The Shoulder Flashcards
Sternoclavicular Joint
Intra articular disc
anterior sternoclavicular ligament
posterior sternoclavicular ligament
costoclavicularligament
Type:
Synovial Saddle Joint
Articular surfaces:
- sternal (medial end of the clavicle): covered in FIBROCARTILAGE, CONVEX superior to inferior, and concave AP (anterior to posterior)
- clavicular notch of the sternum: covered in HYALINE cartilage, reciprically CONCAVE superior to inferior and convex AP
- clavicle moves on sternum = opposite spin roll and glide
Joint Capsule:
- fibrous capsule surrounding the entire joint
- attaching to margins of clavicle and sternum
relatively strong
Structures: Intra articular disc O: firmly attached to the upper border of the sternal end of the clavicle I: costal cartilage of the 1st RIB Function: - improve congruency of the joint - shock absorption/force dissipation - stabilization of SC joint
Anterior/Posterior sternoclavicular ligament
- O: medial clavicle (anterior and posterior)
- I: runs obliquely downwards medially to the sternum
- A: reinforces anterior and posterior aspect of joint capsule
Costoclavicular lligament (very strong)
O: inferior surface of medial clavicle (roughened area)
I: costal cartilage of 1st rib
A: limit elevation of clavicle and prevent excess anterior/posterior movement of medial end of clavicle
- therefore limits scapular elevation, protraction, and retraction
Acromioclavicular Joints
synovial plane joint
articular surface:
- reciprocally shaped oval facets.
- lateral end of clavicle = convex
- anteromedial tip of the acromion process = concave
- both covered in fibrocartilage
Joint capsule = loose fibrous capsule attaching to margins
Superior and Inferior acromioclavicular ligaments
coracoclavicular ligament:
Conoid: (posteromedial and fan shaped)
- O: elbow of coracoid process
- I: conoid tubercle on inferior aspect of clavicle
- A: resist forward movement (scapular protraction)
Trapezoid: (anterolateral and flat quadrilateral band)
- O: superior surface of coracoid process
- I: trapezoid line on inferior aspect of clavicle
- A: resist backward movement (scapular retraction
- both prevent upward displacement of the clavicle
SC Joint Elevation
clavicle rolls superiorly and glides inferiorly
ROM = 60 degrees total
Limited by: tension in costoclavicular ligament and subclavius
SC joint Depression
clavicle rolls inferiorly and glides superiorly
ROM = 60 (total elevation and depression)
Limited by: interclavicular ligament and intra articular disc
AC Joint elevation
acromion glides superiorly
ROM = up to 15 degrees
limited by: tension in coracoclavicular lig
AC joint depression
acromion glides inferiorly
ROM = up to 15
Limited by: coracoid process coming into contact with the under surface of the clavicle
SC joint protraction
clavicle glides posteriorly (axis of movement is the costoclavicular ligament)
ROm = 35 degrees
limited by: costoclavicular and posterior SC ligament
SC joint retraction
clavicle glides anteriorly
ROM = 35 degrees
limited by: costoclavicular and anterior SC ligament
AC joint protraction
acromion glides anteriorly??
ROM = minimal
limited by: posterior AC jiont capsule and conoid ligaments
AC joint retraction
acromion glides posteriorly
ROM = minimal
llimited by: anterior AC joint capsule and trapezoid ligament
SC joint scap lateral rotation
clavicle rolls superiorly and glides inferiorly
ROM = 60 degrees
limited by: costoclavicular ligament and subclavius
SC joint scap medial rotation
clavicle rolls inferiorly and glides superiorly
ROM = 60 degrees
limited by interclavicular ligament and intra articular disc
AC joint scap lateral rotation
acromion swings upwards and outwards in relation to clavicle
ROM = 30 degrees
limited by both parts of coracoclavicular ligament
AC joint scap medial rotation
acromion medially rotates back to original position
ROM = 30 degrees
limited by both parts of coracoclaviular ligament
Scapulohumeral rhythm
coordinated rhtym between scapula and humerus during shoulder flexion and abduction
initial 25-30 degrees of flexion/abduction from the GH joint alone, then scapular lateralrotation occurs in conjunction to permit full ROM
articular surfaces of the GHJ
Hemispherical head of the humerus
- covered in hyaline cartilage
- faces: medially, superiorly and posteriorly at appprox 30 degrees from frontal plane
Glenoid fossa of the scapula:
- pear shaped and covered in hyaline cartilage
- situated on lateral aspect of scapula
- faces anterolaterally
- poor congruency = 1:4 ratio with head of humerus
glenoid labrum
- deepens the glenoid fossa
- made of fibrocartilage
- triangular in cross section
- attached to articular margins of glenoid fossa
Bursa of the GHJ
subscapular bursa = extends through capsule anteirorly
infraspinatus bursa = extends through the capsule posteriorly
subacromial bursa = non communicating.
- separates coracoacromial arch and the deltoid from superolateral aspect of the shoulder joint??
Ligaments of the GHJ
superior glenohumeral
middle glenohumeral
inferior glenohumeral
coroacohumeral ligament
coracoacromial ligament
transversehumeral ligament
Superior glenohumeral Ligament ORIANS
O: upper part of the glenoid labrum
I : runs laterally to upper surface of lesser tubercle
A: anterior stability of GHJ
Middle glenohumeral ligament
O: below the superior glenohumeral ligamanet on glenoid labrum
I: anterior aspect of the lesser tubercle below subscapularis insertion
A: anterior stability of GHJ
Inferior Glenohumeral ligament
O: glenoid fossa
I: anteroinferior part of the anatomical neck of the humerus
A: anterior stability of GHJ
Coracohumeral ligament
O: lateral border of coracoid process
- divides at intertubercular groove
I: two tubercles of humeral head (greater and lesser)
A: prevent downwards displacement of the humerus
coracoacromial ligament
O: coracoid process
I: acromion process
A: prevents superior displacement of the humerus
- helps dissipate forces transmitted upwards through humerus
transverse humeral ligament
O: greater tubercle of humerus
I: lesser tubercle of humerus at upper end of bicipital groove
A: holds the long head of biceps in place
- bridges the gap between the two tubercles
GHJ Flexion
spin and inferior glide?? (come back to this)
ROM = approx 180
- later 60 is made possible by scapular lateral rotaiton
limited by:
- extensors and posterior capsule
GHJ extension
spin ???
ROM = approx 90
- last 20 degrees is made possible by medial rotation of the scapula
limited by:
- contact of greater tubercle of the humerus with coracoacromial arch
- anterior capsule
- shoulder flexors
abduction
ROm = 180
- last 60 is made possible by lateral rotation of scap (reduces contact between greater tubercle and coracoarcomial arch)
superior roll and inferior glide
limited by:
- contact between greater tubercle and coracoacromial arch
- tension in rotator cuff muscles and shoulder adductors
adduction
ROM = 30 degrees
- accompanied by scapular rotation
infeiror roll and superior glide
limited by contact with the trunk
lateral rotation
rom = 80 degrees
arm at side = posterior roll and anterior glide
arm at 90 = spin
limited by tension in medial rotators and anterior capsule
medial rotation
rom = 100-110 (when the forearm is taken behind the trunk
arm at side = anterior roll and posterior glide
arm at 90 = spin
limited by lateral rotators and posterior capsule
why is the GHJ inherently unstable
incongruency of joint surfaces
poor size ratio of articular surfaces
lax capsule
weak ligaments
what improves the GHJ stability
glenoid labrum
long head of biceps tendon
rotator cuffs and larger overlying muscles
Serratus Anterior
O: fleshy digitations from the upper 8-9 ribs and intercostal fascia
R: backwards
I: costal surface of the medial border of the scapula
A/: protract and laterally rotate the scapula
NS: long thoracic nerve C5-C7
Function: movements which drive the scapula forward
- stabilizer of scap during upper llimb movements
Winged scapula
paralysis of serratus anterior
medial border of scapula stands away from the chest wall
limited lateral rotation of the scapula so arm cannot be abducted more than 90 degrees
pectoralis minor
O: ribs 3-5 and intercostal fascia
R: superolaterally
I: upper surface and medial border of the acromion process via short flat tendon
A: medially rotate and depress the scapula
NS: medial pectoral nerve C8-T1
Function:
pull scapular down and forwards during pushing/punch
accessory muscle for inspiration
subclavius
O: 1st rib and cartilage via short thick tendon, in front of costoclavicular ligament
R: obliquely up and laterally
I: subclavian groove on inferior surface of the clavicle
A: depression of the clavicle + reverse origin to elevate the 1st rib
NS: nerve to subclavius C4-C6
Function: stabilize clavicle during scapular movements
Upper trapezius
O:
- medial 1/3rd of superior nuchal line and occipital bone
- ligamentum nuchae
- spinous processes of C7-T12
R: downwards and laterally
I: posterior lateral 1/3 of clavicle
A: elevation, lateral rotation, and retraction of scapula
NS:
motor = spinal part of cranial nerve XI (accessory nerve
sensory = ventral rami of C3,4
middle trapezius
O:
- medial 1/3rd of superior nuchal line and occipital bone
- ligamentum nuchae
- spinous processes of C7-T12
R: horizontally
I: medial border of the acromion and upper border of the crest of the scapula spine
A: retraction of scapula
NS:
motor = spinal part of cranial nerve XI (accessory nerve)
sensory = ventral rami of C3,4
lower trapezius
O:
- medial 1/3rd of superior nuchal line and occipital bone
- ligamentum nuchae
- spinous processes of C7-T12
R: up and laterally
I: inferior surface of medial end of the spine of scapula (via converged tendon)
A: depression, retraction and lateral rotation of scapula
NS: spinal part of cranial nerve Xi (accessory nerve)
and ventral rami of C3,4
Rhomboid major
O: spinous processes of T2-T5 and supraspinous ligament
R: obliquely down and laterally
I: medial border of scapula between spine and inferior angle of scapula
A: retraction and medial rotation of scapula
NS: dorsal scapular nerve C5
Function = scapula stabilizer
Rhomboid Minor
O: spinous processes of C7-T1 and supraspinous ligament
R: obliquely down and laterally
I: medial border of the scap at the level of the root of the spine of scapula
A: retraction and medial rotation of scapula
NS: dorsal scapular nerve C5
Function = scapula stabilizer
levator scapulae
O: Transverse processes of C1-C4
R: down and laterally
I: medial border of the scapula between the superior angle and base of the spine of scape
A: scapular elevation, retraction and medial rotation
NS: dorsal scapular nerve C5
Anterior Deltoid
O: anterior border of the lateral 1/3rd of the clavicle
R: obliquely down and posteriorly
I: deltoid tuberosity on the lateral side of the humerus via short thick tendon
A: flexion and medial rotation of the GHJ
NS: axillary nerve C5-C6
Middle deltoid
O: lateral margin of the acromion process via 4 tendinous slips
R: downwards
I: deltoid tuberoisty via short thick tendon
A: abduction of the GHJ
NS: axillary nerve C5-C6
Posterior Deltoid
O: lower lip of the spine of the scapula R: obliquely down and anterior I: deltoid tuberosity via short thick tendon A: extend and laterally rotate the GHJ NS: axillary nerve C5-C6
Function of the deltoid
middle fibres = main abductor after initation of supraspinatus
Resist downward displacement of the humerus
Clavicular head of Pectoralis Major
O: medial 1/2 of the anterior surface of the clavicle
R: down and laterally
I: lateral lip of the intertubercular groove via flat tendon. covering the long head of the biceps tendon
A: flex the GHJ joint to 90 degrees, horizontally flex the GHJ, adduct GHJ, medially rotate the GHJ
NS: medial pectoral nerve (C8-T1) and lateral pectoral nerve (C5-C7)
Sternal head of pectoralis major
O: body of manubrium and sternum, adjacent upper 6 ribs costal cartilages, and external oblique via aponeurosis
R: horizontal and superolaterally
I: intertubercular groove via flat tendon (covering long head of biceps tendon)
– also forms the posterior lamina which passes upwards and behind the anterior lamina to the upper part of the groove
A: extend the flexed arm (especially against resistance) back to the anatomical position
adduction
medial rotation
NS: medial pectoral nerve (C8-T1) and lateral pectoral nerve (C5-C8)
corachobrachialis
O: apex of the coracoid process via rounded tendon
R: inferiorly and laterally
I: roughened area halfway down the medial side of the humeral shaft opposite to the deltoid tuberosity
A: adduction of GHJ + may assist flexion
NS: musculocutaneous nerve (C5-C7)
latissimus dorsi
O: spinous processes T7-T12, all lumbar and sacral vertebra via thoracolumbar fascia, intervening suprapinous and interspinous ligaments, outer lip of posterior iliac crest
R: upwards and laterally
I: floor of the intertubercular groove via flat thin tendon
- en route, some fibres attach to the outer srface of the lower 3-4 ribs (Ribs 9-12) and inferior angle of the scapula
A: extensor of flexed arm, adductor of GHJ, medial rotator of GHJ
NS: thoracodorsal nerve (C6-8)
Teres Major
O: dorsal surface of the inferior angle of scapula (below teres minor)
R: upwards, anteriorly and laterally
I: medial lip of the intertubercular groove (via broad flat tendon) + tendon is separated from lats by a bursa)
A: adducts GHJ, medially rotates and may assist with extension of flexed shoulder
NS: lower subscapular nerve (C5-C6)
Rotator cuff muscles
supraspinatus, infraspinatus, teres minor, subscapularis
Supraspinatus
O: medial 2-3rds of the supraspinous fossa
R: laterally
I: upper facet on the greater tubercle of the humerus
- tendon forms within the muscle as it passes laterally below trapezius, the acromion process, and the coracoacromial ligament
- tendon blends with the superior aspect of the GH capsule
A: initiates the first 20 degrees of abduction on GHJ
NS: suprascapular nerve (C4,C5,C6)
Infraspinatus
O: medial 2/3rds of the infraspinous fossa
R: laterally and merge to a narrow tendon
I: middle facet on the greater tubercle of the humerus
A: lateral rotation of the GHJ
NS: suprascapular nerve (C4,5,6)
Function: stabilize the head of humerus in the glenoid during GHJ movements with other rotator cuff muscles
Teres Minor
O: upper 2/3rds of the LATERAL BORDER of the SCAPULA
R: upwards and laterally
I: lowest facet on the greater tubercle of the humerus via narrow tendon which also reinforces the posterior part of the capsule
A: lateral rotation of the GHJ + adducts the abducted arm
NS: axillary nerve C5,6
Function: resist UPWARD displacement of head of humerus during active contraction of the deltoid
Subscapularis
forms most of the posterior aspect of the axilla (lies behind serratus anterior)
O: medial 2/3rd of the sub scapular fossa
R: fibres wind around the head of humerus anteirorly
I: LESSER TUBERCLE of humerus via broad thick tendon (other 3 insert to Greater tubercle)
A: medially rotate the GHJ and adduct the GHJ
NS: upper and lower subscapular nerve (C4,5,6)
Function: hold the head of humerus in the glenoid fossa, resisting upwards displacement during active contraction of biceps, tricpes and deltoid
The axilla
Apex: first rib, clavicle and scapula
Base = axillary fascia
Posterior = latissimus doris, teres major, subscapularis
median wall = serratus anterior
contents: brachial plexus, axillary artery and vein, axillary lymph nodes, and quantity of fat and loose areolar tissue
The axillary nerve
- arises from the ventral rami of C5, C6, the superior trunk, and the posterior cord
- in the axilla, it passes posteriorly to the axillary artery and anterior to subscapularis
- it passes close to the inferior aspect of the shoulder joint and through the quadrilateral space
- it divides into anterior and posterior branches
it then winds around the surgical neck of the humerus
motor = deltoid and teres minor Sensory = skin on lateral aspect of the shoulder (via lateral cutaneous nerve of the arm)
Quadrilateral space
formed by:
- teres minor = superiorly
- teres major = infeirorly
- shaft of humerus = laterally
- long head of triceps = medially
- allows passage for axillary nerve and poseterior circumflex artery
