Logo

    Related Topics

    From Musculoskeletal System

    Pivot Joints
    e.g., atlanto-axial joint
    Ribs (12 Pairs)
    12 pairs of bones that form the sides of the thoracic cage.
    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    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.
    Lumbar Vertebrae (L1 - L5)
    Vertebrae in the lower back (L1-L5).
    Humerus
    Upper arm bone connecting the shoulder to the elbow.
    Gluteus Maximus
    Largest muscle in the buttocks responsible for hip extension.
    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.
    Biceps Brachii
    Muscle responsible for elbow flexion.
    Sacroiliac Ligaments
    Ligaments connecting the sacrum to the iliac bones.
    Masseter
    Muscle that elevates the mandible.
    Radius
    Forearm bone on the thumb side.
    Patellar Tendon
    Tendon connecting the patella to the tibia.
    Flexor and Extensor Groups
    Muscles responsible for flexing and extending the hand and wrist.
    Sartorius
    Longest muscle in the body responsible for hip flexion.
    Zygomatic Bones
    Cheekbones that form part of the orbit.
    Gliding (Plane) Joints
    e.g., between carpals
    Patella
    Knee cap, protecting the knee joint.
    Wormian Bones
    Sutural bones in the skull.
    Latissimus Dorsi
    Back muscle responsible for arm adduction and extension.
    Saddle Joints
    e.g., thumb joint
    Interspinous Ligament
    Spinal ligament between adjacent vertebral spinous processes.
    Buccinator
    Muscle that helps with chewing and blowing air out.
    Hamstrings
    Biceps Femoris, Semitendinosus, Semimembranosus.
    Inferior Nasal Conchae
    Bones inside the nasal cavity that filter and humidify air.

    Symphyses

    Reviewed by our medical team

    Cartilaginous joints where bones are connected by fibrocartilage.

    1. Overview

    A symphysis is a type of cartilaginous joint where two bones are joined together by a pad of fibrocartilage. These joints are amphiarthrotic, meaning they allow limited movement while maintaining strong structural integrity. Symphyses are found in the axial skeleton and serve important roles in absorbing shock and providing stability to the body’s midline.

    2. Location

    Symphyses are located along the midline of the body, primarily in the axial skeleton. Major examples include:

    • Pubic symphysis: Between the two pubic bones of the pelvis.

    • Intervertebral discs: Between the vertebral bodies from C2 to the sacrum.

    • Manubriosternal joint: Between the manubrium and the body of the sternum (may ossify with age).

    3. Structure

    Symphyses are composed of:

    • Articulating bones: Covered with a thin layer of hyaline cartilage.

    • Fibrocartilaginous disc: A strong, compressible pad of fibrocartilage situated between the bones.

    • No synovial cavity: Unlike synovial joints, symphyses do not contain a joint capsule or synovial fluid.

    • Limited vascularity: Fibrocartilage has a poor blood supply, especially in central areas.

    Despite their simplicity, symphyses are durable and adaptable, with a structure optimized for both stability and resilience.

    4. Function

    Symphyses serve key mechanical and supportive functions:

    • Shock absorption: The fibrocartilage discs cushion forces transmitted between bones, especially during weight-bearing activities.

    • Limited movement: Allow slight movement for flexibility, such as vertebral bending or expansion of the pelvis during childbirth.

    • Joint stability: Provide firm articulation in regions where strength and minimal mobility are required.

    5. Physiological role(s)

    Symphyses play roles beyond mechanical function:

    • Spinal flexibility: Intervertebral symphyses allow bending, twisting, and compression of the vertebral column while protecting the spinal cord.

    • Pelvic expansion: The pubic symphysis loosens under the influence of hormones like relaxin during pregnancy, allowing safe passage during childbirth.

    • Height maintenance: Intervertebral discs contribute to overall height and slightly compress throughout the day with activity.

    6. Clinical Significance

    Symphyses are involved in several clinical conditions:

    • Degenerative disc disease:

      • Intervertebral discs may lose hydration and elasticity with age, leading to pain, reduced flexibility, and nerve compression.

    • Herniated disc:

      • Protrusion of the nucleus pulposus through the annulus fibrosus in intervertebral symphyses, potentially compressing spinal nerves.

    • Symphysis pubis dysfunction (SPD):

      • Common during pregnancy due to increased ligament laxity; causes pain in the pubic area and difficulty with walking or climbing stairs.

    • Ankylosis:

      • Fusion of the symphysis, either due to age (e.g., manubriosternal joint) or disease (e.g., ankylosing spondylitis).

    • Inflammatory conditions:

      • Symphysitis or inflammation of a symphysis joint can cause localized pain, such as osteitis pubis seen in athletes or post-surgery patients.

    Did you know? The tibia is the second largest bone in the body after the femur.