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    Related Topics

    From Musculoskeletal System

    Clavicle
    Collarbone connecting the arm to the body.
    Inferior Nasal Conchae
    Bones inside the nasal cavity that filter and humidify air.
    Brachioradialis
    Muscle responsible for forearm flexion.
    Humerus
    Upper arm bone connecting the shoulder to the elbow.
    Cranial Bones
    Bones of the skull that protect the brain.
    Ligamentum Flavum
    Spinal ligament connecting the laminae of adjacent vertebrae.
    Adductors
    Muscles that bring the thighs toward the midline.
    Tibialis Anterior
    Muscle that dorsiflexes and inverts the foot.
    Hamstrings
    Biceps Femoris, Semitendinosus, Semimembranosus.
    Coccyx
    Tailbone, the remnant of the tail in humans.
    Acromioclavicular Ligament
    Ligament that connects the acromion to the clavicle.
    Ball-and-Socket Joints
    e.g., shoulder, hip
    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    Saddle Joints
    e.g., thumb joint
    Gliding (Plane) Joints
    e.g., between carpals
    Gluteus Maximus
    Largest muscle in the buttocks responsible for hip extension.
    Sternocleidomastoid
    Muscle that rotates and flexes the neck.
    Skull
    Bony structure of the head that encases the brain.
    Syndesmoses
    Fibrous joints where bones are connected by ligaments.
    Gastrocnemius
    Calf muscle responsible for plantarflexion of the foot.
    Sacrum
    Triangular bone at the base of the spine.
    Quadriceps
    Rectus Femoris, Vastus Medialis, Vastus Lateralis, Vastus Intermedius.
    Anterior Cruciate Ligament (ACL)
    Knee ligament that stabilizes the joint.
    Femur
    Thigh bone, the longest and strongest bone in the body.
    Metacarpals (5 bones)
    5 bones forming the palm of the hand.

    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? The pelvic girdle consists of the ilium, ischium, and pubis.