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Flashcards in UL Joints Deck (17):

Sternoclavicular joint

• Medial end of clavicle and sternum
• Saddle type of synovial
• Costoclavicular and sternoclavicular are important ligaments
• Can compress trachea if dislocated


Acromioclavicular joint (ACJ)

• Lateral end of clavicle and acromion of scapula
• Plane type of synovial
• Coracoacromial ligament and Coracoclavicular ligament are important ligaments
• Shoulder separation: ACJ is dislocated and coracoclavicular ligaments are torn


Shoulder joint

• Head of the humerus and glenoid cavity
• Ball and Socket type of synovial
• ligaments: Fibrous capsule, Glenohumeral ligament (superior, middle & inferior), transverse humeral, coracohumeral ligaments, glenoidal labrum
• Muscular rotator cuff muscles keep the head opposed to the glenoid cavity
• Subscapular bursa is continuous with the joint.
• Subacromial (subdeltoid) bursa is not communicated with the joint.
• Movements of the shoulder joint: Flexion, Extension, Adduction, Abduction, medial rotation, lateral rotation,curcumduction

Muscles producing the movements:
• Flexion-Pectoralis major (clavicular head), Deltoid (anterior part), Coracobrachialis assisted biceps
• Extension: Deltoid (posterior part), Teres major, Latissimus dorsi, long head of triceps
• Abduction: supraspinatus (0-15 degree) supraspinatus initiates abduction, Deltoid (15-90 degrees), Trapezius and serratus anterior (above 90 degrees, overhead abduction)
• Adduction: Pectoralis major, Latissimus dorsi, subscapularis, infraspinatus and teres minor
• Medial rotation: subscapularis, pectoralis major, deltoid (ant. Fibers) latissimus dorsi
• Lateral rotation: Infraspinatus, Teres minor, deltoid (posterior part)
• Resisting downward dislocation: Deltoid with other muscles from above

Clinical anatomy of the shoulder joint:
• Dislocated anterioroinferiorly usually (head of the humerus is dislocated downwards and forwards)
• supraspinatus tendinitis cause Subacromial bursitis – a painful condition due to inflammation of the bursa.
• In such patients, pain occurs during 50-130º abduction (Painful arc syndrome)
• Arm drop test for testing supraspinatus muscle
• Rotator cuff injuries – repeated use (eg Baseball pitchers) may allow humeral head to impinge on the coracoacromial arch causing inflammation of the rotator cuff resulting in degenerative tendonitis of the rotator cuff.
• Axillary nerve injury- when glenohumeral joint dislocates
• Glenoidal labrum tear – may occur in baseball or football players.
• Frozen shoulder- adhesive fibrosis and scarring between the joint capsule, rotator cuff, and deltoid.
• The person will have difficulty in abducting the arm.


Elbow joint

• Capitulum & trochlea of humerus and trochlear notch of ulna & head of the radius
• hinge type of synovial
• Ulnar and radial collateral ligaments are very strong
• Movements: Flexion and extension:
• Flexion: Brachialis, biceps and brachioradialis (to drink beer!)
• Extension: Triceps and unconeus

• subcutaneous olecranon bursa may become inflamed causing bursitis.(student elbow)
• Tennis elbow (Lateral humeral epicondylitis): pain at common extensor origin
• Golfer’s elbow (medial humeral epicondylitis): pain at common flexor origin
• Carrying angle: more in females
• Avulsion fracture of medial epicondyle: In chidren, can damage ulnar nerve


Radioulnar joint

Superior radioulnar joint:
• Pivot type of synovial
• Supination and pronation take place
• Annular ligament surrounds the head and upper part of the neck of radius & attached to ulna
• Subluxation of the head of the radius from the annular ligament occurs in children (below 6 years age) when they are lifted by their forearm as in climbing a bus or catching them by forearm while they attempt to run away!

Middle radioulnar joint:
• Interosseus membrane connects the two bones.

Inferior radioulnar joint:
• Pivot type of synovial
• supination and pronation
• Supination: by biceps brachii and supinator (musculocutaenous and radial nerve)
• Pronation: pronator teres and pronator quadrates (median nerve)


Wrist joint / Radiocarpal joint

• Lower end of the radius, scaphoid, lunate, triquetrum and the triangular articular disc of the distal radio-ulnar joint.
• Ulna is separated from the wrist joint by the articular disc and hence not taking part in the wrist joint.
• ellipsoid joint: biaxial joint

• Radiocarpal, radial and ulnar collateral ligaments are its ligaments.
• Flexion: FCR & FCU
• Extension: ECRL, ECRB & ECU
• Adduction: Ulnar deviation: FCU & ECU
• Abduction: FCR & ECRL, ECRB


Fracture of the scaphoid

• Most common among carpal bones. A fall on the palm when hand is abducted. Pain felt on the lateral side of the wrist (snuff box) during dorsiflexion.
• It may lead to avascular necrosis of the proximal fragment of the scaphoid due to lack of blood supply (recurrent branch of radial artery).


Fracture of the hamate OR pisiform

• May result in non-reunion of the fragments due to muscle pull.
• Ulnar nerve and Ulnar artery may be damaged.


Anterior dislocation of the Lunate

• Fall on the dorsiflexed (looks like extended, "flexed" to extensor side) wrist may cause the lunate to displace and compress the median nerve leading to carpal tunnel syndrome.


Intercarpal joints

plain type of synovial – gliding


Carpometacarpal joint of thumb

Saddle type of synovial - modified biaxial joint


Carpometacarpal joints of other digits

plane type of synovial – gliding


Metacarpo-phalangeal joints (MP joints)

condyloid joints


Proximal interphalangeal joints (PIP joints)

hinge joint synovial – uniaxial


Distal interphalangeal joints (DIP joints)

hinge joint synovial


Bull Rider's Thumb

Damage to radial collateral ligament of MPJ of the thumb


Skier's Thumb

game-keeper's thumb- rupture or chronic laxity of ulnar collateral ligament of the 1st MP joint