Shoulder- Diogo Flashcards
What is the most proximal bone of the upper limb? It is palpable along its entire length in the upper anterior part of the shoulder.
the clavicle
What is the second most proximal bone of the upper limb? It is a triangular bone in the upper posterior part of the shoulder.
scapula
Which side of the clavicle is nearest to the vertebrae?
medial end of the clavicle
The scapular of the spine can be viewed in direction of the anatomical position?
posteriorly
This is the point of the scapula that is a continuation of the spine of the scapula. It is also known as the point of shoulder.
acromium
What forms the head of the humerus?
glenoid cavity
What is the difference between a shoulder separation and a shoulder dislocation?
shoulder separation: tearing of acromioclavicular ligament and/or coracoclavicular ligament
shoulder dislocation: humerus is going out of the shoulder
What nerve is most exposed to a fracture of a humerus?
axillary nerve
What part of the humerus is most susceptible to fracture?
the surgical neck
the anatomical head of the humerus almost never breaks
All movements of the shoulder occur with what joint? Do this joint affect arm movement?
sterno-clavicular joint
Yes it does affect arm movement
What lies at the sternal angle?
the 2nd rib
What anatomical view do you see the coracoid process through which many nerves run?
anterior view
What are the 3 stages of shoulder separation?
Stage I: simple sprain of the acromioclavicular joint capsule; no space width changes in AC and CC; looks the same in a radiograph
Stage II: subluxation of AC joint; AC joint capsule significantly damaged; AC space width at least 50% greater than normal; CC space is normal; shoulder separate
Stage III: acromioclavicular ligament AND coracoclavicular ligament is dislocated; AC and CC space widths are both 50% greater than normal; both AC and CC are significantly damaged
What joins the clavicle to the coracoid process?
coracoclavicular ligament
The acromium is attached to what side of the clavicle?
the lateral end of the clavicle
The hyaline cartilage covering the head of the humerus is very small as the articulation for it is very small. This very small articulation allows for what? Are there consequences to this type of retention in humans?
The space between the acromium and the head of the humerus is small as it is tightly packed with muscle and hyaline cartilage.
allows for a very mobile arm that can rotate 180 degrees
of all primates we’ve retained this small articulation; we don’t need it to survive and we pay the price for it as most injuries in sports are due to “too high” mobility
This does not happen in the femur however.
The humerus should be the most lateral? True or false?
False.
The acromium should be the most lateral
The axillary nerve extends _________beneath the shoulder capsule joint.
posteriorly
Looking through the superior view of the body, order the following:
- shoulder joint
- acromioclavicular joint
- coracoacromial ligament
- acromioclavicular joint
- coracoacromial ligament
- shoulder joint
What is cleidocranial dysostosis?
an hereditary condition characterized by defective ossification of cranial bones and the clavicles
Where do most fractures of the clavicles occur?
80% of clavicle fractures occur in the middle third
no nerves are injured when you fracture the clavicle
What are the 6 movements of the scapula?
- elevation (levator scapulae m. and upper trapezius)
- depression ( lower trapezius)
- protraction AKA abduction: towards the anterior of the body (serratus anterior)
- retraction AKA adduction: towards the back of the body (middle trapezius and rhomboid m. )
- lateral rotation (upper and middle trapezius)
- medial rotation (rhomboid m.)
What are the 6 movements of the arm?
- flexion (decreasing angle of of elbow joint)
- extension (increasing angle of elbow joint)
- internal rotation (rotating limb toward medial)
- external rotation (rotating limb away from medial line)
- abduction (moving limb away from the medial line)
- adduction (moving limb towards the medial line)
Only the shoulder joints move in arm movements. True or false?
FAAALLLSEEE
The shoulder joint and sterno-clavicular joint moves for the abduction and adduction movement of the arm.
What joint is moving during the 6 movements of the scapula?
sterno-clavicular joint
For every 2 degree of arm movement one degree is for the shoulder joint and the other degree is for the sterno-clavicular joint. True or false?
True
For 90 degrees that you adduct the arm, how many degrees are being done by the sterno-clavicular joint and the shoulder joint?
45 degrees each for the sterno-clavicular joint and the shoulder joint
For every 2 degree of arm movement one degree is for the shoulder joint and the other degree is for the sterno-clavicular joint.
What are the four anterior nerves that innervate muscles on the posterior side?
- dorsal scapula nerve
- suprascapular nerve
- subscapular nerve
- axillary nerve
How do these nerves below avoid the scapula to go to the posterior side?
- dorsal scapula nerve
- suprascapular nerve
- subscapular nerve
- axillary nerve
- dorsal scapula nerve: goes medial to the scapula
- suprascapular nerve: goes above the scapula
- subscapular nerve: goes below the scapula
- axillary nerve: goes lateral to the scapula
What are the 3 trapezius muscles in all animals and where do they each come from anatomically?
upper trapezius: comes from the head
middle trapezius: comes from the nuchal region
lower trapezius: comes from the vertebrae
The trapezius muscles are cranial muscles that are not innervated by the ventral rami but are innervated CN XI also known as what?
accessory nerve
For sensory innervation, what cranial nerves are used?
CN III????????
CN IV
Motor innervation used what cranial nerves?
???????
What is the origin and insertion of the trapezius muscles?
origin: head and vertebrae (part that moves less)
insertion: scapula (part that moves during muscle contraction
the upper goes to the clavicle
the middle and lower goes to the spine of the scapula???????
Why do humans have a huge nuchal ligament?
- bipedalism
- human have a huge head so it needs to be supported
- the trapezius muscle is deep to the vertebrae so wouldn’t really support the head
If the trapezius laterally rotates the scapula 20 degrees what is the movement? How many degrees of arm movement?
abduction
40 degrees???????
What are the four groups of muscles that are innervated by nerves that move from the anterior side to the posterior side?
- trapezius muscles
- Rhomboid Major and Rhomboid Minor, Levator Scapulae Muscle
- Latissimuss Dorsi Muscle, Teres minor muscle, subscapular muscle
- Serratus anterior muscle
What is the common function of the the brothers, levator scapulae muscle, rhomboid major muscle, and rhomboid minor muscle?
medial rotation of the scapula
The levator scapulae can medially rotate and do what other scapula movement? What nerve innverates the levator scapulae?
elevates the scapula
levator scapulae is innervated by the dorsal scapular nerve C5 and C3 and C4 nerve fibers
In addition to medially rotating the scapular, the rhomboid major and minor can also do what movement of the scapula?
retract the scapula
they are innervated by the dorsal scapular nerve C5
Both rhomboids can retract the shoulder and medially rotate the scapula.
What is the most powerful PROTRACTOR of the shoulder and one of the prime movers for LATERAL rotation of the scapula? What is it innervated by?
Serratus anterior muscle
loss of the serratus anterior’s actions weakens the ability to raise the arm above the shoulder
serratus anterior is innervated by the long thoracic nerve
What is the cause of “winging” of the scapula?
-isolated serratus anterior palsy results in pronounced flaring of the inferior angle or “winging” of the scapula when the outstretched arm is thrust forward
Pectoralis minor and subclavius can do what SHOULDER movement?
Pectoralis minor: lowers and protracts the shoulder
subclavius: lowers the shoulder
What are the four rotator cuff muscles?
- subscapularis
- supraspinatus
- infraspinatus
- teres minor
What is the prime mover for abduction of the arm at the shoulder joint? IT can also flex, internally rotate, extend, and externally rotate the arm.
deltoid
which is innervated by the axillary nerve (C5 and C6)
Pectoralis minor can do what ARM movements?
adduction
flexion
internal rotation
Latissmuss dorsi can do what arm movements?
extension
adduction
internal rotation
it is innervated by the thoracodorsal nerve
Teres major can do what arm movements?
internal rotation
adduction
innervated by the lower subscapular nerve (C5 and C6)
Adduction of the arm 180 degrees fro mthe anatomical position is dependent upon the coordinated action of what four major shoulder muscles?
- supraspinatus m.
- deltoid m.
- trapezius m.
- serratus anterior m.
The shoulder muscles can be subdivided functionally into what four groups?
(1) the muscles that suspend the shoulder girdle from the spine
(2) the muscles that pull upon the shoulder girdle from the anterior chest wall
(3) the muscles of the rotator cuff
(4) the prime movers of abduction and adduction of the arm at the shoulder joint.
What are the 4 shoulder muscles that suspend the shoulder girdle from the spine?
trapezius muscles
levator scapulae muscle
rhomboid minor
rhomboid major
The levator scapulae m., rhomboid minor, and rhomboid major are all innervated by what muscle?
dorsal scapulae nerve
What are the the muscles that pull upon the shoulder girdle from the anterior chest wall?
serratus anterior
pectoralis minor
subclavius
Infraspinatus is innervated by what nerve?
the suprascapular nerve (C5 and C6);
Teres minor is innervated by what nerve?
the axillary nerve (C5 and C6)
What innervates the subscapularis?
the upper and lower subscapular nerves (C5 and C6)
What muscles are prime movers of abduction and adduction of the arm at the shoulder joint?
Deltoid is the sole prime mover for abduction of the arm at the shoulder joint from about 10 to 180 degrees abduction.
There are three prime movers of adduction of the arm at the shoulder joint: pectoralis major, teres major, and latissimus dorsi.
Supraspinatus muscle and infraspinatus muscle are innervated by what nerve?
suprascapular nerve (C5 and C6)
Pectoralis major, teres major, latissimus dorsi, and deltoid are all innervated by what nerve?
Pectoralis major is innervated by the medial and lateral pectoral nerves.
Teres major is innervated by the lower subscapular nerve (C5 and C6).
Latissimus dorsi is innervated by the thoracodorsal (middle subscapular) nerve.
Deltoid is innervated by the axillary nerve (C5 and C6).
What are the roles of the four muscles that allow for 108 degree abduction of the arm from an anatomical position?
Supraspinatus action is required to initiate the first 5-10o of arm abduction from the anatomical position. Supraspinatus thus acts as the sole prime mover of arm abduction at the shoulder joint during the first 5-10 degrees of arm abduction from the anatomical position.
Deltoid action is required to complete arm abduction at the shoulder joint after 10 degrees arm abduction has been achieved. Deltoid thus acts as the prime mover of arm abduction at the shoulder joint from 10 degrees arm abduction onward.
Trapezius and serratus anterior action are required throughout arm abduction from the anatomical position to 180 degrees abduction. Their action as the prime movers of lateral rotation of the scapula is the basis of their contribution.
In the absence of trapezius and serratus anterior action, the arm can be abducted by only about 110 degrees, with all of this abduction occurring as just upward rotation of the humerus at the shoulder joint.
Which nerve is more perpendicular to the humerus?
subscapular nerve
What is the subacromial impingement syndrome?
The space directly beneath the acromion (and directly above the shoulder joint) is called the subacromial space, and packed into that space are a group of important structures: 1) the tendon of the long head of the biceps muscle, 2) the subacromial bursa, and 3) the rotator cuff.
Every time the arm is moved at the shoulder joint, supraspinatus’ insertion tendon and the subacromial-subdeltoid bursa move within the relatively narrow subacromial space.
Some arm movements lessen the height of the subacromial space to such an extent that supraspinatus’ insertion tendon and/or the subacromial-subdeltoid bursa become at risk of being entrapped, or impinged, within the subacromial space.
Such repetitive impingement can lead to inflammation or even disruption of supraspinatus’ insertion tendon and/or the subacromial-subdeltoid bursa. The anatomical basis of subacromial impingement is that because the rotator cuff tendons (in particular, the insertion tendon of supraspinatus) and the subacromial-subdeltoid bursa pass through the relatively narrow subacromial space as they extend from the scapular region toward the humerus, they are subject to intermittent or repetitive impingement during arm movements at the shoulder joint.
The only muscles involved in abduction of the arm at the shoulder joint, namely, supraspinatus and deltoid, are each innervated by what nerves?
nerve fibers from only two spinal nerves: C5 and C6
suprascapular nerve transmits only C5 and C6 nerve fibers to supraspinatus, and the axillary nerve transmits only C5 and C6 nerve fibers to deltoid
However, each muscle receives more innervation from C5 than C6 nerve fibers. The preponderance of C5 nerve fibers in the innervation of both supraspinatus and deltoid explains why C5 nerve fibers control abduction of the arm at the shoulder joint.
What do the 3 subscapular nerves innervate?
Upper: innervates the superior portion of the subscapularis m.
Middle: also known as the thoracodorsal nerve innervates latissimus dorsi m.
Lower: teres major m.
The movement of the muscle is one that contracts the muscle NOT stretch the muscle (they’re not comfortable that way).
FACTSS!!!!
Paralysis of a muscle will always go in the opposite direction it normally goes.
FACTSS!!!!!
Paralysis of the serratus anterior will move posteriorly instead of anteriorly as it is pulled.
If you lose the thoracic nerve, which movement of the arm is affected?
abduction
What are the 3 origins of the pectoralis major muscle? What is the muscle innervated by? What are the 3 movements of the muscle?
clavicle (clavicular head)
sternum (sternal head)
ribs (abdominal head)
innervated by the lateral and medial pectoral nerve
flexion of humerus
medial rotation
adduction
Which nerves innervates the abdominal muscles?
ventral primary rami
Which nerves innervate the serratus posterior superior and inferior?
ventral primary rami
What are the 6 functions of the humerus?
- flexion
- extension
- medial rotation
- lateral rotation
- abduction
- adduction
What is the common function between pectoralis major m. and latissimus dorsi m.?
medial rotation
What are the origins and insertions of the pectoralis minor m. ?
What are the movements of scapula it performs?
What is it innervated by?
Origins: ribs 3-5
insertion: coracoid process of the scapula
protraction (anterior muscle pulling scapula anteriorly)
depression (below the scapular)
NO ROTATION
innervated by ONLY the MEDIAL pectoral nerve
Why is the subclavius m. the boring m. What are its origin and insertion? What movement does it participate in? What is it innervated by?
origin: 1st rib
insertion: clavicle
depression of the clavicle
innervated by nerve to the subclavius or subclavian nerve
You have more anterior muscles than posterior muscles. True or false?
FALLSEE!
The deltoid muscle is truly a posterior muscle. True or false? What is its brother?
True
teres minor m
both are innervated by the axillary nerve
When you have a patient with a rotator cuff problem, what muscles do you focus on?
subscapularis m.
suprascapularis m.
infrascapularis m.
teres minor m.
What is the function of the subscapularis m. ?
internal rotation: rotates the head of the humerus medially
adduction: when the arm is raised, it draws the humerus forward and downward.
It is a powerful defense to the front of the shoulder-joint, preventing displacement of the head of the humerus.
What is the vein in the intersection between the deltoid and pectoralis major m. ?
cephalic vein
Identification and recognition of the cephalic vein in the deltopectoral triangle (deltopectoral space or groove) is of critical importance when considering emergency catheterization procedures
If you lose the C5 nerve, what are the functions of the hand that you lose?
Dr. Wilson
