Name the 4 basic articulations of the shoulder joint complex.
- Glenohumeral joint.
- Acromioclavicular joint.
- Sternoclavicular joint.
- Scapulothoracic articulation/scapulothoracic linkage
(functional linkage between the scapula and thorax).
Which joint in the body is the least stable and easy to dislocate?
The shoulder joint (glenohumeral joint)
Classify the type of the shoulder joint.
ball-and-socket type of synovial joint
State the articular surfaces of the shoulder joint.
Head of the humerus and the glenoid cavity of the scapula.
Identify 4 ligaments of the shoulder joint.
- Capsular ligament
- Glenohumeral ligaments - superior, middle and inferior.
- Coracohumeral ligament
- Transverse humeral ligament
Identify 2 accessory ligaments and their significance.
- Coracoacromial ligament: It protects the superior aspect
of the joint. - Coracoacromial arch: This is an osseoligamentous structure that
forms a protective arch for the head of humerus above and prevents its superior displacement above the glenoid cavity.
Identify 3 bursae related to the shoulder joint, their location and the significance.
- Subscapular bursa: It lies between the tendon of subscapularis and the neck of the scapula; and protects the tendon from friction against the neck. This bursa usually communicates with the joint cavity.
- Subacromial bursa: It lies between the coracoacromial ligament and acromion process above, and supraspinatus tendon and joint capsule below. It continues downwards beneath the deltoid, hence it is sometimes also referred to as subdeltoid bursa. facilitates the
movements of supraspinatus tendon under the coracoacromial arch. - Infraspinatus bursa: It lies between the tendon of infraspinatus and posterolateral aspect of the joint capsule.
Which is the biggest bursa in the body.
Subacromial bursa ( subdeltoid bursa)
identify the relations of the shoulder joint.
Superiorly: to coracoacromial arch, subacromial bursa, supraspinatus muscle, and deltoid muscle.
Inferiorly: to long head of triceps, axillary nerve, posterior circumflex humeral vessels.
Anteriorly: to subscapularis, subscapular bursa, coracobrachialis, short head of biceps brachii and deltoid.
posteriorly: to infraspinatus, teres minor and deltoid.
Name 3 arteries that supply the glenohumeral joint.
- Anterior and posterior circumflex humeral arteries.
- Suprascapular artery.
- Subscapular artery.
Name 3 nerves that supply the glenohumeral joint.
- Axillary nerve.
- Suprascapular nerve.
- Musculocutaneous nerve.
Identify 4 factors providing stability to the shoulder joint.
- Rotator cuff muscles - grasps the head of the humerus and pulls it medially to hold it against the smaller and shallow glenoid cavity. Also helps the head of humerus rotating against the glenoid fossa during joint motion.
- Coracoacromial arch - forms, the secondary socket of the glenohumeral joint and protects the joint from the above and prevents the upward dislocation of the head of humerus.
- Long head of biceps tendon - passes above the head of humerus intracapsular, hence prevents its upward displacement.
- Glenoid labrum - provides protection by deepening the shallow glenoid cavity.
Identify the movements at the shoulder joint and the muscles producing them (main and accessory muscles).
- Flexion (a) Main muscles * Pectoralis major (clavicular part)
* Deltoid (anterior fibres)
(b) Accessory muscles * Biceps brachii (short head)
* Coracobrachialis
* Sternocostal head of pectoralis
major - Extension (a) Main muscles * Deltoid (posterior fibres)
* Latissimus dorsi
(b) Accessory muscles * Teres major
* Long head of triceps - Adduction (a) Main muscles * Pectoralis major (sternocostal part)
* Latissimus dorsi
(b) Accessory muscles * Teres major
* Coracobrachialis
* Short head of biceps
* Long head of triceps - Abduction (a) Main muscles * Deltoid (lateral fibres)
* Supraspinatus
(b) Accessory muscles * Serratus anterior
* Upper and lower fibres of
trapezius - Medial rotation (a) Main muscle * Subscapularis
(b) Accessory muscles * Pectoralis major
* Latissimus dorsi
* Deltoid (anterior fibres)
* Teres major - Lateral rotation (a) Main muscle * Deltoid (posterior fibres)
(b) Accessory muscles * Infraspinatus
* Teres minor
Identify the type of joint formed by the acromioclavicular joint.
Plane type of the synovial joint between the lateral end
of the clavicle and acromion process of the scapula.
Identify the articular surfaces of the acromioclavicular joint.
These are small facets present on the lateral end of clavicle and the medial margin of the acromion process of the scapula. The articular surfaces are covered with fibrocartilage.
Identify the ligaments of the acromioclavicular joint and their significance.
- Acromioclavicular ligament: It strengthens the acromioclavicular joint superiorly.
- Coracoclavicular ligament: consists of two parts: (a) conoid and
(b) trapezoid. it is largely responsible for suspending the weight of the scapula and upper limb from clavicle.
Name the strongest ligament of the upper limb.
Coracoclavicular ligament
Identify the movement of the acromioclavicular joint.
permits the rotation of acromion of scapula at the acromial end of the clavicle.
Identify the type of joint formed by the sternoclavicular joint.
Saddle type of the synovial joint.
Identify the articular surfaces of the sternoclavicular joint.
The rounded sternal end of clavicle articulates with the shallow socket at the superolateral angle of the manubrium sterni and adjacent part of the 1st costal cartilage.
Name the ligaments of the sternoclavicular joint.
- Anterior and posterior sternoclavicular ligaments.
- Interclavicular ligament.
- Costoclavicular ligament.
