Muscular System: Parts w Definitions

occipitalis

A muscle of the scalp, part of the occipitofrontalis, located at the back of the head. It draws the scalp posteriorly.

splenius capitis

A muscle located in the back of the neck, it extends the head and supports its rotation. It is involved in movements such as tilting and turning the head.

Trapezius

A large triangular muscle located in the upper back, it extends the neck, elevates the shoulders, and aids in the movement of the scapulae.

aponeurosis of occipitofrontalis

A broad, flat tendon that connects the occipitalis and frontalis muscles, allowing for movement of the scalp.

occipitofrontalis

A muscle located in the forehead and the back of the head, responsible for raising the eyebrows, and moving the scalp.

orbicularis oris

The muscle that encircles the mouth, responsible for movements such as puckering and closing the lips.

orbicularis oculi

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

zygomaticus major

A muscle that controls smiling by elevating the corners of the mouth and is located in the cheek area.

sternocleidomastoid

A muscle in the neck that helps rotate and flex the head.

deltoid

A large triangular muscle that covers the shoulder and is responsible for arm abduction, flexion, and extension.

infraspinatus

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

triceps

A large muscle located at the back of the upper arm that functions to extend the elbow.

teres minor

A small muscle located in the shoulder that helps in the lateral rotation and stabilization of the shoulder joint.

teres major

A muscle located beneath the shoulder joint that assists in the movement and stability of the arm, particularly in adduction and extension.

latissimus dorsi

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

flexor carpi ulnaris

A muscle of the forearm that flexes and adducts the wrist.

external oblique

A muscle located on the side of the abdomen that helps rotate and bend the trunk, as well as support the abdominal wall.

erector spinae

it is covered by lumbar fascia

gluteus maximus

The largest muscle in the buttocks, responsible for hip extension and outward rotation of the thigh.

semitendinosus

A muscle located in the posterior compartment of the thigh, it aids in knee flexion and hip extension.

biceps femoris

a muscle in the back of the thigh which helps to flex the leg.

semimembranosus

a muscle in the posterior (back) compartment of the thigh, located deep to the semitendinosus muscle

gastrocnemius

the chief muscle of the calf of the leg, which flexes the knee and foot.

tendo calcaneus

also known as the Achilles tendon or calcaneal tendon, is the thickest and strongest tendon in the human body.

tendons of extensor digitorum longus

passes under the superior and inferior extensor retinaculum at the anterior surface of the ankle joint before reaching it's distal insertion

extensor digitorum longus

a muscle in the anterior compartment of the lower leg that extends the lateral four toes and contributes to dorsiflexion of the ankle (lifting the foot upwards).

soleus

a broad muscle in the lower calf, below the gastrocnemius, that flexes the foot to point the toes downward.

tibialis anterior

the large, thick muscle on the front of your lower leg, lateral to the tibia

peroneus longus

a muscle in the lower leg's lateral compartment that helps with foot eversion (turning the sole of the foot outward) and plantarflexion (pointing the toes down).

ligamentum patellae

the continuation of the quadriceps tendon that extends from the apex (bottom point) of the patella (kneecap) to the tibial tuberosity on the top of the shinbone

vastus medialis

one of the four muscles that form the quadriceps femoris group, located in the anterior (front) compartment of the thigh.

vastus lateralis

the largest muscle of the quadriceps femoris group, located on the outer side of the thigh

rectus femoris

the anterior muscle of the thigh and a major component of the quadriceps muscle group

gracilis

the most superficial and longest muscle in the medial compartment of the thigh, extending from the pubic bone to the tibia

sartorius

he longest muscle in the human body, located in the thigh

adductor longus

a large, fan-shaped muscle on the medial (inner) side of the thigh, originating from the pubic bone and inserting onto the linea aspera of the femur

pectineus

a large, fan-shaped muscle on the medial (inner) side of the thigh, originating from the pubic bone and inserting onto the linea aspera of the femur

iliopsoas

the primary hip flexor, formed by the joining of the psoas major and iliacus muscles, connecting the lumbar spine and ilium to the lesser trochanter of the femur

extensor carpi radialis longus and brevis

produce wrist extension and abduction (radial deviation)

Brachioradialis

a superficial forearm muscle located on the lateral (thumb side) of the forearm.

pronator teres

a fusiform muscle in the superficial layer of the anterior forearm that originates from the humerus and ulna and inserts onto the radius, primarily serving to rotate the forearm to a palm-down position (pronation)

brachialis

the primary elbow flexor, lying deep to the biceps brachii in the upper arm

biceps brachii

a two-headed muscle located on the front of the upper arm, responsible for flexing the elbow and supinating the forearm (turning the palm up).

pectoralis major

a large, fan-shaped muscle of the chest that forms the bulk of the anterior chest wall.

serratus anterior

a fan-shaped muscle originating on the ribs and inserting on the scapula,

rectus abdominis

makes up the top layer of your abdominal muscles

tensor fasciae latae

a superficial muscle in the lateral thigh that, along with the iliotibial (IT) band, contributes to pelvic stability.