Anatomy - Ch. 5 Humerus and Shoulder Girdle (tori)

The humerus

is the largest and longest bone of the upper limb.

- Its length on an adult equal approximately one-fifth of body height.

- articulates with the scapula (shoulder blade) at the shoulder joint.

The proximal humerus

is the part of the upper arm that articulates with the scapula, making up the shoulder joint.

- The most proximal part is the rounded head of the humerus.

anatomic neck of humerus

The slightly constricted area directly below and lateral to the head

- appears as a line of demarcation between the rounded head and the adjoining greater and lesser tubercles.

lesser tubercle

The process directly below the anatomic neck on the anterior surface of the humerus

greater tubercle

The larger lateral process of the humerus

- pectoralis major and supraspinatus muscles attach.

intertubercular groove

The deep groove between these two tubercles

surgical neck of humerus

The tapered area below the head and tubercles

- distal is the long body of the humerus.

- named because it is the site of frequent fractures requiring surgery

The deltoid tuberosity

is the roughened raised triangular elevation along the anterolateral surface of the body (shaft) to which the deltoid muscle is attached.

The shoulder girdle

consists of two bones: the clavicle and the scapula

- The function of the clavicle and scapula is to connect each upper limb to the trunk or axial skeleton. - Anteriorly: the shoulder girdle connects to the trunk at the upper sternum.

posteriorly: the connection to the trunk is incomplete because the scapula is connected to the trunk by muscles only.

- Each _____ and each upper limb connect at the shoulder joint between the scapula and the humerus.

The clavicle (collarbone)

is a long bone with a double curvature that has three main parts: two ends and a long central portion

- located over the upper anterior rib cage

- the female ___ is usually shorter and less curved than the male ___

Clavicle AP axial view

angle 15-20 degrees cephalad to get an unobstructed view of the clavicle

acromial extremity of clavicle

lateral end of clavicle

- flattened and has a downward curvature at its attachment with the acromion

acromioclavicular joint

the joint where the acromion and the clavicle meet

- generally can be readily palpated

- small synovial joint of the plane(gliding) movement

- The primary movement is a gliding action between the end of the clavicle and the acromion.

- secondary movement also occurs as the scapula moves forward and backward with the clavice. This movement allows the scapula to adjust its position as it remains in close contact with the posterior chest wall.

sternal extremity of clavicle

bulbous medial end of clavicle.

- more triangular in shape, broader, and is directed downward.

- Articulates with the manubrium, which is the upper part of the sternum.

sternoclavicular joint

Joint between sternum and clavicle.

- is easily palpated,

- the combination of both joints on either side of the manubrium helps to form an important positioning landmark called the jugular notch.

- double plane, or gliding, joint

The scapula

forms the posterior part of the shoulder girdle

- is a flat triangular bone with three borders, three angles, and two surfaces

- upper margin of the scapula is at the level of the second posterior rib

- lower margin is at the level of the seventh posterior rib (T7)

Most superior part of the scapula

acromion process

Most anterior part of the scapula

coracoid process

most posterior of the scapula

the spine

medial border of the scapula

the long edge or border near the vertebrae

superior border of scapula

the uppermost margin of the scapula

lateral border

the border nearest the axilla

lateral angle

sometimes called the head of the scapula

- is the thickest part and ends laterally in a shallow depression called the glenoid fossa.

scapulohumeral joint (shoulder joint)

humeral head articulates with the glenoid cavity of the scapula

- ball-and-socket (spheroidal) joint, which allows great freedom of movement.

- These movements include flexion, extension, abduction, adduction, circumduction, and medial (internal) and lateral rotation

Grashey View of shoulder

To see glenoid fossa

The body (blade) of the scapula

is arched for greater strength.

- The thin, flat, lower part of sometimes is referred to as the wing or ala of the scapula

costal surface

The anterior surface of the scapula

- named this because of its proximity to the ribs

subscapular fossa

The middle area of the costal surface presents a large concavity or depression, known as the ____

The acromion

is a long, curved process that extends laterally over the head of the humerus.

- overhangs the shoulder joint posteriorly.

- expanded distal end of the spine that extends superiorly and posteriorly to the Glenoid fossa

coracoid process

is a thick, beaklike process that projects anteriorly beneath the clavicle.

- Located more anteriorly in relationship to the glenoid fossa

The suprascapular notch

is a notch on the superior border that is partially formed by the base of the coracoid process.

spine of scapula

prominent structure on the dorsal, or posterior, surface of the scapula

- starts at the vertebral border as a smooth triangular area and continues laterally to end at the acromion.

- The ridge is thickened and is termed the crest

- separates the posterior surface into an infraspinous fossa and a supraspinous fossa.

The lateral view of the scapula

- demonstrates relative positions of the various parts of the scapula

- The thin scapula looks like the letter Y in this position.

- The upper parts of the Y are the acromion and the coracoid process.

- The lower portion of the Y is the body of the scapula.

- Acromion and coracoid processes in profile

- Humeral head and glenoid cavity superimposed

inferosuperior Axial Projection

This projection results in a lateral view of the head and neck of the humerus.

- it also demonstrates the relationship of the humerus to the glenoid cavity which makes up the scapulohumeral joint

Joints of the shoulder girdle

sternoclavicular, acromioclavicular, scapulohumeral

- synovial

- diarthrodial

- Dislocations at the shoulder joint occur more frequently than at any other joint in the body.

The glenoid cavity

is very shallow, allowing the greatest freedom in mobility of any joint in the human body but at some expense to its strength and stability.

RADIOGRAPHS OF THE PROXIMAL HUMERUS

commonly taken on non-trauma patients when gross fractures or dislocations of the humerus have been ruled out.

- delineate well the scapulohumeral joint

- revealing possible calcium deposits or other pathology.

- Note specifically the location and shapes of the greater tubercle and the lesser tubercule on these external, internal, and neutral rotation radiographs

- By studying the position and relationships of the greater and lesser tubercles on a radiograph of the shoulder, you can determine the rotational position of the arm.

The external rotation position of the proximal humerus

represents a true AP projection of the humerus in the anatomic position, as determined by the epicondyles of the distal humerus.

- Positioning requires supination of the hand and external rotation of the elbow so that the entepicondylar line is parallel to the image receptor (IR)

- the greater tubercle is now seen laterally in profile.

- The lesser tubercle is located anteriorly, just medial to the greater tubercle.

the internal rotation position of the proximal humerus

- the hand and arm are rotated internally until the epicondyles of the distal humerus are perpendicular to the IR, placing the humerus in a true lateral position.

- The hand must be pronated and the elbow adjusted to place the epicondyles perpendicular to the IR

- a lateral position of the proximal humerus in which the greater tubercle now is rotated around to the anterior and medial aspect of the proximal humerus.

- The lesser tubercle is seen in profile medially.

Neutral rotation position of the proximal humerus

- is appropriate for a trauma patient when rotation of the part is unacceptable.

- The epicondyles of the distal humerus appear at an approximate 45° angle to the IR.

- A 45° oblique position of the humerus results when the palm of the hand is facing inward toward the thigh.

- is approximately midway between the external and internal positions

- greater tubercle & lesser tubercle not in profile

AC joint separation

refers to trauma to the upper shoulder region resulting in a partial or complete tear of the AC or coracoclavicular (CC) ligament or both ligaments.

- represent nearly half of all athletic shoulder injuries, often resulting from a fall onto the tip of the shoulder with the arm in adduction.

Currently there are six classifications, ranging from a sprain to a complete separation of the distal clavicle from acromion as a result of ligament tears.

Acromioclavicular dislocation

refers to an injury in which the distal clavicle usually is displaced superiorly.

- This injury most commonly is caused by a fall and is more common in children than adults.

Bankart lesion

is an injury of the anteroinferior aspect of the glenoid labrum.

- This type of injury often is caused by anterior dislocation of the proximal humerus.

- Repeated dislocation may result in a small avulsion fracture in the anteroinferior region of the glenoid rim.

Bursitis

is an inflammation of the bursae, or fluid-filled sacs enclosing the joints.

- The shoulder is the most common joint to develop bursitis, with repetitive motion being the most common cause.

- However, trauma, rheumatoid arthritis, and infection can also produce bursitis.

- It generally involves the formation of calcification in associated tendons, causing pain and limitation of joint movement.

Hill-Sachs defect

is a compression fracture of the articular surface of the posterolateral aspect of the humeral head that often is associated with an anterior dislocation of the humeral head.

Idiopathic chronic adhesive capsulitis

(frozen shoulder) is a disability of the shoulder joint that is caused by chronic inflammation in and around the joint.

- It is characterized by pain and limitation of motion. (Idiopathic means of unknown cause.)

Impingement syndrome

is impingement of the greater tuberosity and soft tissues on the coracoacromial ligamentous and osseous arch, generally during abduction of the arm.

Osteoarthritis, also called degenerative joint disease (DJD)

is a noninflammatory joint disease characterized by gradual deterioration of the articular cartilage with hypertrophic bone formation.

- is the most common type of arthritis and is considered part of the normal aging process.

- It generally occurs in persons older than 50 years, chronically bariatric persons, and athletes.

Osteoporosis

and resultant fractures are to the result of a reduction in the quantity of bone or atrophy of skeletal tissue.

- occurs in postmenopausal women and elderly men, resulting in bony trabeculae that are scanty and thin.

- Most fractures sustained by women older than 50 years are related to ____.

Rheumatoid arthritis (RA)

is a chronic systemic disease characterized by inflammatory changes that occur throughout the connective tissues of the body.

- The inflammation begins in synovial membranes and can later involve the articular cartilage and bony cortex.

- occurs more frequently in women than men.

- Radiographic evidence of ___ includes loss of joint space, destruction cortical bone and bony deformity.

Rotator cuff pathology

is an acute or a chronic traumatic injury to one or more of the rotator cuff muscles: teres minor, supraspinatus, infraspinatus, and subscapularis.

- limit the range of motion of the shoulder.

- The most common injury of the rotator cuff is impingement of the supraspinatus tendon as it passes beneath the acromion, caused by a subacromial bone spur.

- Repeated irritation associated with the bone spur can lead to a partial or complete tear of the supraspinatus tendon, as evident on MRI and sonographic examination of the shoulder

Shoulder dislocation

is traumatic removal of the humeral head from the glenoid cavity.

- 95% are anterior, in which the humeral head is projected anterior to the glenoid cavity.

Tendonitis

is an inflammatory condition of the

tendon that usually results from a strain.

CT

evaluate soft tissue and skeletal involvement of lesions and soft tissue injuries

- determining the extent of fracture

MRI

evaluate soft tissue and skeletal involvement of lesions and soft tissue injuries

- Diagnosis of rotator cuff injuries

Nuclear medicine

useful in demonstrating osteomyelitis, metastatic bone lesions, and cellulitis.

Ultrasound

is useful for musculoskeletal imaging of joints such as the shoulder to evaluate soft tissues within the joint for possible rotator cuff tears; bursa injuries; or disruption and damage to nerves, tendons, or ligaments.

- also allows for dynamic evaluation during joint movement.