The shoulder and arm part 2

Question 1

Summarise the joints of the region

Answer 1

Sterno-clavicular joint
Acromio-clavicular joint
Gleno-Humeral joint (Shoulder joint)
Scapulo-thoracic joint (sometimes referred to as a “virtual” or “physiological” joint)
Elbow joint

The pectoral girdle = SCJ + ACJ + GHJ + STJ

Question 2

Which joints make up the pectoral girdle

Answer 2

The pectoral girdle = SCJ + ACJ + GHJ (arguable not part of pectoral girdle)+ STJ

Question 3

Describe the sternoclavicular joint

Answer 3

The sternoclavicular joint occurs between the proximal end of the clavicle and the clavicular notch of the manubrium of the sternum together with a small part of the first costal cartilage (Fig. 7.23). It is synovial and saddle shaped. The articular cavity is completely separated into two compartments by an articular disc. The sternoclavicular joint allows movement of the clavicle, predominantly in the anteroposterior and vertical planes, although some rotation also occurs.

Question 4

Describe the reinforcement of the sternoclavicular joint

Answer 4

The sternoclavicular joint is surrounded by a joint capsule and is reinforced by four ligaments:
▪
The anterior and posterior sternoclavicular ligaments are anterior and posterior, respectively, to the joint.
▪
An interclavicular ligament links the ends of the two clavicles to each other and to the superior surface of the manubrium of the sternum.
▪
The costoclavicular ligament is positioned laterally to the joint and links the proximal end of the clavicle to the first rib and related costal cartilage.

Question 5

Summarise the acromoclavicular joint

Answer 5

The acromioclavicular joint is a small synovial joint between an oval facet on the medial surface of the acromion and a similar facet on the acromial end of the clavicle (Fig. 7.24, also see Fig. 7.31). It allows movement in the anteroposterior and vertical planes together with some axial rotation.

Question 6

Describe the reinforcement of the acromioclavicular joint

Answer 6

The acromioclavicular joint is surrounded by a joint capsule and is reinforced by:
▪
a small acromioclavicular ligament superior to the joint and passing between adjacent regions of the clavicle and acromion, and
▪
a much larger coracoclavicular ligament, which is not directly related to the joint, but is an important strong accessory ligament, providing much of the weight-bearing support for the upper limb on the clavicle and maintaining the position of the clavicle on the acromion—it spans the distance between the coracoid process of the scapula and the inferior surface of the acromial end of the clavicle and comprises an anterior trapezoid ligament (which attaches to the trapezoid line on the clavicle) and a posterior conoid ligament (which attaches to the related conoid tubercle).

Question 7

Summarise the gleno-humeral joint

Answer 7

The glenohumeral joint is a synovial ball and socket articulation between the head of the humerus and the glenoid cavity of the scapula (Fig. 7.25). It is multiaxial with a wide range of movements provided at the cost of skeletal stability. Joint stability is provided, instead, by the rotator cuff muscles, the long head of the biceps brachii muscle, related bony processes, and extracapsular ligaments. Movements at the joint include flexion, extension, abduction, adduction, medial rotation, lateral rotation, and circumduction.

Question 8

What are the articular surfaces of the gleno-humeral joint

Answer 8

The articular surfaces of the glenohumeral joint are the large spherical head of the humerus and the small glenoid cavity of the scapula (Fig. 7.25). Each of the surfaces is covered by hyaline cartilage.

Question 9

What is the glenoid cavity expanded and deepened by

Answer 9

The glenoid cavity is deepened and expanded peripherally by a fibrocartilaginous collar (the glenoid labrum), which attaches to the margin of the fossa. Superiorly, this labrum is continuous with the tendon of the long head of the biceps brachii muscle, which attaches to the supraglenoid tubercle and passes through the articular cavity superior to the head of the humerus.

Question 10

Describe the synovial membrane of the gleno-humeral joint

Answer 10

The synovial membrane attaches to the margins of the articular surfaces and lines the fibrous membrane of the joint capsule (Fig. 7.26). The synovial membrane is loose inferiorly. This redundant region of synovial membrane and related fibrous membrane accommodates abduction of the arm.

Question 11

Describe the formation of bursa

Answer 11

The synovial membrane protrudes through apertures in the fibrous membrane to form bursae, which lie between the tendons of surrounding muscles and the fibrous membrane. The most consistent of these is the subtendinous bursa of the subscapularis, which lies between the subscapularis muscle and the fibrous membrane. The synovial membrane also folds around the tendon of the long head of the biceps brachii muscle in the joint and extends along the tendon as it passes into the intertubercular sulcus. All these synovial structures reduce friction between the tendons and adjacent joint capsule and bone.

Question 12

Describe other bursae that are associated with the GHJ but aren’t connected to it

Answer 12

In addition to bursae that communicate with the articular cavity through apertures in the fibrous membrane, other bursae are associated with the joint but are not connected to it. These occur:
▪
between the acromion (or deltoid muscle) and supraspinatus muscle (or joint capsule) (the subacromial or subdeltoid bursa),
▪
between the acromion and skin,
▪
between the coracoid process and the joint capsule, and
▪
in relationship to tendons of muscles around the joint (coracobrachialis, teres major, long head of triceps brachii, and latissimus dorsi muscles).

Question 13

Describe the fibrous membrane of the joint capsule

Answer 13

The fibrous membrane of the joint capsule attaches to the margin of the glenoid cavity, outside the attachment of the glenoid labrum and the long head of the biceps brachii muscle, and to the anatomical neck of the humerus
On the humerus, the medial attachment occurs more inferiorly than the neck and extends onto the shaft. In this region, the fibrous membrane is also loose or folded in the anatomical position. This redundant area of the fibrous membrane accommodates abduction of the arm.

Question 14

Describe the openings in the fibrous membrane

Answer 14

Openings in the fibrous membrane provide continuity of the articular cavity with bursae that occur between the joint capsule and surrounding muscles and around the tendon of the long head of the biceps brachii muscle in the intertubercular sulcus.

Question 15

Describe the thickenings of the fibrous membrane

Answer 15

The fibrous membrane of the joint capsule is thickened:
▪
anterosuperiorly in three locations to form superior, middle, and inferior glenohumeral ligaments, which pass from the superomedial margin of the glenoid cavity to the lesser tubercle and inferiorly related anatomical neck of the humerus (Fig. 7.27);
▪
superiorly between the base of the coracoid process and the greater tubercle of the humerus (the coracohumeral ligament); and
▪
between the greater and lesser tubercles of the humerus (transverse humeral ligament)—this holds the tendon of the long head of the biceps brachii muscle in the intertubercular sulcus

Question 16

What is stability of the GHJ provided by

Answer 16

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

Question 17

Describe the role of the rotator cuff muscles and biceps brachii in stabilising the GHJ

Answer 17

Tendons of the rotator cuff muscles (the supraspinatus, infraspinatus, teres minor, and subscapularis muscles) blend with the joint capsule and form a musculotendinous collar that surrounds the posterior, superior, and anterior aspects of the glenohumeral joint (Figs. 7.28 and 7.29). This cuff of muscles stabilizes and holds the head of the humerus in the glenoid cavity of the scapula without compromising the arm’s flexibility and range of motion. The tendon of the long head of the biceps brachii muscle passes superiorly through the joint and restricts upward movement of the humeral head on the glenoid cavity.

Question 18

Describe the blood supply and innervation of the GHJ

Answer 18

Vascular supply to the glenohumeral joint is predominantly through branches of the anterior and posterior circumflex humeral and suprascapular arteries.
The glenohumeral joint is innervated by branches from the posterior cord of the brachial plexus, and from the suprascapular, axillary, and lateral pectoral nerves.

Question 19

What structure is found between the superior surface of the humerus and the inferior surface of the acromion?

Answer 19

Subacromial bursa

Question 20

What type of joint is the GHJ

Answer 20

Ball-and-socket synovial joint.
The glenoid fossa (the socket) is shallow, but slightly deepened by a cartilaginous labrum. However, muscles required for joint stability. (eg. Rotator cuff group

Question 21

What does the joint capsule consist of

Answer 21

The fibrous capsule and the synovial membrane

Question 22

Describe the relationship between the rotator cuff and the GHJ

Answer 22

Main function is to hold the humeral head within the glenoid

The rotator cuff depresses the humeral head

Question 23

Summarise the movements of the shoulder joint and the muscles involved

Answer 23

Abduction: swing arm up - deltoid and supraspinatus contraction
Adduction: swing arm down - pectoralis major, teres major, latissimus dorsi and triceps contraction
Flexion: swing arm forward - pectoralis major and deltoid contraction (also coracobrachialis)
Extension: swing arm backwards - deltoid, teres major, latissimus dorsi and triceps contraction
Lateral rotation: thumb out - deltoid, teres minor and infraspinatus contraction
Medial rotation: thumb in - deltoid, pectoralis major, teres major and latissimus dorsi contraction (also subscapularis)

Question 24

Describe the movements of the scapula-thoracic joint

Answer 24

Elevation / Depression of the scapula
Protraction / Retraction of the scapula
Rotation of the scapula

Question 25

Explain why the GHJ is succeptible to dislocation

Answer 25

The glenohumeral joint is extremely mobile, providing a wide range of movement at the expense of stability. The relatively small bony glenoid cavity, supplemented by the less robust fibrocartilaginous glenoid labrum and the ligamentous support, make it susceptible to dislocation.

Question 26

Describe anterior dislocations of the GHJ

Answer 26

Anterior dislocation (Fig. 7.32) occurs most frequently and is usually associated with an isolated traumatic incident (clinically, all anterior dislocations are anteroinferior). In some cases, the anteroinferior glenoid labrum is torn with or without a small bony fragment. Once the joint capsule and cartilage are disrupted, the joint is susceptible to further (recurrent) dislocations. When an anteroinferior dislocation occurs, the axillary nerve may be injured by direct compression of the humeral head on the nerve inferiorly as it passes through the quadrangular space. Furthermore, the “lengthening” effect of the humerus may stretch the radial nerve, which is tightly bound within the radial groove, and produce a radial nerve paralysis. Occasionally, an anteroinferior dislocation is associated with a fracture, which may require surgical reduction.

Question 27

Describe posterior dislocation of the GHJ

Answer 27

Posterior dislocation is extremely rare; when seen, the clinician should focus on its cause, the most common being extremely vigorous muscle contractions, which may be associated with an epileptic seizure caused by electrocution.

Question 28

Summarise the axilla

Answer 28

The gateway for nerves and blood vessels to enter and leave the upper limb Shaped like a pyramid Contains: Arteries – axillary artery and its branches Veins – axillary vein and its tributaries Lymphatic vessels and lymph nodes (important!) Nerves – the brachial plexus

Question 29

What is the axilla formed by

Answer 29

``` The axilla is the gateway to the upper limb, providing an area of transition between the neck and the arm (Fig. 7.40A). Formed by the clavicle, the scapula, the upper thoracic wall, the humerus, and related muscles, the axilla is an irregularly shaped pyramidal space with: ▪ four sides, ▪ an inlet, and ▪ a floor (base) ``` Essentially, the axilla is the transition between the shoulder and the arm

Question 30

How do structures pass through the axilla

Answer 30

The axillary inlet is continuous superiorly with the neck, and the lateral part of the floor opens into the arm. All major structures passing into and out of the upper limb pass through the axilla (Fig. 7.40C). Apertures formed between muscles in the anterior and posterior walls enable structures to pass between the axilla and immediately adjacent regions (the posterior scapular, pectoral, and deltoid regions).

Question 31

Describe the shape and formation of the axillary inlet

Answer 31

The axillary inlet is oriented in the horizontal plane and is somewhat triangular in shape, with its apex directed laterally (Fig. 7.40A,B). The margins of the inlet are completely formed by bone: ▪ The medial margin is the lateral border of rib I. ▪ The anterior margin is the posterior surface of the clavicle. ▪ The posterior margin is the superior border of the scapula up to the coracoid process. The apex of the triangularly shaped axillary inlet is lateral in position and is formed by the medial aspect of the coracoid process.

Question 32

Describe the structures that pass through the axillary inlet

Answer 32

Major vessels and nerves pass between the neck and the axilla by crossing over the lateral border of rib I and through the axillary inlet (Fig. 7.40A). The subclavian artery, the major blood vessel supplying the upper limb, becomes the axillary artery as it crosses the lateral margin of rib I and enters the axilla. Similarly, the axillary vein becomes the subclavian vein as it passes over the lateral margin of rib I and leaves the axilla to enter the neck. At the axillary inlet, the axillary vein is anterior to the axillary artery, which, in turn, is anterior to the trunks of the brachial plexus.

Question 33

Which structures are found overlying rib 1

Answer 33

The inferior trunk (lower trunk) of the brachial plexus lies directly on rib I in the neck, as does the subclavian artery and vein. As they pass over rib I, the vein and artery are separated by the insertion of the anterior scalene muscle

Question 34

Describe the boundaries of the axilla

Answer 34

Anterior wall- The anterior wall of the axilla is formed by the lateral part of the pectoralis major muscle, the underlying pectoralis minor and subclavius muscles, and the clavipectoral fascia Medial wall- The medial wall of the axilla consists of the upper thoracic wall (the ribs (4th rib) and related intercostal tissues) and the serratus anterior muscle Lateral wall- The lateral wall of the axilla is narrow and formed entirely by the intertubercular sulcus of the humerus (Fig. 7.44). The pectoralis major muscle of the anterior wall attaches to the lateral lip of the intertubercular sulcus. The latissimus dorsi and teres major muscles of the posterior wall attach to the floor and medial lip of the intertubercular sulcus, respectively Posterior wall- The posterior wall of the axilla is complex (Fig. 7.45 and see Fig. 7.50). Its bone framework is formed by the costal surface of the scapula. Muscles of the wall are: ▪ the subscapularis muscle (associated with the costal surface of the scapula), ▪ the distal parts of the latissimus dorsi and teres major muscles (which pass into the wall from the back and posterior scapular region), and ▪ the proximal part of the long head of the triceps brachii muscle (which passes vertically down the wall and into the arm).

Question 35

Describe the floor of the axilla

Answer 35

The floor of the axilla is formed by fascia and a dome of skin that spans the distance between the inferior margins of the walls (Fig. 7.47 and see Fig. 7.40B). It is supported by the clavipectoral fascia. On a patient, the anterior axillary fold is more superior in position than is the posterior axillary fold. Inferiorly, structures pass into and out of the axilla immediately lateral to the floor where the anterior and posterior walls of the axilla converge and where the axilla is continuous with the anterior compartment of the arm.

Question 36

Summarise the arteries of the region

Answer 36

``` Subclavian artery passes over the first rib to become… Axillary artery at the lower border of teres major becomes the… Brachial artery Gives off a large branch in the arm – profunda brachii Divides as the level of the elbow into… Ulnar and Radial arteries ```

Question 37

Describe the different parts of the axillary artery

Answer 37

The subclavian artery in the neck becomes the axillary artery at the lateral margin of rib I and passes through the axilla, becoming the brachial artery at the inferior margin of the teres major muscle. The axillary artery is separated into three parts by the pectoralis minor muscle, which crosses anteriorly to the vessel (Fig. 7.49): ▪ The first part is proximal to the pectoralis minor. ▪ The second part is posterior to the pectoralis minor. ▪ The third part is distal to the pectoralis minor.

Question 38

Describe the 6 branches of the axillary artery

Answer 38

Generally, six branches arise from the axillary artery: ▪ One branch, the superior thoracic artery, originates from the first part. ▪ Two branches, the thoraco-acromial artery and the lateral thoracic artery, originate from the second part. ▪ Three branches, the subscapular artery, the anterior circumflex humeral artery, and the posterior circumflex humeral artery, originate from the third part

Question 39

Describe the superior thoracic artery

Answer 39

The superior thoracic artery is small and originates from the anterior surface of the first part of the axillary artery (Fig. 7.50). It supplies upper regions of the medial and anterior axillary walls.

Question 40

Describe the thoraco-acromial artery

Answer 40

The thoraco-acromial artery is short and originates from the anterior surface of the second part of the axillary artery just posterior to the medial (superior) margin of the pectoralis minor muscle (Fig. 7.50). It curves around the superior margin of the muscle, penetrates the clavipectoral fascia, and immediately divides into four branches—the pectoral, deltoid, clavicular, and acromial branches, which supply the anterior axillary wall and related regions. Additionally, the pectoral branch contributes vascular supply to the breast, and the deltoid branch passes into the clavipectoral triangle where it accompanies the cephalic vein and supplies adjacent structures

Question 41

Describe the lateral thoracic artery

Answer 41

The lateral thoracic artery arises from the anterior surface of the second part of the axillary artery posterior to the lateral (inferior) margin of the pectoralis minor (Fig. 7.50). It follows the margin of the muscle to the thoracic wall and supplies the medial and anterior walls of the axilla. In women, branches emerge from around the inferior margin of the pectoralis major muscle and contribute to the vascular supply of the breast.

Question 42

Which muscles are found in the axilla

Answer 42

Muscles: biceps brachii (supraglenoid tubercle/coracoid process - radial tuberosity) and coracobrachalis (Coracoid process - humerus midshaft)

Question 43

Describe the subscapular branch of the axillary artery

Answer 43

The subscapular artery is the largest branch of the axillary artery and is the major blood supply to the posterior wall of the axilla (Fig. 7.50). It also contributes to the blood supply of the posterior scapular region. The subscapular artery originates from the posterior surface of the third part of the axillary artery, follows the inferior margin of the subscapularis muscle for a short distance, and then divides into its two terminal branches, the circumflex scapular artery and the thoracodorsal artery.

Question 44

Describe the branches of the subscapular artery

Answer 44

The circumflex scapular artery passes through the triangular space between the subscapularis, teres major, and long head of the triceps muscle. Posteriorly, it passes inferior to, or pierces, the origin of the teres minor muscle to enter the infraspinous fossa. It anastomoses with the suprascapular artery and the deep branch (dorsal scapular artery) of the transverse cervical artery, thereby contributing to an anastomotic network of vessels around the scapula. ▪ The thoracodorsal artery approximately follows the lateral border of the scapula to the inferior angle. It contributes to the vascular supply of the posterior and medial walls of the axilla.

Question 45

Describe the anterior circumflex humeral artery

Answer 45

The anterior circumflex humeral artery is small compared to the posterior circumflex humeral artery, and originates from the lateral side of the third part of the axillary artery (Fig. 7.50). It passes anterior to the surgical neck of the humerus and anastomoses with the posterior circumflex humeral artery. This anterior circumflex humeral artery supplies branches to surrounding tissues, which include the glenohumeral joint and the head of the humerus.

Question 46

Describe the posterior circumflex humeral artery

Answer 46

The posterior circumflex humeral artery originates from the lateral surface of the third part of the axillary artery immediately posterior to the origin of the anterior circumflex humeral artery (Fig. 7.50). With the axillary nerve, it leaves the axilla by passing through the quadrangular space between the teres major, teres minor, and long head of the triceps brachii muscle and the surgical neck of the humerus. The posterior circumflex humeral artery curves around the surgical neck of the humerus and supplies the surrounding muscles and the glenohumeral joint. It anastomoses with the anterior circumflex humeral artery and with branches from the profunda brachii, suprascapular, and thoraco-acromial arteries.

Question 47

Describe the divisions of the subclavian artery as it passes into the axilla and down the arm.

Answer 47

As the subclavian artery passes over the first rib it becomes the axillary artery The axillary artery then becomes the brachial artery as it passes the inferior border of teres major The brachial artery has an important branch - profundi brachii Brachial artery then divides into radial and ulnar arteries at the level of the elbow

Question 48

Describe the passage of the brachial artery in the arm

Answer 48

In the proximal arm, the brachial artery lies on the medial side. In the distal arm, it moves laterally to assume a position midway between the lateral epicondyle and the medial epicondyle of the humerus. It crosses anteriorly to the elbow joint where it lies immediately medial to the tendon of the biceps brachii muscle. The brachial artery is palpable along its length. In proximal regions, the brachial artery can be compressed against the medial side of the humerus.

Question 49

Summarise the branches of the brachial artery

Answer 49

Branches of the brachial artery in the arm include those to adjacent muscles and two ulnar collateral vessels, which contribute to a network of arteries around the elbow joint (Fig. 7.66B). Additional branches are the profunda brachii artery and nutrient arteries to the humerus, which pass through a foramen in the anteromedial surface of the humeral shaft.

Question 50

Describe the profundal brachii artery

Answer 50

The profunda brachii artery, the largest branch of the brachial artery, passes into and supplies the posterior compartment of the arm (Fig. 7.66A,B). It enters the posterior compartment with the radial nerve and together they pass through the triangular interval, which is formed by the shaft of the humerus, the inferior margin of the teres major muscle, and the lateral margin of the long head of the triceps muscle. They then pass along the radial groove on the posterior surface of the humerus deep to the lateral head of the triceps brachii muscle.

Question 51

Describe the branches of the profunda brachii artery

Answer 51

Branches of the profunda brachii artery supply adjacent muscles and anastomose with the posterior circumflex humeral artery. The artery terminates as two collateral vessels, which contribute to an anastomotic network of arteries around the elbow joint

Question 52

Describe the arteries and veins in the posterior scapula region

Answer 52

Three major arteries are found in the posterior scapular region: the suprascapular, posterior circumflex humeral, and circumflex scapular arteries. These arteries contribute to an interconnected vascular network around the scapula

Question 53

Describe the suprascapular artery

Answer 53

The suprascapular artery originates in the base of the neck as a branch of the thyrocervical trunk, which, in turn, is a major branch of the subclavian artery (Figs. 7.38 and 7.39). The vessel may also originate directly from the third part of the subclavian artery. The suprascapular artery normally enters the posterior scapular region superior to the suprascapular foramen, whereas the nerve passes through the foramen. In the posterior scapular region, the vessel runs with the suprascapular nerve. In addition to supplying the supraspinatus and infra­spinatus muscles, the suprascapular artery contributes branches to numerous structures along its course.

Question 54

Summarise the veins of the region

Answer 54

In limbs, venous return is via superficial and deep vessels Cephalic vein (superficial) runs up lateral border of arm Basilic vein (superficial) runs up the medial border of arm Basilic veins joins venae comitantes to form the axillary vein in the arm Cephalic vein joins axillary vein in the axilla Axillary vein becomes the subclavian vein at the level of the first rib

Question 55

Describe the importance of anastomoses in the posterior scapular region

Answer 55

Lots of muscles acting there- may squeeze and compress vessels- so need anastomoses to maintain an adequate supply.

Question 56

Summarise the axillary vein

Answer 56

The axillary vein begins at the lower margin of the teres major muscle and is the continuation of the basilic vein (Fig. 7.51), which is a superficial vein that drains the posteromedial surface of the hand and forearm and penetrates the deep fascia in the middle of the arm.

Question 57

Describe the passage of the axillary vein in the axilla

Answer 57

The axillary vein passes through the axilla medial and anterior to the axillary artery and becomes the subclavian vein as the vessel crosses the lateral border of rib I at the axillary inlet. Tributaries of the axillary vein generally follow the branches of the axillary artery. Other tributaries include brachial veins that follow the brachial artery, and the cephalic vein.

Question 58

Describe the passage of the cephalic vein

Answer 58

The cephalic vein is a superficial vein that drains the lateral and posterior parts of the hand, the forearm, and the arm. In the area of the shoulder, it passes into an inverted triangular cleft (the clavipectoral triangle) between the deltoid muscle, pectoralis major muscle, and clavicle. In the superior part of the clavipectoral triangle, the cephalic vein passes deep to the clavicular head of the pectoralis major muscle and pierces the clavipectoral fascia to join the axillary vein. Many patients who are critically unwell have lost blood or fluid, which requires replacement. Access to a peripheral vein is necessary to replace the fluid. The typical sites for venous access are the cephalic vein in the hand or veins that lie within the superficial tissues of the cubital fossa.

Question 59

Describe the superficial venous anatomy of the arm

Answer 59

There is are two main superficial veins: cephalic (lateral) and basilic (medial) Above the elbow the basilic vein joins the venae comitantes of the brachial artery to form the axillary vein- basillic vein goes deep The cephalic vein drains into the axillary vein more superiorly (passes through delto-pectoral groove)

Question 60

Describe the consequences of rib 1 fracture

Answer 60

As the subclavian artery passes out of the neck and into the axilla, it is fixed in position by the surrounding muscles to the superior surface of rib I. A rapid deceleration injury involving upper thoracic trauma may cause a first rib fracture, which may significantly compromise the distal part of the subclavian artery or the first part of the axillary artery. Fortunately, there are anastomotic connections between branches of the subclavian artery and the axillary artery, which form a network around the scapula and proximal end of the humerus; therefore, even with complete vessel transection, the arm is rarely rendered completely ischemic (ischemia is poor blood supply to an organ or a limb).

Question 61

Describe the consequences of anterior dislocation of the head of the humerus

Answer 61

Anterior dislocation of the humeral head may compress the axillary artery, resulting in vessel occlusion. This is unlikely to render the upper limb completely ischemic, but it may be necessary to surgically reconstruct the axillary artery to obtain pain-free function. Importantly, the axillary artery is intimately related to the brachial plexus, which may be damaged at the time of anterior dislocation.

Question 62

Which small vein joins the cephalic and basilic veins in the cubital fossa?

Answer 62

Median cubital vein

Question 63

Describe the deep venous system of the arm

Answer 63

The follow the arteries back as venae commitantes | Subclavian vein: formed from axillary vein at level of first rib

Question 64

Where do all lymphatics from the upper limb drain to

Answer 64

All lymphatics from the upper limb drain into lymph nodes in the axilla

Question 65

Where else do the axillary nodes receive drainage from

Answer 65

In addition, axillary nodes receive drainage from an extensive area on the adjacent trunk, which includes regions of the upper back and shoulder, the lower neck, the chest, and the upper anterolateral abdominal wall. Axillary nodes also receive drainage from approximately 75% of the mammary gland.

Question 66

What ae the groups of lymph nodes found in the shoulder and arm

Answer 66

Cubital lymph nodes Delto-pectoral lymph nodes Axillary lymph nodes

Question 67

What is quadrangular space syndrome

Answer 67

Hypertrophy of the quadrangular space muscles or fibrosis of the muscle edges may impinge on the axillary nerve. Uncommonly, this produces weakness of the deltoid muscle. Typically it produces atrophy of the teres minor muscle, which may affect the control that the rotator cuff muscles exert on shoulder movement.

Question 68

What 3 spaces are formed by the long heads of the triceps trachii in the axilla

Answer 68

The long head of the triceps brachii muscle passes vertically through the posterior wall of the axilla, and, together with surrounding muscles and adjacent bones, results in the formation of three apertures through which major structures pass through the posterior wall: ▪ the quadrangular space, ▪ the triangular space, and ▪ the triangular interval

Question 69

What is the quadrangular space

Answer 69

The quadrangular space provides a passageway for nerves and vessels passing between the axilla and the more posterior scapular and deltoid regions (Fig. 7.45). When viewed from anteriorly, its boundaries are formed by: ▪ the inferior margin of the subscapularis muscle, ▪ the surgical neck of the humerus, ▪ the superior margin of the teres major muscle, and ▪ the lateral margin of the long head of the triceps brachii muscle. Passing through the quadrangular space are the axillary nerve and the posterior circumflex humeral artery and vein.

Question 70

What is the triangular space

Answer 70

The triangular space is an area of communication between the axilla and the posterior scapular region (Fig. 7.45). When viewed from anteriorly, it is formed by: ▪ the medial margin of the long head of the triceps brachii muscle, ▪ the superior margin of the teres major muscle, and ▪ the inferior margin of the subscapularis muscle. The circumflex scapular artery and vein pass into this space.

Question 71

What is the triangular interval

Answer 71

This triangular interval is formed by: ▪ the lateral margin of the long head of the triceps brachii muscle, ▪ the shaft of the humerus, and ▪ the inferior margin of the teres major muscle (Fig. 7.45). The radial nerve passes out of the axilla traveling through this interval to reach the posterior compartment of the arm.

Question 72

What covers the vessels and nerves running through the axilla

Answer 72

Axillary Sheath

Question 73

What are the contents of the axilla

Answer 73

The proximal parts of the biceps brachii and coracobrachialis muscles pass through the axilla Axilllary artery Axillary Vein the axillary process of the breast, and collections of lymph nodes, which drain the upper limb, chest wall, and breast.

Question 74

Describe the relationship between the axillary vein and artery

Answer 74

The axillary vein passes through the axilla medial and anterior to the axillary artery and becomes the subclavian vein as the vessel crosses the lateral border of rib I at the axillary inlet. Tributaries of the axillary vein generally follow the branches of the axillary artery. Other tributaries include brachial veins that follow the brachial artery, and the cephalic vein.

Question 75

Describe how the cephalic vein joins to the axillary vein and its clinical significance

Answer 75

The cephalic vein is a superficial vein that drains the lateral and posterior parts of the hand, the forearm, and the arm. In the area of the shoulder, it passes into an inverted triangular cleft (the clavipectoral triangle) between the deltoid muscle, pectoralis major muscle, and clavicle. In the superior part of the clavipectoral triangle, the cephalic vein passes deep to the clavicular head of the pectoralis major muscle and pierces the clavipectoral fascia to join the axillary vein. Many patients who are critically unwell have lost blood or fluid, which requires replacement. Access to a peripheral vein is necessary to replace the fluid. The typical sites for venous access are the cephalic vein in the hand or veins that lie within the superficial tissues of the cubital fossa.

Question 76

List the lymph nodes in the axillary region

Answer 76

20-30 lymph nodes- divided into 5 groups: ``` Humeral (lateral) nodes Pectoral (anterior) nodes Subscapular (posterior) nodes Central nodes Apical nodes ```

Question 77

Describe how the lymphatics joint to the venous system

Answer 77

Efferent vessels from the apical group converge to form the subclavian trunk, which usually joins the venous system at the junction between the right subclavian vein and the right internal jugular vein in the neck. On the left, the subclavian trunk usually joins the thoracic duct in the base of the neck.

Question 78

Describe the relationship between lymph nodes and breast cancer

Answer 78

Lymphatic drainage from the lateral part of the breast passes through nodes in the axilla. Significant disruption to the normal lymphatic drainage of the upper limb may occur if a mastectomy or a surgical axillary nodal clearance has been carried out for breast cancer. Furthermore, some patients have radiotherapy to the axilla to prevent the spread of metastatic disease, but a side effect of this is the destruction of the tiny lymphatics as well as the cancer cells. If the lymphatic drainage of the upper limb is damaged, the arm may swell and pitting edema (lymphedema) may develop.

Question 79

Which two nerves are found near the axilllary lymph nodes

Answer 79

Long thoracic nerve | Thoraco-dorsal nerve

Question 80

Summarise the lymphatics of the shoulder and arm

Answer 80

Superficial and deep systems, run with veins Cubital lymph nodes Axillary nodes are also draining nodes for the distal parts of the upper limb