Shoulder Region Anatomy PDF

The Shoulder Region is composed of: 4 Bones Table of Contents 3 bony articulations I. BONES...

The Shoulder Region is composed of: 4 Bones Table of Contents 3 bony articulations I. BONES 3 soft tissue articulations A. Humerus 20 muscles a. Humeral Head b. Angles c. Bicipital groove BONES d. Tuberosities Greater Lesser e. Palpation Humerus f. Fossa g. Epicondyle B. Clavicle a. Humeral Neck C. Sternum D. Scapula Shape: half of sphere a. Process Angular value: 150 degrees b. Acromial Variation Orientation: Medially, Posteriorly, and superiorly c. Glenoid fossa II. TRUE JOINTS (3 bony articulations) (MPS) A. Shoulder Girdle B. Glenohumeral Joint a. Coracohumeral Ligament Surgical neck most common site of fracture b. Glenohumeral Ligament most common site of surgery c. Transverse Humeral Ligament ○ circumflex artery aka C. Acromioclavicular Joint axillary artery a. AC Ligament artery that may be b. Coracoclavicular Ligament damaged when D. Sternoclavicular Joint a. SC ligament surgery is done Anterior Posterior Anatomical end of the glenohumeral b. Costoclavicular ligament neck capsule c. Interclavicular ligament III. FALSE JOINTS (3 soft tissue articulations) A. Scapulothoracic Joint B. Bicipital groove C. Suprahumeral Joint D. Scapulohumeral Rhythm IV. MUSCLES A. Scapular stabilizer muscles of the shoulder complex a. Serratus anterior b. Trapezius c. Rhomboids d. Pectoralis minor e. Levator Scapulae B. Glenohumeral stabilizing muscles of the shoulder a. Supraspinatus b. Infraspinatus c. Teres minor d. Subscapularis e. Teres major f. Coracobrachialis C. Large Muscle Movers of the shoulder b. Angles a. Deltoid b. Latissimus Dorsi c. Pectoralis Major Angle of aka: neck shaft angle inclination angular value: 130-150 degrees # alli 💟 1  Angle of aka: retro torsion, posterior d. Tuberosities torsion torsion angle form between humeral head and 2 epicondyles Greater laterally located angular value: 30 degrees Tuberosity Orientation: posteriorly and laterally Facets: ○ Superior - insertion of the supraspinatus ○ Middle - insertion of the infraspinatus ○ Inferior - insertion of the teres minor (all SITS muscles except for subscapularis) Lesser medially located Tuberosity Insertion of: - teres major - subscapularis - latissimus dorsi Orientation: medially and anteriorly c. Bicipital groove e. Palpation aka: intertubercular sulcus greater tuberosity — internal rotation long head of biceps tendon: tendon that passes lesser tuberosity — external rotation in the groove ligaments that holds the structure in the groove in f. Fossa place ○ Transverse humeral ligament coracoid fossa – anteromedially located ○ Glenohumeral ligament radial fossa – anterolaterally located olecranon fossa – posteriorly located ANGLES OF BICIPITAL GROOVE 15 degrees – least common angle 30 degrees 45 degrees 60 degrees – 2nd most common angle 75 degrees – most common angle 90 degrees – widest and deepest angle g. Epicondyle medial epicondyle – origin of wrist flexors lateral epicondyle – origin of wrist extensors # alli 💟 2  Clavicle Sternum aka: collar bone, key bone, cleido, s-shape, like a aka: shield bone, breast bone, dagger crank Main parts: 1st and last bone to ossify ○ manubrium most commonly fractured long bone ○ body flat: shape of acromial end ○ xiphoid process (xiphos-sword) prism: shape of sternal end FUNCTIONS: Jugular notch Aka: suprasternal notch ○ acts as a strut Level: T2 ○ keeps arms away from the body ○ prevent the sliding of scapula anteriorly, Manubriosternal Aka: sternal angle, angle ○ downward and medially angle of louis Level: T4-T5 Xiphisternal joint Level: T9 Anterior view Medial 2/3 – convex Lateral 2/3 – concave Posterior view Medial 2/3 – concave Lateral 2/3 – convex Scapula Anteromedial Most common site of fracture 2/3 Moi: FOOSH (fall on an Process outstretched hand) Particularly in middle 2/3 Coracoid Orientation: process ○ anteriorly ○ medially Cleidocranial Dysostosis: condition with the ○ inferiorly absence of clavicle → AMI Acromion Orientation: process ○ posterior ○ lateral ○ superiorly → PLS # alli 💟 3 Acromial variation 1. Type I – flat or bigliani 2. Type II – gentle anterior curve 3. Type III – marked curve, hooking TRUE JOINTS two or more bones meet to allow movement synovial joints Shoulder Girdle Glenoid fossa term that refers to the scapula, clavicle and the manubrium Orientation anterior, lateral, superiorly Angular value 60 degrees Shoulder girdle 60 degrees elevation Shape pear shape Shoulder girdle 5-10 degrees Characteristics wide inferior, narrow depression superior (WINS) Shoulder girdle scapula moves protraction away from midline Sprenger’s deformity: congenital high scapula (5-6 inches/ 13-15cm) 25 degrees Shoulder girdle 25 degrees retraction Shoulder girdle maximum range occurs upward rotation with the full shoulder flexion Shoulder girdle downward rotation Scapular tilting # alli 💟 4  arm in adducted arm Glenohumeral aka: Z ligament ligament connects glenoid labrum to the humeral neck to the lesser tubercle weakest ligament of the shoulder (superior, middle, inferior) Transverse connects the lesser and humeral greater tubercle ligament 1. Glenohumeral joint Articulation: humeral head and glenoid fossa DOF: 3 DOF Type: BUSE (ball-and-socket, universal, synovial, enarthrodial) Most commonly sublux or dislocated joint because of the following reasons: ○ Shallow glenoid fossa ○ Loose capsule ○ Wide ROM permit 2. Acromioclavicular joint ○ Few ligamentous support Glenoid labrum: Plane synovial joint ○ Deepens the articulation DOF: 3 DOF ○ Serves as a attachments of ligaments ○ Elevation and depression Bursae: closed, fluid-filled sac that works as a ○ Protraction and retraction cushion and gliding surface to reduce friction ○ Upward and downward rotation 2 most important bursae: Orientation: ○ Subacromial bursae: between the ○ acromial end – medially and slight superiorly supraspinatus tendon and coracoacromial ○ clavicular end – laterally and slight inferiorly arch ○ capsule – fibrocartilage/ meniscus ○ Subdeltoid bursae: between deltoid muscle during full arm elevation the AC joints contribute and the supraspinatus tendon and humeral 20-30 degrees of upward rotation of scapula head along an antero-postero axis Ligaments of GH joint Ligaments of AC joint Coracohumeral connects the coracoid Acromioclavicular provides horizontal stability ligament process and humerus ligament particularly the lesser and greater tubercle. Coracoclavicular provides vertical stability strongest ligament of the ligament ○ Conoid (conical) – shoulder located medially and can support the dependent posteriorly arm ○ Trapezoid (triangular) prevents inferior dislocation – located anteriorly and acts to limit the ER of the laterally # alli 💟 5  ○ protraction and retraction (10cm protraction/ 5cm retraction) 3. Sternoclavicular joint ○ upward and downward rotation (60 degrees) articulation between sternum and sternal end of clavicle Functions of ST joint only joint that connects the UE directly to axial increasing the rom of shoulder to provide greater skeleton reach DOF: 3 DOF maintains favourable length-tension relationship ○ Protraction and retraction for the deltoid muscle to function ○ Elevation and depression above 90 degrees of GH elevation ○ Transverse rotation of scapula provides gh stability in overhead positions and Capsule: fibrocartilage/ meniscus handstands Disk and clavicle: where elevation and shock absorption depression occurs elevation of the body during crutch walking Disk and sternum: where protraction and retraction occurs Ligaments of SC joint Sternoclavicular Anterior SC ligament: ligament check the anterior motions Posterior SC ligament: check the posterior motions Costoclavicular between clavicle and the ligament 1st rib 2. Bicipital groove prevents superior motion/ elevation groove between the lesser and the greater allows inferior motions/ tubercle of humerus depression where the tendon of long head of biceps passes Interclavicular connects the right and ligament left clavicle FALSE JOINTS pseudo / functional joint there is no bone to bone connection or articulation 1. Scapulothoracic joint Articulation: between fascia of the thorax and fascia of serratus anterior DOF: 3 DOF ○ elevation and depression (10cm elevation/ 2cm depression) # alli 💟 6  3. Suprahumeral joint Trapezius aka: musculus cucularis, shawl muscle aka: supraspinatus outlet, subacromial palpation: inclined articulation: between humeral neck and forward or prone position, coracoacromial arch (arch between coracoid and shoulder abduction and acromion process) scapular retraction O upper: occipital bone middle: ligamentum nuchae lower: spinous process C7-T12 I upper: acromial end of clavicle (obliquely downward) middle: spine of scapula (horizontal) lower: acromion process (obliquely upward) N spinal Accessory (C3-C4 and spinal portion of CN XI) MUSCLES OF THE SHOULDER COMPLEX A upper: elevation and upward rotation of I. Scapular stabilizer muscles of the shoulder scapula, extension, complex lateral flexion and contralateral rotation of the neck Serratus anterior Aka: saw muscle, middle: upward boxer’s muscle rotation and adduction important in raising arm of scapula overhead lower: upward rotation, isolation: 135 degrees of adduction and scaption depression of scapula palpation: arm in 135 degrees scaption palpation of lower Rhomboids covered by trapezius digitations palpation: hand is placed upper and middle portion in the small of the back, covered by pectoralis place the finger major underneath the medial border of scapula.raise the hand off the small of O 1-9th ribs the back. I anterior surface of medial border of O major: spinous process scapula of C6-C7 and T1-T4 minor: ligamentum N long thoracic nerve nuchae A protraction and I medial border of upward rotation scapula N Dorsal scapular nerve # alli 💟 7  A major: adductor and downward rotation of downward rotation of scapula, lateral flexion scapula and ipsilateral rotation minor: adduction of of cervical spine scapula Pectoralis minor Pectus = breast bone Palpation: hand place in II. Glenohumeral stabilizing muscles of the the small of the back shoulder (pects major relaxed), one finger just below the coracoid process, press Supraspinatus Palpation: prone arm down gently, raise the hanging on the edge of hand off the small of the the table, perform back abduction Others: palpating finger Other: trunk inclined placed distal to the forward, lift a heavy object coracoid process (sitting on a table) push down on the table with the hands as if to elevate the body. O supraspinous fossa of scapula I upper facet of greater O 2nd to 5th ribs tubercle of humerus I coracoid process N suprascapular nerve N medial pectoral nerve A abduction of GH joint (primary muscle for A depression and anterior abduction – tilt of scapula, elevation 90-180 degrees of ribs 2-5 greater contraction) Levator scapulae Palpation: place forearm Infraspinatus Palpation: prone or in the small of the back, standing with trunk shrugs the shoulder, may inclined forward arms be palpated in the neck hang vertically, palpating region anterior to the fingers placed below the trapezius and posterior to deltoid on scapula, the the SCM. subjects ER the shoulder. Isolation of action: shrugs briefly and quickly and in a short range, if too much trapezius will O infraspinatus fossa contract. I middle facet of greater tubercle of humerus O transverse process of N suprascapular nerve C1-C4 A ER and adduction of I medial border of GH joint scapula near the superior angle N dorsal scapular nerve Teres minor Palpation: same as infraspinatus; palpated A elevation and lateral to the infraspinatus # alli 💟 8  and spine of the scapula ○ it emerges from the underneath the inferior border of the pectoralis major O lateral border of Medial to and parallel with scapula the tendon of the short head of the biceps. I lower facet of greater The biceps is first tubercle of humerus identified by supination of the forearm the palpating N axillary nerve fingers then follow the short head of biceps A ER and adduction of proximally until the muscle GH joint tapers off. Subscapularis Palpation: trunk is O coracoid process inclined forward, fingers placed in the axilla I medial surface of anterior to the latissimus humerus dorsi with gentle pressure, IR the shoulder. N musculocutaneous nerve O costal surface of A flexion and adduction of scapula GH joint I lesser tubercle of humerus N subscapular nerve III. Large Muscle Movers of the shoulder A IR of GH joint Teres major Palpation: prone on table Deltoid Aka: Shield Muscle with arms hanging on the - (delta-the letter A, side, palpated fingers eidos- resemblance) placed on the inferior Palpation: aspect of the axillary ○ Anterior: arm in border of the scapula, IR horizontal position, the GH joint ○ then resist adduction - Note: the inferior border lies close to O inferior angle of scapula the upper portion of the I crest of lesser tubercle pectoralis of humerus major ○ Middle: has the best N subscapular nerve anatomic position for abduction and is seen A IR, adduction and contracting whenever extension of GH joint this movement is carried out of the abducted position is Coracobrachialis Palpation – may be maintained palpated in the distal ○ Posterior: shoulder portion of axillary region, hyperextension arm elevated above against resistance or horizontal. resisted horizontal # alli 💟 9  abduction. body. O anterior – clavicle O inferior and medial (acromial end) clavicle, costocartilages Middle – acromion of ribs 2-6 and body of process sternum Posterior – spine of the scapula I –crest of greater tubercle of humerus I deltoid tuberosity N medial and lateral N Axillary Nerve pectoral nerve A anterior – flexion, A GH adduction, horizontal adduction of horizontal adduction GH joint and IR; Middle – abduction of sternocostal head GH joint extends the GH joint Posterior – extension, from fully horizontal abduction of flexed position. GH joint Latissimus dorsi Latus – broad Broadest muscle of the back Palpation: laterally in the axilla line, resisted shoulder adduction or extension O spinous process of T6-L5, dorsolumbar fascia, posterior iliac crest, lower ribs I crest of lesser tubercle of humerus N thoracodorsal nerve A shoulder IR, extension and adduction and scapular depression and elevation of pelvis Pectoralis major Fan shape muscle Palpation: easily palpated along its origin along the sternum or distal to the clavicle. The entire muscle contract when horizontal adduction is resisted. As in pressing the palms together in front of the # alli 💟 10