kin 191 b – shoulder anatomy and evaluation

KIN 191B – Advanced Assessment of Upper

Extremity InjuriesShoulder Anatomy and Evaluation

Sternum

• Manubrium – attachment site for clavicle– Jugular notch

• Body

• Xiphoid process

Sternum

Clavicle

Humerus• Head and neck• Greater tuberosity• Lesser tuberosity• Bicipital (intertubercular) groove– Long head of biceps tendon

• Deltoid tuberosity• Angle of inclination– Shaft of humerus and head of humerus in frontal plane

(normally 130-150 degrees)• Angle of torsion– Shaft of humerus and head of humerus in transverse plane

(significant variance amongst individuals)

Humerus

Scapula

• Vertebral (medial), axillary (lateral) and superior border

• Inferior and superior angles• Glenoid, subscapular, supraspinous and

infraspinous fossas• Scapular spine• Acromion process• Coracoid process

Scapula

Plane of the Scapula

• In anatomic position, glenoid angles 30 degrees from frontal plane – this is the plane of the scapula

• More functional arc of motion than cardinal planes and places rotator cuff muscles in optimal length-tension relationship

Sternoclavicular Joint• Proximal clavicle and manubrium• Anterior and posterior SC ligaments– Resist anterior and posterior displacement of proximal

clavicle• Costoclavicular ligament– Inferior proximal clavicle and rib 1 – axis of movement for

clavicle (elevation, depression, medial, lateral)• Interclavicular ligament– Connects both SC joints

• Fibrocartilaginous SC disc– Functions similar to meniscus of knee, axis of rotation for

clavicle

Sternoclavicular Joint

Acromioclavicular Joint

• Distal clavicle and acromion process• Superior and inferior AC ligaments• Coracoclavicular ligament – provides most

intrinsic stability to AC joint– Conoid portion – medial, triangular• Restricts superior clavicular motion

– Trapezoid portion – lateral, quadrilateral• Restricts lateral movement of distal clavicle over

acromion process

Acromioclavicular Joint

Glenohumeral Joint

• Glenohumeral ligaments (joint capsule)– Superior, middle and inferior GH ligaments are thickenings

of joint capsule• Coracohumeral ligament– Blends with superior joint capsule from coracoid process

• Coracoacromial arch/ligament– Connects 2 prominences of the same bone, often involved

in impingement syndromes/conditions• Glenoid labrum – deepens “ball and socket”

Glenohumeral Joint

Glenoid Labrum

Scapulothoracic Articulation

• Not a synovial joint – no bony articulation

• Articulation via muscular attachments

Muscular Anatomy

• Muscles acting on the scapula– Rhomboid major/minor– Levator scapulae– Serratus anterior– Pectoralis minor/major– Trapezius– Latissimus dorsi

• Responsible for– Moving glenoid to allow

for increased shoulder ROM

– Fixation of scapula on thorax to provide rotator cuff muscles base of support during contractions

Rhomboids

• O: major – T2-5 spinous processes, minor – C7, T1 spinous processes

• I: vertebral (medial) border of scapula

• N: dorsal scapular• A: scapular retraction,

elevation, downward rotation

Levator Scapulae

• O: C1-4 transverse processes

• I: superior angle of scapula

• N: dorsal scapular• A: scapular elevation,

downward rotation

Serratus Anterior

• O: anterior portion of ribs 1-8

• I: vertebral (medial) border of scapula from superior angle to inferior angle

• N: long thoracic• A: scapular protraction

and upward rotation, fixates vertebral border of scapula to thorax

Pectoralis Major

• O: clavicular head – medial half of clavicle, sternal head – lateral portion of sternum

• I: greater tuberosity of humerus (lateral lip of bicipital groove)

• N: medial and lateral pectoral• A: sternal head – shoulder

depression and horizontal adduction, clavicular head – flexion, internal rotation and horizontal adduction

Pectoralis Minor

• O: anterior portion of ribs 3-5

• I: coracoid process• N: lateral pectoral• A: anterior tilt of

scapula

Trapezius• Upper fibers

– Base of occiput/upper cervical spinous processes to distal clavicle, elevate and upwardly rotate scapula

• Middle fibers– Lower cervical/upper thoracic

spinous processes to acromion process, retract scapula

• Lower fibers– Lower thoracic spinous processes

to spine of scapula, depress and upwardly rotate scapula

• N: accessory nerve (CN XI)

Latissimus Dorsi

• O: T6-12 spinous processes, thoracolumbar fascia, iliac crest

• I: intertubercular (bicipital) groove

• N: thoracodorsal (middle subscapular)

• A: adduction, internal rotation, extension

Muscular Anatomy

• Muscles acting on the humerus– Rotator cuff (SITS)

• Supraspinatus, infraspinatus, teres minor, subscapularis– Deltoid– Pectoralis major– Latissimus dorsi– Teres major– Long head of triceps– Biceps, short/long head– Coracobrachialis

Supraspinatus

• O: supraspinous fossa• I: greater tuberosity• N: suprascapular• A: abducts and

externally rotates humerus

Infraspinatus

• O: infraspinous fossa• I: greater tuberosity• N: suprascapular• A: externally rotates

humerus

Teres Minor

• O: axillary (lateral) border of scapula

• I: greater tuberosity• N: axillary• A: externally rotates

humerus

Subscapularis

• O: subscapular fossa• I: lesser tuberosity• N: upper and lower

subscapular• A: internally rotates

humerus

Deltoid

• Anterior fibers – distal clavicle, shoulder flexion, horizontal adduction and internal rotation

• Middle fibers – acromion process

• Posterior fibers – spine of scapula, shoulder extension, horizontal abduction and external rotation

• I: deltoid tuberosity• N: axillary• A: shoulder abduction

Teres Major

• O: inferior angle of scapula, axillary (lateral) border of scapula

• I: medial lip of bicipital groove

• N: lower subscapular• A: internal rotation,

adduction, extension

Triceps Brachii• Long head – inferior

glenoid rim/tuberosity• Lateral head – lateral and

posterior proximal humerus

• Medial head – medial distal humerus

• I: olecranon process• N: radial• A: extends elbow, long

head adducts and extends humerus

Biceps Brachii

• Long head – superior glenoid rim/tuberosity

• Short head – coracoid process

• I: radial tuberosity• N: musculocutaneous• A: elbow and shoulder

flexion

Transverse Humeral Ligament

• Bridges bicipital groove from greater to lesser tuberosity

• Stabilizes long head of biceps tendon in groove

Coracobrachialis

• O: coracoid proces• I: medial humeral

shaft• N: musculocutaneous• A: flexion and

adduction

Neurovascular Anatomy

• Neurological anatomy– Brachial plexus review

• Vascular anatomy– Subclavian artery becomes axillary artery as it

passes first rib, which becomes brachial artery as it passes distal to teres major

Brachial Plexus

Vascular Supply

Bursae

• Subacromial bursa• Sits superior to rotator

cuff tendons in subacromial space

• Reduces friction from movement of overlying deltoid

• Provides protection against inferior surface of acromion process

Rotator Cuff Muscle Activity

• During shoulder (GH) abduction:– At ~70 degrees, humeral head depressed by

infraspinatus, teres minor and subscapularis to allow humeral head to clear acromion process

– At ~115 degrees, humeral head externally rotated by infraspinatus and teres minor to clear greater tuberosity of humerus under acromial arch

Scapulothoracic Rhythym

• During first 30 degrees of GH abduction, scapular is “setting” – may have slight upward rotation

• From 30-180 degrees, for every 2 degrees of GH motion is 1 degree of scapular motion (rotation)

• During first 90 degrees, scapula rotates with SC joint as pivot point

• During last 90 degrees, scapula rotates with AC joint as pivot point– Conoid portion of coracoclavicular ligament becomes taut

and produces posterior rotation of clavicle allowing for more AC and scapular motion

Location of Pain

• Localized pain in shoulder typically associated with localized injury

• Pain radiating proximally and/or distally increases likelihood of neurological involvement

Onset of Symptoms

• Acute onset– Fracture, GH subluxation or dislocation, AC sprain

• Chronic/insidious onset– Inflammatory conditions (tendonitis, bursitis)– Pain after activity first, then during, and finally at

all times

Mechanism of Injury

• Direct trauma or forces– Acute soft tissue and/or bony injury

• Repetitive overhead movements (throwing, swimming, tennis)– Overuse syndromes, inflammatory conditions,

impingement syndromes

Current Symptoms

• Unusual sounds or sensations

• Quantity and quality of pain, aggravating and alleviating factors

• Radiating pain – neurological involvement

• Dysfunction and/or decreased performance

History of Previous Injury

• Previous cervical spine injury can predispose individual to shoulder injury from neurological compromise (weakness)

• Prior AC or GH injury can affect shoulder biomechanics and thereby increase the risk of overuse conditions/muscle imbalances

General Postural Assessment

• Head– Lateral flexion or rotation may indicate muscle

spasm and/or cervical nerve root injury• Upper extremity– Splinted to side of body/rib cage– Forearm supported– “limp arm” from brachial plexus injury– Deformity from GH dislocation

Anterior Structures

• Level of shoulders– AC joints, SC joints, clavicle

• Clavicular contour– Displacement with joint injury or fracture

• Deltoid contour symmetry– Normally rounded, may be flattened secondary to GH

dislocation or axillary nerve injury• Biceps brachii symmetry– Bulges from biceps tendon rupture

Lateral Structures

• Deltoid contour (as before)

• Acromion process– “step off” deformity at AC joint (“piano key”)

• Humeral position– Anterior or posterior displacement with

dislocation

Posterior Structures

• Vertebral alignment - scoliosis• Scapular position symmetry– Superior angle at T2 spinous process, inferior angle at T7

spinous process– “winging” scapula

• Muscle tone– Increased tone secondary to spasm/injury– Decreased tone (atrophy) secondary to neurological

compromise or disuse• Humeral position (as before)

Palpation – Anterior Structures

Jugular notchSC jointClavicleAcromion processAC jointCoracoid processHumeral headGreater tuberosity

Lesser tuberosityBicipital grooveHumeral shaftPectoralis majorCoracobrachialisDeltoidBiceps brachii

Palpation – Posterior Structures

• Spine of scapula• Superior angle• Inferior angle• Rotator cuff– Subscapularis– Supraspinatus– Infraspinatus– Teres minor

• Teres major• Rhomboids• Levator scapulae• Trapezius• Latissimus dorsi• Posterior deltoid• Triceps brachii

Special Tests

• Range of motion testing– Active, passive and resistive ROM– Combination movements

• Neurological evaluation

• Vascular evaluation

• Ligamentous/capsular testing

Active Ranges of Motion

• Flexion – 180 degrees– Biceps brachii, coracobrachialis, anterior and

middle deltoid, pectoralis major (clavicular head)

• Extension – 60 degrees– Posterior deltoid, latissimus dorsi, teres major,

triceps brachii (long head)

Active Ranges of Motion

• Abduction – 180 degrees– Deltoid, supraspinatus, biceps brachii

• Adduction - ~45 degrees if shoulder flexed slightly to avoid body interference– Pectoralis major, latissimus dorsi, teres major,

coracobrachialis, triceps brachii

Active Ranges of Motion

• Internal rotation – limited by body in neutral position, 70-80 degrees at 90/90– Subscapularis, pectoralis major, latissimus dorsi, teres

major, anterior deltoid

• External rotation – 40-50 degrees in neutral position, 80-90 degrees at 90/90– Infraspinatus, teres minor, supraspinatus, posterior deltoid

Active Ranges of Motion

• Horizontal abduction – 45 degrees from plane of scapula at 90 degrees abduction– Posterior deltoid, infraspinatus, teres minor

• Horizontal adduction – 120 degrees from plane of scapula at 90 degrees abduction– Pectoralis major, anterior deltoid

Active Ranges of Motion• Scapular protraction

– Serratus anterior, pectoralis minor• Scapular retraction

– Trapezius, rhomboids, levator scapulae• Scapular elevation

– Upper trapezius, levator scapulae, rhomboids• Scapular depression

– Lower trapezius, pectoralis minor, subclavius• Scapular downward rotation

– Rhomboids, pectoralis minor• Scapular upward rotation

– Trapezius, serratus anterior

Scapular Ranges of Motion

Apley’s Scratch Tests

• Touch opposite shoulder in front– Adduction, horizontal adduction, internal rotation,

scapular protraction

• Touch opposite shoulder in back– Abduction, external rotation, scapular protraction,

elevation and upward rotation

• Touch opposite scapula from behind– Adduction, internal rotation, scapular retraction and

downward rotation

Passive Ranges of Motion

• Critical to stabilize proximal segment in order to accurately assess end feel – patient positioning

• Flexion and extension – firm end feel• Abduction – firm end feel (GH and total)• Adduction – not typically assessed• ER/IR – firm end feels• Horizontal abduction/adduction – firm end feels

unless soft tissue obstructs adduction

Resisted Ranges of Motion

• Must stabilize proximal segment to isolate movement and/or muscle/s

• Graded on 0-5 scale – keep in mind effects of gravity, especially in presence of significant weakness

Gerber Lift-Off Test

• Humerus internally rotated and dorsal aspect of hand placed against back

• Positive test for subscapularis weakness if unable to lift hand off spine

Scapular Winging

• Perform “push-up” against wall

• Positive test for serratus anterior weakness and/or long thoracic nerve injury if vertebral (medial) border of scapula lifts off thorax

Neurological Evaluation

• Brachial plexus dermatomes and myotomes• Sensory and motor tests for terminal branches

of brachial plexus– Axillary, radial, median, ulnar, musculocutaneous

• Awareness of innervation of muscles acting on scapula and humerus

Vascular Evaluation

• Axillary pulse can sometimes be palpable in axilla

• Brachial pulse felt along medial shaft of humerus or in cubital fossa near biceps tendon

• Radial pulse is most common evaluation site

Ligamentous/Capsular Testing

• To be discussed in detail with specific shoulder pathologies