Upper and Lower Body Muscles: Anatomy, Origins, Insertions, Actions

Occipitofrontalis

A muscle that covers the top of the skull and is responsible for raising the eyebrows and wrinkling the forehead.

Cranial aponeurosis

A fibrous sheet that connects the occipitofrontalis muscle to the skull.

Orbicularis oculi

A circular muscle around the eye that allows for blinking and closing the eyelids.

Zygomaticus major/minor

Muscles that elevate the corners of the mouth, contributing to smiling.

Orbicularis oris

A circular muscle around the mouth that controls movements of the lips.

Buccinator

A muscle of the cheek that helps in chewing by keeping food between the teeth.

Masseter

A powerful muscle that elevates the mandible, playing a key role in chewing.

Temporalis

A fan-shaped muscle on the side of the head that assists in closing the jaw.

Sternocleidomastoid

A muscle that allows for rotation and flexion of the neck.

Platysma

A superficial muscle that covers the neck and helps in depressing the jaw.

Semispinalis capitis

A muscle located in the back of the neck that aids in extending and rotating the head.

Intercostals

Muscles located between the ribs that assist in breathing by expanding and contracting the thoracic cavity.

Diaphragm

A dome-shaped muscle that separates the thoracic cavity from the abdominal cavity and is the primary muscle of respiration.

External oblique

Muscles located on the sides of the abdomen that help in trunk rotation and lateral flexion.

Internal oblique

Muscles located beneath the external obliques that assist in trunk rotation and flexion.

Transversus abdominis

The deepest abdominal muscle that helps stabilize the core.

Rectus abdominis

A long muscle that extends along the front of the abdomen, commonly known as the 'abs', responsible for flexing the spine.

Erector spinae

A group of muscles that run along the spine and are responsible for extending the back.

Iliocostalis

The most lateral muscle of the erector spinae group that helps in extending and laterally flexing the spine.

Longissimus

The intermediate muscle of the erector spinae group that extends the spine and rotates the head.

Spinalis

The most medial muscle of the erector spinae group, assisting in spinal extension.

Quadratus lumborum

A muscle of the lower back that helps in lateral flexion of the spine.

Trapezius

A large muscle that extends from the neck to the middle of the back, responsible for moving, rotating, and stabilizing the shoulder blade.

Pectoralis minor

A thin, flat muscle located beneath the pectoralis major that helps in stabilizing the scapula.

Serratus anterior

A muscle that helps in the upward rotation of the scapula and is important for shoulder movement.

Levator scapulae

A muscle that elevates the scapula and assists in neck movement.

Rhomboid major

A muscle that retracts the scapula and helps in stabilizing it.

Rhomboid minor

A smaller muscle that also retracts and stabilizes the scapula.

Pectoralis major

A large muscle of the chest that is responsible for the movement of the shoulder joint.

Latissimus dorsi

A large muscle of the back that extends, adducts, and rotates the arm.

Deltoid

A muscle that forms the rounded contour of the shoulder and is responsible for arm abduction.

Supraspinatus

A muscle that assists in arm abduction and stabilizes the shoulder joint.

Teres minor

A small muscle that helps in the lateral rotation of the arm.

Teres major

A muscle that assists in the medial rotation and adduction of the arm.

Infraspinatus

A muscle that laterally rotates the arm and stabilizes the shoulder joint.

Subscapularis

A muscle that medially rotates the arm and stabilizes the shoulder joint.

Biceps brachii

A muscle of the upper arm that flexes the elbow and supinates the forearm.

Brachialis

A muscle that flexes the elbow joint.

Brachioradialis

A muscle that flexes the forearm at the elbow.

Triceps brachii

A muscle of the upper arm that extends the elbow.

Pronator teres

A muscle that pronates the forearm.

Flexor carpi radialis

A muscle that flexes and abducts the wrist.

Extensor carpi radialis longus

A muscle that extends and abducts the wrist.

Flexor digitorum profundus

A muscle that flexes the fingers and the wrist.

Flexor digitorum superficialis

A muscle that flexes the fingers and the wrist.

Extensor digitorum

A muscle that extends the fingers.

Opponens pollicis

A muscle that allows for opposition of the thumb.

Rectus femoris

A muscle of the quadriceps that extends the knee and flexes the hip.

Vastus lateralis

A muscle of the quadriceps that extends the knee.

Vastus medialis

A muscle of the quadriceps that extends the knee.

Vastus intermedius

A muscle of the quadriceps that extends the knee.

Sartorius

A muscle that flexes, abducts, and laterally rotates the hip.

Biceps femoris

A muscle of the hamstrings that flexes the knee and extends the hip.

Semitendinosus

A muscle of the hamstrings that flexes the knee and extends the hip.

Semimembranosus

A muscle of the hamstrings that flexes the knee and extends the hip.

Adductor magnus

A muscle that adducts the thigh and assists in hip extension.

Adductor longus

A muscle that adducts the thigh.

Adductor brevis

A muscle that adducts the thigh.

Gracilis

A muscle that adducts the thigh and flexes the knee.

Iliopsoas

A major hip flexor composed of psoas major and iliacus.

Psoas major

A muscle that flexes the hip and stabilizes the lumbar spine.

Iliacus

A muscle that flexes the hip.

Gluteus maximus

The largest muscle of the buttocks, responsible for hip extension and external rotation.

Gluteus medius

A muscle that abducts and medially rotates the thigh.

Gluteus minimus

A muscle that abducts and medially rotates the thigh.

Piriformis

A muscle that laterally rotates the hip.

Obturator externus

A muscle that laterally rotates the thigh.

Quadratus femoris

A muscle that laterally rotates the thigh.

Tibialis anterior

A muscle that dorsiflexes and inverts the foot.

Extensor digitorum longus

A muscle that extends the toes and dorsiflexes the foot.

Peroneus longus

A muscle that everts and plantarflexes the foot.

Peroneus brevis

A muscle that everts and plantarflexes the foot.

Gastrocnemius

A muscle that plantarflexes the foot and flexes the knee.

Soleus

A muscle that plantarflexes the foot.

Plantaris

A small muscle that assists in knee flexion and plantarflexion of the foot.

Flexor digitorum longus

A muscle that flexes the toes and plantarflexes the foot.

Flexor hallucis longus

A muscle that flexes the big toe and plantarflexes the foot.

Tibialis posterior

A muscle that plantarflexes and inverts the foot.