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    Related Topics

    From Musculoskeletal System

    Sesamoid Bones
    e.g., patella, some found in hands/feet.
    Carpals (8 bones)
    8 wrist bones.
    Rotator Cuff Tendons
    Tendons of the rotator cuff muscles.
    Posterior Longitudinal Ligament
    Spinal ligament running along the back of the vertebral column.
    Sartorius
    Longest muscle in the body responsible for hip flexion.
    Tarsals (7 bones)
    7 ankle bones.
    Obliques (External and Internal)
    Muscles responsible for torso rotation.
    Sutures (in the skull)
    Fibrous joints between skull bones.
    Thoracic Cage
    Ribs and sternum forming the protective cage for the heart and lungs.
    Sacroiliac Ligaments
    Ligaments connecting the sacrum to the iliac bones.
    Coccyx
    Tailbone, the remnant of the tail in humans.
    Saddle Joints
    e.g., thumb joint
    Hyoid Bone
    U-shaped bone in the neck that supports the tongue.
    Flexor Tendons
    Tendons that help flex the fingers and toes.
    Lateral Collateral Ligament (LCL)
    Knee ligament that stabilizes the outer knee.
    Zygomaticus
    Muscle that raises the corners of the mouth.
    Abductor Digiti Minimi Muscle
    The abductor digiti minimi muscle is a hypothenar muscle that abducts and flexes the little finger, aiding grip and precision in hand movements.
    Coracoacromial Ligament
    Ligament that connects the acromion to the coracoid process.
    Pelvic Floor Muscles
    Muscles that support pelvic organs.
    Acromioclavicular Ligament
    Ligament that connects the acromion to the clavicle.
    Metacarpals (5 bones)
    5 bones forming the palm of the hand.
    Masseter
    Muscle that elevates the mandible.
    Fibula
    Smaller bone in the lower leg, located alongside the tibia.
    Ligamentum Flavum
    Spinal ligament connecting the laminae of adjacent vertebrae.
    Vomer Bone
    Bone forming the nasal septum.

    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 sternocleidomastoid muscle helps rotate the head.