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    Related Topics

    From Musculoskeletal System

    Lateral Collateral Ligament (LCL)
    Knee ligament that stabilizes the outer knee.
    Pelvic Floor Muscles
    Muscles that support pelvic organs.
    Iliolumbar Ligament
    Ligament connecting the ilium and lumbar vertebrae.
    Posterior Cruciate Ligament (PCL)
    Knee ligament that stabilizes the joint.
    Trapezius
    Muscle responsible for moving, rotating, and stabilizing the scapula.
    Coracoacromial Ligament
    Ligament that connects the acromion to the coracoid process.
    Gliding (Plane) Joints
    e.g., between carpals
    Medial Collateral Ligament (MCL)
    Knee ligament that stabilizes the inner knee.
    Ribs (12 Pairs)
    12 pairs of bones that form the sides of the thoracic cage.
    Temporal Bones
    Bones forming the lower sides of the skull and housing the ears.
    Sesamoid Bones
    e.g., patella, some found in hands/feet.
    Humerus
    Upper arm bone connecting the shoulder to the elbow.
    Sternum
    Breastbone located in the center of the chest.
    Parietal Bones
    Bones forming the sides and roof of the skull.
    Pectoralis Major
    Chest muscle responsible for shoulder movement.
    Obliques (External and Internal)
    Muscles responsible for torso rotation.
    Temporalis
    Muscle involved in closing the jaw.
    Thoracic Cage
    Ribs and sternum forming the protective cage for the heart and lungs.
    Metacarpals (5 bones)
    5 bones forming the palm of the hand.
    Patellar Tendon
    Tendon connecting the patella to the tibia.
    Rotator Cuff Muscles
    Supraspinatus, Infraspinatus, Teres Minor, Subscapularis.
    Ulna
    Forearm bone on the pinky side.
    Biceps Brachii
    Muscle responsible for elbow flexion.
    Lumbar Vertebrae (L1 - L5)
    Vertebrae in the lower back (L1-L5).
    Levator Ani
    Pelvic floor muscle responsible for lifting the anus.

    Phalanges (14 bones)

    Reviewed by our medical team

    14 bones forming the toes.

    1. Overview

    The phalanges are the 14 long bones that form the fingers of the hand. Each finger consists of multiple phalanges, which provide the skeletal framework necessary for dexterous hand movements, gripping, and manipulation of objects. These bones are small yet highly mobile and essential for fine motor function.

    2. Location

    The phalanges are located in the distal region of the hand:

    • Proximally: Articulate with the metacarpals at the metacarpophalangeal (MCP) joints.

    • Distally: Form the tips of the fingers (distal phalanges).

    • Each finger (digits 2–5): Has three phalanges – proximal, middle, and distal.

    • Thumb (digit 1): Has only two phalanges – proximal and distal (no middle phalanx).

    3. Structure

    The 14 phalanges are classified based on their position within each digit:

    • Proximal phalanges (5): Articulate with the metacarpals and form the base of each finger.

    • Middle phalanges (4): Present in digits 2–5; absent in the thumb.

    • Distal phalanges (5): Form the tips of the fingers and support the nail bed.

    Each phalanx is a miniature long bone composed of:

    • Base: Proximal end, wider for articulation.

    • Shaft (body): Long cylindrical portion.

    • Head: Distal end, rounded for articulation (except in distal phalanges, which are flattened).

    They are made of cortical and cancellous bone and are lined by periosteum, which supports vascularization and healing.

    4. Function

    The phalanges serve crucial mechanical and functional roles in hand movement:

    • Enable finger motion: Allow flexion, extension, abduction, and adduction at various interphalangeal and metacarpophalangeal joints.

    • Gripping and holding: Essential for precision and power grips.

    • Support fine motor skills: Facilitate tasks like writing, typing, and manipulating small objects.

    • Provide leverage: Serve as attachment points for flexor and extensor tendons, enhancing the effectiveness of muscle contraction.

    5. Physiological role(s)

    Beyond movement, the phalanges contribute to:

    • Tactile sensitivity: Serve as the framework beneath the fingertips, where sensory receptors for touch and temperature are concentrated.

    • Tool interaction: Act as physical extensions of the hand, increasing reach and mechanical advantage.

    • Support nail growth: The distal phalanges anchor nail beds, protecting the tips of the fingers.

    • Force transmission: Transmit forces from fingertips to the hand and wrist during object manipulation or impact.

    6. Clinical Significance

    The phalanges are prone to trauma and overuse injuries due to their size and function:

    • Fractures:

      • Common in contact sports, workplace injuries, or falls; may involve any phalanx and can range from simple to comminuted fractures.

    • Dislocations:

      • Most frequently occur at the interphalangeal or MCP joints, typically from hyperextension injuries.

    • Mallet finger:

      • Avulsion injury of the extensor tendon at the distal phalanx, often due to sudden force to a flexed finger tip.

    • Boutonnière and Swan-neck deformities:

      • Deformities of the interphalangeal joints often associated with rheumatoid arthritis or tendon imbalance.

    • Osteoarthritis and rheumatoid arthritis:

      • Degenerative or inflammatory joint disease affecting the DIP, PIP, or MCP joints, leading to pain, stiffness, and deformity.

    • Congenital anomalies:

      • Conditions such as syndactyly (fusion), polydactyly (extra fingers), or brachydactyly (shortened phalanges) may affect structure and function.

    Did you know? Bone marrow is the site where red blood cells are made.