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    Related Topics

    From Musculoskeletal System

    Radius
    Forearm bone on the thumb side.
    Femur
    Thigh bone, the longest and strongest bone in the body.
    Ellipsoidal (Condyloid) Joints
    e.g., wrist
    Parietal Bones
    Bones forming the sides and roof of the skull.
    Hamstrings
    Biceps Femoris, Semitendinosus, Semimembranosus.
    Fibula
    Smaller bone in the lower leg, located alongside the tibia.
    Pubis
    Part of the pelvis that joins with the opposite side to form the pubic symphysis.
    Scapula
    Shoulder blade providing attachment for muscles of the upper limb.
    Thoracic Vertebrae (T1 - T12)
    Vertebrae in the upper and mid-back (T1-T12).
    Frontal Bone
    Bone forming the forehead and upper part of the orbits.
    Coccyx
    Tailbone, the remnant of the tail in humans.
    Buccinator
    Muscle that helps with chewing and blowing air out.
    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.
    Maxillae
    Upper jaw bones that house the teeth and form part of the orbit.
    Sphenoid Bone
    Bone forming part of the base of the skull and sides of the orbits.
    Clavicle
    Collarbone connecting the arm to the body.
    Lumbar Vertebrae (L1 - L5)
    Vertebrae in the lower back (L1-L5).
    Acetabulum
    The acetabulum is the pelvic socket that connects with the femoral head to form the hip joint, vital for stability, movement, and weight-bearing.
    Thoracic Cage
    Ribs and sternum forming the protective cage for the heart and lungs.
    Palatine Bones
    Bones forming part of the hard palate and nasal cavity.
    Vertebral Column
    Spinal column consisting of vertebrae.
    Metacarpals (5 bones)
    5 bones forming the palm of the hand.
    Mandible
    Lower jawbone that houses the teeth.
    Gliding (Plane) Joints
    e.g., between carpals
    Gastrocnemius
    Calf muscle responsible for plantarflexion of the foot.

    Temporalis

    Reviewed by our medical team

    Muscle involved in closing the jaw.

    1. Overview

    The temporalis is a broad, fan-shaped muscle located on the side of the head. It is one of the primary muscles of mastication (chewing) and plays a major role in elevating and retracting the mandible (lower jaw). As a powerful and efficient jaw closer, the temporalis is essential for biting and grinding food.

    2. Location

    The temporalis muscle is located in the temporal fossa of the skull:

    • Origin: Temporal fossa and deep surface of the temporal fascia.

    • Course: Fibers converge downward, passing deep to the zygomatic arch (cheekbone).

    • Insertion: Coronoid process of the mandible and the anterior border of the mandibular ramus.

    3. Structure

    The temporalis muscle has a distinctive fan-shaped morphology:

    • Muscle type: Skeletal muscle (voluntary).

    • Fiber orientation: Posterior fibers run more horizontally, while anterior fibers run vertically, allowing for different movement vectors.

    • Tendon: The tendon passes beneath the zygomatic arch and inserts on the mandible.

    • Innervation: Deep temporal branches of the mandibular nerve (CN V3), a branch of the trigeminal nerve.

    • Blood supply: Deep temporal arteries, branches of the maxillary artery.

    4. Function

    The temporalis muscle has two main actions:

    • Elevation of the mandible: Closes the jaw during biting and chewing.

    • Retraction of the mandible: Posterior fibers pull the mandible backward, especially after protrusion.

    These functions work in coordination with other muscles of mastication like the masseter and medial/lateral pterygoids.

    5. Physiological role(s)

    The temporalis supports important daily and survival functions:

    • Mastication: Enables effective chewing and crushing of food.

    • Speech and articulation: Assists in jaw stabilization required for verbal communication.

    • Postural support of the mandible: Maintains resting tone to prevent jaw from hanging open.

    • Sensory feedback: Via muscle spindles, it contributes to proprioception of jaw position and movement.

    6. Clinical Significance

    The temporalis is involved in several musculoskeletal and neurological conditions:

    • Temporomandibular joint (TMJ) dysfunction:

      • Overactivity or spasm of the temporalis can cause jaw pain, limited range of motion, or headaches.

      • May present with tenderness at the temples or pain radiating toward the ear.

    • Tension-type headaches:

      • Temporalis muscle tension is a common contributor to stress-induced headaches.

    • Bruxism (teeth grinding):

      • Involuntary clenching or grinding of teeth can cause hypertrophy and soreness of the temporalis.

      • Long-term bruxism may lead to dental wear, jaw fatigue, and muscle imbalance.

    • Temporal arteritis (giant cell arteritis):

      • Inflammation of the superficial temporal artery may mimic temporalis-related pain; can lead to serious complications like vision loss.

    • Myofascial pain syndrome:

      • Trigger points in the temporalis can refer pain to the forehead, teeth, and upper jaw.

    Did you know? The coccyx is the remnant of the tailbone in humans.