Upper Limb - Shoulder

What is the region of upper limb attachment to the trunk called?

Pectoral Girdle

What bones make up the pectoral girdle?

Clavicle and scapula

What forms the proximal end of the humerus?

Clavicle and scapula

What are the superficial muscles of the shoulder?

Trapezius and deltoid muscles

What do the trapezius and deltoid muscles form?

Smooth muscular contour over lateral part of shoulder

What do the muscles connecting the scapula and clavicle do?

Connect scapula to trunk and clavicle to arm

What is the clavicle?

The only bony attachment between the trunk and upper limb

What is the shape of the clavicle?

S-shaped with a forward-facing convex part medial and a forward-facing concave part lateral

What is the acromial end of the clavicle?

The lateral end of the clavicle that is flat

What is the sternal end of the clavicle?

The medial end of the clavicle that is more robust and quadrangular in shape

What does the acromial end of the clavicle articulate with?

Facet on medial surface of acromion of scapula

What does the sternal end of the clavicle articulate with?

Manubrium of sternum and first costal cartilage

What is the tuberosity on the inferior surface of the lateral third of the clavicle?

Consists of a tubercle (Conoid Tubercle) and lateral roughening (Trapezoid Line) for attachment of coracoclavicular ligament

What is the superior surface of the clavicle like?

Smoother than the inferior surface

What is the scapula?

A large triangular bone with three angles, three borders, two surfaces, and three processes

What are the three angles of the scapula?

Lateral, superior, and inferior

What are the three borders of the scapula?

Superior, lateral, and medial

What are the two surfaces of the scapula?

Costal and posterior

What are the three processes of the scapula?

Acromion, spine, and coracoid

What is the lateral angle of the scapula?

A marked area with a shallow comma-shaped Glenoid Cavity.

What does the Glenoid Cavity articulate with?

The head of the humerus to form the glenohumeral joint.

What is the Infraglenoid Tubercle?

A large triangular-shaped roughening inferior to the glenoid cavity, serving as an attachment site for the long head of the triceps brachii muscle.

Where is the Supraglenoid Tubercle located?

Superior to the glenoid cavity, serving as the attachment site for the long head of the biceps brachii muscle.

What does the Spine of the scapula divide the posterior surface into?

The smaller, superior Supraspinous Fossa and the larger, inferior Infraspinous Fossa.

What is the Acromion?

An anterolateral projection of the spine that arches over the glenohumeral joint and articulates with the clavicle.

What is the Greater Scapula Notch (Spinoglenoid Notch)?

The region between the lateral angle of the scapula and the attachment of the spine to the posterior surface.

What is the Costal Surface of the scapula characterized by?

A shallow concave Subscapular Fossa.

What is the function of the costal surface and margins?

Provide muscle attachment and allow movement over the thoracic wall.

What is the function of the subscapularis muscle?

It moves freely over the underlying thoracic wall.

What is the function of the lateral border of the scapula?

It provides a strong and thick attachment site for muscles.

What is the function of the medial border and superior border of the scapula?

It is thin and sharp.

What is the coracoid process?

A hook-like structure that projects anterolaterally and is positioned inferior to the lateral part of the clavicle.

What is the suprascapular notch?

It is immediately medial to the root of the coracoid process.

What can be palpated on the patient's scapula?

The spine, acromion, tip of the coracoid process, inferior angle, and much of the medial border.

What is the proximal humerus composed of?

The head, anatomical neck, and greater and lesser tubercles.

What is the function of the head of the proximal humerus?

It articulates with the glenoid cavity of the scapula.

What is the anatomical neck of the proximal humerus?

Border between the epiphysis and metaphysis

What is the function of the greater and lesser tubercles?

They serve as attachment sites for four rotator cuff muscles of the glenohumeral joint.

Where is the greater tubercle located?

It is lateral in position.

What are the three large smooth facets on the superior and posterior surfaces of the greater tubercle for?

Muscle tendon attachments.

What muscle attaches to the superior facet of the greater tubercle?

The supraspinatus muscle.

What muscle attaches to the middle facet of the greater tubercle?

The infraspinatus muscle.

What muscle attaches to the inferior facet of the greater tubercle?

The teres minor muscle.

What is the Deep Intertubercular Sulcus (Bicipital Groove)?

It separates the lesser and greater tubercles and continues onto the proximal shaft of the humerus.

What passes through the Deep Intertubercular Sulcus?

The tendon of the long head of the biceps brachii.

What are the roughenings on the intertubercular sulcus for?

They mark the sites for attachment of the pectoralis major, teres major, and latissimus dorsi muscles.

What is the Deltoid Tuberosity?

It is a V-shaped roughening on the lateral surface of the humerus, continuous with the lateral lip of the intertubercular sulcus, where the deltoid muscle attaches.

What muscle attaches to the medial surface of the humerus?

The coracobrachialis muscle.

What is the surgical neck of the humerus?

Area between metaphysis and diaphysis

What structures pass posterior to the surgical neck?

The axillary nerve and posterior circumflex humeral artery.

Is the surgical neck weaker than the more proximal regions of the humerus?

Yes.

What nerves and arteries can be damaged by fractures in the surgical neck region?

The axillary nerve and posterior circumflex humeral artery.

What is the superior half of the shaft of the humerus?

It is the upper portion of the long bone of the arm.

How many joints are there in the pectoral girdle?

There are three joints.

What are the names of the three joints in the pectoral girdle?

The sternoclavicular, acromioclavicular, and glenohumeral joints.

What do the sternoclavicular and acromioclavicular joints do?

They link the two bones of the pectoral girdle to each other and the trunk.

What movements do the sternoclavicular and acromioclavicular joints enable?

They enable the scapula to be positioned over a wide range on the thoracic wall.

What is the glenohumeral joint?

It is the articulation between the humerus of the arm and the scapula.

What is the Sternoclavicular Joint?

Occurs between proximal end of clavicle and Clavicular Notch of Manubrium of Sternum.

What type of joint is the Sternoclavicular Joint?

Synovial and saddle shaped.

What separates the articular cavity of the Sternoclavicular Joint?

An articular disc.

What movements are allowed by the Sternoclavicular Joint?

Anteroposterior and vertical planes, with some rotation.

What ligaments reinforce the Sternoclavicular Joint?

Anterior and Posterior Sternoclavicular Ligaments, Interclavicular Ligament, and Costoclavicular Ligament.

What does the Interclavicular Ligament do?

Links the ends of the two clavicles together and to the superior surface of the manubrium of the sternum.

What does the Costoclavicular Ligament do?

Links the proximal end of the clavicle to the first rib and related costal cartilage.

What is the Acromioclavicular Joint?

Synovial joint between an oval facet on medial surface of acromion and similar facet on acromial end of clavicle.

What movements are allowed by the Acromioclavicular Joint?

Anteroposterior and vertical planes, with some axial rotation.

What ligament reinforces the Acromioclavicular Joint?

Acromioclavicular Ligament superior to the joint and passing between adjacent regions of the clavicle and acromion.

What is the Coracoclavicular Ligament?

Provides weight-bearing support for the upper limb on the clavicle and maintains position of the clavicle on the acromion.

What is the structure of the Coracoclavicular Ligament?

It spans the distance between the coracoid process of the scapula and the inferior surface of the acromial end of the clavicle. It comprises an anterior Trapezoid Ligament and a posterior Conoid Ligament.

What is the Glenohumeral Joint?

It is a synovial ball and socket articulation between the head of the humerus and the glenoid cavity of the scapula.

What is the function of the Glenohumeral Joint?

It allows for a wide range of movements at the cost of skeletal stability. Joint stability is provided by rotator cuff muscles, long head of biceps brachii, related bony processes, and extracapsular ligaments.

What movements are possible at the Glenohumeral Joint?

Flexion, extension, abduction, adduction, medial rotation, lateral rotation, and circumduction.

What are the articular surfaces of the Glenohumeral Joint?

The large spherical head of the humerus and the small glenoid cavity of the scapula. Each surface is covered by hyaline cartilage.

What is the Glenoid Labrum?

It is a fibrocartilaginous collar that deepens and expands the glenoid cavity peripherally. It attaches to the margin of the fossa and is continuous with the tendon of the long head of the biceps brachii muscle.

Where does the superior part of the Glenoid Labrum attach?

It attaches to the margins of the articular surfaces and lines the fibrous membrane of the joint capsule.

What is the function of the synovial membrane in the Glenohumeral Joint?

It is loose inferiorly and helps to lubricate the joint and reduce friction.

What is the region that accommodates abduction of the arm?

Fibrous membrane

What are the synovial structures that reduce friction between tendons and adjacent joint capsule and bone?

Bursae

What is the most consistent bursa between the subscapularis muscle and fibrous membrane?

Subtendinous Bursa of the Subscapularis

Which bursa folds around the tendon of the long head of the biceps brachii muscle?

Bursa of the long head of the biceps brachii muscle

What is the function of the synovial structures?

To reduce friction between tendons and adjacent joint capsule and bone

What are the other bursae associated with the joint but not connected to it?

Subacromial or Subdeltoid Bursa, bursae between acromion and skin, bursae between coracoid process and joint capsule

Which muscles are associated with the bursae between acromion and supraspinatus muscles?

Supraspinatus muscles

Which muscles are associated with the bursae between coracoid process and joint capsule?

Coracobrachialis, teres major, long head of triceps, brachii, and latissimus dorsi muscles

Where does the fibrous membrane of the joint capsule attach on the glenoid cavity?

Margin of the glenoid cavity, outside the attachment of the glenoid labrum and long head of biceps brachii muscle

Where does the medial attachment of the fibrous membrane occur on the humerus?

More inferiorly than the neck and extends onto the shaft

What happens to the fibrous membrane in the anatomical position?

It is loose or folded

What does the area where the fibrous membrane is loose or folded accommodate?

Abduction of the arm

What are the openings in the fibrous membrane of the joint capsule?

Openings in the fibrous membrane provide continuity of the articular cavity with bursae.

What are the three locations where the fibrous membrane of the joint capsule is thickened?

The fibrous membrane is thickened anterosuperiorly to form the Superior, Middle, and Inferior Glenohumeral Ligaments.

Where do the Superior, Middle, and Inferior Glenohumeral Ligaments attach?

They pass from the superomedial margin of the glenoid cavity to the lesser tubercle and inferiorly related anatomical neck of the humerus.

What is the function of the Coracohumeral Ligament?

The Coracohumeral Ligament extends superiorly between the base of the coracoid process and the greater tubercle of the humerus.

What is the function of the Transverse Humeral Ligament?

The Transverse Humeral Ligament holds the tendon of the long head of the biceps muscle in the intertubercular sulcus.

What provides joint stability in the glenohumeral joint?

Joint stability is provided by surrounding muscle tendons and a skeletal arch formed by the coracoid process, acromion, and coracoid-acromial ligament.

What forms a musculotendinous collar around the glenohumeral joint?

The tendons of the rotator cuff muscles blend with the joint capsule to form a musculotendinous collar.

What is the function of the musculotendinous collar?

The musculotendinous collar stabilizes and holds the head of the humerus in the glenoid cavity without compromising flexibility and range of motion.

What is the function of the tendon of the long head of biceps brachii?

The tendon of the long head of biceps brachii restricts upward movement of the humeral head on the glenoid cavity.

What is the predominant vascular supply to the glenohumeral joint?

The vascular supply is predominantly through branches of the anterior and posterior circumflex humeral and suprascapular arteries.

What nerves innervate the glenohumeral joint?

Posterior cord of the brachial plexus, suprascapular, axillary, and lateral pectoral nerves