[002] The Shoulder Flashcards
What are the 4 upper limb areas?
• Shoulder
• Arm
• Forearm
• Hand
Why is the trunk compressed in humans compared to other animals?
Due to the upright position, we have a reduced anteriposterior diameter which pushes the scapula more posteriorly
What does the clavicle articulate with?
Medically: with the manubrium of sternum and the first costal cartilage
Laterally: with the acromion
What is the Conoid Tubercle?
A small projection from the posterioinferior surface of the lateral end of the clavicle. This is the attachment site for the Conoid ligament
Why is the clavicle the most commonly broken long bone in the body?
As it is very long and acts as the single bony connection between the trunk and shoulder
What are the parts of the scapula in the anterior view?
- The acromion
- The Coracoid process
- The subscapular fossa
What are the parts of the scapula in the posterior view?
- Acromion
- Coracoid process
- Spine
- Greater scapular notch
- Suprascapular notch
- Supraspinous fossa
- Infraspinous fossa
What are the parts of the scapula in the lateral view?
- Supraspinous fossa
- Infraspinous fossa
- Spine
- Coracoid process
- Supraglenoid tubercle
- Glenoid
- Infraglenoid tubercle
- Subscapular fossa
What are the parts of the humerus in the anterior view?
- Head
- Greater tubercle
- Lesser tubercle
- Bicipital groove
- Deltoid tuberosity
What are the parts of the humerus in the posterior view?
- Anatomical head
- Surgical neck
- Head
- Triceps
- Radial groove
What are the 3 shoulder joints?
- Sternoclaviular joint
- Acromioclaricular joint
- Glenohumeral joint
What does the sternoclavicular joint join?
The manubrium of the sternum and the first costal cartilage and the clavicle.
How is the sternoclavicular joint reinforced
- Sternoclavicular ligaments
- Costoclaricular ligaments
- Interclavicular ligament
What does the acromioclavicular joint join?
It is between the clavicle and the acromion process of the scapula
What is the acromioclavicular joint reinforced by?
The acromioclavicular ligament and the coracoclavicular ligament
What are the 3 types of shoulder separation injuries associated with the acromioclavicular ligament?
Type l: partial ear of acromioclavicular ligament
Type 2: complete tear of acromioclavicular ligament
Type 3: complete tear of acromioclavicular and coracoclavicular ligament
What does the glenohumeral joint join?
The glenoid of the scapula and the head of the humerus
Why is the glenonumeral joint highly unstable?
As the head of the humerus is much larger than the glenoid of the scapula - it is still highly mobile
What structures provide stability to the glenohameral joint?
- Glenoid labrum - fibrocartilage cap that expands and deepens the glenoid
- Biceps tendon - attaches the supraglenoid tubercle to the bicipital groove on the humerus
- Synovial and fibrous joint membranes - surrounds the entire joint
- Rotator cuff muscles
- Arch of the coracoid and acromion process
What are bursae?
Regions where the synovial membrane of the joint protrudes outside the fibrous membrane. These reduce friction between the surrounding ligaments, muscles and tendons during joint movement.
What is the origin, insertion and innervation of the trapezius?
Origin: C7-T12
Insertion: lateral 1/3 ef clavicles acromion and spine of scapula
Innervation: C3, C4 and cranial nerve XI
What is the origin, insertion and innervation of the levator scapulae?
Origin: C1-C4
Insertion: upper medial border of scapula
Innervation: C3,C4,C5
What is the origin, insertion and innervation of the rhomboids?
Origin:C7-T1 (minor) and T2-T5 (major)
Insertion: medial edge of the scapula (minor) and below the spine of the scapula (major)
Innervation: C4,C5
What is the origin, insertion and innervation of the deltoids?
Origin: clavicle and scapula
Insertion: deltoid tuberosity of humerus
Innervation: C5-C6
What is the origin, insertion and innervation of the latissimus dorsi?
Origin:T6-L5, ribs 10-12, sacrum, iliac crest
Insertion: floor of intertubular sulcus
Innervation:C6,C7,C8
What is the origin, insertion and innervation of the pectoralis major?
Origin: contains 2 heads - sternocostal head (anterior surface of the sternum and first 7 costal cartilages) and the clavicular head (medial half of the clavicle)
Insertion: lateral lip of bicipital groove of the humerus
Innervation: C5-T1
What is the origin, insertion and innervation of the pectoralis minor?
Origin: anterior surfaces of ribs 3-5
Insertion: coracoid process
Innervation: C5-T1
What is the origin, insertion and innervation of the subclavius?
Origin: first rib
Insertion: middle third of clavicle
Innervation: C5-C6
What is the origin, insertion and innervation of the coracobrachialis?
Origin: coracoid process
Insertion: medial aspect of humerus
Innervation: C5-C7
What is the origin, insertion and innervation of the serratus anterior?
Origin: lateral surfaces of ribs 1-8/9
Insertion: medial border of scapula
Innervation: C5-C7 (long thoracic nerve)
What is a winged scapula?
When the scapula separates away from the rib cage when pressing against a wall.
What is the origin, insertion and innervation of the supraspinatus (rotator cuff)?
Origin: supraspinous fossa of scapula
Insertion: superior fact of the greater tubercle of humerus
Innervation: C5-C6 (suprascapular nerve)
What is the origin, insertion and innervation of the infraspinatus (rotator cuffs)?
Origin: infraspinous fossa of scapula
Insertion: middle facet of the greater tubercle of humerus
Innervation: C5-C6 (suprascapular nerve)
What is the origin, insertion and innervation of the teres minor (rotator cuffs)?
Origin: lateral infraspinous fossa
Insertion: inferior facet of the greater tubercle of humerus
Innervation: axillary nerve C5-C6
What is the origin, insertion and innervation of the teres major?
Origin: posterior surface of scapula near inferior angle
Insertion: medial lip of bicipital groove
Innervation: inferior subscapular nerve C5-C6
What is the origin, insertion and innervation of the subscapularis?
Origin: subscapular fossa
Insertion: lesser tubercle of humerus
Innervation: superior and inferior subscapular nerves C5-C7
What are biarticular muscles?
Muscles that cross/span 2 joints e.g. triceps and biceps
What does the subscapular nerve innervate?
The supraspinatus and infraspinatus
Where does the suprascapular nerve come from and where does it travel through?
It comes from the superior trunk of the brachial plexus and travels through the suprascapular foremen between the scapula and supraspinatus and then through the greater scapular notch to innovate the infraspinatus
What does the axillary nerve innervate?
Teres minor, deltoid and provides cutaneous innervation to the regimental badge area of the arm.
Where does the axillary nerve arise from and where does it pass though?
It arises from the posterior cord of the brachial plexus and passes posterior to the surgical neck of the humerus.
Why are anastomosis important in the shoulder?
As there is a range of movement in the shoulder, certain positions of the upper limb could result in the occlusion of arteries, resulting in ischaemia of these regions. So anastomoses are present so it one vessel is occluded, the other vessels will remain unorcluded and can compensate to maintain blood supply
What does the thyrocervical trunk go into?
Supra scapular artery > circumflex scapular artery > subscapular artery > axillary artery
