Joints of the Pectoral and Shoulder Region
Sternoclavicular JointSternoclavicular Joint
It is an articulation between the medial end of the clavicle, the manubrium sterni, and the 1st costal cartilage. It is synovial double-plane joint.Sternoclavicular Joint
The joint is surrounded by capsule which is attached to the margins of the articular surfaces, the capsule is lined by Synovial membrane which is also attached to the margins of the cartilage covering the articular surfaces.Sternoclavicular Joint
The capsule is reinforced in front of and behind the joint by the strong sternoclavicular ligaments (Ant. & Post.). There is also a strong acessory ligament called costoclavicular ligament attached between the 1st rib and the end of the clavicle.Sternoclavicular Joint
■ Articular disc: is a flat fibrocartilaginous disc lies within the joint and divides the joint’s interior into two compartments.■ Nerve supply: The supraclavicular nerve and the nerve to the subclavius muscle.Sternoclavicular Joint
Movements Forward and backward movement of the clavicle takes place in the medial compartment. Elevation and depression of the clavicle take place in the lateral compartment.Sternoclavicular Joint
Important Relations■ Anteriorly: The skin and some fibers of the sternocleidomastoid and pectoralis major muscles.■ Posteriorly: on the right, the brachiocephalic artery; on the left, the left brachiocephalic vein and the left common carotid artery.Shoulder Joint
Shoulder Joint■ Type: Synovial ball-and-socket joint.■ Articulation: between the rounded head of the humerus and the shallow, pear-shaped glenoid cavity of the scapula.
Shoulder Joint
The articular surfaces are covered by hyaline articular cartilage, and the glenoid cavity is deepened by the presence of a fibrocartilaginous rim called the glenoid labrum.Shoulder Joint
■ Capsule: it surrounds the joint and is attached medially to the margin of the glenoid cavity outside the labrum; laterally, it is attached to the anatomic neck of the humerus.Shoulder Joint
■ Capsule: It is strengthened by the ligaments and by the tendons of the subscapularis, supraspinatus, infraspinatus, and teres minor muscles (the rotator cuff muscles).Shoulder Joint
■ Ligaments: The glenohumeral ligaments are three weak bands of fibrous tissue that strengthen the front of the capsule. The transverse humeral ligament strengthens the capsule and bridges the gap between the two tuberosities. The coracohumeral ligament strengthens the capsule above and stretches from the root of the coracoid process to the greater tuberosity of the humerus.Shoulder Joint
4. Accessory ligaments: The coracoacromial ligament extends between the coracoid process and the acromion. Its function is to protect the superior aspect of the joint.
■ Ligaments:
Shoulder Joint
■ Synovial membrane: This lines the capsule and is attached to the margins of the cartilage covering the articular surface. It forms a tubular sheath around the tendon of the long head of the biceps brachii. It extends through the anterior wall of the capsule to form the subscapularis bursa beneath the subscapularis muscle.■ Nerve supply: The axillary and suprascapular nervesShoulder Joint
Movements The shoulder joint has a wide range of movements, and this on the expense of the stability of the joint. The inferior part of the capsule is the weakest area. The shoulder joint is the most commonly dislocated large joint in the body. The strength of the joint depends mainly on the tone of the rotator cuff muscles that cross in front, above, and behind the joint.Shoulder Joint
Movements■ Flexion: Normal flexion is about 90° and is performed by the anterior fibers of the deltoid, pectoralis major, biceps, and coracobrachialis muscles.■ Extension: Normal extension is about 45° and is performed by the posterior fibers of the deltoid, latissimus dorsi, and teres major muscles.Shoulder Joint
Movements■ Abduction: Normally, is 180°, it occurs both at the shoulder joint and between the scapula and the thoracic wall. It is performed by middle fibers of the deltoid, assisted by the supraspinatus. ■ Adduction: Normally, about 45°. This is performed by the pectoralis major, latissimus dorsi, teres major, and teres minor muscles.Shoulder Joint
Movements■ Lateral rotation: Normally, is 40° to 45°. This is performed by the infraspinatus, the teres minor, and the posterior fibers of the deltoid muscle.■ Medial rotation: Normally, about 55°. This is performed by the subscapularis, the latissimus dorsi, the teres major, and the anterior fibers of the deltoid muscle.■ Circumduction: it is a combination of the above movements.Surface anatomy
Surface anatomy
Clavicle The clavicle is situated at the root of the neck and throughout its entire length lies just beneath the skin and can be easily palpated.Anterior Surface
Surface anatomy
Deltopectoral Triangle This small, triangular depression is situated below the outer third of the clavicle and is bounded by the pectoralis major and deltoid muscles.Anterior Surface
Surface anatomy
Axillary Folds The anterior axillary fold: is formed by the lower margin of the pectoralis major muscle and can be palpated between the finger and thumb. This can be made to stand out by asking the patient to press his or her hand against the ipsilateral hip.Anterior Surface
Surface anatomy
Axilla: The structures can be felt in the axilla: The inferior part of the head of the humerus. The pulsations of the axillary artery. The cords of the brachial plexus. The medial wall of the axilla (formed by the upper ribs covered by the serratus anterior muscle). The lateral wall (formed by the coracobrachialis and biceps brachii muscles and the bicipital groove of the humerus).Anterior Surface
Surface anatomy
Scapula The spine of the scapula can be palpated and traced medially to the medial border of the scapula, which it joins at the level of the 3rd thoracic spine. The superior angle of the scapula can be felt through the trapezius muscle and lies opposite the 2nd thoracic spine. The inferior angle of the scapula can be palpated opposite the 7th thoracic spine.Posterior Surface
Surface anatomy
Axillary Folds The posterior axillary fold: is formed by the tendon of latissimus dorsi and the lower border of the teres major muscle. It can be easily palpated between the finger and thumb.
Posterior Surface