practical three

Direct (fleshy) attachment

The connective tissue of the muscle belly blends directly with the periosteum of the bone.

Indirect attachment

A muscle attaches to a bone or other structure through a tendon or aponeurosis.

Tendon

A cord of dense fibrous connective tissue that attaches a muscle to a bone.

Aponeurosis

A flat sheet of dense fibrous connective tissue that attaches a muscle to another structure.

Muscle belly

The thick, bulging middle portion of a muscle.

Prime mover (agonist)

The muscle primarily responsible for producing a movement.

Antagonist

A muscle that performs the opposite action of another muscle around the same joint.

Synergist

A muscle that helps another muscle perform the same action around the same joint.

Fixator

A muscle that stabilizes a joint or body part so another muscle can move effectively.

Flexion

Movement that decreases the angle between two body parts.

Extension

Movement that increases the angle between two body parts.

Dorsiflexion

Moving the foot upward toward the shin.

Plantar flexion

Pointing the foot downward, away from the shin.

Abduction

Moving a limb away from the body's midline.

Adduction

Moving a limb toward the body's midline.

Circumduction

Moving a body part in a circular motion around a joint.

Rotation

Turning a bone around its long axis.

Medial rotation

Turning a limb inward toward the body's midline.

Lateral rotation

Turning a limb outward away from the body's midline.

Supination

Rotating the forearm so the palm faces upward in anatomical position.

Pronation

Rotating the forearm so the palm faces downward in anatomical position.

Inversion

Turning the sole of the foot inward toward the body's midline.

Eversion

Turning the sole of the foot outward away from the body's midline.

Protraction

Moving a body part forward.

Retraction

Moving a body part backward.

Elevation

Moving a body part upward.

Depression

Moving a body part downward.

Opposition

Moving the thumb to touch the tips of the fingers on the same hand.

Sphincter action

Closing a circular opening in the body.

Orbicularis oculi

Closes the eyelids for blinking and squinting.

Orbicularis oris

Closes the lips.

Zygomaticus major

Pulls the corners of the mouth upward and backward during smiling.

Risorius

Pulls the corners of the mouth laterally, or sideways.

Levator labii superioris (quadratus labii superioris)

Raises the upper lip.

Depressor labii inferioris (quadratus labii inferioris)

Pulls the lower lip downward.

Depressor anguli oris (triangularis)

Pulls the corners of the mouth downward.

Mentalis

Protrudes the lower lip.

Buccinator

Compresses the cheek to keep food between the teeth during chewing and helps move food into position.

Platysma

Pulls the lower lip and corners of the mouth downward and helps depress the mandible.

Masseter

Elevates the mandible to close the jaw during chewing.

Temporalis

Elevates and retracts the mandible.

Digastric

Elevates the hyoid bone when both bellies contract; the anterior belly can depress the mandible when the hyoid is fixed.

Stylohyoid

Elevates the hyoid bone.

Mylohyoid

Elevates the hyoid bone and raises the floor of the mouth.

Sternohyoid

Depresses the hyoid bone.

Omohyoid

Depresses the hyoid bone.

Sternocleidomastoid (SCM)

Both muscles contracting together flex the neck; one contracting alone laterally flexes the neck to the same side and rotates the head to the opposite side. It also assists inhalation.

Scalenes

Flex the neck and elevate the first and second ribs during inhalation.

Trapezius

Retracts the scapula and extends the neck.

Splenius (capitis)

Extends the neck.

Erector spinae

A group of three muscle columns that extend the neck and vertebral column.

Iliocostalis

The lateral column of the erector spinae group.

Longissimus

The intermediate column of the erector spinae group.

Spinalis

The medial column of the erector spinae group.

External intercostals

Elevate the ribs and increase thoracic volume during inhalation.

Internal intercostals

Depress the ribs and decrease thoracic volume during forced exhalation.

Diaphragm

The primary muscle of inhalation; contracts and moves downward to increase thoracic volume. It can also compress abdominal contents.

Rectus abdominis

Flexes the vertebral column and compresses abdominal contents.

External oblique

Flexes the vertebral column and compresses abdominal contents.

Internal oblique

Flexes the vertebral column and compresses abdominal contents.

Linea alba

A tendinous seam, or white line, running from the sternum to the pubic symphysis.

Pectoralis minor

Protracts and depresses the scapula and can assist inhalation.

Serratus anterior

Protracts the scapula, moving it forward around the rib cage.

Subclavius

Depresses and stabilizes the clavicle.

Levator scapulae

Elevates, retracts, and rotates the scapula.

Rhomboid major and minor

Retract the scapula, pulling it toward the vertebral column.

Buccinator

Draws corners of mouth posteriorly, compresses cheek to hold food between teeth.

Suprahyoid muscles

Muscles above the hyoid bone that help elevate it and assist movements of the jaw and swallowing.

Infrahyoid muscles

Muscles below the hyoid bone that help depress the hyoid bone.

Superficial muscles of thorax

Movers of the scapula.