Carpometacarpal, metacarpophalangeal and interphalangeal (hand) articulations

Question 1

Carpometacarpal join of the thumb

Answer 1

• Bewtween the base of the first metacarpal bone and os trapezium
• Joint capsule is attached to the margins of joint surfaces
• Sellar joint - allows movement along two axes: abduction/adduction and opposition/reposition (thumb agains or away form other fingers)
• Thumb opposition allows grasping of tools

Question 2

Carpometacarpal joints of the II. to IV. metacarpal bones

Answer 2

• Between bases of 2nd to 5th metacarpal bones and the distal row of carpal bones
• Joint capsule is firm and attaches to margins of joint surfaces
• Joint cavity communicates with mediocarpal joint via a slit through os trapezium and os trapezoideum
• Joint capsule is reinforced by an entire row of ligaments: lig. carpometacarpalia palmaria, dorsalia et interossea, lig. metacarpalia palmaria, dorsalia et interossea

Question 3

Metacarpophalangeal joints

Answer 3

• Between metacarpal heads and joint surfaces on the bases of proximal phalanges
• Joint pits deepened on palmar side using laminae fibrocartilaginea palmares
• Joint capsule attached to margins of joint surfaces and onto the margin of lamina fibrocartilaginea
• Frontal and dorsal parts of the joint are thinner and looser
• Side of capsule is strong and is reinforced using lig. collaterale ulnare et radiale
• Heads of 2nd to 5th metacarpus are joiuned on the palmar side by lig. metacarpeum transversum profundum
• Lamina fibrocartilaginea palmars of the thumb joins two sesamoid bones
• Ellipsoid joints allowing: flexion/extension and abduction/adduction

Question 4

Interphalangeal joints of the hand

Answer 4

• Adjoining phalanges meet using trochlear joints
• Head is formed by trochlea phalangis
• Pit is formed by the base of the distally situated phalanx
• Joint pits are arched on palmar side using ;ig. fibrocartilaginea palmaris
• Joint capsule reinforced using lig. collaterale radiale et ulnare
• Dorsal side reinforced by aponeurosis of finger extensors
• Movements in one axis: flexion/extension