Ulnar Deviation: Understanding Normal and Abnormal End Feels

What is the end feel of the ulnar deviation?

The normal end feel for ulnar deviation of the wrist is typically firm or capsular, characterized by a slight give or stretch as the joint capsule and ligaments reach their maximal tautness, limiting further motion.

Introduction to End Feel

In the realm of manual therapy and exercise science, "end feel" refers to the quality of resistance felt by an examiner as a joint is passively moved to its extreme range of motion. It provides crucial diagnostic information about the structures limiting movement and the overall health of the joint. Understanding end feel helps clinicians differentiate between normal physiological limits and pathological conditions. Each joint and specific movement typically has a characteristic normal end feel, which can be described as soft, firm, or hard (bony).

Understanding Ulnar Deviation

Ulnar deviation is a movement of the wrist joint where the hand moves towards the little finger side. This motion occurs primarily at the radiocarpal and midcarpal joints of the wrist. It is less common in daily activities than radial deviation, but forms a critical component of wrist mobility. The typical range of motion for ulnar deviation is approximately 30 to 45 degrees, though this can vary slightly between individuals. The primary muscles involved in this movement include the flexor carpi ulnaris and the extensor carpi ulnaris.

The Normal End Feel of Ulnar Deviation

As previously stated, the normal end feel for ulnar deviation is firm, also often described as capsular. This means that as the wrist is passively moved into its full ulnar deviation, the examiner feels a distinct, elastic resistance that gives slightly, similar to stretching a firm piece of leather. It is not abrupt or rigid like bone-on-bone contact, nor is it soft and mushy like soft tissue approximation.

Anatomical Structures Contributing to the Firm End Feel:

The firm end feel in ulnar deviation is primarily due to the passive tension of specific anatomical structures on the opposite (radial) side of the wrist, which become taut and limit further motion:

• Joint Capsule: The wrist joint capsule, particularly its radial aspects, becomes stretched and taut.
• Ligaments: The radial collateral ligament is the primary ligament that becomes taut and resists further ulnar deviation. Other ligaments, such as portions of the dorsal and palmar radiocarpal ligaments, also contribute to the passive tension.
• Passive Muscle Tension: The muscles on the radial side of the forearm and wrist, such as the extensor carpi radialis longus and brevis and the flexor carpi radialis, are stretched to their physiological limit, contributing to the overall resistance.
• Bony Approximation: While less significant than in radial deviation (where the scaphoid and radius approximate), some approximation of carpal bones may occur, but it is not the primary limiter and does not result in a hard end feel.

Assessing End Feel

Assessing end feel is a standard component of a comprehensive orthopedic examination performed by qualified healthcare professionals such as physical therapists, chiropractors, and athletic trainers. The process involves:

• Passive Movement: The examiner gently moves the patient's joint through its full available range of motion.
• Gentle Overpressure: At the very end of the range, the examiner applies slight, controlled overpressure to feel the quality of resistance that limits further motion.
• Qualitative Assessment: The examiner then categorizes this resistance based on its feel (e.g., firm, soft, hard, empty, springy block).

This assessment helps to identify the specific tissue or structure that is limiting motion and can provide clues about the underlying pathology if an abnormal end feel is detected.

Clinical Significance: Abnormal End Feels

Any deviation from the normal firm/capsular end feel for ulnar deviation can indicate a pathological condition. Recognizing abnormal end feels is crucial for accurate diagnosis and effective treatment planning.

Common Abnormal End Feels and Their Potential Implications for the Wrist:

• Soft (Boggy) End Feel:
  • Description: A mushy, yielding sensation, often feeling like soft tissue compression or swelling.
  • Potential Implications: Joint effusion (swelling within the joint capsule), synovitis (inflammation of the synovial membrane), soft tissue edema, or a torn meniscus (less common in the wrist but possible with specific carpal injuries).
• Hard (Bony) End Feel (Abnormal):
  • Description: An abrupt, unyielding sensation, like bone hitting bone, occurring where it should not normally.
  • Potential Implications: Osteoarthritis with osteophyte formation, loose body within the joint, fracture, heterotopic ossification, or severe capsular contracture. (Note: A hard end feel is normal for movements like elbow extension).
• Empty End Feel:
  • Description: No mechanical resistance is felt at the end of the range, but the patient reports severe pain that prevents the examiner from reaching the true end range of motion.
  • Potential Implications: Severe acute inflammation (e.g., acute bursitis, capsulitis), fracture (especially unstable), severe ligamentous rupture, or psychogenic pain.
• Springy Block End Feel:
  • Description: A rebound or spring-like resistance, usually occurring within the range of motion rather than at the extreme end.
  • Potential Implications: Internal derangement, torn cartilage (e.g., triangular fibrocartilage complex tear in the wrist), or a displaced meniscoid structure (like a loose body getting caught).
• Spasm End Feel:
  • Description: An involuntary muscle contraction that prevents further movement, often accompanied by pain.
  • Potential Implications: Acute inflammation, protective muscle guarding due to injury (e.g., acute ligament sprain, muscle strain), or instability.

Conclusion

The end feel of ulnar deviation is a critical objective measure in assessing wrist joint health. A normal, firm or capsular end feel indicates healthy joint capsule and ligamentous structures. Any deviation from this normal quality, such as a soft, hard, empty, or springy block end feel, serves as a vital diagnostic clue, prompting further investigation into potential pathologies. For anyone experiencing limited or painful wrist motion, a professional assessment by a qualified healthcare provider is essential to determine the underlying cause and guide appropriate treatment.