Lecture 2 - Shoulder Anatomy PDF

10/12/22 Jordan University of Science and Technology Faculty of Applied Medical Sciences Department of Rehabilitation science Musculoskeletal Anatomy The Shoulder...

10/12/22 Jordan University of Science and Technology Faculty of Applied Medical Sciences Department of Rehabilitation science Musculoskeletal Anatomy The Shoulder complex Anatomy DR. MOHAMMAD AL-WARDAT, PT, PH.D First Semester 2022-2023 Osteology Scapula Clavicle Shoulder 1. Shoulder / Pectoral girdle Scapula § Clavicle Sternum § Scapula Humerus 2. Humerus (Upper end) (Arm) Elbow Costal 1. Humerus (Distal end) Rib Cartilage 2. Radius/Ulna (Upper end) Wrist Forearm 1. Radius/Ulna (Distal end) Ulna 2. Carpal Radius Hand Carpal 1. Metacarpal Metacarpal 2. Phalanges Phalanges 1 10/12/22 Osteology Clavicle & Scapula Function 1. Transmits force from upper limp to axial skeleton 2. Provides rigid support & maximizes the movement of upper limp. 3. Provides attachment for muscles. 4. Forms boundary of Cervicoaxillary Canal for protection of upper limp neurovascular bundle. Osteology Right Clavicle Superior view Lateral Medial Posterior view Tubercle Clavicle (collar bone) : Long bone w/o bone marrow, Double curves – S shape Acromial facet Acromioclavicular Joint Sternal facet Sternoclvicular joint Subclavian groove Origin of subclavian M. Conoid tubercle Attachment site for conoid ligament Trapizoid line Attachment site for Trapizoid ligament 2 10/12/22 Osteology Osteology (Scapula = 3*3 + 3*2) 3 Superior à Levator Scapula M. (Insertion) Angles Inferior à Levels 7th Rib, Spine of 7th Thoracic vertebra Latissimus dorsi M. (Insertion) Lateral (Glenoid cavity) à Glenohumeral joint 3 Medial (Vertebral) à 4 Insertions Borders Lateral (Axillary) à Teres Minor & Major M. (Origin) Superior 3 Spine à Deltoid M. (Origin), Trapezius M.(Insertion) Processes Coracoid à Muscles 2 Origin, 1 Insertion, 2 Lig. Acromion à 1 joint, origin of Deltoid M. 2 Anterior Surfaces (subscapular fossa) à Subscapular M. Posterior 1. Supraspinous fossa à Supraspinatus M. 2. Infraspinous fossa à Infraspinatus M. 2 Suprascapular notch à Suprascapular nerve passes through Notches Greater scapular notch à Suprascapular artery & Suprascapular nerve (Spinoglenoid notch ) pass around 2 Supraglenoid à Origin of long head of Biceps M. Tubercles Infraglenoid à Origin of long head of Triceps M. 3 10/12/22 Osteology (Scapula) Osteology (Scapula) Anterior View Medial Border 4 10/12/22 Osteology (Scapula) Posterior View Medial Border Osteology (Humerus) Proximal Head à GlenoHumeral Joint End Anatomical neck à Capsule of GlenoHumeral Joint Greater Tubercle (Tuberosity) o Superior facet à Supraspinatus M. (Insertion) o Middle facet à Infraspinatus M. (Insertion) o Inferior facet à Teres Minor M. (Insertion) Lesser Tubercle (Tuberosity) à Subscapularis M (Insertion) Intertubercle Groove (Sulcus) à Long head of Biceps brachii M. Surgical neck Body shaft Deltoid tuberosity à Deltoid M. (Insertion) Radial groove à Radial Nerve Distal Lateral Supracondylar ridge End Medial Supracondylar ridge 3*2+3*1 Lateral Epicondyle Medial Epicondyle Lateral Condyle (Capitulum) à Articulates with radius Medial Condyle (Trochlea) à Articulates with Ulna Radial Fossa à Receives radial head Coronoid Fossa à Receives Coronoid process (Ulna) Olecranon Fossa à Receives Olecranon process (Ulna) 5 10/12/22 Osteology (Humerus) Osteology (Humerus) 6 10/12/22 Arthrology The Shoulder region joints: 1. Sternoclavicular joint 2. Acromioclavicular joint 3. Glenohumeral joint 4. Scapulothoracic joint (functional joint) Arthrology (Sternoclavicular & Acromioclavivular Joints) Main Lig. Accessory Lig. 7 10/12/22 Arthrology (Movements available in scapulothoracic joint) Elevation Depression Retraction Protraction Upward rotation Downward rotation lateral rotation Medial rotation Arthrology (Shoulder Joints) Glenohumeral Lig. Coracohumeral Lig. Coracoacromial Lig. Transverse Humeral Lig. Subscapularis Bursa (reduce friction) Biceps log head tendon Main Lig. Accessory Lig. ** Glenohumeral Lig. à hold proximal humer in the glenoid fossa ** Coracohumeral Lig. à stabilze GH joint in overhead movements ** Coracoacromial Lig. à V-shape, prevent humeral displacement during shoulder abduction 8 10/12/22 Arthrology (Shoulder Joints) Arthrology (Shoulder Joints) Quadrangular Space 9 10/12/22 Arthrology (Movements available in glenohumeral joint) Arthrology (Scapulohumeral Rhythm ) Integrated movements of GH, ST, AC & SC Three functional purposes: 1. Allows for greater overall shoulder ROM 2. Maintains optimal contact / length- relationship of GH joint/ muscles For 180º à Ratio of GH to Scapular motion is 2:1 q 1st phase(0º-90º) Scapula elevation 30º through SC & AC joints. GH abducts 60º q 2nd phase(90º-180º) Scapula upward rotation & elevation 30º AC 25º upward rotation+ SC 5º elevation GH abducts 60º 10 10/12/22 11 10/12/22 Muscle structure Muscles connect Muscles connect Muscles connect Vertebra to Shoulder Thoracic cage to Scapula to Humerus Shoulder 1. Trapezius 1. Pectoralis Major 1. Deltoid 2. Latissimus Dorsi 2. Pectoralis Minor 2. Supraspinatus 3. Levator Scapula 3. Serratus Anterior 3. Infraspinatus 4. Rhomboid Major 4. Subclavius 4. Teres Major 5. Rhomboid Minor 5. Teres Minor 6. Subscapularis 7. Coracobrachialis 8. Biceps Brachii 9. Triceps brachii Muscle structure (Muscles connect shoulder to vertebra) A Trapezius Origin Occipital bone, ligamentum nuchae, spine of C7-T12 Insertion Upper fibers àlateral 1/3 of clavicle middle & lower fibers à acromion & spine of scapula Innervation Accessory nerve – 9th cranial Nerve Action Neck à Extension, Lateral flexion & Rotation (contralaterally) Upper fibers à Scapula Elevation Middle fibers à Scapula Retraction Lower fibers à Scapula Upward Rot. 12 10/12/22 Muscle structure (Muscles connect shoulder to vertebra) A Latissimus Dorsi Origin Iliac crest, lumbar fascia, spines T6-T12, lower 3-4 ribs, & inferior angle of scapula Insertion Floor of bicipital groove of humerus Innervation Thoracodorsal Nerve C6, 7, 8 Action Shoulder Extension, Adduction, Medial Rot. Muscle structure (Muscles connect shoulder to vertebra) A Levator Scapula Origin Transverse processes of C I - C 4 Insertion Superior angle of the scapula Innervation Dorsal scapular nerve C3, 4, 5 Action Scapula Elevation & Downward rotation Neck Extension, Lateral flexion & Rotation (ipsilaterally) 13 10/12/22 Muscle structure (Muscles connect shoulder to vertebra) A Rhomboid Major & Minor Origin Spinous processes C 7 - T 1 (Minor) Spinous processes T 2 - T 5 (Major) Insertion Medial border of scapula Minor from root of spine to inferior angle Innervation Dorsal scapular nerve C4-C5 Action Scapula Elevation, Retraction, Major Downward rotatation Muscle structure (Muscles connect shoulder to Thoracic cage) B Pectoralis Major Pek tor al us ma'jor "pectoral" Latin chest "major" Latin larger Origin Medial clavicle, sternum, costal cartilages of ribs 1-7 Insertion Lateral lip of the bicipital groove of Humerus Innervation Medial & lateral pectoral nerves C5-T1 Action Shoulder Horizontal Adduction, Internal Rot. Shoulder flexion (Clavicle fiber) Shoulder Extension from overhead position (Costal fiber) Shoulder adduction from below shoulder height Shoulder Abduction from above shoulder height 14 10/12/22 Muscle structure (Muscles connect shoulder to Thoracic cage) B Pectoralis Minor p e k t o r al us mi'nor "pectoris" Latin chest "minor" Latin smaller Origin Ribs 3-5 Insertion Coracoid process of scapula Innervation Medial pectoral nerve C6, 7, 8 Action Scapula Protraction, Depression Ribs 3-5 Elevation Muscle structure (Muscles connect shoulder to Thoracic cage) B Subclavias sub cla v e e us "sub" Latin under "clavius" Latin key Origin 1st rib at junction with costocartilage Insertion Clavicle, middle 1/3 of inferior surface Innervati Nerve to subclavius C5, 6 on Action Flexes the clavicle inferiorly Elevates first rib 15 10/12/22 Muscle structure (Muscles connect shoulder to Thoracic cage) B Serratus Anterior ser a'tus an te're or "serra" Latin saw " a n t e r i o r " Latin toward the front Origin Outer surfaces of upper 8 or 9 ribs Insertion Scapula – Medial border (anterior surface) Innervation Long thoracic Nerve C5, 6, 7 Action Scapula Protraction, Depression, Upward Rot. Assists in inspiration Muscle structure (Muscles connect Humerus to Scapula) C Deltoid del'toyd "delta" Greek the letter delta " o i d " Latin resemblance Origin Lateral 1/3 of clavicle, acromion, spine of scapula Insertion Deltoid tuberosity of humerus Innervation Axillary nerve C5, 6 Action Shoulder abduction Anterior fiber à Shoulder Flexion, Internal Rot. Horizontal Adduction Posterior fiber à Shoulder extension, External Rot, Horizontal Abduction. 16 10/12/22 Muscle structure (Muscles connect Humerus to Scapula) C Coracobrachialis kor'a ko bra ke al'is " c o r a c o " G r e e k coracoid process " b r a c h i a l i s " Latin arm Origin Coracoid process of the scapula Insertion Medial shaft, middle one-third of humerus Innervation Musculocutaneous nerve C 5, 6, 7 Action Shoulder Flexion, Adduction Muscle structure (Muscles connect Humerus to Scapula) C Biceps Brachii b i " s e p s bra'ke i " b i c e p s " Latin two heads " b r a c h i i " Latin arm Origin Long head: Supraglenoid tubercle of scapula Short head: Coracoid process of scapula Insertion Radial tuberosity & Bicipital aponeurosis overlying common flexor tendon Innervation Musculocutaneous nerve C 5, 6, 7 Action Shoulder flexion, Abduction (long head), Adduction (short head) Forearm Supination, Flexion 17 10/12/22 Muscle structure (Muscles connect Humerus to Scapula) C Teres Major ter'ez ma'jor "teres" Latin round " m a j o r " Latin large Origin Inferior part of Scapula lateral border Insertion Bicipital groove - Medial lip Innervation Lower subscapular nerve C5-C7 Action Shoulder Extension, External Rot., Adduction Muscle structure (Muscles connect Humerus to Scapula) C Teres Minor ter'ez ma'jor "teres" Latin round " minor" Latin small Origin Scapula lateral border Externally rotates, adducts, extends, and horizontally abducts the shoulder Innervation Insertion Greater Tubercle (Inferior Facet) Innervation Axillary nerve C5-C6 Action Shoulder Extension, External Rot., Adduction, Horizontal Abduction 18 10/12/22 Muscle structure (Muscles connect Humerus to Scapula) C Subscapularis sub'skap yu la'ns " s u b " Latin under " s c a p u l a " Latin shoulder blade Origin Scapula – Subscapular Fossa Insertion Lesser Tubercle of Humerus Innervation Upper and lower subscapular nerves C 5, 6, 7 Action Shoulder Internal Rot. Muscle structure (Muscles connect Humerus to Scapula) C Triceps Brachii tri'seps bra'kei "triceps" Latin three heads "brachii" Latin arm Origin Long head: Scapula – Infraglenoid tubercle Lateral head: Proximal 1/2 of posterior shaft of humerus Medial head: Distal 1/2 of posterior shaft of the humerus Insertion Olecranon process of the ulna Innervation Radial nerve C6-C8 Action Long head à Shoulder Extension, Adduction Elbow Extension 19 10/12/22 Muscle structure (Muscles connect Humerus to Scapula) C Supraspinatus su pra spi na'tus "supra" Latin above "spina" Latin spine (of the scapula) Origin Scapula – Supraspinous fossa Insertion Greater Tubercle (superior facet) Innervation Suprascapular C4, 5, 6 Action Initiates Shoulder Abduction Muscle structure (Muscles connect Humerus to Scapula) C Infraspinatus in'fra spi na'tus " i n f r a " Latin below "spina" Latin spine (of the scapula) Origin Scapula Infraspinous fossa Insertion Greater Tubercle (Middle facet) Innervation Suprascapular C4, 5, 6 Action Shoulder External Rot. Adduction, Extension, Horizontal Abduction 20 10/12/22 SHOULDER ROTATOR CUFF The rotator cuff is a common name for the group of 4 distinct muscles and their tendons, which provide strength and stability during motion to the shoulder complex. They are also referred to as the SITS muscle, with reference to the first letter of their names Supraspinatus, Infraspinatus Teres minor, Subscapularis The rotator cuff muscles arise from the scapula and connect to the head of the humerus, forming a cuff around the glenohumeral joint. Rotator Cuff Anatomy 1. Subscapularis muscle 2. Supraspinatus muscle 3. Infraspinatus muscle 4. Teres minor muscle 21 10/12/22 ROTATOR CUFFANATOMY The rotator cuff muscles stabilize the humeral head while the powerful pectoralis major, latissimus dorsi, anterior deltoid, and triceps brachii pull the arm forward and across the body. Once the ball is released, the posterior deltoid, teres minor, infraspinatus, rhomboids, and trapezius must eccentrically contract to slow the motion of the arm. These agonist and antagonist muscles work together to make this motion fluid and effective. Movement Muscles Scapula elevator Levator scapula Trapezius upper fiber Scapula retractors Trapezius middle fiber Rhomboids Ms Scapula upwards rotators Serratus anterior Scapua Depressor Pectoralis minor Trapizus lower fiber Scapula protractors Pectoralis minor Serratus anterior Scapula downward rotators Levator scapula Rhomboids Pectoralis minor 22 10/12/22 Movement Muscles Shoulder flexors Deltoid – anterior fiber Coracobrachilais Biceps brachii Shoulder extensor Latissimus dorsi Teres major Shoulder abductors Deltoid – middle fiber Supraspinatus Shoulder adductors Latissimus dorsi Teres major / minor Coracobrachialis Shoulder horizontal abductors Deltoid – posterior fiber Teres minor Shoulder horizontal adductors Pectoralis major Shoulder Medial rotators Pectoralis major Subscapulrais Shoulder lateral rotators Infraspinatus Movement Muscles Movement Muscles Flexion 1. Deltoid Extension 1. Deltoid (anterior fibers) (posterior fibers) 2. Pectoralis major 2. Latissimus dorsi (clavicular fibers) 3. Teres major 3. Coracobrachialis 4. Pectoralis major 4. Biceps brachii (sternal fibers) 5. Triceps brachii (long head) Abduction 1. Deltoid (all Adduction 1. Pectoralis major fibers) 2. Latissimus dorsi 2. Supraspinatus 3. Teres major 3. Pectoralis major 4. Teres minor (overhead) 5. Coracobrachialis 6. Biceps brachii (short head) 23 10/12/22 Movement Muscles Movement Muscles Medial 1. Deltoid External 1. Deltoid Rotation Rotation (anterior fibers) (posterior fibers) 2. Pectoralis major 2. Infraspinatus 3. Latissimus dorsi 3. Teres minor 4. Teres major 5. Subscapularis Horizontal 1. Deltoid Horizontal 1. Pectoralis major Abduction Adduction (posterior fibers) 2. Latissimus dorsi 2. Infraspinatus 3. Teres major 3. Latissimus dorsi 4. Teres minor 4. Teres minor 5. Coracobrachialis 6. Biceps brachii (short head) 24