Elbow, Wrist, Hand Joints

characteristics of anterior aspect of the humerus

medial/lateral columns, trochlea, capitellum, medial (coronoid) fossa, lateral (radial) fossa

location of trochlea

medial distal end of humerus

location of capitellum

lateral distal end of humerus

coverage of articular cartilage on distal humerus

covers trochlea and capitellum, but only trochlea covering wraps all the way to the back

function of coronoid and radial fossas

allow prominences on the radius and ulna to engage and produce full elbow motion

characteristics of posterior aspect of the humerus

articular cartilage of trochlea, olecranon fossa, ulnar groove

function of olecranon fossa

articulation with proximal part of the ulna

function of ulnar groove

for passage of ulnar nerve

parts of the “C” on the ulna

top: olecranon, anterior: coronoid process, back: trochlear notch

function of radial notch of ulna

articulation with the radial head

function of ulnar tuberosity

attachment site for some muscles

location of articular cartilage on radius

surrounds the top and periphery of the head

joints that make up the elbow joint

medial: trochlea and trochlear notch, lateral: capitulum and radial head

movements that can occur at the elbow

flexion and extension

primary determinant of movement at the elbow

olecranon and coronoid process fit around the distal humerus

attachment of elbow joint capsule

arround periphery of the ulna, humerus, and annular ligament

third joint in elbow capsule

proximal radial ulnar joint (radial notch and radial head)

collateral ligaments in elbow

medial/ulnar and lateral/radial

function of elbow collateral ligaments

stability in the frontal plane to resist valgus and varus forces

location/attachments of MCL

covers trochlea and attaches proximally at the medial epicondyle and distally at the coronoid and olecranon processes

function of MCL

resist valgus force

attachments of the LCL

lateral epicondyle to the annular ligament

components of the lateral collateral ligamentus complex (LCLC)

lateral collateral ligament and lateral ulnar collateral ligament (LUCL)

function of LCLC

resist varus forces

attachments of LUCL

lateral epicondyle to the proximal lateral ulna

why do no ligaments attach to the radius

allows for pronation and supination at the forearm

function of proximal and distal radioulnar joints

pronation and supination of forearm

key stabilizer at the proximal radioulnar joint

annular ligament because it wraps around the entire radial notch and head

tissues of the annular ligament

outer: dense regular CT, inner: articular cartilage

structures involved in proximal radioulnar joint

radial notch and radial head

structures involved in distal radioulnar joint

distal medial radius/ulnar notch and ulnar head

key stabilizer of distal radioulnar joint

triangular fibrocartilaginous complex (TFCC)

function of TFCC

fills large space between ulna and the carpal bones

function of interosseous membrane

indirect stabilization of joints

what happens to the forearm bones during pronation

distal radius goes over the ulnar head, proximal radial head spins in the annular ligament

proximal row of carpal bones from lateral to medial

scaphoid, lunate, triquetrum, pisiform

distal row of carpal bones from lateral to medial

trapezium, trapezoid, capitate, hamate

function of bony prominences on the carpal bones

help create the carpal tunnel

joints that make up the wrist joint

radiocarpal: radius and proximal carpals, midcarpal: proximal and distal carpals

function of intercarpal ligaments

maintain the positions and alignment of the carpal bones

main bones in the articulation of the radiocarpal joint

scaphoid and lunate articulate with the radius

medial side of the radiocarpal joint

TFCC with the triquetrum

components of the TFCC

ulnocarpal disc, palmar radioulnar ligament, dorsal radioulnar ligament, ulnocarpal meniscus homologue, extensor carpi ulnaris tendon sheath

function of ulnocarpal disc

fibrocartilage that covers the ulnar head and attaches to the styloid process

function of the radioulnar ligaments

go around the ulnocarpal disc

function of ulnocarpal meniscus homologue

extends to the triquetrum

shape of carpal bones

rounded from side to side, other articulating surface is disc shaped

types of extrinsic carpal ligaments

dorsal extrinsic, palmar extrinsic, radial collateral, ulnar collateral

function of extrinsic carpal ligaments

stability of the joint and maintain position of the carpal bones

characteristics of the CMC joint in the thumb

saddle shaped surfaces, looser capsule and ligaments, articulation between trapezium and first metacarpal

motion of thumb in the sagittal plane

abduction and adduction

motion of the thumb in the frontal plane

flexion and extension

what appears on the dorsal side of MCPJs

extensor mechanism/aponeurosis

what appears on the palmar side of MCPJs

transverse metacarpal ligament

function of transverse metacarpal ligament

ties the MCPJs together

tissue of volar plates

fibrocartilage

function of volar plates

allows for better attachment of flexor tendon sheaths as they go to the fingers for full flexion and extension

mechanism of volar plates

acts like axillary recess

attachments of true collateral ligaments of the MCPJs

metacarpal head to the base of the proximal phalanx

attachments of false/accessory collateral ligaments of MCPJs

metacarpal head to the volar plate

why is finger abduction limited with MCPJs are flexed

volar plate folds up which drags the collateral ligaments tight and causes them to stabilize in the frontal plane

surface structure of PIPs, DIPs, and IPs

head of phalanx is rounded with a groove going from front to back, base of phalanx is concave with a ridge in the middle

structure/function relationship in interphalangeal joints

when the ridge sits in the groove it provides more bony stability to resist abduction/adduction

location of volar plates

MCPJs and IPs

location of true and false collateral ligaments

MCPJs and IPs