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    Related Topics

    From Musculoskeletal System

    Pelvic Floor Muscles
    Muscles that support pelvic organs.
    Sternocleidomastoid
    Muscle that rotates and flexes the neck.
    Synchondroses
    Cartilaginous joints where bones are connected by hyaline cartilage.
    Sartorius
    Longest muscle in the body responsible for hip flexion.
    Flexor Tendons
    Tendons that help flex the fingers and toes.
    Tarsals (7 bones)
    7 ankle bones.
    Saddle Joints
    e.g., thumb joint
    Acromioclavicular Joint
    The acromioclavicular joint connects the clavicle and scapula at the top of the shoulder, enabling smooth scapular motion and stability during arm movements.
    Gastrocnemius
    Calf muscle responsible for plantarflexion of the foot.
    Sacroiliac Ligaments
    Ligaments connecting the sacrum to the iliac bones.
    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    Hyoid Bone
    U-shaped bone in the neck that supports the tongue.
    Ethmoid Bone
    Bone forming part of the nasal cavity and the orbit.
    Sphenoid Bone
    Bone forming part of the base of the skull and sides of the orbits.
    Flexor and Extensor Groups
    Muscles responsible for flexing and extending the hand and wrist.
    Soleus
    Calf muscle responsible for plantarflexion of the foot.
    Coccygeus
    Pelvic floor muscle supporting the coccyx.
    Anterior Cruciate Ligament (ACL)
    Knee ligament that stabilizes the joint.
    Trapezius
    Muscle responsible for moving, rotating, and stabilizing the scapula.
    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.
    Humerus
    Upper arm bone connecting the shoulder to the elbow.
    Maxillae
    Upper jaw bones that house the teeth and form part of the orbit.
    Ligamentum Flavum
    Spinal ligament connecting the laminae of adjacent vertebrae.
    Posterior Longitudinal Ligament
    Spinal ligament running along the back of the vertebral column.
    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.

    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? Bones in the feet form arches that provide balance and flexibility.