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    Related Topics

    From Musculoskeletal System

    Gluteus Maximus
    Largest muscle in the buttocks responsible for hip extension.
    Patella
    Knee cap, protecting the knee 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.
    Flexor and Extensor Groups
    Muscles responsible for flexing and extending the hand and wrist.
    Metacarpals (5 bones)
    5 bones forming the palm of the hand.
    Scapula
    Shoulder blade providing attachment for muscles of the upper limb.
    Synchondroses
    Cartilaginous joints where bones are connected by hyaline cartilage.
    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    Symphyses
    Cartilaginous joints where bones are connected by fibrocartilage.
    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.
    Fibula
    Smaller bone in the lower leg, located alongside the tibia.
    Posterior Longitudinal Ligament
    Spinal ligament running along the back of the vertebral column.
    Sutures (in the skull)
    Fibrous joints between skull bones.
    Palatine Bones
    Bones forming part of the hard palate and nasal cavity.
    Posterior Cruciate Ligament (PCL)
    Knee ligament that stabilizes the joint.
    Sesamoid Bones
    e.g., patella, some found in hands/feet.
    Hinge Joints
    e.g., elbow, knee
    Hyoid Bone
    U-shaped bone in the neck that supports the tongue.
    Acromioclavicular Ligament
    Ligament that connects the acromion to the clavicle.
    Diaphragm
    Primary muscle for breathing.
    Pubis
    Part of the pelvis that joins with the opposite side to form the pubic symphysis.
    Facial Bones
    Bones forming the structure of the face.
    Sternocleidomastoid
    Muscle that rotates and flexes the neck.
    Zygomatic Bones
    Cheekbones that form part of the orbit.
    Carpals (8 bones)
    8 wrist bones.

    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? The adult human body contains around 60,000 miles of blood vessels.