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Shoulder Anatomy Guide—Things to find in the lab Muscles Deltoid: from clavicle, acromion, scapula spine to humerus, axillary nerve, needed for reverse TSA Rotator cuff: Suprapinatus: from supraspinatus fossa to greater tuberosity, suprascapular nerve, most commonly torn cuff tendon Infraspinatus: from infraspinatus foss to greater tuberosity, suprascapular nerve, out with spinoglenoid cyst from labral tear Teres Minor: from lateral border of scapula to greater tuberosity, axillary nerve Subscapularis: from anterior scapula to lesser tuberosity, upper and lower subscapular nerves, tendon fibers extend laterally to create transverse humeral ligament over biceps groove -tears lead to long head of biceps subluxations -confluent with capsule laterally, divergent medially, reflected with anterior approach Teres major: inferior lateral scapula to intertubercular groove, lower subscap nerve, internal rotation and adduction. Latissimus Dorsi: T7-T12 and iliac crest to intertubercular groove, thoracodorsal, adduction and IR Pectoralis major: from clavicle and sternum to intertubercular groove, lateral and medial pectoral, adduction and IR Know the relationship between the Teres Minor, Latissimus and Pectoralis major muscle insertions for OITE Pectoralis minor: Ribs to coracoid, medial pectoral, scapulastabilizer, anterior to axillary aa. Serratus anterior: ribs to antero-medial scapula, long thoracic nerve, medial winging when out Biceps: short (coracoid) and long (superior glenoid) heads, long head is intraarticular and can be important pain generator; often involved in SLAP tears, whack in old people, tenodesis in younger The Straps (short head of biceps and coracobrachialis): coracoid to arm, help to protect neurovascular structures, musculocutaneous nerve Triceps: 3 origins—long head (infraglenoid tubercle), lateral head (posterior humerus), medial head (distal posterior humerus); radial nerve, elbow extension Ligaments Coracoclavicular (CC) ligaments: conoid and trapezoid--conoid is medial and stronger, run from base of coracoid to undersurface of clavicle -Provide vertical stability—ruptured with Type III AC injuries Coracoacromial (CA) ligament: from tip of coracoid to anterior undersurface of acromion -ligament that connects a bone to itself -may cause impingement (if you believe in it) -released with subacromial decompressions -want to keep if massive cuff tear and concerned about future anterior glenohumeral escape Coracohumeral (CH) ligament: extraarticular; found in the rotator interval, resists inferior translation Acromioclavicular (AC) ligments: superior is strongest, helps with A-P stability -don’t over-resect the distal clavicle or you will detach the superior ligament attachment (>8mm) Superior glenohumeral ligament (SGHL): runs from superior glenoid to lesser tuberosity, resists posterior/inferior translation in adduction Middle glenohumeral ligament (MGHL): from anterior labrum to anatomic neck, limits ER and inferior translation when adducted, limits anterior translation in 45 degrees abduction Inferior glenohumeral ligament (IGHL): anterior and posterior component border the axillary pouch, stabilize in abduction -anterior component important for anterior stability—fails in anterior dislocations and leads to Bankart lesion Rotator interval: capsular tissue between subscap and supraspinatus, boundries are coracoid, transverse humeral ligament, subcap and supra; contains coracohumeral ligament and SGHL Vascular structures Anterior circumflex: humeral head Posterior circumflex: greater tuberosity Thoracoacromial trunk: clavicular, acromial, deltoid, and pectoral branches Lateral thoracic: to serratus anterior with long thoracic nerve (lateral has ‘a’ for artery) Spaces Triangular space: teres minor, teres major, long head of triceps; contains circumflex scapular artery Quadrangular space: Teres minor, teres major, long head of triceps, lateral triceps; contains axillary nerve, posterior circumflex artery Triangular interval: teres major, long and lateral triceps; contains radial nerve and deep artery of arm Pathology Winged scapula: Accessory nerve CN XI: trapezius and SCM, lateral winging Long thoracic nerve (C5-7): innervate serratus anterior, medial winging when out Instability: TUBS: traumatic, unilateral, Bankart lesion, surgical treatment Hill Sachs lesion: post. humeral head bony defect from ant dislocation AMBRI: atraumatic, multi-directional, bilateral, treat with rehab or inferior capsule repair Bankart lesion: anterior/inferior labrum tear resulting from ant dislocation, can be bony, periosteum is torn ALPSA: anterior labrum periosteal sleeve avulsion; similar to bankart but periosteum stays intact and labrum medializes HAGL: humeral avulsion of the anterior IGHL, see contrast leaking at humeral neck GLAD: glenoid labral articular disruption; anteroinferior labrum tear involving articular surface, not with dislocations GIRD: glenoid internal rotation deficit; seen in throwing athletes SLAP: superior labrum anterior-posterior lesions: labral tears at biceps anchor, common in throwing athletes Buford complex: NOT pathologic, anatomic variant where there is an anterosuperior labrum deficiency associated with a cord-like MGL—DO NOT FIX Deltopectoal Approach Internervous plane is axillary (deltoid) and med/lat pectoral (pec major) Incision: begin by marking out landmarks (coracoid, clavicle, acoromion) Straight incision from lateral coracoid to deltoid insertion in plane between deltoid and pec major, cephalic vein runs in this interval Superficial dissection: Continue dissection through subq tissue maintaining hemostasis. Bring the cephalic vein either medial or lateral according to your preference. There tend to be more branches on the lateral side but bringing it medially helps to protect it during glenoid preparation. The clavipectoral fascia is opened on the lateral side of the coracobrachialis. The interval is developed and the “3 sisters” (anterior circumflex a. and accompanying 2 veins) are tied off. Deep dissection The subscap is identified attaching to the lesser tuberosity. It can be released just medial to its insertion to leave some tendon for reattachment during closure. The interval between the subscap and capsule is developed and the 2 layers are taken down individually. The subscap and capsule are divergent medially and are more easily separated here. The long head of the biceps can be found in the intertubercular groove just lateral to the subscap attachment. Tendon fibers continue over the groove as the transverse humeral ligament. Brachial Plexus (C5-T1) Real Tarheels Drink Cold Beer (Roots, Trunks, Divisions, Cords, Branches) Roots: C5-T1, long thoracic and dorsal scap Trunks: upper, middle, lower; suprascap n. Divisions: anterior/posterior for each trunk Cords: Lateral :C5,6,7 contributions, lat pect n., musculocutaneous, median Medial: C8, T1 contributions, med pect n, media brachial and antebrachial cutaneous nn, median, ulnar Posterior: C5-T1 contributions, upper and lower subscaps, thoracodorsal, axillary, radial Long thoracic nerve (C 5, 6, 7): serratus ant. Dorsal scapular nerve (C 3,4,5): levator scap, rhomboids Suprascapular nerve (C5-6): supra- and infra- spinatus; under ligament, can be compressed at spinoglenoid notch Lateral pectoral nerve (C5,6,7): pec major and minor, named for cord origin Medial pectoral nerve (C8-T1): pic major and minor, named for cord origin Upper and lower subscaps (C5-6): subscapularis, lower also gets teres major Thoracodorsal nerve (C7-8): between upper and lower subscaps, latissimus dorsi, runs with artery Medial cutaneous nerve of arm (C8-T1): sensory only Medial cutaneous nerve of forearm (C8-T1): medial forearm sensation, runs with basilic v. Ulnar nerve (C8-T1): FCU, ulnar half of FDP, palmaris brevis, FPB (deep head), ADM, FDM, opponens, dorsal and volar interossei, ulnar two lumbricals; sensation to half of ring and small fingers; runs in cubital tunnel post to med epicondyle then between 2 heads of FCU on to Guyons canal; Median nerve (C6,7,8,1): pronator teres, FCR, PL, FDS; AIN: radial 2 FDP, FPL, PQ; recurrent motor branch: APB, opponens pollicis, FPB (superficial head), radial 2 lumbricals; runs between 2 heads of PT through ligament of Struthers and under FDS to carpal tunnel; sensation to palm and radial 3 ½ fingers Axillary nerve (C5-6): deltoid and teres minor, runs with post circumflex humeral artery through quadrangular space, identified during open shoulder surgery with “tug test”: pulling on nerve in axillary pouch and feeling it tension on the underside of the deltoid Radial nerve (C5-T1): triceps, anconeus, ECRL, ECRM, BR, PIN: ECU, EDM, EDC, supinator, APL, EPB, EPL, EIP; runs with deep artery of arm in triangular interval into spiral groove and divides into PIN and sensory branch at elbow, PIN runs between 2 heads of supinator; sensation to posterior forearm and dorsal 3 ½ radial fingers Musculocutaneous nerve (C5-7): coracobrachialis, biceps, brachialis; pierces through coracobrachialis, can be injured with excessive medial retraction of strap muscles, continues on as lateral cutaneous nerve of forearm