Lecture 9 - The Shoulder Joint Flashcards
(15 cards)
What is the structure of the glenohumeral joint?
Glenoid fossa - cavity on the upper lateral scapula
Humeral head which articulates with this (Good ROM)
Greater tubercle and lesser tubercle of the humerus
Intertubercular groove (bicipital groove)
Deltoid tuberosity
Outline the mobility vs stability of the shoulder
High ROM
Rotation occurs in all planes and axes
Lower stability
Labrum and fibrous joint capsule that adds some stability
Rotator cuff tendons and superior, middle and inferior glenohumeral ligaments add stability
Lack of support under the joint capsule
What are the movements at the shoulder?
Sagittal plane - Flexion - arm moves upwards , extension - opposite
Frontal plane- Abduction, adduction
Horizontal plane - Horizontal abduction and adduction
Internal and external rotation
What are the muscles of the glenohumeral joint?
Superficial - Anterior - Pectoralis Major
Posterior - Latissimus Dorsi and Teres Major
Deltoid
Deep - Rotator cuff - supraspinatus, infraspinatus, teres minor and subscapularis
Superficial - Biarticular brachial muscles - biceps and triceps brachii
Outline the Pectoralis Major
Convergent muscle architype - upper and lower fibres have different lines of pull
O - Anterior, medial clavicle, anterior surface of first 6 ribs cartilages, sternum
I - Flat tendon on the outer lip of the intertubercular groove of the humerus
Actions - Adduction, horizontal adduction, internal rotation
Outline the Latissimus Dorsi
O - Posterior crest of ilium, back of sacrum, spinous processes of lumbar and lower 6 thoracic vertebrae
I - Medial lip of the intertubercular groove of the humerus
Actions - adduction, horizontal abduction, extension, internal rotation
Outline the Teres Major
O - Inferior third of lateral border of scapula
I - Medial lip of the intertubercular groove of the humerus
Actions - Adduction, horizontal abduction, extension, internal rotation
Outline the deltoid
Anterior - Abduction, flexion, horizontal adduction
O - lateral third of the clavicle
Middle - Abduction
O - Acromion process
Posterior - Abduction, extension, horizontal abduction
O - Lower lip of the posterior spine of the scapula
All insert onto the deltoid tuberosity
Outline the anterior rotator cuff muscle
Subscapularis
O - Entire surface of the anterior sub- scapular fossa
I - Lesser tubercle of humerus
Internal rotation
Outline the posterior rotator cuff muscles
Supraspinatus - above the spine of the scapula
Infraspinatus - below the spine of the scapula
Teres minor - lateral border of the scapula
All insert onto the head of the humerus
Actions - External rotation - I and TM , weak abduction - S
What are the rotator cuff injuries?
Damage from rapid/ballistic overhead movements e.g. throwing and racket sports as large ROM and taking it to limits so easy to lose control
- Muscle and tendon strains due to excessive forces
- Impingement - Supraspinatus - underneath the acromial process in the sub acromial space. Hypertrophy of supraspinatus, gets trapped, inflamed and fills more space
Shoulder joint laxity - prior dislocation
Outline the triceps brachii long head
O - Infraglenoid tubercle of the scapula
I - Olecranon process of the ulna
Action at shoulder : extension, adduction and horizontal abduction
Weak for these
Outline the biceps brachii
Long head
O - supraglenoid tubercle of the scapula
I - radial tuberosity
Short head
O - Coracoid process of the scapula
I - Radial tuberosity
Action at the shoulder : Weak shoulder flexion and horizontal adduction
What is the Bicipital aponeurosis?
Mesh of connective tissue that spreads around the forearm to spread the point of loading and improves the lever arm at the elbow
Outline shoulder dislocation
98% are anterior dislocations
2 common causes
Excessive abduction and externally rotated under load
Impact forcing the humeral head forward
