Glenohumeral Joint (Shoulder Joint) Flashcards
Describe the Humerus’s structure at the proximal end. Name its bony points and landmarks.
Humeral head
Anatomical neck
Greater tuberosity
Lesser tuberosity
Surgical neck
Bicipital groove
What kind of Joint is the GH joint
Ball and socket synovial with 3 degrees of movement
What is the GH joint caspule?
The Joint capsule stretches from the Glenoid labrum to the anatomical neck of humerus.
It is slack in the anatomical position providing little stability to the joint.
In abduction it becomes taught.
The Capsule is strengthened by ligaments and blends with the rotator cuff to support the joint
What 6 ligaments support the GH joint
Superior GH ligament to lesser tuberosity
Middle GH Ligament lower on the head
Inferior GH ligament lower on the head
Transverse Humeral holds the bicep tendon in the groove
Coracohumeral holds the joint stable
Coracoacromial resists superior movement of the humerus
What bursa makes up the GH joint
Subacromial Bursa - underlying the subacromial space, works to reduce friction adn allows for shock absorbtion.
The subscapular bursa is between the tendons of subscapularis preventing friction.
What muscles make up the rotator cuff?
Subscapularis (ant)
Supraspinatus
infraspinatus
teres minor
What is the role of the Rotator cuff?
To centralise the humeral head on to the glenoid labrum
As the deltoid contracts superiorly the infraspinatus and teres minor will contract to pull the humerus into the glenoid fossa (centralisation)
During thee first 30 degrees of abduction the subscapularis contracts and there is no movement at the scapula the deltoid takes over after that.
Pectoralis Major (A)
M - Paired superficial muscle on anterior thorasic cage (made up of the clavicular, sternocostal and abdominal part)
O -
Clavicular - anterior medial half of clavicle
Sternocostal - sternum, costal cartilidge of ribs 1-6
Abdominal - anterior rectus sheath
I - greater tubercle of humerus
N - Lateral and medial pectoral nerves
A - arm adduction, int rotation, flexion extension.
Anterior deltoid (A)
M - Thick triangular shoulder muscle with a wide origin.
O - Lateral 1/3 of clavicle (clavicular part)
I - Deltoid tuberosity of humerus
N - Axillary nerve
A - Flexion and internal rotation of the arm.
Middle Deltoid (A)
M - Thick triangular shoulder muscle with a wide origin.
O - Acromion (acormial part)
I - Deltoid tuberosity of the humerus
N - Axillary nerve
A - Abducts the arm beyond the intial 30 degrees after subscapularis
Posterior deltoid (A)
M - Thick triangular shoulder muscle with a wide origin.
O - Spine of scapula
I - Deltoid tuberosity of the humerus
N - Axilllary Nerve
A - Extension and extrenal rotation of the arm
Biceps Brachii Muscle (A)
M - A two headed muscle in the anterior arm which crosses the GH joint and elbow joint.
O
- Short Head - Apex of the Coracoid process of the scapula
- Long head - Supraglenoid tubercle of the scapula
I - Radial tuberosity of the radius and deep fascia of the forearm
N - Musculocutaeneous nerve
A - Flexion and supination at th eelbow
Flexor at the GH joint
Triceps Brachii (A)
M - A three headed muscle on the posterior aspect of the arm
O -
Long - infraglenoid tubercle of scapula
Medial - posterior humerus
Lateral - Posterior humerus
I - Olecranon of ulna and fascia of forearm
N - Radial Nerve
A -
Elbow - extension
Shoulder - extension and adduction/
Supraspinatus (A)
O - Supraspinatus Fossa
I - Greater tubercle of humerus
N - Suprascapular nerve
A - Inital abduction of the arm and stabilisation of the humeral head in the glenoid cavity
Infraspinatus (A)
O - Infranspinatous fossa of scpaula
I - Greater tubercle of humerus
N - Subscapular nerve
A - External rotation of the arm at the GHJ, Stabilisation of the humeral head in the glenoid cavity
