4.0) Inferior Radioulnar Joint + Wrist Flashcards
Inferior radioulnar joint
Pivot,complex,synovial,uniaxail
Inferior radioulnar joint
Articular surface
See file
Inferior radioulnar joint
Joint capsule
See file
Inferior radioulnar joint
Synovial membrane
Large compared to size of joint
Extends upwards above joint margins of radius and ulna in front of Interosseous membrane as recessus sacciformis
Interosseous membrane
Continuous fascia strong fibrous sheet between Interosseous boarders of radius and ulna
Fibres pass obliquely and inferomedially
Deficient superiorly continuous fascia posteriorly of pronator quadratas
Interosseous membrane functions
- Static stabiliser of both radioulnar joints maintaining contact of articulating surfaces
- Minimising torsional stresses on the bones very strong bond acts as an internal brace
- Provides an increased surface area for muscle attachments in the forearm helping to compartmentalise these muscles into an anterior (flexor muscle compartment) and posterior (extensor muscle compartment)
- Tension during pronation and supination *midpronation
- Due to fibres passing obliquely medially and downwards it Facilitate great transmission through upper limb its able to transmit force from radius onto ulna then humeroulna articulation then axail skeleton
- Increased surface area muscle attachment in forearm fills gap between radius and ulna
Stability
Extremely stable
Articular disc
Interosseous membrane
Pronator quadratus
Movements
Rotation distal end radius around head do ulna during pronation and supination
Axis of pronation and supination coincide axis hand= middle finger
Radial rotation therefore accompanied by movement of head of ulna
As the radius rotates about the ulna the ulna is displaced. Displacement is a result of slight extension and medial displacement of ulna at elbow.
Side-to-side movement between trochlear humerus and trochlear notch is mechanically amplified at distal ulna
Extension+lateral displacement of ulna= aconeus= occur simultaneously during pronation
Pronation
Radius crosses ulna and is anterior
Supination
Radius and ulna are parallel to each other
When elbow is fully extended biceps is unable to produce supination as its tendon runs parallel to shaft of radius so cannot produce radial rotation
Wrist
Not a single joint
Articulations between:
Forearm- radiocarpal joint
Carpal bones- intercarpal, midcarpal
Carpus
8 individual small bones arranged around the carpitate
X2 rows : proximal and distal
- Proximal articulate with inferior radioulnar joint ( except pisiform)
- Proximal and distal articulate each other= midcarpal joint
- Distal and metacarpal= carpometacarpal joint
What are the proximal bones of carpus
Lateral to medial
Scaphoid
Lunate
Triquetral
Pisiform
All except pisiform articulate with the distal radius and articular disc at inferior radioulnar joint
What are the distal bones of carpus
Lateral to medial
Trapezium
Trapezoid
Capitate
Hamate
Radiocarpal joint classification
ellipsoid, complex, synovial, bi-axial joint
Radiocarpal joint
Articular surface
See file
Radiocarpal joint
Joint capsule
See file
Radiocarpal joint
Synovial membrane
Locks synovial membrane lines joint capsule attaching to margins of all articular surfaces
Manifolds – particularly posteriorly
Due to disc + completeness of interosseous ligaments uniting proximal surface of proximal carpal row synovial cavity is limited to radiocarpal space
Periforation = communication inferior radioulnar joint
Radiocarpal joint
Caspular ligaments
Dorsal radiocarpal ligament
Palmer radiocarpal ligament
Palmer ulnocarpal ligament
Dorsal radiocarpal ligament
Posterior lower end of radius ——— posterior surface of scaphoid lunate triquetral
Inferomedially
Palmer radiocarpal ligament
Anterior lower radius and styloid process ——anterior surface of proximal row of carpal bones
Broad band passing downwards and medially
Palmer ulnocarpal ligament
Anterior articular disk and base of ulnar styloid process ————- anterior surfaces of proximal carpal bones
Fibres extending inferolaterally
What happens to anterior and posterior Caspular ligaments
Become taut in extension and flexion of radiocarpal joint
Radiocarpal joint
Ligaments
Radial collateral carpal ligament
Ulnar collateral carpal ligament
Radial collateral carpal ligament
Tip radial styloid process to lateral side of the scaphoid
Ulnar collateral carpal ligament
Rounded cord
Ulnar styloid process base of pisiforms and medial posterior non-articular surfaces off triquetral ( blends middle part of flexor retinaculum)
Movement off radiocarpal joint
Flexion
Extension
Abduction
Adduction
Flexion radiocarpal + Midcarpal joint
NROM+ limiting factors
0 to 90°
Midcarpal contributes the most
Dorsal radiocarpal ligament
Tension in extensor tendons
Extension radiocarpal and midcarpal joint
0 to 85°
Radiocarpal joint makes greatest contribution
Palmar radiocarpal ligament
Palmer ulnocarpal ligament
Tension flexor tendons
Abduction radiocarpal and midcarpal joint
Radial deviation
0–15°
Ulnar collateral ligament
Impact scaphoid tubercle on radial styloid
Adduction radiocarpal and midcarpal joint
Ulnar deviation
0-45°
Radial collateral ligament
Intercarpal joints
Classification
Between x2 rows of carpals
Completed joint x2 rows = midcarpal joint
Plane, compound, synovial, multiaxail
Intercarpal proximal row joint
Plane synovial distal scaphoid lunate and triquetral
Bones are bound together by interosseous dorsal+Palmer ligaments = minimal movement
Intercarpal proximal row joint
Ligaments
- Interosseous intercarpal ligaments
•short bands attaching to margins of the joint surfaces radiocarpal articulation
Whole anteroposterior length
- palmar+dorsal intercarpal ligaments
- transverse bands grim scaphoid to lunate
- lunate to triquetral anteroposterior aspects
Pisiform
?
Pg140
Joints of intercarpal distal row
Intercarpal interosseous ligament palmar and dorsal same as proximal joint
Arrangements allows gliding movement between bones is minimal but increases movement at radiocarpal and mid carpal joints
Difference in interosseous ligament in proximal and distal row
Distal row ligament is less extensive
Leaving clefts between bones
Runs transversely uniting trapezium to trapezoid to capitate to hamate
Midcarpal joint
Completed joint x2 rows = midcarpal joint
Midcarpal joint
Articulating surfaces
See file
Midcarpal joint
Joint capsule
See file
Midcarpal joint
Intercarpal synovial cavity
Lines the capsule and all non articular surfaces attaching to margins of all joint surfaces
Large complex
Midcarpal joint
Ligaments
Palmar intercarpal (radiate capitate lig)
Dorsal intercarpal
Radial collateral
Ulnar collateral
Interosseous ligament
Palmar intercarpal (radiate capitate lig)
Runs from bones of proximal row to head of capitate
Dorsal intercarpal
Runs from bones of one row to the other
Radial collateral
Strong, continuation radiocarpal collateral ligament
Runs from scaphoid to trapezium
Ulnar collateral
Runs from triquetral and hamate
Continuation ulnar collateral carpal lig
Interosseous ligament
Slender
Lateral side capitate to scaphoid
Movements midcarpal joints
Flexion
Extension
Abduction
Adduction
Transverse anteroposterior axis through head of capitate
**Movements occur in combination with radiocarpal joints
Flexors of the wrist
flexor carpi ulnaris flexor carpi radialis palmaris longus Flexor digitorum superficialis Flexor digitorum profundus Flexor pollicis longus
Flexor pollicis longus
Extensors of the wrist
extensor carpi ulnaris extensor carpi radialis longus extensor carpi radialis brevis Extensor digitorum Extensor indicis Extensor digiti minimi Extensor pollicis longus Extensor pollicis brevis
Flexor carpi ulnaris
S: most medial superficial flexors
O:
1) humeral head: common flexor origin- medial epicondyle humerus+ fascia
2) Ulnar head: medial boarder olecranon, aponeurosis upper 2/3 posterior ulna
I: long tendon into pisiform, hook hamate
D: inferiorly
A:flexes hand at wrist, ulnar deviation. Stabilising pisiform during abduction of pinky
*synergist prevents unwanted extension
F:
NS: ulnar nerve C7,8
Flexor carpi radialis
S: fusiform, most lateral
O: medial epicondyle of humerus + fascia
I: long tendon passes beneath flexor retinaculum
Distally: palmar surface bases 2nd,3rd metacarpals
D: oblique lateral
A: flexion, oblique nature= pronation, help flex elbow, radial deviation
F:
NS: median nerve C6,7
Palmaris longus
S: small a scent 10% population between ulnar is and radialis
O: medial epicondyle
I: via flexor retinaculum to apex of palmar aponeurosis
D: inferiorly
A: flexion of wrist flexion metacarpalphalangeal
F:
NS: median nerve C8
extensor carpi ulnaris
S:
O: lat epicondyle + fascia+ aponeurosis posterior boarder of ulna
I: medial side base 5th metacarpal
D: inferomedially
A: extends wrist, works with other muscles=ulnar deviation
F:
NS: posterior Interosseous radial nerve C7,8
extensor carpi radialis longus
S: posterior compartment
O: anterior lower 1/3 lat supercondylar ridge, lat epicondyle common extensor tendon
I: posterior base 2nd metacarpal
D: distally
A: extend wrist
F:
NS: radial nerve C6,7
extensor carpi radialis brevis
S:
O: lateral epicondyle common extensor tendon
I: posterior base 3rd metacarpal
D:
A: extension radial deviation
F:
NS: posterior Interosseous radial C6,7
Flexor retinacula
Anterior to carpus
Strong band for retention of long flexor tendons
Converts the carpal sulcus into a tunnel
Attachments:
Laterally: Tubercle of scaphoid lips of trapezium
Medially: pisiform hook of hamate
Extensor retinacula
Thickening of the deep fascia
Attachments:
Laterally: distal part of the anterior surface of radius
Medially: distal end ulna pisiform triquetral UCL
Septa run from its deep surface to the distal ends of the radius and ulna converting the grooves on the dorsum of the wrist into 6 separate tunnels each lined by synovial sheath
Muscles in the
Superficial,intermediate, Deep anterior compartment of the arm
Superficial:
- flexor carpi ulnaris
- flexor carpi radialis
- palmaris longus
- pronator teres.
Intermediated:
- Flexor digitorum superficialis
Deep:
- flexor digitorum profundus
- flexor pollicis longus
- pronator quadratus.
Muscles in the
Superficial and Deep posterior compartment of them arm
Superficial:
- extensor carpi radialis brevis
- extensor carpi ulnaris
- extensor digitorum
- extensor digiti minimi
Deep:
- supinator
- abductor pollicis longus
- extensor pollicis brevis
- extensor pollicis longus
- extensor indicis.
