulohumeral Rhythm Principals:
3) When in the frontal plane (think abduction), clavicular retraction (15-20 degrees) at the ___ joint is present
SC
Scapulohumeral Rhythm Principals:
4) As the shoulder reaches full abduction, the scapula (posteriorly/anteriorly) tilts and can also (externally/internally) rotate.
posteriorly; externally
Scapulohumeral Rhythm Principals:
5) Clavicle rotates (posteriorly/anteriorly) secondary to coracoclavicular ligament
posteriorly
Of note, people diagnosed with subacromial impingement syndrome showed (reduced/increased) posterior rotation of clavicle
reduced
Scapulohumeral Rhythm Principals:
6) The humerus naturally (externally/internally) rotates: When naturally abducting your shoulder to the ceiling you get to a point where you feel a restriction or a bump. In order to complete the motion you have to (externally/internally) rotate your humerus. This allows for the (greater/lesser) tubercle to pass posterior to the acromion and avoid impingement.
externally; externally; greater
External rotation ROM mostly happens before __ degrees of abduction
80
(Proximal/distal) stability is what allows you to have (distal/proximal) mobility
Proximal; distal
(Proximal/Distal) stabilizers: Muscles that originate on the spine, ribs, and cranium and insert on the scapula and clavicle.
Proximal
What are two examples of proximal stabilizers?
The trapezius and the serratus anterior
(Distal/Proximal) mobilizers: Muscles that originate on the scapula and clavicle and insert on the humerus or forearm.
Distal
What are two examples of distal mobilizers?
The deltoid and the biceps brachii
What muscles function to elevate the scapula from most responsible to least responsible?
Upper trapezius, levator scapulae, & the rhomboids
What muscles function to depress the scapula from most responsible to least responsible?
Lower trapezius, latissimus dorsi, pectoralis minor, & the subclavius
What muscle(s) function to protract the scapula from most responsible to least responsible?
The serratus anterior
What muscles function to retract the scapula from most responsible to least responsible?
Middle trapezius, rhomboids, & the lower trapezius
The ____ and the (lower/middle) trapezius are both synergists as retractors of the scapula but are also direct antagonists
rhomboids; lower
What muscles function to elevate the arm at the glenohumeral joint from most responsible to least responsible?
The anterior deltoid, middle deltoid, and the supraspinatus
What muscles work to flex the shoulder from most responsible to least responsible?
The anterior deltoid, coracobrachialis, & the biceps brachii
What muscles work to abduct the shoulder from most responsible to least responsible?
The middle deltoid and the supraspinatus
Force dispersed over a bigger surface area causes (less/more) compression on any one point. If you take your hand and you “press” with a certain amount of force on someone’s back and then you take the knob of your knuckle and compress with the same force the knuckle is going to hurt a lot more because it has a (smaller/larger) surface area.
less; smaller
What muscles function to upwardly rotate the scapula from most responsible to least responsible?
The serratus anterior, upper trapezius, and lower trapezius
The serratus anterior, upper trapezius, and lower trapezius form a force couple when (upwardly/downwardly) rotating the scapula because they are kind of pulling in (different/same) directions in order to create a rotation.
upwardly; different
Even though the middle trap and the rhomobids are not considered upward rotators, they are very active during this movement. The (middle/lower) trap and the ____ are retractors. If the serratus anterior is doing a lot of upward rotation as its primary movement it has to be turned on with a high load in order to upwardly rotate the scapula. If it is contracting with that much force it is also protracting, so it is pulling you into the forward direction. In order to fight that the middle trapezius and the rhomboids have to be active in order to keep upward rotation but not protract.
middle trap and the rhomboids
In a normal person who has a very strong serratus anterior, the downward rotation caused by the deltoid and supraspinatus is negated. If the serratus anterior is weak and does not turn on the scapula will not properly (upwardly/downwardly) rotate and you will see a (downward/upward) rotation of the scapula.
upwardly; downward
Remember that the serratus anterior helps with (external/internal) rotation and (posterior/anterior) tilting of the scapula. You can see internal rotation and anterior tilting in a patient with a weak serratus anterior which results in scapular winging.
external; posterior
What muscle group blends in with the capsule and are regulators of dynamic stability at the GH joint?
The rotator cuff muscles
(There aren’t/ there are) thick or rigid ligaments that are present in the rotator cuff muscles and that is what allows you to have all of this mobility. So the rotator cuff has to function at a very high level in order to maintain stability of that joint.
There aren’t
The overall the pull of the fibers of the rotator cuff muscles are (medial/lateral) and (inferior/superior), so into the glenoid and down.
medial and inferior
The contraction of the (horizontally/vertically) oriented supraspinatus causes a compression force directly into the glenoid fossa. It stabilizes the humeral head in the fossa during its superior roll into abduction.
horizontally
All of the rotator cuff muscles apart from the supraspinatus have an (inferiorly/superiorly) directed line of force/vector. These forces counteract the strong (superior/inferior) directed force of the Deltoid muscle.
inferiorly; superior
You can tell that someone has a rotator cuff tear just by looking at an xray because the head of the humerus would be riding (high/low) because you would see that the head of the humerus really isn’t in the socket and it is very close to the subacromial space because the cuff forms this ring around the humerus and if there is a massive cuff tear all of the tendons are torn and what happens is there are no more force couples there and there isn’t any inferior pull from the rotator cuff muscles so the deltoid runs unopposed and so the humeral head is up in the subacromial space.
high
What two rotator cuff muscles externally rotate the humerus at end range of abduction ?
Infraspinatus and teres minor
