Shoulder Flashcards
What is the pectoral girdle?
The bony ring of clavicle, acromion and scapula
And the acromioclavicular joint
Name the muscles in the anterior shoulder/top arm/ peck region
Sternocleidomastoid Trapezius Deltoid Triceps brachii Biceps brachii Brachialis Pectoralis major Serratus anterior
Name the muscles in the posterior region of the shoulder/ back
Trapezius Infraspinatus Deltoid Teres minor Teres major Triceps lateral Triceps long Latissimus dorsi
Describe the pectoral girdle
What are it’s properties and how does this affect its function
Doesn’t go all the way around posteriorly
Not attached to the vertebral column
Attached by muscles
Very flexible and movable
What are the deltoids?
Muscles in your shoulder that makes it look round
Which joint joins the arm to the axial skeleton?
Sternoclavicular
Where does the humerus articulate at the shoulder joint?
The glenoid fossa in the scapula
What is the function of the acromion?
Keeps the arm away from the thorax
Freedom of movement
Describe the shape of the clavicle, and it’s function
S shaped
Increases resilience
What does the clavicle protect?
Brachial plexus
Major underlying vessels (axillary artery and vein)
Apex of lung
Describe the shape of the scapula, what is its location?
Triangular flat home
Posterolateral aspect of the thorax
2nd-7th ribs
Spine ridge posteriorly separates the supraspinous fossa and infraspinous fossa
What is the ‘point of the shoulder’
Acromion
What do the rhomboid muscles do?
Retraction muscles of back
Pulls shoulder back to the vertebrae
Medial to the scapula
What do the levator scapulae muscles do?
Attaches to the top of the scapula and lifts it
Describe the anterior osteology of the scapula
Acromion
Coracoid process
Glenoid cavity
Subscapular fossa
Describe the posterior osteology of the scapula
Supraspinous fossa Coracoid process Acromion Neck of the scapula Infraspinous fossa
Describe the lateral osteology of the scapula
Acromioclavicular joint
Coracoid process
Glenoid cavity
Lateral border
Which muscle elevates the scapula?
Trapezius (descending)
Which muscle depresses the scapula?
None
Just gravity
Which muscle protracts the scapula?
Serratus anterior
Pectoralis minor
Which muscle causes upward rotation of the scapula?
Trapezius (descending) Serratus anterior (inferior)
Which muscle causes downward rotation of the scapula?
Lattisimus dorsi
Name the different structures around the glenohumeral joint
Subacromial bursa Acromion Clavicle Articular cartilage Glenoid labrum Fibrous capsule Synovial membrane Long head of the biceps tendon
Name the ligaments around the glenohumeral joint
Acromioclavicular ligament
Coracoclavicular
Coracoacromial
Transverse humeral ligament
What movements does the shoulder do?
Flexion - extension
Abduction - adduction
Medial - lateral rotation
Circumspection (combo of flexion, extension, abduction, adduction)
What are flexors?
Muscles anteriorly that bring the arm into flexion
What muscles act to flex the glenohumeral joint?
Chief flexors:
Pectoralis major (clavicular part)
Deltoid (anterior part)
Which muscles act to stabilise the glenohumeral joint?
Anterior:
Coracobrachialis
Biceps brachii
Posterior:
Teres major
Long head of the triceps brachii
Which muscles act to extend the glenohumeral joint?
Latissimus dorsi
Deltoid (posterior fibres)
Which muscles act to abduct the glenohumeral joint?
Deltoid (all parts especially the Central fibres) - posterior, central and anterior
Deltoid can’t start abduction as they are too lateral,
Supraspinatus starts the first 10 degrees of abduction
Supraspinatus and deltoid: 10 degrees to 110 degrees
Deltoid only: 110 degrees to 180 degrees
What are the names of the 4 rotator cuff muscles
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
Where do the 4 rotator cuff muscles attach?
Attach to the greater tuberosity
Supraspinatus
Infraspinatus
Teres minor
Attach to the lesser tuberosity
Subscapularis
Which muscles are the chief adductors of the glenohumeral joint?
Pectoralis major
Lattisimus dorsi
(Gravity is the prime mover)
Chief medial rotator
Subscapularis
Chief lateral rotator
Infraspinatus
What does the sensory axillary nerve innervate?
Regimental badge
What happens at an 180 degree shoulder abduction?
120 degrees at the glenohumeral joint
60 degrees at the scapulothoracic joint
2:1 ratio
Where does the humerus articulate with the scapula?
Glenoid cavity of the scapula
That is lined with glenoid labrum (fibrocartilage)
The fibrous joint capsule is loose and baggy
What movements occur at the glenohumeral joint?
Flexion-extension
Abduction-adduction
Medial and lateral rotation
Circumduction (combination of flexion, extension, abduction and adduction)
Why is there a large freedom of movement at the glenohumeral joint?
Laxity of the articular capsule
Large humeral head compared to shallow/small glenoid cavity
