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    Related Topics

    From Musculoskeletal System

    Rotator Cuff Tendons
    Tendons of the rotator cuff muscles.
    Ball-and-Socket Joints
    e.g., shoulder, hip
    Glenohumeral Ligaments
    Shoulder ligaments that stabilize the shoulder joint.
    Ligamentum Flavum
    Spinal ligament connecting the laminae of adjacent vertebrae.
    Achilles Tendon
    Tendon connecting the calf muscle to the heel bone.
    Saddle Joints
    e.g., thumb joint
    Anterior Cruciate Ligament (ACL)
    Knee ligament that stabilizes the joint.
    Carpals (8 bones)
    8 wrist bones.
    Triceps Brachii
    Muscle responsible for elbow extension.
    Tibia
    Shin bone, the larger bone in the lower leg.
    Pelvic Floor Muscles
    Muscles that support pelvic organs.
    Sesamoid Bones
    e.g., patella, some found in hands/feet.
    Levator Ani
    Pelvic floor muscle responsible for lifting the anus.
    Syndesmoses
    Fibrous joints where bones are connected by ligaments.
    Ethmoid Bone
    Bone forming part of the nasal cavity and the orbit.
    Annular Ligament
    The annular ligament is a strong fibrous band encircling the head of the radius, stabilizing the proximal radioulnar joint and allowing smooth rotation of the forearm.
    Coccygeus
    Pelvic floor muscle supporting the coccyx.
    Sutures (in the skull)
    Fibrous joints between skull bones.
    Buccinator
    Muscle that helps with chewing and blowing air out.
    Acromioclavicular Ligament
    Ligament that connects the acromion to the clavicle.
    Quadriceps
    Rectus Femoris, Vastus Medialis, Vastus Lateralis, Vastus Intermedius.
    Sphenoid Bone
    Bone forming part of the base of the skull and sides of the orbits.
    Interspinous Ligament
    Spinal ligament between adjacent vertebral spinous processes.
    Latissimus Dorsi
    Back muscle responsible for arm adduction and extension.
    Ischium
    Part of the pelvis that supports weight while sitting.

    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? Your hand has 5 metacarpal bones.