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    Related Topics

    From Musculoskeletal System

    Ribs (12 Pairs)
    12 pairs of bones that form the sides of the thoracic cage.
    Latissimus Dorsi
    Back muscle responsible for arm adduction and extension.
    Pectoralis Major
    Chest muscle responsible for shoulder movement.
    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.
    Gliding (Plane) Joints
    e.g., between carpals
    Rotator Cuff Muscles
    Supraspinatus, Infraspinatus, Teres Minor, Subscapularis.
    Ischium
    Part of the pelvis that supports weight while sitting.
    Sesamoid Bones
    e.g., patella, some found in hands/feet.
    Femur
    Thigh bone, the longest and strongest bone in the body.
    Masseter
    Muscle that elevates the mandible.
    Gomphoses
    Fibrous joints where a peg fits into a socket (e.g., teeth in jaw).
    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.
    Zygomatic Bones
    Cheekbones that form part of the orbit.
    Pivot Joints
    e.g., atlanto-axial joint
    Sacrum
    Triangular bone at the base of the spine.
    Occipital Bone
    Bone forming the back and base of the skull.
    Sutures (in the skull)
    Fibrous joints between skull bones.
    Vomer Bone
    Bone forming the nasal septum.
    Scapula
    Shoulder blade providing attachment for muscles of the upper limb.
    Vertebral Column
    Spinal column consisting of vertebrae.
    Lacrimal Bones
    Bones forming part of the eye socket and housing the tear ducts.
    Ellipsoidal (Condyloid) Joints
    e.g., wrist
    Trapezius
    Muscle responsible for moving, rotating, and stabilizing the scapula.
    Posterior Cruciate Ligament (PCL)
    Knee ligament that stabilizes the joint.
    Rectus Abdominis
    Abs muscle that flexes the trunk.

    Frontal Bone

    Reviewed by our medical team

    Bone forming the forehead and upper part of the orbits.

    1. Overview

    The frontal bone is a flat, unpaired cranial bone that forms the forehead, the superior part of the orbits (eye sockets), and the anterior part of the cranial floor. It plays a vital role in protecting the frontal lobes of the brain and contributes to the shape and structure of the upper face. The frontal bone is part of the neurocranium and has both protective and structural functions.

    2. Location

    The frontal bone is located in the anterior region of the skull:

    • Superiorly: Forms the forehead and part of the anterior cranial vault.

    • Inferiorly: Contributes to the roof of the orbits and the nasal cavity.

    • Laterally: Articulates with the parietal bones at the coronal suture and with the zygomatic bones at the frontozygomatic suture.

    • Posteriorly: Connects with the parietal bones via the coronal suture.

    3. Structure

    The frontal bone is a flat bone with distinct anatomical features:

    • Squamous part (forehead region): Broad and flat; extends upward from the orbits.

    • Orbital part: Forms the roof of each orbit and part of the floor of the anterior cranial fossa.

    • Nasal part: Articulates with the nasal bones and the frontal processes of the maxillae.

    • Glabella: Smooth area between the eyebrows, just above the nasal bridge.

    • Supraorbital margin: The superior rim of the orbit, containing the supraorbital foramen or notch for passage of vessels and nerves.

    • Frontal sinuses: Paired air-filled cavities within the bone, located above the orbits; variable in size and shape.

    • Sutures: The frontal bone fuses with the parietal bones at the coronal suture and may have a persistent metopic suture in some adults (normally fuses during childhood).

    4. Function

    The frontal bone serves several key structural and protective functions:

    • Protects the brain: Shields the frontal lobes from trauma.

    • Forms the forehead: Provides the contour and shape of the upper face.

    • Supports the orbits: Contributes to the orbital roof and thus protects the eyes.

    • Attachment point for facial muscles: Especially for muscles involved in facial expression (e.g., frontalis).

    5. Physiological role(s)

    Besides structural and protective roles, the frontal bone has several physiological contributions:

    • Frontal sinuses: Reduce the weight of the skull, produce mucus to humidify air, and contribute to voice resonance.

    • Neurovascular passage: The supraorbital foramen allows passage of the supraorbital nerve and vessels supplying the forehead and scalp.

    • Muscle interface: Supports the function of the epicranius muscle, which is responsible for forehead movement and facial expressions like raising the eyebrows.

    6. Clinical Significance

    The frontal bone is associated with several clinical considerations:

    • Fractures:

      • Frontal bone fractures, especially involving the frontal sinus or orbital roof, are often the result of high-impact trauma and may be associated with brain injury or CSF leaks.

    • Frontal sinusitis:

      • Inflammation or infection of the frontal sinuses can lead to headache, facial pain, and nasal congestion; may require drainage or antibiotics.

    • Persistent metopic suture:

      • In some adults, the metopic suture fails to fuse completely, which can be mistaken for a skull fracture on radiographs.

    • Craniotomy site:

      • The frontal bone is commonly accessed during neurosurgical procedures (e.g., frontal craniotomy) to reach the frontal lobes of the brain.

    • Congenital anomalies:

      • Craniosynostosis (premature fusion of cranial sutures) involving the coronal suture can lead to abnormal forehead shape and brain development issues.

    Did you know? Your hand has 5 metacarpal bones.