Muscles of the human body

Introduction to Muscles

  • Importance of muscles in movement and function of the human body.

Muscle Naming

  • Biceps brachii: Prime mover of elbow flexion.

  • Brachioradialis: Synergist assisting in elbow flexion.

  • Brachialis: Another synergist to the biceps brachii.

Fascicular Arrangement Types

  • Circular: Muscles arranged in concentric rings.

  • Convergent: Muscle fibers converge toward a single tendon.

  • Unipennate: Fibers attach to one side of a tendon.

  • Parallel: Fibers run parallel to the length of the muscle.

  • Bipennate: Fibers attach to both sides of a tendon.

  • Fusiform: Spindle-shaped muscles with a central belly.

  • Multipennate: Multiple directions of muscle fibers attached to a central tendon.

Major Muscles of the Body

Anterior View (Superficial and Deep)

  • Occipitofrontalis: Covers the forehead and upper skull.

  • Deltoid: Shoulder muscle for arm abduction.

  • Pectoralis major & minor: Chest muscles; important for arm movements.

  • Rectus abdominis: Core muscle, known as the six-pack.

  • Biceps brachii: Prominent in the upper arm; flexes the elbow.

Posterior View (Superficial and Deep)

  • Trapezius: Upper back muscle; moves should blades and extends the neck.

  • Latissimus dorsi: Large muscle on the back; responsible for arm movement.

  • Gluteus maximus/minimus: Major muscles of the buttocks, important for hip movement.

Facial Muscles

  • Epicranial aponeurosis: Connective tissue that connects the frontal and occipital muscles.

  • Orbicularis oculi: Surrounds the eye; used in blinking.

  • Buccinator: Compresses the cheeks.

Eye Muscles

  • Superior/Inferior rectus: Move the eyes upward and downward.

  • Medial/Lateral rectus: Control eye movement towards the nose and away from it.

  • Superior/Inferior oblique: Allow the eyes to roll.

Muscles of Mastication

  • Masseter: Major chewing muscle, elevates the jaw.

  • Temporalis: Assists in closing the jaw.

  • Pterygoid muscles (medial and lateral): Control jaw movements.

Muscles of the Tongue

  • Genioglossus: Protrudes the tongue.

  • Hyoglossus: Depresses the tongue.

  • Palatoglossus: Elevates the back of the tongue during swallowing.

Neck Muscles

Suprahyoid and Infrahyoid Muscles

  • Digastric: Involved in depressing the mandible.

  • Thyrohyoid: Elevates the larynx.

  • Sternohyoid: Lowers the hyoid bone.

Major Neck Muscles

  • Sternocleidomastoid: Rotates the head and flexes the neck.

  • Trapezius: Elevates shoulders and extends the neck.

Abdominal Muscles

  • Rectus abdominis: Flexes the spine and compresses abdominal cavity.

  • External/Internal oblique: Rotate and flex the trunk.

  • Transversus abdominis: Compresses the abdominal contents.

Thoracic Muscles

  • Pectoralis major and minor: Critical for arm movement.

  • Intercostals: Aid in breathing by expanding and contracting the thoracic cavity.

Pelvic and Perineum Muscles

  • Levator ani: Supports pelvic viscera.

  • Bulbospongiosus: Involved in perineal contractions.

Muscles of the Shoulder and Upper Arm

  • Deltoid: Main muscle for shoulder abduction.

  • Biceps brachii: Flexes the forearm.

  • Triceps brachii: Extends the forearm.

Forearm Muscles

  • Brachioradialis: Flexes the forearm.

  • Flexor carpi radialis and ulnaris: Move the wrist.

  • Extensors: Extend the fingers and wrists.

Muscles of the Thigh and Pelvis

  • Gluteus maximus: Powerful hip extender.

  • Quadriceps: Group of muscles that extend the knee.

  • Hamstrings: Flex the knee.

Muscles of the Lower Leg

  • Gastrocnemius and Soleus: Major muscles for plantar flexion of the foot.

  • Tibialis anterior: Dorsiflexes the foot.

Foot Muscles

  • Flexor/Extensor Digitorum: Control toe movements.

  • Intrinsic muscles: Aid in maintaining the arches of the foot.

  • Underlined Main Muscle Movement:

    • Muscle Movement: Often involves several muscles working together for flexion, extension, and rotation, depending on the specific activity.

  • Muscle that Wraps Around the Eye:

    • Orbicularis oculi: Surrounds the eye and is used in blinking.

  • Term that Means Tongue:

    • Glossus: Refers to muscles associated with the tongue (e.g., genioglossus, hyoglossus, palatoglossus).

  • Number of Hamstring Muscles:

    • Three: Consist of the biceps femoris, semitendinosus, and semimembranosus.

  • Number of Quadriceps Muscles:

    • Four: Include the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius.