The shoulder, elbow, wrist and hand joints Flashcards
Review of features of the shoulder, elbow, wrist and hand joints
What are the limiting factors for the movement of the elbow?
Soft tissue apposition in the anterior forearm + upper arm. Coronoid process contacting coronoid fossa + radial head contacting radial fossa. Tension in posterior capsule. Tension in triceps
What is the carrying angle?
The natural bend at the elbow; is larger in females b/c of hips
What is cubitus varus and valgus?
Varus means that carrying angle is <5 degrees, valgus means that carrying angle is >15 degrees
How is the joint congruency poor?
Lateral side of the elbow is not well designed to resists traction, leading to “pulled elbow” in children
What articulations are involved in the cubital joint?
Trocheal notch of ulna with the the trochlea of humerus. Head of radius with capitulum of humerus.
What articulation is involved in the superior radioulnar joint?
Radial head + fibrous osseous ring formed by concave radial notch and annular ligament
What is the annular radial ligament?
Ligament which forms a collar around the superior radioulnar joint; lined with a synovial membrane
What is the ulnar collateral ligament?
On the medial side; origins from medial epicondyle and attaches to coronoid process + olecranon of ulna
What is the radial collateral ligament?
On the lateral side; origins from lateral epicondyle and blends with annular ligament
What is the function of interosseous membrane?
Provides attachment site for muscles; transfers forces from radius to ulna. Posterior and anterior fibres run at 90 degrees to each other
What are the articulations of the sternoclavicular joint?
Clavicle with the manubrium of the sternum
What increases the congruency of the sternoclavicular joint?
The intra-articular disc; binds at top and bottom
What ligaments are involved in the sternoclavicular joint?
Interclavicular, anterior + posterior sternoclavicular, costoclavicular
Which ligament spans the gap between the sternal ends of the clavicle, and how does it reinforce the joint capsule?
Interclavicular; reinforces superiorly
Which ligament reinforces the sternoclavicular joint capsule anteriorly and posteriorly?
The anterior and posterior sternoclavicular ligaments
Which ligament extends from the first rib to the clavicle, and what is the function of this ligament?
Costoclavicular; acts as falcrum for clavicle elevation and depression; axis of rotation during protraction and retraction
Which articulations are involved in the acromioclavicular joint?
Lateral end of clavicle with the acromion of the scapula
Which ligaments are involved in the acromioclavicular joint?
Acromioclavicular, coracoclavicular (conoid and trapezoid)
Which ligament of the acromioclavicular joint is intrinsic?
The acromioclavicular
Which ligament of the acromioclavicular joint is extrinsic?
The coracoclavicular
Where does the acromioclavicular ligament extend from and to, and how does it reinforce the joint capsule?
Extends horizontally from acromion to lateral clavicle; reinforces superiorly
Which ligament extends vertically from coracoid process of scapula to conoid tubercle of clavicle?
Conoid ligament
Where does the trapezium ligament extend to and from?
Extends from coracoid process of scapula to trapezoid line of clavicle
What articulations are involved in the glenohumeral joint?
The head of humerus with the glenoid fossa of scapula
What improves the congruency of the glenohumeral joint, and why?
The glenoid labrum; deepens fossa as humerus so much larger
Which ligaments are involved in the GHJ?
Glenohumeral ligaments (superior, medial, inferior), coracohumeral, transverse humeral
Where do the glenohumeral ligaments extend to and from?
Extend from humerus to glenoid fossa
Where does the coracohumeral ligament extend to and from?
Attaches base of coracoid process to greater tubercle of humerus
Where does the transverse humeral ligament extend to and from?
Spans the two tubercles of the humerus
What is the scapulothoracic articulation?
Only bony attachment attaching upper limb to axial skeleton; fulfils function of joints but has no joint capsule
What is the vital bursa of the shoulder?
Subacromial/sub deltoid bursa; in 90% of people, exists as one big
What is the subacromial articulation?
A pseudo-joint, where the bone articulated against another restraining surface
What is the major group of structures which stabilises the GHJ?
The rotator cuff
Name the muscles of the rotator group
SITS: supraspinatus, infraspinatus, teres minor, subscapularis (+Biceps LH)
What is the intra-articular pressure of the GHJ?
Negative pressure, sucks in humeral head; one capsule is injured or joint dislocated, pressure is lost forever
What articulations are involved in the radiocarpal joint?
Distal surface of radius with scaphoid, lunate + triquetral
What is the function of the triangular fibrocartilage complex?
Allows better load absorption; allows pronation and supination whilst maintaining wrist flexion/extension; attaches to ulna styloid process + edge of radius, and articulates with triquetral
What articulations are involved in the midcarpal joint?
Articulation b/w proximal row of carpus + distal row
What ligaments stabilise the wrist joint?
Palmar radiocarpal, dorsal radiocarpal, ulnar collateral, radial collateral
Which ligaments ensure the hand follows the forearm in supination and pronation?
Palmar radiocarpal (sup), dorsal radiocarpal (pro)
Where does the palmar radiocarpal ligament extend to and from?
Extends from anterior inferior radius to both rows of carpal bones
Where does the dorsal radiocarpal ligament extend to and from?
From posterior inferior radius to both rows of carpal bones
Which ligaments prevent excess lateral joint displacement?
Ulnar and radial collateral
Where does the ulnar collateral ligament extend to and from?
Ulnar styloid process to triquetrum + pisiform
Where does the radial collateral ligament extend to and from?
Radial styloid process to scaphoid + trapezium
What are the articulations of the intercarpal joints?
Between every carpus; allows tiny bits of movement
What are the articulations of carpometacarpal joints?
Between carpus bones and metacarpals
Why is the 1st carpometacarpal prone to grinding?
Tendons which move joint lie parallel to 1st metacarpal, and so joint is compressed by muscle contraction
What allows opposition and reposition?
The passive rotation of CMC joint; compound movement of flexion, adduction and passive medial rotation
What movements are thumb flexion and extension?
Thumb moving laterally and medially
What movements are thumb abduction and adduction?
Thumb moving away from and towards palm at 90 degrees angle
What are the three arches of the hand?
The proximal transverse, distal transverse, and longitudinal
Which arch is formed by the distal row of the carpus bones?
Proximal transverse arch
Which arch forms the carpal tunnel?
Proximal transverse arch
Which transverse arch is relatively mobile?
Distal transverse arch
Which arch follows the shape of the 2nd and 3rd rays?
Longitudinal arch
What are rays comprised of?
The finger bones, associated metacarpal and carpal bones
Which carpal bone do the 4th and 5th rays share?
Hamate
Which rays are more rigid?
2nd and 3rd; joints of digits rigidly joined to distal row of carpus
Which rays are more mobile?
1st, 4th and 5th; joints form mobile radial and ulnar borders
What is the purpose of the carpal tunnel?
Allows space for structures to pass from forearm to hand
Which ligaments pin and tie the proximal transverse arch to form the carpal tunnel?
The transverse carpal ligament, flexor retinaculum, and palmar aponeurosis
What causes carpal tunnel syndrome?
Any swelling of the wrist or inflammation of the tendons within, which will compress the median nerve
What hand features do the metacarpophalangeal joints form?
The knuckles
What movements are allowed at the metacarpophalangeal joints?
Flexion, extension, abduction, adduction
Which ligaments are present at metacarpophalangeal joints?
Medial and lateral collateral ligaments
Where are fibrous digital sheaths and palmar plates present?
Metacarpophalangeal joints and interphalangeal joints
What does the deep transverse metacarpal ligament do?
Binds metacarpophalangeal joints 2-4 together
What are the interphalangeal joints?
Joints between phalanges; digits 2-5 have proximal and distal; thumb only has one
