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Full arm bones.png

Clavicle

Connects upper limb to trunk

S shaped bone, located between sternum & scapula

Medial end: round, articulates with manubrium of sternum @ sternoclavicular joint

Lateral end: flattened, articulates with scapula @ acromioclavicular joint

Curved forwards @ medial 2/3rd

Forms strut that supports upper limb, keeping limb away from thorax so arm has max freedom of motion

Fractures

Clavicle bone.png

Commonly fractures

Weakest part is junction of middle and lateral thirds (curve changes)

Scapula

Scapula bone.png

Flat triangular bone, lies against ribs 2-7

3 borders: superior, medial and lateral borders

3 angles: medial, inferior and lateral (forms glenoid fossa)

Glenoid fossa articulates with head of humerus

Forms glenohumeral (shoulder) joint

Coracoid process extends from superior border

Directed forwards & slightly laterally
Provides attachment for ligaments/muscles

Spine of scapula protrudes from posterior surface

Extends laterally to form acromion process
Divides posterior surface of scapula into supraspinous and infraspinous fossae

Acromion forms acromioclavicular joint with capsule

Anterior surface of scapula has subscapular fossa


Humerus

Humerus bone.png

Proximally, has rounded head, articulates with glenoid fossa of humerus to form glenohumeral joint

Head forms 1/3 sphere, much larger than glenoid fossa

Anatomical neck separates head from shaft of humerus

Surgical neck lies below head, is a common site of fracture

Lesser and greater tubercles are elevations on proximal end of humerus

Lesser is anterior and medial, greater is lateral
Groove between tubercles is intertubular glove (sulcus)

Shaft rounded in upper half, triangular in lower half

Lower end forms expanded condyle, has articular and nonarticular parts

Articular
Rounded capitulum, articulates with head of radius
Trochlea, shaped like a pulley, articulates with trochlear notch of ulna
Nonarticular
Medial epicondyle, prominent bony projection on medial side, subcutaneous, easily felt at elbow
Lateral epicondyle, smaller than medial epicondyle
Lateral supracondylar ridge, sharp lateral margin just above lower end
Medial supracondylar ridge, similar ridge on medial side
Coroniod fossa, depression just above anterior aspect of trochlea for coronoid process of ulna
Radial fossa, depression just above anterior aspect of capitulum for head of radius
Olecranon fossa, just above posterior aspect of trochlea
Accommodates olecranon process of ulna when elbow extended

Radius

Forearm bones.png

Head is @ upper end, shaped like disc

Articulates superiorly with capitulum of humerus
Medially with radial notch of ulna

Separated from shaft by narrow neck

Radial tuberosity just below medial part of neck

Lower end is widest part

On med surface is ulnar notch for head of ulna
Lat surface prolonged downwards, forms styloid process

Inf end articulates with wristbones (scaphoid and lunate) to form wrist joint

Ulna

Base proximal, head distal

Upper end presents

  • Trochlear notch, for articulation with trochlea of humerus
  • Olecranon (‘tip of the elbow'), forms posterior and superior parts of trochlear notch
  • Coronoid process, projects forwards from shaft, forms lower part of trochlear notch
    • Projects inferiorly into ulnar tuberosity
    • Laterally into radial notch for articulation with head of radius

Distal end formed by head and small styloid process extending from medial side


Hand

Hand bones.png

Wrist

8 small, irregularly shaped carpal bones, arranged in two rows, proximal and distal

Proximal row (lat -> med): scaphoid, lunate, triquetral, and pisiform

Articulates with radius and ulna

Distal row (lat -> med): trapezium, trapezoid, capitate, hamate

Articulates with five metacarpal bones at carpometacarpal joint

5 metacarpals

Form framework for palm of hand

Long bones

Base articulates with distal row of carpus

Heads articulate with proximal phalanx of digits

Metacarpals numbered from one (for thumb) to five (for the little finger)

Phalanges

Long bones

Base proximally, head distally

14 phalanges in each hand

Two for thumb (prox and dist)
Three (prox, middle, dist) for each finger

Synovial joints

Features

Articulating surfaces lined with articular (usually hyaline) cartilage

Encapsulated with fibrous joint capsule, afford stability to the joint

Non-articulating surfaces and joint capsule lined with synovial membrane

Produces synovial fluid (oily, lubricating fluid, minimises friction, provides nutrition to articular cartilage

Usually reinforced by ligaments, limit movements and support joint

Types

Classified by shape of articular surfaces and types of movements permitted

E.g. ball-and-socket, hinge, saddle, pivot, gliding

Joints of upper limb

Acromioclavicular joint

Gliding joint between acromion of scapula and lat end of clavicle
Moves as unit with shoulder joint
Stabilized by coracoclavicular ligament

Shoulder joint

Ball and socket joint between glenoid fossa of scapula and head of humerus

Elbow joint

Hinge joint between trochlea and capitum of humerus and ulna (trochlear notch) and radius (head)

Prox and dist radioulnar joints

Pivot joints between ulna and radius

Wrist joint

Radius and articular disc articulate with prox row of carpal bones
Condyloid joint

Carpometacarpal joint of thumb

Saddle joint, very mobile

Metacarpophalangeal joints

Condyloid joints

Interphalangeal joints

Hinge joints