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    Related Topics

    From Musculoskeletal System

    Extensor Tendons
    Tendons that help extend the fingers and toes.
    Thoracic Vertebrae (T1 - T12)
    Vertebrae in the upper and mid-back (T1-T12).
    Ellipsoidal (Condyloid) Joints
    e.g., wrist
    Femur
    Thigh bone, the longest and strongest bone in the body.
    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.
    Facial Bones
    Bones forming the structure of the face.
    Vomer Bone
    Bone forming the nasal septum.
    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.
    Metacarpals (5 bones)
    5 bones forming the palm of the hand.
    Diaphragm
    Primary muscle for breathing.
    Gliding (Plane) Joints
    e.g., between carpals
    Vertebral Column
    Spinal column consisting of vertebrae.
    Hamstrings
    Biceps Femoris, Semitendinosus, Semimembranosus.
    Cranial Bones
    Bones of the skull that protect the brain.
    Brachioradialis
    Muscle responsible for forearm flexion.
    Hyoid Bone
    U-shaped bone in the neck that supports the tongue.
    Levator Ani
    Pelvic floor muscle responsible for lifting the anus.
    Quadriceps Tendon
    Tendon that connects the quadriceps to the patella.
    Pectoralis Major
    Chest muscle responsible for shoulder movement.
    Lumbar Vertebrae (L1 - L5)
    Vertebrae in the lower back (L1-L5).
    Saddle Joints
    e.g., thumb joint
    Inferior Nasal Conchae
    Bones inside the nasal cavity that filter and humidify air.
    Radius
    Forearm bone on the thumb side.
    Pubis
    Part of the pelvis that joins with the opposite side to form the pubic symphysis.
    Ligamentum Flavum
    Spinal ligament connecting the laminae of adjacent vertebrae.

    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 wrist has 8 bones, while the ankle has 7.