Muscle Anatomy Overview

Overview of Human Muscular System The following notes detail the various muscles found in the human body, categorized by their location and function. ## Head and Neck Muscles - Epicranius: Composed of the Frontalis and Occipitalis muscles. Responsible for raising eyebrows and moving the scalp. - Frontalis: Part of the Epicranius; assists in forehead movement and expression. - Occipitalis: Another part of the Epicranius; assists in moving the scalp back. - Temporalis: A muscle involved in mastication, located on the side of the head. - Orbicularis Oris: Circular muscle around the mouth, responsible for lip movements. - Orbicularis Oculi: Circular muscle around the eyes, responsible for closing the eyelids. - Masseter: A strong muscle for elevating the mandible, involved in chewing. - Buccinator: A muscle in the cheek that helps with chewing by keeping food between the teeth. - Zygomaticus Major: Responsible for smiling; elevates the corners of the mouth. - Zygomaticus Minor: Aids in facial expressions, specifically smiling. - Transversus Nasalis: Compresses nasal passage. - Sternocleidomastoid: Rotates and flexes the neck, named for its attachment points. - Splenius Capitis: Extends and rotates the head; located at the back of the neck. - Splenius Cervicis: Similar function as Splenius Capitis but located lower in the neck. - Platysma: A thin muscle that covers the neck; helps in facial expressions. ## Shoulders and Upper Limb Muscles - Trapezius: A large muscle that moves the shoulder blade and extends the neck. - Coracobrachialis: Flexes and adducts the arm at the shoulder. - Pectoralis Major: A chest muscle that flexes, extends, adducts, and rotates the arm medially. - Pectoralis Minor: A smaller chest muscle that stabilizes the scapula. - Teres Major: Assists in the internal rotation and adduction of the arm. - Teres Minor: Works alongside the rotator cuff muscles. - Latissimus Dorsi: A large back muscle responsible for extension, adduction, and medial rotation of the arm. - Deltoid: The shoulder muscle that allows for arm abduction and flexion. - Supraspinatus: A rotator cuff muscle that initiates the abduction of the arm. - Subscapularis: A rotator cuff muscle that assists in internal rotation of the arm. - Infraspinatus: A rotator cuff muscle crucial for external rotation. ## Abdomen and Torso Muscles - External Oblique: A muscle on each side of the abdomen; aids in trunk rotation and flexion. - Internal Oblique: Lies under the external oblique; also aids in trunk rotation and flexion. - Rectus Abdominis: The 'abs' muscle; responsible for flexing the lumbar spine. - Transverse Abdominis: The innermost abdominal muscle layer; stabilizes the core. - Serratus Anterior: A muscle primarily involved in the protraction of the scapula. - Serratus Posterior: Assists in respiration by elevating the ribs. - Linea Alba: A fibrous structure that runs vertically down the midline of the abdomen. - Rhomboid Major: Retracts the scapula and stabilizes it. - Rhomboid Minor: Similar role to the Rhomboid Major but smaller and located above it. - Levator Scapulae: Elevates the scapula and helps in neck movement. ## Lower Limb Muscles - Psoas Major: A major hip flexor muscle, crucial for walking and running. - Iliacus (Iliopsoas): Works with Psoas Major in hip flexion. - Gluteus Maximus: The largest gluteal muscle, involved in hip extension. - Gluteus Medius: A muscle located on the lateral aspect of the hip; important for hip stability. - Gluteus Minimus: The smallest gluteal muscle, assists in hip abduction. - Tensor Fasciae Latae: Helps hip abduction and stabilizes the hip and knee. - Iliotibial Tract/Band: A connective tissue that runs along the thigh, assisting in stabilizing the knee. - Pectineus: A muscle that assists in flexing and adducting the thigh. - Adductor Longus: Helps in adduction and flexion of the thigh at the hip. - Adductor Magnus: A large muscle that assists in adduction and also aids in hip extension. - Gracilis: A long, thin muscle that assists in thigh adduction and knee flexion. - Sartorius: The longest muscle in the body; aids in flexing, abducting, and laterally rotating the thigh. - Biceps Femoris: Part of the hamstring group; involved in knee flexion and hip extension. - Semitendinosus: Another hamstring muscle; assists in knee flexion and hip extension. - Semimembranosus: The innermost hamstring muscle; similarly assists in knee flexion and hip extension. - Rectus Femoris: A part of the quad muscle group; extends the knee and flexes the hip. - Vastus Lateralis: The outermost quad muscle; responsible for knee extension. - Vastus Medialis: The most inner quad muscle; aids in knee extension. - Vastus Intermedius: Lies beneath the Rectus Femoris; also aids in knee extension. - Soleus: A muscle in the calf responsible mainly for plantarflexion of the foot. - Tibialis Anterior: Responsible for dorsiflexion of the foot. - Gastrocnemius: A calf muscle involved in knee flexion and plantarflexion. - Fibularis (Peroneus) Longus: A muscle allowing foot eversion and supporting the arch of the foot. - Extensor Digitorum Longus: Assists in extending the toes and dorsiflexion of the foot.