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    From Musculoskeletal System

    Zygomaticus
    Muscle that raises the corners of the mouth.
    Saddle Joints
    e.g., thumb joint
    Obliques (External and Internal)
    Muscles responsible for torso rotation.
    Metatarsals (5 bones)
    5 bones forming the mid-foot.
    Rectus Abdominis
    Abs muscle that flexes the trunk.
    Pivot Joints
    e.g., atlanto-axial joint
    Metacarpals (5 bones)
    5 bones forming the palm of the hand.
    Femur
    Thigh bone, the longest and strongest bone in the body.
    Hinge Joints
    e.g., elbow, knee
    Achilles Tendon
    Tendon connecting the calf muscle to the heel bone.
    Coccygeus
    Pelvic floor muscle supporting the coccyx.
    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.
    Sartorius
    Longest muscle in the body responsible for hip flexion.
    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    Thoracic Cage
    Ribs and sternum forming the protective cage for the heart and lungs.
    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.
    Sesamoid Bones
    e.g., patella, some found in hands/feet.
    Trapezius
    Muscle responsible for moving, rotating, and stabilizing the scapula.
    Sternocleidomastoid
    Muscle that rotates and flexes the neck.
    Tibialis Anterior
    Muscle that dorsiflexes and inverts the foot.
    Temporalis
    Muscle involved in closing the jaw.
    Diaphragm
    Primary muscle for breathing.
    Frontal Bone
    Bone forming the forehead and upper part of the orbits.
    Sacrum
    Triangular bone at the base of the spine.
    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.

    Zygomatic Bones

    Reviewed by our medical team

    Cheekbones that form part of the orbit.

    1. Overview

    The zygomatic bones are paired facial bones that form the prominent part of the cheeks and contribute to the lateral wall and floor of the orbit. Often referred to as the “cheekbones,” they are key structural components of the midface and play a critical role in facial aesthetics, articulation with surrounding bones, and protection of orbital contents.

    2. Location

    The zygomatic bones are located on the lateral aspect of the midface:

    • Lateral to: The maxilla and nasal bones.

    • Inferior to: The frontal bone and lateral margin of the orbit.

    • Anterior to: The temporal bone, with which it forms the zygomatic arch.

    Each zygomatic bone articulates with four bones: the frontal, maxilla, sphenoid, and temporal bones.

    3. Structure

    Each zygomatic bone has a robust and quadrangular shape, with several important features:

    • Orbital surface: Forms part of the lateral wall and floor of the orbit.

    • Temporal surface: Faces posteriorly to form part of the zygomatic arch.

    • Maxillary surface: Articulates with the maxilla, contributing to the infraorbital rim.

    • Zygomatic arch: Formed by the zygomatic process of the temporal bone and temporal process of the zygomatic bone; serves as a bridge between face and skull.

    • Zygomaticofacial foramen: Allows passage of the zygomaticofacial nerve and vessels to the skin of the cheek.

    4. Function

    The zygomatic bones serve several structural and functional roles:

    • Facial contour: Provide the prominence of the cheeks and define facial width and aesthetics.

    • Orbital protection: Form part of the orbit and help shield the eye from lateral impact.

    • Muscle attachment: Serve as attachment sites for facial expression muscles (e.g., zygomaticus major and minor).

    • Bridge to cranium: Link facial bones with the neurocranium via the zygomatic arch.

    5. Physiological role(s)

    Though the zygomatic bones are not directly involved in metabolic functions, they contribute indirectly to important physiological roles:

    • Facial muscle coordination: Facilitate facial expressions such as smiling and speaking.

    • Mechanical load transfer: Distribute masticatory forces from the maxilla to the cranial base through the zygomatic arch.

    • Support of orbital structures: Maintain orbital geometry essential for proper ocular alignment and vision.

    6. Clinical Significance

    Zygomatic bones are frequently involved in facial trauma and reconstructive surgery:

    • Zygomatic fractures:

      • Often result from blunt trauma (e.g., sports injuries, vehicle accidents).

      • May cause flattening of the cheek, trismus (jaw movement limitation), diplopia (double vision), or infraorbital nerve injury.

    • Tripod fracture:

      • A common type of zygomatic complex fracture involving three points: zygomatic arch, orbital floor, and maxillary articulation.

      • Often requires surgical realignment and fixation.

    • Zygomaticomaxillary complex (ZMC) fracture:

      • Involves the zygomatic bone and its articulations; affects aesthetics and function.

    • Cosmetic and reconstructive relevance:

      • Important in procedures involving midfacial augmentation or repair after trauma or congenital deformity.

    • Infections and tumors:

      • Though rare, the zygomatic bone may be affected by osteomyelitis, fibrous dysplasia, or metastatic lesions.

    Did you know? Bone marrow is the site where red blood cells are made.