Shouler Region 22-23(1) (1).pptx

Anatomy of the Shoulder Region Dr Catherine Hennessy [email protected] Learning Outcomes Describe the anatomical structures allowing movement and stability at the shoulder region Identify the main arterial, venous and neural elements present in the shoulder region Explain the elements of the p...

Anatomy of the Shoulder Region Dr Catherine Hennessy [email protected] Learning Outcomes Describe the anatomical structures allowing movement and stability at the shoulder region Identify the main arterial, venous and neural elements present in the shoulder region Explain the elements of the pectoral girdle Describe the shoulder joint and its stabiliising structures Describe the muscles of the shoulder region Explain the contents of the axilla Describe the cords and terminal branches of the brachial plexus. Skeletal Component Clavicle Scapula Humerus Acromion Pectoral girdle Coracoid Greater tubercle Two joints: 1. Glenohumeral joint 2. Acromioclavicular joint Intertubercular sulcus/bicipital groove Lesser tubercle Ligaments of the Shoulder Region Stabilize/support the shoulder region - very strong Coracoclavicular Acromioclavicular Coracoacromial Glenohumeral - Superior - Middle - Inferior Coracoclavicular and coracoacromial ligaments Coracoclavicular Coracoclavicular Coracoacromial - Two parts - Major stabilizing ligament Coracoacromial - Forms arch - Provides support for head of humerus - Prevents superior dislocation Glenohumeral Joint Highly mobile ball and socket joint Head of humerus - Abduction/Adduction Flexion/Extension Circumduction Lateral/Medial rotation Glenoid fossa Glenohumeral Joint Highly mobile ball and socket joint - Abduction/Adduction Flexion/Extension Circumduction Lateral/Medial rotation Abduction of the Glenohumeral Joint Performed by the (middle fibres) of Deltoid Deltoid Origin Spine of scapula + acromion + clavicle Insertion Deltoid tuberosity of the humerus Action Middle fibres: Abduction of the GH joint Anterior fibres: Flexion and medial rotation of the GH joint Posterior fibres: Extension and lateral rotation of the GH joint Nerve Supply Axillary nerve Adduction of the Glenohumeral Joint Performed by Latissimus Dorsi and Pectoralis Major (see lecture 1) Ab/Adduction of the Glenohumeral Joint Glenohumeral joint accommodates parts of movement Rotation of scapula increases range of movement Abduction: Upper fibres trapezius Adduction: Rhomboids Serratus anterior Lower fibres trapezius Levator scapulae Flexion of the Glenohumeral Joint Biceps Brachii Short head of biceps Long head of biceps Long head: Supraglenoid tubercle of scapula Short head: Coracoid process of scapula I Tuberosity of the radius A Flexion of GH jt Flexion of elbow jt Supination of the radio-ulnar joints Coracoid Coracobrachialis Supraglenoid tubercle Brachialis (flexes elbow jt) O NS Musculoskeletal nerve Coracobrachialias O Coracoid process of scapula I Midshaft of the medial humerus A Flexion of GH jt Adduction of GH jt NS Musculoskeletal nerve + anterior fibres of Deltoid Extension of the Glenohumeral Joint Triceps Brachii Lateral head of triceps Long head of triceps Olecranon O Long head: Infraglenoid tubercle of scapula Lateral head: Posterior humerus superior to spiral groove Medial head: Posterior humerus inferior to spiral groove I Olecranon process of the Ulna A Extension of GH jt (Long Head only) Extension of elbow jt Medial head NS Radial nerve of triceps Infraglenoid tubercle + posterior fibres of Deltoid + Latissimus Dorsi Factors Increasing Shoulder Joint Stability Glenohumeral Joint Stability Large humeral head Shallow glenoid fossa Unstable structure Most frequently dislocated joint Clinical: Anterior dislocation common (Humeral head descends inferiorly and ends up anterior) Factors Increasing Stability 1. Coracoacromial arch 2. Glenohumeral ligaments 3. Deepening of glenoid fossa by glenoid labrum 4. Long heads of biceps (above) and triceps (below) 5. Tendons of rotator cuff muscles Coracoacromial Arch Acromion Coracoacromial ligament Acromion process Coracoacromial ligament Coracoid process Anterior Anterior View Prevents superior dislocation Glenohumeral Ligaments Acromion Coracoid Glenohumeral ligaments (superior, middle, inferior) Anterior Supports anterior of joint Glenoid Labrum Acromion Coracoid Glenoid labrum (fibrocartilaginous ring) Anterior Deepens glenoid fossa Long Head of Biceps and Triceps Origin - Long Head of Biceps Supraglenoid tubercle Transverse Humeral Ligament Bicipital groove Origin - Long Head of Triceps Long head biceps passes through joint capsule Infraglenoid tubercle Tendons of Rotator Cuff Muscles Four muscles Insert on humerus close to joint Fuse with the joint capsule Forms cuff around joint Rotator Cuff Muscles Acromion Supraspinatus Coracoacromial arch Coracoid Subscapularis Subacromial bursa Infraspinatus Teres Minor Subscapular bursa Anterior Surround joint on all sides except inferiorly Rotator Cuff Muscles - Origins Supraspinous fossa Supraspinatus Spine Infraspinous fossa Infraspinatus Teres minor Axillary nerve Rotator Cuff Muscles - Insertions Supraspinatus, Infraspinatus and Teres Minor insert into the greater tubercle Greater tubercle S I T Subscapularis – Origin and Insertion Anterior Lesser tubercle Subscapular fossa Subscapularis Rotator Cuff Function/Action Together: Stabilize humeral head on glenoid fossa Supraspinatus A: Initiate abduction Infraspinatus A: Lateral rotation Teres minor A: Lateral rotation Posterior Rotator Cuff Function/Action Subscapularis A: Medial rotation Anterior Teres Major Should also be considered with the rotator cuff muscles Teres Major O Inferior angle of scapula I Medial lip of bicipital groove of humerus A Medial rotation of GH jt Extension of GH jt N S Lower subscapular nerve Inferior angle of scapula Teres major Medial lip of bicipital groove Rotator Cuff Injuries Supraspinatus most commonly injured Supraspinatus impingement Limited space for tendon under coracoacromial arch - Impingement due to repetitive overhead activities - Common in athletes (throwers) Blood and Nerve Supply to Shoulder Region Blood Supply to the Shoulder Rich blood supply from subclavian and axillary arteries Scapula anastomosis Allows continuous supply of blood to shoulder region during movement Dorsal scapular artery Subscapular artery Suprascapular artery Scapula Anastomosis Anterior Posterior Suprascapular Thyrocervical trunk ia n v a l c Sub l l ar i x A y Subscapular Dorsal scapular Suprascapular Nerve Supply to the Shoulder From the brachial plexus Suprascapular nerve - Supraspinatus and infraspinatus Trunks Cords Cords of the Brachial Plexus Within axilla Below pectoralis minor Posterior Cord From the brachial plexus Trunks Cords Axillary nerve – Deltoid and Teres Minor Radial nerve – Triceps Upper/Lower Subscapular nerve – Subscapularis and Teres M Middle Subscapular (Thoracodorsal) nerve – Latissimus Dors Quadrangular Space s tricep Axillary nerve and Posterior Circumflex Humeral artery es Ter r o min res Te jor ma Humerus of head Long Teres Minor Deltoid Teres Major Long Head of Triceps Nerve supply to Deltoid and Teres Minor and badge area Clinical – fracture of surgical neck can damage nerve and vessel Lateral Cord Trunks Lateral Pectoral nerve – Pectoralis Major Cords Musculocutaneous nerve – Biceps Coracobrachialis Brachialis Median nerve Medial Cord Trunks Cords Medial Pectoral nerve – Pectoralis Major and Minor Median nerve Ulnar Medial Cutaneous nerve of the arm and forearm– Cutaneous Innervation by Terminal Branches Map looks different to dermatome map Terminal branches contain axons from multiple spinal nerves cervical plexus axillary (badge area) radial Dermatome map musculocutaneous From medial cord medial cutaneous ulnar median Clinical: Altered sensation in one of the above areas indicates damage to a more distal nerve segment (i.e. distal nerve injury) Upper Limb Dermatomes “An individual area of skin innervated by a single spinal nerve” Established during development Lots of overlap/variation Clinical: Altered sensation in the region of a dermatome indicates damage to specific spinal nerve of spinal cord segment (i.e. proximal nerve injury) Motor Innervation Motor axons within each root innervate a different functional group of muscles (myotomes) C5 Shoulder abductor (Deltoid) Roots C6 Elbow flexors (Biceps) C5 C6 C7 Elbow extensors (Triceps) Wrist flexors/extensors C7 C8 C8 Digit flexors/extensors T1 Digit ab/adductors T1