VIDEO
CONTENT
QUIZ
MATERIALS
Quick Facts
Key Features
Surface Anatomy
Landmark
Surfaces
Ossification
Variations
Clinical Correlates
Quick Facts about the Lunate Bone
- Location: Hand
- Bone Type: Short bone
- Key Features: Palmar and dorsal surfaces; radial, scaphoid, capitate, and triquetrum articular facets
- Articulates With: Radius, triquetrum, hamate, capitate, and scaphoid bones
- Arterial Supply: Dorsal carpal branch of radial and ulnar arteries
Key Features & Anatomical Relations of the Lunate
- Shape: Semilunar
- Position in the Hand: Proximal row of carpal bones
- Surfaces: Includes proximal, distal, palmar, and dorsal surfaces
- Landmarks: Articular facets for articulation with adjacent bones
Location and Articulation
- Proximity: Above the capitate and hamate bones, below the radius, medial to the scaphoid, lateral to the triquetrum
- Joints: Forms part of the radiocarpal joint, and also articulates with other carpal bones at the lunotriquetral, lunohamate, lunocapitate, and scapholunate joints
Surface Anatomy of the Lunate
- Palpation: The lunate can be felt on the dorsal wrist, proximal to the capitate bone, especially when the wrist is flexed
Landmark of the Pisiform Bone
- Triquetrum Articular Facet (Facies articularis triquetra ossis pisiformis): This is a small, flat, oval area on the dorsal aspect of the pisiform bone. It creates a joint surface for articulation with the triquetrum, forming the pisotriquetral joint.
Each of these features serves a purpose in hand anatomy and function:
- The palmar surface of the pisiform provides attachment for ligaments and a part of the tendon of the flexor carpi ulnaris muscle.
- The dorsal surface is less clinically significant but serves as a point of attachment for ligaments that connect the pisiform to other carpal bones.
- The triquetrum articular facet is crucial for the mobility and stability of the wrist as it is the interface for the pisiform-triquetrum articulation.
Surfaces of the Pisiform Bone
- Palmar Surface (Facies palmaris ossis pisiformis): This is the front surface of the pisiform bone. It faces towards the palm of the hand.
- Dorsal Surface (Facies dorsalis ossis pisiformis): This is the rear surface of the pisiform bone. It is oriented towards the back of the hand.
Ossification of the Lunate
- Ossification Centers: One, emerging in the fourth to fifth years of life
- Ossification Completion: Occurs during adolescence
Variations in Lunate Anatomy
- Carpal Coalition: Fusion between the lunate and triquetrum (os lunatotriquetrum)
- Accessory Bones: May be present associated with the lunate
Clinical Correlates
- Lunate Dislocation: The lunate is the most commonly dislocated carpal bone
- Perilunate Dislocation: Dislocation of the carpal bones surrounding the lunate
- Kienböck’s Disease: Avascular necrosis of the lunate
- Fractures: Although less common, the lunate can fracture
