Logo

    Related Topics

    From Musculoskeletal System

    Clavicle
    Collarbone connecting the arm to the body.
    Saddle Joints
    e.g., thumb joint
    Sesamoid Bones
    e.g., patella, some found in hands/feet.
    Sternocleidomastoid
    Muscle that rotates and flexes the neck.
    Parietal Bones
    Bones forming the sides and roof of the skull.
    Hyoid Bone
    U-shaped bone in the neck that supports the tongue.
    Metacarpals (5 bones)
    5 bones forming the palm of the hand.
    Patella
    Knee cap, protecting the knee joint.
    Deltoid
    Shoulder muscle responsible for arm abduction.
    Anterior Scalene Muscle
    The anterior scalene muscle is a deep neck muscle that elevates the first rib during inspiration and aids in neck flexion and stability, located between key neurovascular structures.
    Wormian Bones
    Sutural bones in the skull.
    Temporalis
    Muscle involved in closing the jaw.
    Thoracic Vertebrae (T1 - T12)
    Vertebrae in the upper and mid-back (T1-T12).
    Thoracic Cage
    Ribs and sternum forming the protective cage for the heart and lungs.
    Rectus Abdominis
    Abs muscle that flexes the trunk.
    Latissimus Dorsi
    Back muscle responsible for arm adduction and extension.
    Tarsals (7 bones)
    7 ankle bones.
    Gliding (Plane) Joints
    e.g., between carpals
    Coracoacromial Ligament
    Ligament that connects the acromion to the coracoid process.
    Extensor Tendons
    Tendons that help extend the fingers and toes.
    Pelvic Floor Muscles
    Muscles that support pelvic organs.
    Temporal Bones
    Bones forming the lower sides of the skull and housing the ears.
    Ischium
    Part of the pelvis that supports weight while sitting.
    Symphyses
    Cartilaginous joints where bones are connected by fibrocartilage.
    Brachioradialis
    Muscle responsible for forearm flexion.

    Ellipsoidal (Condyloid) Joints

    Reviewed by our medical team

    e.g., wrist

    1. Overview

    An ellipsoidal joint, also known as a condyloid joint, is a type of synovial joint that permits movement in two planes: flexion–extension and abduction–adduction. These biaxial joints have an oval-shaped condyle of one bone fitting into the elliptical cavity of another, allowing angular but not rotational movement. Ellipsoidal joints are essential for precise, controlled motion and are found in areas requiring coordinated mobility and stability.

    2. Location

    Ellipsoidal joints are present in several key areas of the body:

    • Wrist joint (radiocarpal joint): Between the distal radius and the scaphoid and lunate carpal bones.

    • Metacarpophalangeal joints (MCPs): Between the heads of metacarpal bones and bases of proximal phalanges in the fingers (knuckle joints).

    • Atlanto-occipital joint: Between the occipital condyles of the skull and the superior facets of the atlas (C1 vertebra).

    • Metatarsophalangeal joints (MTPs): Similar joints in the toes.

    3. Structure

    Ellipsoidal joints are structured for complex movement within a confined range:

    • Articular surfaces: One surface is an oval convex condyle, and the other is a reciprocally shaped concave surface.

    • Joint capsule: Encloses the joint and is lined by a synovial membrane that secretes synovial fluid.

    • Synovial fluid: Lubricates the joint, reduces friction, and nourishes articular cartilage.

    • Ligaments: Surround and stabilize the joint, preventing excessive or abnormal movement.

    • Articular cartilage: Covers the joint surfaces, allowing smooth, low-friction interaction between bones.

    4. Function

    Ellipsoidal joints allow a range of controlled, angular motions:

    • Flexion and extension: Movement in the sagittal plane, such as bending and straightening fingers.

    • Abduction and adduction: Movement in the coronal plane, such as spreading fingers apart or bringing them together.

    • Circumduction: A circular, conical motion combining flexion, extension, abduction, and adduction (but no axial rotation).

    5. Physiological role(s)

    Ellipsoidal joints play crucial roles in fine and gross motor function:

    • Manual dexterity: MCP joints are key to grasping, pinching, and manipulating objects with precision.

    • Postural alignment: Atlanto-occipital joint helps support head posture and balance.

    • Locomotion support: MTP joints contribute to propulsion and toe-off during walking and running.

    • Articulation balance: These joints enable complex joint interplay without compromising stability.

    6. Clinical Significance

    Several conditions can affect ellipsoidal joints and impair their function:

    • Osteoarthritis:

      • Degeneration of articular cartilage in MCP or wrist joints causes stiffness, pain, and loss of function.

    • Rheumatoid arthritis:

      • Commonly affects MCP joints with joint swelling, deformity (e.g., ulnar drift), and inflammation.

    • Atlanto-occipital dislocation:

      • A rare but life-threatening injury where the skull becomes dislodged from the spine, often due to trauma.

    • Joint contracture or stiffness:

      • Prolonged immobility or scarring may limit movement at ellipsoidal joints, particularly in the fingers.

    • Joint injections or aspiration:

      • Inflamed or swollen ellipsoidal joints, especially the wrist, may require corticosteroid injections or fluid removal for relief.

    Did you know? Ligaments hold bones together and are tough yet flexible.