Wrist and Hand Flashcards
What type of bone are metacarpals? phalanges? carpals?
metacarpals and phalanges are long bones; carpals are short bones
What is the radiocarpal joint? What is its structural classification?
radius with the scaphoid and lunate; synovial ellipsoid joint
What is the structural classification of the mid carpal and intercarpal joints?
gliding joints
What does the midcarpal joint space consist of?
all carpal bones except pisiform
What does the distal row consist of? How does it move?
trapezium, trapezoid, capitate, hamate; moves as a unit
What does the proximal row consist of? How does it move?
scaphoid, lunate, triquetrum, pisiform; moves independently
What carpal bone moves most independently?
scaphoid- can move independent to lunate and in different directions
How does the proximal and distal row contribute to flexion-extension?
similar contributions to ROM from the proximal and distal rows
How does the proximal and distal row contribute to abduction-adduction?
distal row follows the fingers; proximal row moves in opposite direction (note- during abduction the scaphoid flexes to avoid impinging on the radial styloid)
What are the attachments of the radial collateral ligament?
radial styloid -> scaphoid
What are the attachment of the ulnar collateral ligament?
ulnar styloid -> triquetrum
What does the palmar radiocarpal ligament resist?
excessive wrist extension
What does the palmar ulnocarpal ligament resist?
excessive wrist extension
What does the dorsal radiocarpal ligament resist?
excessive wrist flexion
What are the intrinsic ligaments? Where are the attachments?
palmar midcarpal ligament, dorsal midcarpal ligament, interosseous ligament between adjacent carpal bones (all attachments are within the carpal region)
What would occur if the ulna was shorter than the radius?
ulna shorter=negative ulnar variance (not going to have force going through triquetrum and lunate to the TFCC to the ulna; more force loading to your radius putting it at risk also removing support for lunate)
What would occur if the ulna was longer than the radius?
ulna longer=positive ulnar variance (TFCC loading- compressing TFCC)
What does the radius articulate with?
scaphoid and lunate
What carpal bone has the greatest contact with the radius?
scaphoid
What does the TFCC articulate with?
lunate and triquetrum
Does the wrist have greater range of flexion or extension?
flexion
Does the wrist have greater range of abduction or adduction?
adduction
What is the significance of a ligamentous injury on the carpal bones?
if someone has ligamentous injury (such as rheumatoid arthritis) than you get a carpal drift or deformity (carpal drifts when you take away their ligamentous support) (each carpal bone drift towards the ulnar in an anterior direction)
What is the most common carpal fracture? Why?
scaphoid bc it is the bone that receives the most force and has greater contact with the radius
What is avascular necrosis?
death of bone tissue due to a lack of blood supply which can lead to tiny breaks in the bones and bones eventual collapse
What carpal is the key stone of the proximal row? Why?
lunate; it is important to the stability of the proximal row- since no muscles attach to it, its stability relies on the shape of articular surfaces and ligaments
What is scapholunate dissocation?
capitate pushes through and seperates the lunate and scaphoid disrupting the scapholunate ligament
What is the structural classification and movements of the 1st carpometacarpal joint?
structural classification- synovial saddle
movements- F-E in plane of palm, Abd-Add perpendicular to palm, opposition- abd+f+mr, conjuct (medial) rotation occurs as a consequence of the oblique CMC ligaments tightening
What is the structural classification and movements of the 2nd-4th carpometacarpal joints?
structural classification- synovial plane
movements- gliding
(2nd MC wedged/least mobile, most stable)(mobility increases 2nd to 5th)
What is the structural classification and movements of the 5th carpometacarpal joint?
structural classification- synovial saddle
movements- F-E, Abd-Add/gliding
What is the structural classification and movements of the 2nd-5th intermetacarpal joints?
structural classification- synovial plane
movements- gliding
What is the structural classification and movements of the 1st-5th metacarpophalangeal joints?
structural classification- synovial ellipsoid
movements- F-E, Abd-Add
(1st is most stable, function relevance- good to have mobility at CMC to oppose and then less mobility at your MCP)
What is the structural classification and movements of the 1st-5th interphalangeal joints?
structural classification- synovial hinge
movements- F-E
(IP of the 1st is least mobile, PIP increasing ROM from 1st-5th, most finger flexion occurs at PIP joints)
What are the thenar hand muscles?
abductor pollicis brevis, flexor pollicis brevis, opponens pollicis
What is the common proximal attachment between all the thenar hand muscles?
flexor retinaculum and trapezium
What are the hypothenar hand muscles?
abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi