Shoulder Functional Anatomy PDF

SHOULDER FUNCTIONAL ANATOMY • Shoulder can be described as a complex of four articulations • Glenohumeral joint • Sternoclavicular joint • Acromioclavicular joint • Scapulothoracic joint SHOULDER FUNCTIONAL ANATOMY • Glenohumeral joint • Controlled by: • GH joint passive stability •...

SHOULDER FUNCTIONAL ANATOMY • Shoulder can be described as a complex of four articulations • Glenohumeral joint • Sternoclavicular joint • Acromioclavicular joint • Scapulothoracic joint SHOULDER FUNCTIONAL ANATOMY • Glenohumeral joint • Controlled by: • GH joint passive stability • Achieved by caspulo - labral / ligamentous structures • Osseous orientation of the scapula and humerus • Glenoid labrum: • • • • Deepens the glenoid, about 9mm deep Provides chock block for movement of the humerus out of the glenoid Intra-articular pressure provided by the capsule-labral complex Negative pressure allows the humeral head to be suctioned into the glenoid SHOULDER FUNCTIONAL ANATOMY • Rotation: • Keep in mind, ext rot is needed for elevation of the shoulder: • Allows for passage of greater tub from under the subacromial arch • • • Increases length–tension of superior subscapularis fibers to assist with elevation From 60 – 120 deg of elevation is where the rotator cuff tendons are closest to the undersurface of the acromion Limited ext rot can increase compression on those structures SHOULDER FUNCTIONAL ANATOMY • Rotation: • • Int rot: usually 60 – 100 deg Although not as important for elevation, loss of it can signify restrictions in the post capsule that may lead to compromise of glenohumeral structures such as rotator cuff, bursa, bicep tendons SHOULDER FUNCTIONAL ANATOMY • Subacromial Space: • Structures Within Suprahumeral Space • Long head of biceps • Superior capsule • Supraspinatus tendon • Upper margins of subscapularis & infraspinatus tendons • Subacromial bursa • Inferior surface of A-C joint SHOULDER FUNCTIONAL ANATOMY • Dynamic Stability • • • • • Rotator cuff provides dynamic stability at varying phases of elevation RC forms force couple with the deltoid Force Couples Acting on Glenohumeral Joint: Transverse plane anterior vs. posterior RC Coronal plane - deltoid vs. inferior RC SHOULDER FUNCTIONAL ANATOMY SHOULDER FUNCTIONAL ANATOMY • Scapulothoracic Joint • • • Not a true joint Scapula rests in 30 deg int rot (transverse plane), 3 deg of upward rot in the frontal plane, 8 deg of ant tipping in the sagittal plane suspended along the thorax due to myofascial attachments Composite motion of the AC and SC joints to contribute to 60 dg of upward elev: • 15 – 30 deg of post tipping • 15-25 deg of ER during arm elevation SHOULDER FUNCTIONAL ANATOMY • • • • Shoulder abduction: Deltoid and supraspinatus initiate. However at start the deltoid has very little effect, as the force vector is parallel to the arm. The supraspinatus is very effective in this position as its force vector is nearly at 90 degrees to the humerus. Once abduction is initiated, the situation reverses. The subscapularis immediately “sucks” the scapula against the thorax; the scapula rotates slightly and settles. Glenohumeral motion continues to take place until 45 degrees, and then the scapula starts to rotate. SHOULDER FUNCTIONAL ANATOMY • • • Shoulder abduction: At 45-60 degrees, the head of the humerus glides inferiorly. At 75 degrees, external rotation of the humerus takes place to prevent the greater tubercle from bumping in the superior edge of the glenoid fossa. At 110 degrees the coracoclavicular ligaments tighten. Osteokinematically, the clavicle rotates posteriorly, arthrokinematically there is anterior rotation in the AC joint (clavicle on scapula). SHOULDER FUNCTIONAL ANATOMY • • • Shoulder abduction: To reach full elevation, the thoracic spine sidebends. If both arms are raised the spine will extend to accommodate for full elevation. The role of the supraspinatus during abduction is twofold. It holds the joint surfaces together (coaptation) and it increases the strength and duration of abduction. SHOULDER FUNCTIONAL ANATOMY AC joint ● Distal clavicle and acromion process ● Planar synovial joint ● Primarily fibrous joint with fibrocartilaginous disc ● Lax joint capsule results in higher incidence of dislocations than the SC joint ● Allows for scapula elevation and rotation ● Relies on ligamentous support for stability ● Resting position: arm at side ● Closed Pack position: Full elevation SHOULDER FUNCTIONAL ANATOMY • AC ligament • Coracoclavicular ligament: limits superior translation. Composed of: • Conoid ligament: • • • From the base of coracoid processes to the clavicle. Fan shaped. Lies in frontal plane. Limits increase of the clavicular-scapular-horizon tal angle (opening of clavicle and scapula). Trapezoid ligament: Runs lateral and superior from the base of the coracoid process to the clavicle. Checks AC Joint compression SHOULDER FUNCTIONAL ANATOMY • Movement of the clavicle • • • • • Rotation: longitudinal axis Protraction / retraction: vertical axis Elevation / Depression: horizontal axis AC movement may occur at all three planes simultaneously to keep the scapula against the thorax causing tipping and rotation of the scapula Provides about 30 deg of the 60 deg scapula upward rotation and 45-50 deg of clavicular rotation SHOULDER FUNCTIONAL ANATOMY • Sternoclavicular joint • The clavicular joint surface is bigger than the sternal joint surface (clavicular notch of the manubrium). • The clavicular joint surface is convex vertically and concave anterior/posterior. The sternal joint surface is convex A-P, concave vertically. • The joint is completely separated by an articular disc, which makes the joint surfaces more congruent. • • Depression of the clavicle (which elevates the sternal end of the clavicle) is controlled by the sternoclavicular ligament and by bone on bone contact of the clavicle on the first rib. Elevation of the clavicle (which depresses the sternal end of the clavicle) is controlled by the costoclavicular ligament. SHOULDER FUNCTIONAL ANATOMY SHOULDER FUNCTIONAL ANATOMY GLENOHUMERAL LIGAMENTS • Superior GHL is either a robust or thin tissue that provides restraint to inferior translations of the humeral head when arm is adducted at the side • Middle GHL provides restraint to anterior humeral translation (ER) with arm in mid range of abduction to ~45 deg; limits ER of shoulder with arm at side as well • Inferior GH ligament is an expansive band of tissue: • Thickened anterior and posterior band • Hammock type axillary pouch CORACOHUMERAL LIGAMENT •Coracohumeral ligament • anterior band • posterior band CLINICAL EXAM OF THE SHOULDER • Examination: • History: CLINICAL EXAM OF THE SHOULDER • CC • When? • Where? • Radiating pain proximal to the elbow along C5-C6 dermatome: • Rotator cuff • Bicep tendon • Bursae • Radicular symptoms to the wrist and hand (cervical etiology) vs pain proximal to the shoulder (cervical vs. myofascial strain of the upper traps from substitution) • Examination: • History: • CLINICAL EXAM OF THE SHOULDER What provokes it? (i.e.: Lifting the shoulder from 60 - 120 (impingement) vs end range of ext rot and abd at 90 deg (instability) • How irritable?: • Onset?: • Gradual • Sudden • Traumatic? • What makes it better?: • rest (inflammatory vs. poor muscular endurance) • placing arm on top of the head • (C8, T1 radiculitis) CLINICAL EXAM OF THE SHOULDER • Examination: CLINICAL EXAM OF THE SHOULDER • Review of systems: • Thorough medical history taking • Review of labs • Examination: CLINICAL EXAM OF THE SHOULDER • What are some questions you could ask? • Examination: • Review of systems: • CLINICAL EXAM OF THE SHOULDER Some Mimics: • Peptic Ulcer: lateral R scapula • MI: R shoulder and arm • • Hepatic / Biliary / Cholecystis R shld; between scapulae; R subscapular nerve Liver abscess, Liver disease (CA, cirrhosis, hepatitis): R shoulder • Gallbladder: R upper trapezius • MI: Left shoulder • Ruptured Spleen: Left pecs / shoulder • Pancreas: Left shoulder CLINICAL EXAM OF THE SHOULDER • Posture: • Cervical positioning • Elevated shoulder (which one is dominant) • Scapula winging: medial border (serratus weakness, long thoracic nerve palsy), inf border: tightness at short head of biceps, pec minor • Scapula vertical position - norm is T2 to T7 • Scapula horizontal position - resting on thorax (vs hanging off thorax) • Thoracic posture - kyphosis vs. gibbus deformity, scoliosis • AROM: • CLINICAL EXAM OF THE SHOULDER • • • Range, pain, substitution patterns, willingness to move, examines contractile and non-contractile tissue Test in all cardinal planes of movement starting with scaption Observe scapula movement and GH movement Shrug sign: excessive overuse of upper traps due to rotator cuff weakness or tear, tight capsular structures with patient leaning towards the opposite side • AROM: • Winging: • CLINICAL EXAM OF THE SHOULDER Medial border: • • • Weak serratus, long thoracic nerve palsy, increased AC joint stress due to lack of serratus contribution with the upper traps thus overstressing the joint Increase subacromial tissue stresses due to increased anterior tipping of the scapula Also can be due to tight posterior capsular structures that pull the scapula into int rot thus lifting the medial border of scapula away from the thorax • AROM: • Winging: • CLINICAL EXAM OF THE SHOULDER Inferior border: • • • scapula tilts anteriorly and inferior angle tilt posteriorly Due to tight pec minor, tight short head of biceps Often seen in the last 60 degrees of eccentric lowering from elevation • AROM: • CLINICAL EXAM OF THE SHOULDER • Painful arc: 60 to 120 deg: due to rotator cuff tendonitis, bursitis, laxity, hypomobility or some combination of the above Apley scratch: compare side by side, if asymmetric check for individual movement limitations • Cross body adduction • Hand behind head • Hand behind back • AROM: • CLINICAL EXAM OF THE SHOULDER Capsular pattern: • • Cyriax felt this to occur with arthritic patients, but could not discern what type (OA vs. RA vs, traumatic arthritis, they all present the same) ER > ABD > IR • PROM: CLINICAL EXAM OF THE SHOULDER • • Examines non-contractile tissue (ligament, joint capsule, fascia, etc) Consider end feels • Accessory Motion: • CLINICAL EXAM OF THE SHOULDER Arthrokinematics: assess the roll, glide, spin, translation • Done in the loose pack position • Assess inert structures • Laxity vs. contracture: normal, hyper or hypomobility • Pain replication • Inflammatory status • Accessory Motion: CLINICAL EXAM OF THE SHOULDER • Directions: • Lateral glide • Posterior glide • Anterior glide • Inferior glide ROTATOR CUFF PATHOLOGY ROTATOR CUFF PATHOLOGY •Rotator cuff pathology •Tendinopathy •Tear •Partial •Complete ROTATOR CUFF PATHOLOGY • Etiological Factors • Age • Occupation / Activity • Trauma • Biomechanics ROTATOR CUFF PATHOLOGY • Etiological Factors • Age • Decreased vascularity to the supraspinatus • Increased zone of avascularity with age • Collagenous tissue replaced with inferior fibrous connective tissue and fatty infiltration • Calcification of the tendons, especially the supraspinatus for unknown reasons ROTATOR CUFF PATHOLOGY • Etiological Factors • Occupation • Repetitive overhead activity: Rates of impingement increase with overhead activity and holding a small object ROTATOR CUFF PATHOLOGY • Etiological Factors • Trauma/FOOSH • Sudden violent contraction of rotator cuff • May cause avulsion from the greater tuberosity • Mid-substance tear ROTATOR CUFF PATHOLOGY • Classification: Neer Classification of Shoulder Impingement Type I: <25 years old, Reversible, swelling, tendonitis, no tears, conservative treatment Type II: 25-40 years old, Permanent scarring, tendonitis, no tears, SAD Type II: >40 years old, Small RTC tear, SAD with debridement/repair Type IV: >40 years old, Large RTC tear, SAD with repair ROTATOR CUFF PATHOLOGY •Classification: •Primary •Secondary • Classification: • Primary: ROTATOR CUFF PATHOLOGY • The area of the RTC that is torn or irritated in primary impingement is typically the superior or bursal side of the RTC. • This is referred to as extra-articular RTC pathology. • This means the source of pathology is outside of the glenohumeral joint itself and confined to the Subacromial space. ROTATOR CUFF PATHOLOGY • Classification: • Primary: • Consequence of the aging process • Mechanical compromise of the subacromial space • DJD AC joint • Subacromial spurring • Rotator cuff atrophy • Rotator cuff/scapular weakness (poor posture) • Increased thoracic kyphosis • Classification: • Secondary: ROTATOR CUFF PATHOLOGY • Secondary Impingement by definition implies that there is a problem with keeping the humeral head centered in the glenoid fossa during movement of the arm. • Classification: • Secondary: ROTATOR CUFF PATHOLOGY • The impingement generally occurs at the coracoacromial space secondary to anterior translation of the humeral head as opposed to the Subacromial space that is seen in primary impingement. • Tearing of the RTC is again Extra-articular however intra-articular tearing is also seen in these patients. • Patients are typically younger and the pain is located in the anterior or anterolateral aspect of the shoulder. The symptoms are usually activity specific and involve overhand activities. ROTATOR CUFF PATHOLOGY •Special Tests: •Neer: Sen (.39 - .93) / Spec (.31 – 1.00) ROTATOR CUFF PATHOLOGY •Special Tests: •Hawkin Kennedy: Sen (.84 - .92) / Spec (.25 - .56) ROTATOR CUFF PATHOLOGY • Special Tests: • Empty can: Sen (.63 - .89) / Spec (.50 .68) ROTATOR CUFF PATHOLOGY • Special Tests: • Internal Rotation Resistance Stress Test: • Shoulder in 90 deg abd / 80 deg ext rot • First pt. isometrically resists ext rot • Then pt isometrically resists int rot • If weakness is noted with int rot but strong with ext rot, then test is positive for internal impingement • If weakness is noted with ext rot but strong with int rot, then test is negative and symptoms may be due to an outlet impingement • Sensitivity 88% / Specificity 96% • PPV 88% / NPV 94% ROTATOR CUFF PATHOLOGY Special Tests: Internal Rotation Resistance Stress Test: ROTATOR CUFF PATHOLOGY Champagne Toast Test: • Diagnostic tool for measuring EMG activity/strength of supraspinatus • 30 deg abduction, mild ER, 30 deg flexion ROTATOR CUFF TEAR ROTATOR CUFF TEAR • Chronic inflammation leads to progressive degenerative changes in the rotator cuff • Eventually chronically overloaded tendons do not • Leads to tendon rupture and failure under normal, physiologic loads • Etiology: • Primary Compressive Disease • Compression of the rotator cuff against: • Anterior third of the acromion • Coracoid process • Coracoacromial ligament • AC joint • Third stage of Neer’s impingement sequence • Common in Type III Acromion ROTATOR CUFF TEAR ROTATOR CUFF TEAR • Etiology: • Full thickness tears: tear either through the entire section of the tendon or tear through the tendon • Often starts at the supraspinatus tendon at the avascular zone • Can progress downwards to the infra, teres and subscap • Can have subluxation of bicep tendon with subscap tears ROTATOR CUFF TEAR ROTATOR CUFF TEAR ROTATOR CUFF TEAR ROTATOR CUFF TEAR Partial Thickness tear: Etiology: • Can occur at the superior side (bursal side) due to compression • Inferiorly at the undersurface (articular side) due to instability and high tensile loads (throwers) • Fibers of the involved tendon(s) are still intact and some are torn ROTATOR CUFF TEAR • Etiology: • Secondary Compressive Disease • Rotator cuff tear due to instability • Instability leads to attenuation of inert structures • Rotator cuff and bicep tendon become compressed and fatigue • Rotator cuff damage progresses through the stages of inflammation and eventually tears ROTATOR CUFF TEAR • Etiology: • Secondary Compressive Disease • Tensile Overload • Heavy eccentric loading due to follow phase of throwing (deceleration) • Forces as high as 1090 N to resist joint distraction, hz add, and int rot at the follow through of a throw • Rotator cuff undergoes tendon overload and failure ROTATOR CUFF TEAR • Etiology: • Secondary Compressive Disease • Macrotrauma • Single traumatic event such as a fall • Forces applied to the cuff rapidly and are beyond what the cuff can normally tolerate • Avulsions from the greater tuberosity and full thickness tears can result • Clinical Exam: • Hx: ROTATOR CUFF TEAR • Shoulder pain for long period of time (> 1 year) • Age > 40 year old • Higher incidence of overhead activities • Trauma ROTATOR CUFF TEAR • Clinical Exam: • Special Tests: • Gerber Lift off test (passive): (Subscapularis) Active lift off test: lift dorsum of hand from lumbar spine • Sen: 0.0 - 0.80 • Spec: 0.61 – 1.00 ROTATOR CUFF TEAR • Clinical Exam: • Special Tests: • Belly press test (Subscapularis) ROTATOR CUFF TEAR • Clinical Exam: • Special Tests: • External Rotation Lag Sign: (ERLS) (Supraspinatus and Infraspinatus)) • 90 / 90 drop lag sign: (Infraspinatus) ROTATOR CUFF TEAR • Clinical Exam: • Special Tests: • Drop arm test: 97.2% specific SHOULDER INSTABILITY SHOULDER INSTABILITY • Definitions: • Laxity: the amount of humeral head movement relative to the glenoid when stress is applied. • Increased laxity leads to hypermobility • Hypermobility by itself is not pathologic • Instability: Excessive, symptomatic laxity or translation of the humeral head relative to the glenoid that is not controlled by the individual SHOULDER INSTABILITY • Classifications of instability (Macrotraumatic vs. Microtraumatic/AMBRI vs. TUBS) • Macrotraumatic vs. Microtraumatic: • Macrotraumatic: single event, trauma, disrupts capsulo-labral structures (Bankart tear) • Microtraumatic: repetitive stresses to the capsulo-labral structures lead to attenuation. (Pitching, swimming, gymnastics) SHOULDER INSTABILITY AMBRII • Atraumatic • Multi-directional • Bilateral • Rehab • Inferior capsular shift • Interval of the rotator cuff SHOULDER INSTABILITY • TUBS • Traumatic • Unilateral • Bankart lesion • Surgery SHOULDER INSTABILITY • Bankart • Traumatic anterior or anterior inferior dislocation • Tears the anterior labrum and associated capsular ligaments • Usually from a sudden, violent force while the shoulder is in ext rot, abd or ext rot and hz abd • Lose the increased surface contact area of the labrum • Labrum deepens the glenoid by as much as 50% SHOULDER INSTABILITY •Complications • Pain • Possible recurrent dislocations • Dependent on age • Younger patients tend to tear the labrum • Older patients tend to also tear the rotator cuff • Observations • Extreme pain and guarding SHOULDER INSTABILITY • Patient holds the arm close to their side with the other arm • May see loss of deltoid contour • May see fullness at the coracoid • Neurovascular exam • Check deltoid sensation • Palpate brachial pulses • Check deltoid, ext rot strength SHOULDER INSTABILITY • Perform this before and after reduction • Reduction without x-rays should be done by experienced clinicians, otherwise refer to E.R. • Reduction under conscious sedation usually preferred after x-rays (A-P, lateral, axillary) are taken • Post reduction exam (spontaneous or induced) • Load and shift test SHOULDER INSTABILITY • Pay attention to the grades 1 – 3 • Possible clicking which may be labral tear • Apprehension tests • Relocation tests SHOULDER INSTABILITY • Factors to consider: • Age • How long has the shoulder been unstable? • What is the magnitude of instability? • Can the pt voluntarily sublux the shoulder? • Is the cause due to trauma or repetitive activities? • What direction does the pt feel the shoulder give away? • Physical Exam: • Subjective: • Complaints of: • “shifting” SHOULDER INSTABILITY • “sliding” • “fatigue” • “giving away” • Impingement type pain • “sharp” • “ache” SHOULDER INSTABILITY • Physical Exam: • Laxity tests: • Humeral translation tests • Load and shift: • Anterior (Sen: 0.50-0.91; Spec: 0.93-1.00). Ant capsule, middle GH liga • Posterior (Sen: 0.14; Spec: 0.100). Post Capsule • Physical Exam: • Laxity tests: • Anterior Drawer SHOULDER INSTABILITY • Posterior Drawer (poor inter and intra-observer agreement (47%) Kappa values 0.5) • Grade 1 and 2 combined intra-observer agreement increased to 73% • Physical Exam: • Anterior apprehension • Jobe Apprehension – Relocation • Sen: 68% • Spec: 100% SHOULDER INSTABILITY • PPV: 100% • NPV: 78% • Anterior Release Test (“Surprise test”) • Sen: 92% • Spec: 89% • PPV: 87% • NPV: 93% • Treatment considerations: • Pure anterior instability without any impingement type pain: SHOULDER INSTABILITY • Often due to a traumatic event • Acute partial or complete dislocation • Clinical and arthroscopic exam is the same as the previously listed considerations without impingement signs • Treatment: • Inflammatory control • Immobilization • Submaximal rotator cuff exercises • (Progression as noted in the impingement lecture!) SHOULDER INSTABILITY • Prone cuff exercises to create post dominant shld • Prone hz ext to prone hz abd • Sidelying ext rot to prone ext rot 90/90 positon • Prone shoulder scaption • Progressing over 4 – 6 week period • Treatment: • Tissue healing indications: 4 – 6 weeks for collagen matrix to begin maturation SHOULDER INSTABILITY • Start progression of rotator cuff exercises to the 90/90 position and PNF diagonals as needed for activity • Progress by increasing speeds of contraction (6 – 8 weeks) • High speed tubing / pulley exercises • Progress from short arc to full ROM in the vulnerable range (12 – 16 weeks) • D2 • 90 / 90 ER / Abd • Treatment: • Early scapula strengthening exercises SHOULDER INSTABILITY • Tyler et al: noted that induced scapula fatigue resulted in decreased rotational torque output of the shoulder • PNF exercises • Manual resistance to cardinal movements • Treatment: • Serratus anterior SHOULDER INSTABILITY • Open chain: • Bear hugs • Supine protraction • Supine / seated punches SHOULDER INSTABILITY • Treatment: • Serratus anterior • Closed chain: • Standing weight shift on hands, elbows on table • Quadruped rocks to scapula protraction • Push up plus progression • 4 point position • Rocks side to side, forward and backwards • Unstable surfaces (BAPS, Wobble board) SHOULDER INSTABILITY • Treatment: • Traps, rhomboids: • Prone hz abd (careful of shoulder beyond the plane of the body) • Thumbs up (4 – 6 weeks) middle trap • Thumbs down (4 – 6 weeks) rhomboids • Rows (careful of shoulder beyond the plane of the body) (6 – 8 weeks) • Pulldown (8 – 10 weeks) • ROM progression: Need to progress based on: SHOULDER INSTABILITY • Age • Direction of instability • Traumatic vs. recurrent • Structural morphology • After immobilization 3 – 4 weeks: • Ext rot: • 0 – 20 deg 3 – 4 weeks at 0 deg abd • 40 – 45 deg 4 – 6 weeks at 45 deg abd SHOULDER INSTABILITY • 60 – 65 deg 6 – 8 weeks at 45 deg abd • 40 -45 deg 8 -10 weeks at 90 deg abd • 60 – 65 deg 10 – 12 weeks at 90 deg abd • FULL ROM 12 – 14 weeks • After immobilization 3 – 4 weeks: • Must be selective and careful when stretching to gain motion SHOULDER INSTABILITY • Must use the considerations mentioned earlier • May need post capsule mobilization • Lack of hz adduction • Lack of int rot • Recurrent sublux / disloc • Treatment considerations: • Neuromuscular retraining SHOULDER INSTABILITY • Closed chain: 100 deg elev progressing to abd • Ball on wall • Quadruped • Triped SHOULDER INSTABILITY • Recurrent sublux / disloc • Treatment considerations: • Rhythmic stabilization • Open chain: Supine at 100 deg elev to abd, progressing to lower angles (90 deg abd / 90 deg ext rot) • Open chain: Standing at 100 deg elev to abd, progressing to lower angles (90 deg abd / 90 deg ext rot) • Theraband • Recurrent sublux / disloc • Treatment considerations: • Rhythmic stabilization SHOULDER INSTABILITY • Closed chain: 100 deg elev progressing to abd • Ball on wall • Quadriped • Triped SHOULDER INSTABILITY • MULTIDIRECTIONAL INSTABILITY • Sulcus Test • Excessive translation of humeral head in the inferior direction • Directly assessed superior portion of glenohumeral ligament with arm at side • Test also allows for patient extremity to be tested in multiple positions of GH joint abduction, stressing different portions of GH capsule and capsular ligaments LEARNING OBJECTIVES • Describe the role of and signs of LHBT pathology • Understand SLAP lesions and peel back mechanism • Understand surgical indications for AC joint pathology • Identify S&S associated with Adhesive capsulitis • Discuss common nerve pathologies associated with the shoulder LONG HEAD OF THE BICEPS TENDON PATHOLOGIES LONG HEAD OF THE BICEPS TENDON PATHOLOGIES • Function Controversial: • Humeral head depressor • May be more effective in the end range of ext rot • GH joint stabilizer • Resists torsional forces when shoulder is abducted, ext rotated • Injury to LHBT results in increased IGHL strain and ant GH translation LONG HEAD OF THE BICEPS TENDON PATHOLOGIES Function: Deceleration of elbow extension at the follow through of a tennis serve, baseball pitch LONG HEAD OF THE BICEPS TENDON PATHOLOGIES • Pathophysiology • Inflammation / Degeneration • Instability • SLAP lesions / Biceps tendon anchor abnormalities LONG HEAD OF THE BICEPS TENDON PATHOLOGIES • LHBT degeneration: • LHBT is continuous and within the synovial capsule of the GH joint • Inflammation of the suprahumeral tissues can inflame the proximal tendon sheath • Pure bicep tendonitis rare, tendonosis more common • Bicep tenosynovitis more common LONG HEAD OF THE BICEPS TENDON PATHOLOGIES • LHBT degeneration: • Mechanism • Primary Impingement changes occur without subacromial compression • Secondary impingement due to subacromial compression • Tight posterior capsule • Lax anterior capsule • Anterior – superior humeral head migration with elevation LONG HEAD OF THE BICEPS TENDON PATHOLOGIES • LHBT degeneration: • Mechanism • LHBT angles laterally 30-40 degrees from it’s insertion into the bicipital groove • Secured into the groove by the transverse ligament and fibrous extensions from the SGHL, CHL and more extensively from the subscapularis • Medially directed force may displace the tendon medially into the subscapularis insertion at the lesser tuberosity • Overhead throwing (cocking phase) with rotator cuff disruption (subscapularis) are key factors that can cause LHBT instability SLAP LESIONS / LHBT ANCHOR ABNORMALITIES: SLAP LESIONS / LHBT ANCHOR ABNORMALITIES: • Eccentric firing at follow through places increased tension on the superior labrum and LHBT insertion • Late phase cocking causes a “peel back” of the superior labrum as the bicep tendon contracts while twisted pulling the labrum away from the glenoid PEEL BACK MECHANISM SLAP LESIONS / LHBT ANCHOR ABNORMALITIES: • History: • Diffuse pain at the anterior / lateral shoulder • May radiate to the proximal humeral area along the C5 dermatome • Difficult to distinguish from supraspinatus pathologies • Instability and tendinopathy of the distal LHBT may present with bicipital groove area pain, tenderness and “popping” • May have similar hx as subacromial impingements SLAP LESIONS / LHBT ANCHOR ABNORMALITIES: • Special tests: • Speed’s: resisted shoulder flexion with ext rot and supination • 67% - 90% Sen • 14% - 55% Spec • Yeargason’s: assess Transverse Ligament integrity: resisted supination/ext rot • 86% Spec • 37% Sen SLAP LESIONS/LHBT ANCHOR ABDNORMALITIES SLAP LESIONS / LHBT ANCHOR ABNORMALITIES: • Conservative Treatment/ Understand pathomechanics: • Rotator cuff pathology • Tight post capsule • Poor overhead mechanics • Instability • Scapula stabilizer weakness or fatigue • Labral pathology SLAP LESIONS / LHBT ANCHOR ABNORMALITIES: • Treatment (similar to rotator cuff pathologies) • Acute: • Rest • Anti-inflammatory • Early mobilization ADHESIVE CAPSULITIS ADHESIVE CAPSULITIS • Pathogenesis: • Inflammation of synovial lining • Neutrophils invade the area • Release of inflammatory agents such as prostaglandins, bradykinins, histamine from other inflamed tissue such as bursa or tendon • pH levels decrease which allows for increased fibroblastic and myofibroblastic activity with neocapillarization • Increase in type 1 collagen deposition, tightening of the joint capsule usually at the anterior and axillary sections of capsule • Contracture of the rotator cuff interval common in patients with AC ROTATOR CUFF INTERVAL Proposed functions of RCI: 1. Contributes to GH stability 2. Increases stability of the LHBT 3. Limits excessive GH motion ADHESIVE CAPSULITIS • Idiopathic • Women > men • Diabetics > non- diabetics • Persons with autoimmune diseases > healthy • Persons with thyroid disorders > healthy • Those who suffered trauma > those who did not • Persons older than 40 > those under 40 ADHESIVE CAPSULITIS • Complex: Endocrine, hormonal, nutritional, inflammatory issues • Pathomechanics: • Global loss of ROM due to the humeral head held tightly within the glenoid fossa • Capsular pattern ER > IR > Abd (Cyriax)Validation? • Contractile tissue such as rotator cuff held in shortened position which can reduce the sarcomere number ADHESIVE CAPSULITIS • Freezing (acute stage): • Constant pain • Pain at night • Pain location at the C5 dermatome • Patient self limits their ROM due to pain • May have tenderness at the supraspinatus or bicep tendon • Loss of motion due to pain, mm guarding / spasm, empty end feel ADHESIVE CAPSULITIS • Thawing: • Gradual return to normal motion • Reduced pain • Self-limiting disorder with multiple ways to treat ADHESIVE CAPSULITIS In general: • ROM loss of >25%in at least 2 planes • ER loss greater than 50% of uninvolved shoulder • Less than 30 degrees of ER Prior suggestions of capsular pattern, and normal, painless strength have been proven inconsistent among patients with AC ACROMIOCLAVICULAR INJURIES ACROMIOCLAVICULAR INJURIES • AC joint • Diathrodial • Primarily rotates and translates ant – post and sup and inf • Surrounded by a joint capsule with synovial capsule • Contains hyaline cartilage early in life that is replaced with fibrocartilage • has an intra-articular disc (meniscus) that degenerates over time • Stabilized by AC ligaments • Coracoclavicular • Conoid • Trapeziod ACROMIOCLAVICULAR INJURIES • AC joint • Dynamic stabilizers: • Serratus Anterior • Upper trapezius • Deltoids • Fascial attachments from these muscles attach to the superior AC ligament ACROMIOCLAVICULAR INJURIES • Mechanism of injury • Fall or blow onto the lateral shoulder with the shoulder adducted • Fall onto an outstretched arm driving the humerus superiorly into the acromion • SC joint is a stable joint, rarely dislocated • Energy is transferred to the clavicle resulting in a fracture or disruption of the AC/CC complex ACROMIOCLAVICULAR INJURIES • Classified by Rockwood: • Type I • Sprain of AC ligaments due to direct force • Coracoclavicular ligaments are intact ACROMIOCLAVICULAR INJURIES • Classified by Rockwood: • Type II • Rupture of AC ligaments • Coracoacromial ligaments are intact • Clavicle is unstable as noted in a stress x-ray ACROMIOCLAVICULAR INJURIES • Classified by Rockwood: • Type III • Complete disruption of both the AC and coracoclavicular ligaments • No disruption of the deltiod and trapezial fascia • High riding clavicle • The UE is kept in an adducted position • Acromion and the UE are displaced inferior relative to the clavicle • Unstable clavicle in the hz and vertical plane • Often treated non-surgically ACROMIOCLAVICULAR INJURIES • Classified by Rockwood: • Type III • Decision to do surgery vs. conservative care immediately depends on: • Occupation • Hand dominance • Recreational pursuits • If after treatment for 3 – 6 months and there is restricted function then surgery may be the best option • Hook plate fixation (right) to stabilize an unstable AC joint ACROMIOCLAVICULAR INJURIES •Types IV-VI •Involves tearing of the AC and CC ligaments with increasing degrees of soft tissue trauma and clavicular displacement •Typically result in surgical intervention PERIPHERAL NERVE INJURIES AT THE SHOULDER PERIPHERAL NERVE INJURIES AT THE SHOULDER Mechanisms of Injury Nerves are sensitive to: Stretch • Elongation of nerve from 8 – 15% compromises blood flow • Nerves may be elongated due to myofascial imbalances • Posture • Activity PERIPHERAL NERVE INJURIES AT THE SHOULDER Mechanisms of Injury Nerves are sensitive to: Compression • Nerves have a rich blood supply to due their high metabolism • They are able to sustain periods of minimal blood flow for a relatively long time before permanent damage occurs (12 – 16 hours) • Acute compression causes tingling • Chronic compression causes numbness PERIPHERAL NERVE INJURIES AT THE SHOULDER Mechanisms of Injury Nerves are sensitive to: Shear forces: • Anatomically the axons are made of the endoneurium, perineurium and epineurium • Inflammation surrounding the axon terminals may lead to decreased gliding due to fibrous adhesions • These tissues must be able glide along each other with movement • Endoneurium involvement results in pain with tension positive neural tension sign • Epineurium involvement results in less pain with tension PERIPHERAL NERVE INJURIES AT THE SHOULDER PERIPHERAL NERVE INJURIES AT THE SHOULDER Levels of Injury Peripheral nerve injuries: • Neuropraxia: decrease or complete conduction block without any physical disruption of the axon • Nerve conduction is normal proximal and distal to the lesion but not at the lesion • Tingling, weakness, intermittent numbness PERIPHERAL NERVE INJURIES AT THE SHOULDER Levels of Injury Peripheral nerve injuries: • Axonotemesis: • Severed axon with the epineural sheath preserved • Distal axon becomes inexcitable after 5 -7 days after the injury • Distal axon Wallerian degeneration occurs • Proximal regeneration begins due to intact nerve cell bodies and intact epineurium at a rate of 1mm/day • Dorsal root ganglion (sensory nerves) • Ventral nerve cell bodies of located in the anterior gray matter (motor nerves) PERIPHERAL NERVE INJURIES AT THE SHOULDER Levels of Injury Peripheral nerve injuries: • Neurotmesis: • Total destruction of the axon, epineurium, myelin, and Schwann cells • Proximal axonal regeneration is unable to occur • Can also occur with axonotmesis in which proximal regeneration is blocked due to intraneural fibrosis PERIPHERAL NERVE INJURIES AT THE SHOULDER Levels of Injury Double Crush Syndrome: • Axons that are chronically irritated are more susceptible to traction injuries due to less extensibility • Occurs when a nerve root that is compressed proximally causes distal axonal pathology due to reduced axoplasmic flow • ie: cervical disc followed by carpal tunnel syndrome • Thoracic outlet syndrome and cubital tunnel syndrome • Results in increased susceptibility for the distal axon segment to become entrapped • Secondary entrapment may be due to normal amounts of: • Compression • Friction • Reverse Double Crush Syndrome: Occurs when nerve is entrapped distally and results in proximal axonal lesion (ie: carpal tunnel syndrome progresses to shoulder symptoms) PERIPHERAL NERVE INJURIES AT THE SHOULDER Neuroanatomy PERIPHERAL NERVE INJURIES AT THE SHOULDER Neuroanatomy PERIPHERAL NERVE INJURIES AT THE SHOULDER Neuroanatomy PERIPHERAL NERVE INJURIES AT THE SHOULDER Neuroanatomy PERIPHERAL NERVE INJURIES AT THE SHOULDER Neuroanatomy PERIPHERAL NERVE INJURIES AT THE SHOULDER • Thoracic Outlet Syndrome • Scalene triangle: • Ant and middle scalenes and first rib • Problems arise due to: • Presence of cervical rib that elevated the 1st rib • Scalene hypertrophy • Fibrous attachments to the cervical rib occupies space • Clinically tested using Adson’s test PERIPHERAL NERVE INJURIES AT THE SHOULDER PERIPHERAL NERVE INJURIES AT THE SHOULDER • Thoracic Outlet Syndrome • Costoclavicular space: • Medial aspect of the clavicle and first rib • Depression of the shoulder and elevation of the 1st rib compresses the neurovascular bundle • Clinically tested using the costoclavicular test: PERIPHERAL NERVE INJURIES AT THE SHOULDER PERIPHERAL NERVE INJURIES AT THE SHOULDER •Coracoid process / pec minor: •Tendon of pec minor and coracoid process •Tested using the hyperabduction maneuver: PERIPHERAL NERVE INJURIES AT THE SHOULDER PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Suprascapular nerve: • Often seen in: • overhead athletes • manual laborers • people undergoing cardiac rehab PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Suprascapular nerve: • Origin: 5th and 6th cervical roots, travels across post cervical triangle, ant upper traps post border of clavicle to upper border of the scapula, passes under the transverse scapula ligament (may be partially or completely ossified) branches to the supraspinatus mm, travels along the floor of the supraspinatus fossa to the rim of the glenoid under the spinoglenoid ligament to innervate the infraspinatus PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Suprascapular nerve: • Compression: • Lies under the rotator cuff • Ganglion cysts • Due to labral, capsular tears that leak fluid • Lipomas • Transverse scapula ligament • Spinoglenoid ligament • Between the supra and infraspinatus • Within the fascial attachments from the omohyoid and subclavius mm PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Suprascapular nerve: • Pathophysiology: • Spinoglenoid liga tension increases with Cross body adduction and int rot follow through from pitching • End range ext rot and abd can impinge the suprascapular nerve at the tendinous portion of the infraspinatus • Compression from the transverse scapular ligament PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Suprascapular nerve: • Pathophysiology: • Damage to the microvascular system from traction, trauma and frictions leading to ischemia. • Traction: • Suprascapular nerve has fixed points • Erbs point (2 -3 cm above the clavicle) • Insertion of the infraspinatus • Exacerbated by: • Overhead activity • Scapula protraction • Infraspinatus contraction that pulls the nerve medially PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Suprascapular nerve: • Compression at the spinoglenoid notch: • Painless mm wasting at the infraspinatus fossa sparing 30 – 40% of the mm • Often not noticed until further advanced since throwing only requires 30 – 40% of infraspinatus capacity PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Suprascapular nerve: • Suprascapular notch compressions: • Wasting at the infra and supraspinatus • Supraspinatus wasting not as easily seen due to the upper traps • Infraspinatus atrophy seen easier • More pronounced when shoulder are in forward flexion • Symptoms tend to vary from painless to vague symptoms: PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Suprascapular nerve: • Insidious onset unless acute trauma • Atrophy in proportion to the duration of the nerve compression • Poorly localized, dull or burning, dull pain at the lateral and posterior shoulder • Activity such as cross body adduction and int rot increase symptoms • Ext rot with abd with infraspinatus contraction increases symptoms due to tethering of the nerve • Scapula Regional Nerve Injuries • Suprascapular nerve: • Treatment: • 4 -6 months of conservative treatment is usual PERIPHERAL NERVE INJURIES AT THE SHOULDER • Posture: reduce scapula protraction • Rest • Anti-inflammatories • ROM • Strengthening compensatory mm groups at the shoulder girdle • Posterior capsule stretching in abduction to stretch the spinoglenoid ligament PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Axillary nerve: • Formed from nerve roots C5-C6 arising from the posterior cord. • Travels below the coracoid process obliquely to the anterior surface of the subscapularis and joint capsule • Continues to travel laterally and posteriorly and exits the quadrilateral space • Long head of triceps (medial) • Humeral shaft (lateral) • Teres minor (superior) • Lats (inferior) • Subscapularis (anterior) PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Axillary nerve: • Innervates the delts, teres minor and lateral deltoid • Injured by acute anterior dislocation / re-location: • 19 – 55% of ant shoulder disloc • Due to stretch • Increases with age > 40 -50 years PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Axillary nerve: • Fracture: • up to 58% of prox humeral fx • Due to stretch PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Axillary nerve: • Quadrilateral space compression • Often are asymptomatic and if present difficult to distinguish between the initial trauma (dislocation, fracture) that caused it • Increased shoulder mm fatigue with overhead activity / exercise • Reduced abd and ext rot strength • Inability to fully elevate the arm • Lateral shoulder numbness • Scapula Regional Nerve Injuries: Workup / Treatment PERIPHERAL NERVE INJURIES AT THE SHOULDER • Quadrilateral space syndrome: • Clinical Signs and Symptoms: • Vague and nonspecific history • Dull, burning pain • Poorly localized post shoulder pain at the posterior / lateral aspects • Insidious onset • Exacerbated by shoulder abd, ext rot, extension • Weakness with overhead activity • Progresses to mm atrophy of the deltoids • May have tenderness at the post shoulder • Weakness of the delts in all directions and teres minor • FABER test of the shoulder held for one minute. Reliability? PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries • Axillary nerve: • Treatment: • 4 -6 months of conservative treatment is usual • Similar to the suprascapular nerve palsy • Electric stim? • Parameters: lo – voltage, longer pulse width (1 msec) galvanic? • Stimulating denervated or partially denervated tissue • Scapula Regional Nerve Injuries: Workup / Treatment PERIPHERAL NERVE INJURIES AT THE SHOULDER • MRI more beneficial for suprascapular nerve problems due to soft tissue anomalies such as: • ganglion cysts • rotator cuff atrophy / hypertrophy • Tracking the course of the suprascapular nerve • If suspect nerve injury, useful to get a baseline EMG and NCV within three weeks. Often is normal for axillary nerve injuries to improve within three weeks of the injury • Suprascapular nerve dysfunctions can exist with normal EMGs and NCVs • Can have false positives with chronic neuropathy. Delay in NCV is seen normally in baseball players as the season progresses PERIPHERAL NERVE INJURIES AT THE SHOULDER • Scapula Regional Nerve Injuries: Workup / Treatment • Surgical Management • Such as: • Nerve grafts • Neurolysis • Nerve transfers • Neuropathy PERIPHERAL NERVE INJURIES AT THE SHOULDER • Long Thoracic Nerve Injury • Ant branches of C5-C7 • C5-C6 branches pass through or on the middle scalene • C7 passes between the ant and middle scalenes • C5-C6 and C7 nerve roots unite distal to the scalenes to form the long thoracic nerve • Travels ant to the post scalene going below the clavicle • Goes under the 1st and 2nd rib to the chest wall at the mid-axillary line PERIPHERAL NERVE INJURIES AT THE SHOULDER • Long Thoracic Nerve Injury • Long thoracic nerve injured due to traumatic and non-traumatic ways: • Trauma • Repetitive micro-trauma which causes traction on the nerve • Often due to rotation and / or sidebend of the cervical spine away from the affect side with the arm held overhead • Points of fixation are the middle scalene and superior serratus anterior PERIPHERAL NERVE INJURIES AT THE SHOULDER • Long Thoracic Nerve Injury • Clinical Signs and Symptoms: • Atraumatic long thoracic nerve injuries may resolve in a year • Long thoracic nerve injuries that are due to brachial plexitis (Parsonage – Turner Syndrome) may take 2 – 3 years to resolve Long Thoracic Nerve Injury Treatment same as the other peripheral nerve injuries: PERIPHERAL NERVE INJURIES AT THE SHOULDER • Often treated conservatively • May need a scapula thoracic brace to hold the scapula in place as the nerve heals • Surgery is done at 1 – 2 years if conservative treatments fail and EMG analysis has not changed • Difficult to return to high level function post – op: • Muscle transfers • Scapula-thoracic fusion • Scapulopexy – fixation of the scapula to the thoracic wall PERIPHERAL NERVE INJURIES AT THE SHOULDER • Spinal Accessory Nerve Injury: • Cranial nerve XI exits the skull at the jugular foramen • Passes obliquely through and penetrates the SCM • Runs subcutaneously at the floor of the post cervical triangle to innervate the upper traps PERIPHERAL NERVE INJURIES AT THE SHOULDER • Spinal Accessory Nerve Injury: • Injured due to its superficial location. Trauma: • Stab wounds • Gun shots • Blunt trauma • MVA • Fall (stretching injury) • Medical procedures: • Radical neck dissection for tumor • Carotid Endarterectomy • Cervical Lymph node biopsy • Subcutaneous mass or cyst resection PERIPHERAL NERVE INJURIES AT THE SHOULDER • Spinal Accessory Nerve Injury: • Clinical Signs and Symptoms: • Pain, weakness, deformity at the upper traps and SCM • Inability to fully abduct or elevate their affect shoulder • Drooping of the shoulder • Winging of the superior / medial border of scapula • Asymmetry at the neckline PERIPHERAL NERVE INJURIES AT THE SHOULDER • Spinal Accessory Nerve Injury: • Clinical Signs and Symptoms: • May be predisposed to: • Subacromial impingement • Frozen shoulder • Muscle spasms of the levator scapulae • Radiculitis from the excessive downward position of the shoulder PERIPHERAL NERVE INJURIES AT THE SHOULDER • Spinal Accessory Nerve Injury: • Clinical Signs and Symptoms: • Unable to shrug the shoulder without downward rotation • Difficulty abducting the arm above shoulder height PERIPHERAL NERVE INJURIES AT THE SHOULDER • Spinal Accessory Nerve Injury: • Conservative Management: (Often not successful) • Surgical Management: • Static stabilization of the medial border of the scapula • Levator scapulae mm and fascial sling transfer • Levator scapulae and rhomboid dynamic mm transfer • Nerve exploration, neurolysis, grafting and repair IMPLICATIONS OF CERVICAL SPINE The Elbow Anatomy, Biomechanics, and Pathology  The elbow joint is a complex joint due to the number of articulations that work together to perform its motions: • Humero-ulnar joint. • Humero-radial joint. • Proximal radio-ulnar joint. • Distal radio-ulnar joint.  While the interactions are complex, the humero-ulnar and humero-radial joints can be viewed together as a uni- axial joint providing the main flexion/extension of the elbow joint with the following range of motion:  flexion: - approximately 145° (actively) approximately 160° (passively)  extension: - approximately 0-15°  Elbow flexion is limited or checked by a muscular end-field from either the triceps muscle or from the biceps if there is a large muscle belly. Elbow extension is limited by a bony end-field. The olecranon abuts against the olecranon fossa to prevent hyperextension. It is common for flexible females to exhibit hyperextension of the elbow up to 20°.  The resting position for the elbow is 90° flexion with the forearm in neutral supination and pronation.  The position of reference is the upper arm and forearm in the frontal plane with the elbow straight and the forearm supinated.  The close-packed position is full extension. The Humero-ulnar Joint  The humero-ulnar joint is the medial joint system between the humerus,(the trochlea) and the ulna (the olecranon). Its classification is a diarthrodial, synovial, hinge (uniaxial) joint. The elbow is a compound joint that is considered to have one degree of freedom for flexion and extension. The trochlea is situated between the two epicondyles of the distal end of the humerus.  The trochlea’s transverse surface is concave and its antero- posterior surface is convex, which melds a convex surface with a concave one to make one complex curved surface shaped like a saddle. Therefore, the humero-ulnar joint is a saddle joint.  The transverse axis of the humerus does not lie at a right angles to its longitudinal axis. The transverse axis lies in a slightly oblique and medially directed line  The ulna tends to have a deviation laterally from the longitudinal axis of the humerus that forms an acute angle of between 7°and 12°. This is known as the carrying angle and occurs with elbow extension. Humero-Ulnar Joint  The carrying angle of the elbow will usually be caused by a few common factors.  The transverse axis through the trochlea tilts medially and obliquely causing the medial surface to lie distal to the lateral surface.  The articular groove between the medial and lateral surfaces of the trochlea circumscribes a spiral. From an anterior view, the groove is directed laterally. As this groove circumscribes the spiral on the trochlea, it faces medially on its posterior surface. The olecranon glides medially on this spiral groove during extension to create the carrying angle and direct the forearm laterally. During flexion the olecranon follows the trochlear groove laterally thereby directing the forearm medially.  This actually creates a medial gapping with lateral gliding and a lateral gapping with medial glide during flexion and extension  Flexion-extension of the elbow is accompanied by a screw- home mechanism with conjunct rotation of the ulna. With the elbow fully flexed, the olecranon is directed laterally. As the elbow is extended, the olecranon circumscribes the trochlear groove to direct itself medially. By following the trochlear groove, the ulna externally rotates (or supinates) during elbow flexion and internally rotates (or pronates) during elbow extension. Whether or not the carrying angle changes in flexion and extension is controversial. It has been described as both decreasing in angle with flexion and not changing at all. If change does indeed occur, it is related to the angulation of the trochlea  The conjunct rotation during flexion and extension at the elbow can be observed of the every time you bring food to your mouth. In order to feed yourself, your forearm must lie medial to the axis of the upper arm. This is achieved by a combination of internal rotation of the glenohumeral-humeral joint and flexion of the elbow with slight supination or external rotation of the forearm. ELBOW JOINT  The forearm is also influenced by the carrying angle. As you completely extend your elbow, the medial structures move apart while the lateral structures become compressed, creating the elbow deformity known as cubitus valgus commonly seen in tennis players, pitchers, and javelin throwers. The radius becomes close-packed against the capitellum during full extension, which causes a tendency for it to glide distally.  Excessive valgus overload during the acceleration phase of pitching. This valgus overload wedges the olecranon into the olecranon fossa. The follow-through phase of a throw can cause impingement farther posteriorly and increase symptoms by adding stress to this area. This valgus stress occurs before full extension of the elbow.  Osteochondritis can also be a secondary pathology with repetitive microtrauma in the throwing athlete . The repetitive compression forces associated with elbow extension in the throwing maneuver may result in cartilage damage and formation of loose bodies. Osteochondrosis and osteochondritis dissecans may be more prevalent in the immature skeleton and are often associated with the “Little League elbow syndrome HUMERAL-RADIAL JOINT  The humero-radial joint forms the lateral relationship between the humerus (capitulum) and the head of the radius. It is a diarthrodial, synovial, hinge joint by classification. The hemispherical capitulum articulates with a concave, oval facet on the proximal head of the radius .  The medial rim of the head of the radius fits into a groove between the trochlea and capitulum . During both flexion-extension and pronation-supination, this capitulo-trochlear groove guides movement and increases the stability of the head of the radius.  The humero-radial joint is a modified saddle joint. The capitulum has no cartilage on its extreme posterior surface. And the articular cartilage of the radius has no contact with the posterior part of the capitulum at full extension.  The radial cartilage is commonly irritated by bony contact with the posterior aspect of capitulum during traumatic hyperextension injuries. An initial stage of cartilage degeneration accompanied by pain and dysfunction can occur as a result of this trauma. This injury is frequently misinterpreted as a lateral epicondylitis. HUMERAL-RADIAL JOINT  As the capitulum assumes a close-packed position against the radius during extreme extension, it creates a lateral compression at the humero-radial joint. If the hyperextension is preceded by a “running start” such as occurs during a tennis player’s backhand swing, the capitulum makes even greater bony contact against the radial cartilage which further increases the chances for injury including micro-trauma to the cartilage, bleeding, swelling, and resultant muscle guarding.  During flexion, the coronoid process of the ulna glides into the coronoid fossa, which is devoid of articular cartilage. If one has small biceps, irritation of the interarticular tissues can occur with pain and dysfunction  The articular cartilage of the head of the radius extends distally around the head to articulate with the annular ligament. The motion that occurs within this joint is a uniaxial spin. Rotation between these structures produces pronation and supination of the forearm.  The radial head is a tapered disk, more oval than round. This oval head of the radius is also tapered like a section of a cone. LIGAMENTS of the Elbow Ligaments of the Elbow  The medial collateral ligament reinforces the humero-ulnar articulation. This triangular shaped ligament extends from the medial epicondyle of the humerus and attaches to the coronoid and olecranon process of the ulna. The medial collateral ligament is a thickening of the joint capsule.  Two distinct ligamentous bundles correspond to the anterior and posterior portions of the ulnar collateral ligament. The posterior bundle consists of collagen bundles within the layers of the capsule; the anterior bundle consists of a similar thickening within the capsular layers, but has an additional ligament complex superficial to the capsular layers  The medial collateral ligament (MCL) resists any valgus load to the joint. The ligament has three bands: the anterior oblique, posterior oblique, and transverse portions. The anterior oblique band originates from the inferior surface of the medial epicondyle. It lies just posterior to the flexion/extension axis, which causes its anterior portion to be taut in extension and the posterior position to be taut in flexion. The anterior band is the primary ligamentous support for the medial elbow. LIGAMENTS  The transverse band originates from the medial olecranon and inserts on the coronoid process of the ulna. This is primarily a thickening of the joint capsule that has only minor contribution to elbow stability.  The posterior oblique band originates from the medial epicondyle and inserts into the posteromedial olecranon. The band is taut in flexion, primarily after 60°.  The fan-shaped radial collateral ligament, also called the lateral collateral ligament, reinforces the humero-radial joint. It runs from the lateral epicondyle of the humerus and attaches to the annular ligament and olecranon process.  The annular ligament is a strong fibrous-osseous ring lined with articular cartilage that surrounds the circumference of the head of the radius. The ligament covers four- fifths of the circumference of the radial head and is funnel shaped tapering distally. Its external surface blends with the joint capsule and radial collateral ligament. The annular ligament is attached to the anterior and posterior edges of the radial notch. Humeral-Radial Joint and Ligaments  When the elbow is semi-flexed, the radio-humeral joint lacks bony stabilization and is vulnerable to injury. The strong biceps tendon inserts into the radial tuberosity and provides a cranial force and can stress on the annular ligament. This lack of bony stabilization frequently results in an elbow dislocation where the radius loses its relationship with the capitulum, the radial notch of the ulna, and the capitulo-trochlear groove.  Since the radius lacks bony stability in flexion, it can only rely on the annular ligament to hold it in place. If one pronates the forearm, not only is a fulcrum created between the radius and ulna, but also the biceps tendon is lengthened to create a greater pull. By lifting the heavy suitcase in this position, an annular ligament rupture can occur due to the cranial pull of the biceps tendon Interosseous Membranes MUSCLES of the FOREARM  Pronator teres O: Humeralhead—Immediately above the medial epicondyle of the humerus, common flexor tendon Ulnar head—Medial side coronoid process of ulna I: Middle of lateral surface of radius A: Pronate forearm and assist in flexion elbow N: Median nerve,C6-C7  Pronator quadratus O: Medial side, anterior surface of distal quarter of ulna I: Lateral side, anterior surface distal quarter radius A: Pronates forearm\ N: Medi