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    Related Topics

    From Musculoskeletal System

    Interspinous Ligament
    Spinal ligament between adjacent vertebral spinous processes.
    Temporal Bones
    Bones forming the lower sides of the skull and housing the ears.
    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.
    Biceps Brachii
    Muscle responsible for elbow flexion.
    Fibula
    Smaller bone in the lower leg, located alongside the tibia.
    Vertebral Column
    Spinal column consisting of vertebrae.
    Gastrocnemius
    Calf muscle responsible for plantarflexion of the foot.
    Deltoid
    Shoulder muscle responsible for arm abduction.
    Hyoid Bone
    U-shaped bone in the neck that supports the tongue.
    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    Gomphoses
    Fibrous joints where a peg fits into a socket (e.g., teeth in jaw).
    Ribs (12 Pairs)
    12 pairs of bones that form the sides of the thoracic cage.
    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.
    Coccyx
    Tailbone, the remnant of the tail in humans.
    Thoracic Cage
    Ribs and sternum forming the protective cage for the heart and lungs.
    Tarsals (7 bones)
    7 ankle bones.
    Femur
    Thigh bone, the longest and strongest bone in the body.
    Pelvic Floor Muscles
    Muscles that support pelvic organs.
    Nasal Bones
    Bones forming the bridge of the nose.
    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.
    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.
    Lumbar Vertebrae (L1 - L5)
    Vertebrae in the lower back (L1-L5).
    Gliding (Plane) Joints
    e.g., between carpals
    Palatine Bones
    Bones forming part of the hard palate and nasal cavity.
    Diaphragm
    Primary muscle for breathing.

    Syndesmoses

    Reviewed by our medical team

    Fibrous joints where bones are connected by ligaments.

    1. Overview

    Syndesmoses are a type of fibrous joint in which two bones are connected by a sheet or bundle of dense connective tissue, primarily collagen. Unlike sutures, which are immobile, syndesmoses allow for slight but important movement (amphiarthroses). These joints provide strength, stability, and shock absorption, particularly in long bones of the limbs.

    2. Location

    Syndesmoses are found in areas where bones are spaced apart but need to be firmly connected. Common examples include:

    • Distal tibiofibular joint: Between the distal ends of the tibia and fibula in the lower leg.

    • Interosseous membrane of the forearm: Connects the shafts of the radius and ulna.

    • Interosseous membrane of the leg: Runs between the tibia and fibula along their lengths.

    3. Structure

    Syndesmoses are composed primarily of dense fibrous connective tissue:

    • Interosseous membrane or ligament: A strong, flexible sheet of collagen fibers that links the bones.

    • Articulating bones: Are not in direct contact but are held at a fixed distance.

    • Vascularity: These structures are relatively avascular, which slows healing when injured.

    • Innervation: Supplied by nerves that may also relay proprioceptive signals.

    The collagen fiber orientation is often oblique or crisscrossed to optimize force transmission and prevent displacement.

    4. Function

    Syndesmoses have multiple mechanical and supportive functions:

    • Stabilize long bones: Prevent separation and provide strength to the limb skeleton.

    • Transmit force: Distribute mechanical loads between bones during motion (e.g., from the radius to the ulna or from the fibula to the tibia).

    • Permit limited movement: Allow for rotation and gliding motions necessary for daily limb function (e.g., forearm pronation/supination).

    • Maintain joint alignment: Keep articulating bones properly oriented during dynamic activities.

    5. Physiological role(s)

    Beyond structural support, syndesmoses play roles in coordination and functional integration of limb movement:

    • Enhance joint congruency: Allow bones to move together as a unit without dislocation.

    • Provide sensory feedback: Contain mechanoreceptors that contribute to limb proprioception and coordination.

    • Support muscle efficiency: Serve as stable anchors for adjacent muscle attachments.

    6. Clinical Significance

    Injury or dysfunction of syndesmoses can affect limb stability and function:

    • High ankle sprain (syndesmotic sprain):

      • Involves injury to the distal tibiofibular syndesmosis.

      • Common in athletes, causing pain above the ankle, difficulty bearing weight, and prolonged recovery.

    • Interosseous membrane rupture:

      • Can occur due to trauma or fracture (e.g., Essex-Lopresti injury of the forearm).

      • Leads to instability between the radius and ulna, affecting grip and rotation.

    • Surgical implications:

      • Stabilization of distal tibiofibular syndesmosis is often required with screws or suture buttons in fracture repair.

    • Chronic syndesmotic injuries:

      • If untreated, can lead to joint instability, arthritis, and altered gait mechanics.

    • Diagnostic imaging:

      • MRI and stress radiographs are often used to assess ligament integrity in syndesmotic joints.

    Did you know? Bones become stronger when stressed by exercise.