OT 531 Musculoskeletal Anatomy: In-Depth Study of the Scapular Region

what occurs when there is an injury to long thoracic nerve?

serratus anterior is paralyzed, anterior border of scapula moves laterally and posteriorly away from thoracic wall (giving wing appearance)

what is the most common injury of the rotator cuff?

supraspinatus tendon

what occurs when there is damage to axillary nerve? common cause? and how do you test this?

atrophy of deltoid, could occur with neck of humerus fracture, arm is abducted against resistance starting from 15 degrees

what is the cause of rotator cuff injury?

repetitive use of upper limb above horizontal; throwing, swimming weightlifting

what could happen if a hockey play is slammed into the boards?

dislocation of acromioclavicular joint

What is calcific supraspinatus tendinitis? what are symptoms?

-Inflammation & calcification of subacromial bursa

-Deposition of calcium in supraspinatus tendon

-pain, tenderness and limitations of movement of glenohumeral joint

-pain usually occurs 50-130 degrees of abduction

what is adhesive capsulitis? what are symptoms? what is the cause?

-scarring between the inflamed capsule of glenohumeral joint, rotator cuff, subacromial bursa and deltoid

-person has trouble abducting arm (has to use scapula to abduct arm)

-another injury: glenohumeral dislocations, calcific supraspinatus tendinitis, rotator cuff tear, bicep tendinitis

suprascapular notch is covered by the....

suprascapular ligament

describe trapezius (innervation, blood supply, where these are found, actions, attachments)

what muscle group?

superficial posterior axio-appendicular, extrinsic shoulder muscles

innervation- Spinal Accessory nerve CN XI (motor)

blood supply- transverse cervical artery

*both found on the deep side of trap

actions-descending part (superior)-elevates scapula

ascending part (inferior)- depresses scapula

middle part (all together)- retract scapula

descending and ascending parts act together to rotate glenoid cavity superiorly

medial attachment- nuchal ligament, external occipital protuberance, spinous processes of C7-T12 vertebrae

lateral attachment- clavicle, acromion, spine of scapula

name the superficial posterior axio-appendicular, extrinsic shoulder muscles

trapezius

latissimus dorsi

describe latissimus dorsi (innervation, blood supply, actions, attachments)

what muscle group?

superficial posterior axio-appendicular, extrinsic shoulder muscles

innervation- thoracodorsal n. from brachial plexus of VPR

blood supply- thoracodorsal artery (branch of the axillary artery)

actions-adduction of the arm/humerus

extension of the humerus

medially rotation shoulder joint/humerus

raises body toward arms during climbing

medial attachments- spinous process of inferior 6 thoracic vertebrae, thoracolumbar fascia, iliac crest, inferior ribs

lateral attachments- groove of humerus (anterior/lateral)

describe rhomboid major innervation and actions, medial/lateral attachments

what muscle group?

deep posterior axio-appendicular, extrinsic shoulder muscles

innervation- dorsal scapular nerve from brachial plexus of VPR

actions-retracts scapula

rotates glenoid cavity inferiorly

fix scapula to thoracic wall

medial- spinous processes of T vertebrae (T2-T5)

lateral- medial border of scapula

describe rhomboid minor innervation and actions, medial/lateral attachments

what muscle group?

deep posterior axio-appendicular, extrinsic shoulder muscles

innervation- dorsal scapular nerve from brachial plexus of VPR

actions-retracts scapula

rotates glenoid cavity inferiorlyfix scapula to thoracic wall

medial- nuchal ligament & spinous processes of C vertebrae (C7-T1)

lateral- medial border of scapula

describe levator scapulae innervation and actions, medial/lateral attachments

what muscle group?

deep posterior axio-appendicular, extrinsic shoulder muscles

innervation- dorsal scapular nerve from brachial plexus of VPR

actions-elevates scapula

rotates glenoid cavity inferiorly

medial- transverse processes of C vertebrae (C1-C4)

lateral- medial border of scapula

where is the dorsal scapular nerve located?

deep to rhomboids, along medial border of scapula

name the deep posterior axio-appendicular, extrinsic shoulder muscles (and spell)

levator scapulae, rhomboid major, rhomboid minor

what is an anastomosis?

The connections between blood vessels that provide an alternate route.

name all of the scapulohumeral muscles, intrinsic shoulder muscles (spell them)

deltoid

teres major

SITS (rotator cuff)

supraspinatus

infraspinatus

teres minor

subscapularis

describe the deltoid (attachments, innervation and actions)

what muscle group?

scapulohumeral muscles, intrinsic shoulder muscles

attachments:

proximal- clavicle, acromion and spine of scapula

distal- deltoid tuberosity of humerus

innervation: axillary nerve from brachial plexus

actions:

clavicular (anterior)- flexes and medially rotates shoulder joint

middle (acromial)- abducts (15 degrees to horizontal)

spinal (posterior)- extends and laterally rotates the shoulder joint

which artery serves the rhomboids?

dorsal scapular artery

describe the order at which muscles abduct the shoulder joint

supraspinatus (initiates the first 15 degrees), deltoid to horizontal, then serratus anterior overhead

describe the teres major muscle (attachments, innervation and actions)

what muscle group?

scapulohumeral muscles, intrinsic shoulder muscles

attachments:

proximal- inferior angle

medial- intertubercular sulcus of humerus (close to LAT)

innervation: lower subscapular nerve

actions: adducts and medially rotates shoulder joint

why does the deltoid have a bunch of different actions?

due to broad range of attachments

describe the supraspinatus muscle (attachments, innervation and actions)

which muscle group?

scapulohumeral muscles, intrinsic shoulder muscles; rotator cuff muscles

attachments:

proximal- supraspinous fossa of scapula (posterior)

distal- superior facet of greater tubercle of humerus

innervation: suprascapular nerve

actions:

initiates the first 15 degrees of abduction of shoulder joint and assists deltoid abduction

acts with other rotator cuff muscles

name the rotator cuff muscles and what group do they belong to

SITS

supraspinatus, infraspinatus, teres minor, subscapularis

belong to scapulohumeral, intrinsic shoulder muscles

describe the infraspinatus muscle (attachments, innervation and actions)

which muscle group?

scapulohumeral muscles, intrinsic shoulder muscles; rotator cuff muscles

attachments:

proximal- infraspinous fossa of scapula (posterior)

distal- middle facet of greater tubercle of humerus

innervation: suprascapular nerve

actions:

laterally rotates shoulder joint

acts with other rotator cuff muscles

what is the purpose of the rotator cuff muscles?

provide stability to the glenohumeral joint because this joint is very shallow

glenohumeral joint is very mobile causing it to be unstable

describe the teres minor muscle (attachments, innervation and actions)

which muscle group?

scapulohumeral muscles, intrinsic shoulder muscles; rotator cuff muscles

attachments:

proximal- lateral border of scapula (posterior)

medial- inferior facet of greater tubercle of humerus

innervation: axillary nerve

actions:

laterally rotates shoulder joint

acts with other rotator cuff muscles

describe the subscapularis muscle (attachments, innervation and actions)

which muscle group?

scapulohumeral muscles, intrinsic shoulder muscles; rotator cuff muscles

attachments:

proximal- subscapular fossa (anterior)

medial- lesser tubercle of humerus (anterior)

innervation: upper and lower subscapular nerves

actions:

medially rotates and adducts shoulder joint

acts with other rotator cuff muscles

name all the intermuscular spaces (spell them)

quadrangular space

triangular space

triangular interval

describe quadrangular space (border and contents)

borders- teres major, teres minor, long head triceps brachii, humerus

contents- axillary nerve and posterior humeral circumflex artery

describe triangular space (border and contents)

borders- teres minor, teres major, long head triceps brachii

contents- circumflex scapular artery (anastomosis)

name an example of anastomosis

circumflex scapular artery (supplies blood to muscles on the posterior scapular)

describe triangular interval (border and contents)

borders- teres major, long and lateral heads of triceps brachii

contents- radial nerve and deep brachial (profunda brachii) artery

head of triceps brachii separates...

teres major and minor

describe how suprascapular artery and nerve passes through suprascapular notch

suprascapular nerve goes under ligament

suprascapular artery goes over ligament

what is AC dislocation?

what is is caused by?

what can also happen with AC dislocation?

-acromioclavicular joint dislocation, clavicle separation from from scapula (AKA shoulder separation)

-contact sports: soccer, football, hockey

-tear on ligament between clavicle and coracoid process (coracoclavicular)

what is the most common type of dislocations? why?

glenohumeral joint, because this is the most mobile therefore least stable joint

what factors help stabilize the glenohumeral joint?

rotator cuff muscles (SITS)

labrum cartilage

describe the different types of glenohumeral dislocations

inferiorly/anteriorly = subcoracoid (most common because of structures superior to the joint such as acromion and coracoid process), anteriorly more likely due to actions of muscles -> flexors pectoralis major pulls humerus forward and to the side causing it to be subcoracoid

posteriorly = NOT subcoracoid

what can tear during a genohumeral dislocation?

labrum cartilage

describe anatomical neck vs surgical neck

anatomical neck- normal for long bone, between epiphysis and diaphysis (closer towards head)

surgical neck- where fracture will occur (further down the bone)

which parts of humerus is fractured and what can occur when they are fractured?

surgical neck: axillary nerve wraps around, could be damaged which would cause damage to deltoid and teres minor

shaft: radial nerve, could be damaged, this could effect muscles of the entire arm

what is the most common rotator muscle to tear?

supraspinatus

what action causes irritation/inflammation to supraspinatus?

abduction, above head motion causes impingment

how to test for weakness in the supraspinatus?

help them get arm up overhead, then tell them to adduct, if they can't control it after 90 degrees arm will drop out of their control

*think about fibers elongating just like intrinsic intermediate muscles when vertebral column is flexing