Overview
This lecture covers the anatomy of the flexor carpi ulnaris muscle in the forearm, focusing on its origin, insertion, and main actions.
Location and Structure
- The flexor carpi ulnaris runs along the medial side of the forearm and crosses the wrist joint.
- It is located near other forearm muscles like the flexor digitorum superficialis and palmaris longus.
- The muscle has two heads: the humeral head (originates from the humerus) and the ulnar head (originates from the ulna).
Origins (Proximal Attachments)
- Humeral head originates from the medial epicondyle of the humerus via the common flexor tendon.
- Ulnar head originates from the olecranon and the upper two-thirds of the posterior border of the ulna.
- Both heads join via a tendinous arch.
Insertions (Distal Attachments)
- Main insertion is on the pisiform bone of the wrist.
- Indirectly connects to the hamate bone and base of the fifth metacarpal through the pisohamate and pisometacarpal ligaments.
- Proximity and ligament connections classify the hamate and fifth metacarpal as additional insertion points.
Actions
- Flexes the wrist joint (bends the wrist forward).
- Adducts the wrist joint (moves the hand towards the ulnar side).
- Weakly assists in flexion of the elbow joint.
Key Terms & Definitions
- Origin — The muscle's attachment site on the bone that remains stationary during contraction.
- Insertion — The site where the muscle attaches to the bone that moves during contraction.
- Common flexor tendon — A shared tendon on the medial epicondyle of the humerus for several forearm muscles.
- Adduction — Movement of a body part toward the body's midline.
- Pisiform, hamate, fifth metacarpal — Carpal and metacarpal bones of the hand involved in the insertion of the flexor carpi ulnaris.
Action Items / Next Steps
- Review diagrams of the flexor carpi ulnaris and its neighboring structures.
- Memorize the muscle's origins, insertions, and actions for quizzes or practical exams.