Flexor pollicis longus

General information

• This section is strictly limited to anatomy, you might be looking for clinical relevant information which is found under the clinical chapters -- muscles section, click here to go to that page
• A part of the lower arm's anterior deep muscle group

Position

• Deep

Origin

• Anterior surface of proximal radius (just distally to tuberositas radii)
• Interosseus membrana
• Processus coroneideus ulna
• Medial epicondyle humerus

Insertion

• Anterior surface of distal phalanx of thumb

Main function

• Wrist
  • Flexion
• CMC
  • Flexion
• MCP
  • Flexion
• IP
  • Flexion

Secondary function

• Elbow
  • Flexion
• Wrist
  • Radial deviation

Nerve innervation

• Segmental
  • C7-Th1
• Peripheral
  • Median nerve

Arterial supply

• Radial artery
• Anterior interosseus artery

• Patient position
  • Sitting or supine
• Localize the muscle belly of flexor carpi radialis and brachioradialis
• Ask the patient to flex the IP-joint of the thumb
• Feel for the contraction between flexor carpi radialis and brachioradialis in the middle of the anterior aspect of the lower arm

• Patient position
  • Sitting or supine
• Fixate the MCP joint by the patient's thumb
• Give resistance towards the palmar surface of the distal phalanx in the direction of extension so that the patient is giving force towards flexion
• Have the patient maintain the position of the thumb throughout the testing