Proximal Phalanx of the Thumb

Parent Structures

• Phalanges

Bone Classification

• Long

Bony Features

• Base of Proximal Phalanx of the Thumb
• Head of Proximal Phalanx of the Thumb
• Shaft of Proximal Phalanx of the Thumb

Attaching Structures as Origin

• Palmar Ligament of the 1st IP - Loosely attached to the front of the neck via the joint capsule

Associated Joints

• 1st Metacarpophalangeal Joint (1st MCP)
• IP of the 1st Phalanx of the Hand

Structures Attaching to Bony Features as Origin

• Head of Proximal Phalanx of the Thumb
  • Collateral Ligaments of the 1st IP - Attached to the Sides

Structures Attaching to Bony Features as Insertion

• Base of Proximal Phalanx of the Thumb
  • 1st Palmar Interossei of the Hand - Dorsal Digital Expansion
  • Abductor Pollicis Brevis - Radial Side
  • Adductor Pollicis - Medial Side – The Tendon contains a sesamoid bone
  • Collateral Ligaments of the 1st MCP - Palmar Aspect of the side
  • Extensor Pollicis Brevis - Dorsal Surface
  • Flexor Pollicis Brevis - Radial Side
  • Palmar Ligament of the 1st MCP - Anterior Aspect