7. Hand Bones Flashcards
Total number of bones in hand?
27 major with additional sesamoid
Function of hand bones?
Provide support and flexibility to soft tissue
3 groups of hand bones
Carpals
Metacarpals
Phalanges (proximal, middle, distal)
Number and location of carpals
8 in the wrist
2 rows - proximal and distal
Number and location of metacarpals
5 in the palm of the hand
Number of phalanges
3 per finger
2 in the thumb
Proximal carpal bones
Scaphoid
Lunate
Triquetrum
Pisiform
Distal carpal bones
Trapezium
Trapezoid
capitate
Hamate
What do carpal bones form?
An arch in the coronal plane
What is the flexor retinaculum?
A membranous band spanning the medial and lateral edges of the arch to form the carpal tunnel
What are the four major projections of the carpal bones?
Hook of hamate
Pisiform
Scaphoid tubercle
Crest of trapezium
Properties of scaphoid
Boat/cashew nut shaped
Largest bone in proximal row
Concave surface for head of capitate
Convex surface for articulation with distal radius
Scaphoid tubercle
Blunt
Non-articular projection
Attachment for flexor retinaculum
Properties of lunate
Crescent shaped
Concave surface articulates with capitate
Large, broad articular surface
Articulates with distal radius
Position of lunate
Centrally in carpal bones between scaphoid and triquetrum
Properties of triquetrum
Pyramidal
3rd from thumb
3 articular surfaces
Articulates with pisiform via single circular elevated facet
Position of triquetrum
Between lunate and pisiform
Proximal row
Properties of pisiform
Pea-shaped
One side flattened for articulation with triquetrum
Attachment point for flexor retinaculum
Sesamoid bone
Properties of trapezium
Irregularly sided bone
Large saddle shape
Articulates with base of MC1
What is the trapezium crest?
Long and narrow raised tubercle
Properties of trapezoid bone
Boot shaped
Smallest carpal in distal row
Articulates with base of MC2
Properties of capitate bone
Largest carpal
Distal end divided by 2 ridges into 3 facets
Head is rounded and smooth
Capitate articulations?
Distal end - metacarpal 2,3 sometimes 4
Head - lunate and scaphoid
Properties of hamate
Hook of hamate
Attachment point of flexor retinaculum
Double facet on base
Articulates with MC4 and 5
Properties of metacarpals
Tubular bones
Round distal articular heads
Rectangular proximal bases
Metacarpal articulations?
Bases all articulate laterally with eachother
Distally articulate with phalanges
Proximally articulate with 4 distal carpals
Properties of metacarpal 1
Shortest
Broad
More robust than others
Simple proximal articular surface is saddle shaped
Properties of metacarpal 2
Longest metacarpal
Base has long, curved blade like wedge
Articulations of metacarpal 2?
Trapezoid
Capitate
Trapezium
MC3
Properties of metacarpal 3?
Sharp projection (styloid process)
Articulations of metacarpal 3?
Capitate
MC2
MC4
Properties of metacarpal 4
Shorter and more gracile than 2 or 3
Fairly square base
3/4 articular facets
Articulations of metacarpal 4?
Capitate
Hamate
MC3
MC5
Properties of metacarpal 5?
Thinnest and shortest
Only 2 basal facets
Articulations of metacarpal 5?
Hamate
MC4
Properties of phalanges?
Shorter than MCs
No rounded heads
Anteroposteriorly flattened
Properties of thumb phalanges?
Shorter and thicker
No intermediate phalanx
Function of non-articular tubercle of metacarpals?
Attachment point for collateral ligaments
Properties of proximal phalanx
Single, concave proximal articular facet for metacarpal head
Properties of intermediate phalanx
Double proximal articular facet for head of proximal phalanx
Distal articular facet
Properties of distal phalanx
Double proximal articular facet for head of intermediate phalanx
Terminal/Distal end has non-articular pad
Name of non-articular pad on distal phalanx?
Distal phalangeal tuberosity
Where does flexor carpi radialis attach?
Base of 2nd metacarpal
Third metacarpal
Trapezial tuberosity
Origin and insertion of opponens pollicis?
Origin - trapezium, flexor retinaculum
Insertion - metacarpal bone of the thumb
Attachments of flexor retinaculum?
Origin - scaphoid tubercle, ridge of trapezium
Insertion - pisiform, hook of hamate