The most significant muscles of the head.
- Insert into the skin or other muscles instead of bone.
Mucles of Facial Expression
Draws the corners of the mouth outward and upward, has often been referred to as the "similing muscle."
Involved in puckering the lips, and is sometimes called the "kissing muscle."
Helps puff the cheeks out and has consequently been called the "trumpters muscle."
Helps raise the eyebrows.
Draws the corners of the mouth laterally as in tension, or "false smiling."
Pulls the lower lip down and back, as in a look of horror.
- Zygomaticus Major
- Orbicularis Oris
Muscles of Facial Expression
Have to do with chewing or grinding food.
- Internal (medial) pterygoid
- External (lateral) pteygoid
Muscles of Mastication
Named because it is attached to the temporal bone.
Comes from the Greek for "chewer."
Named for one of their attachments, which is the wing-shaped portion of the sphenoid bone.
Internal and External Pteygoid Muscles
The top of the head is covered by a combination of two muscles plus a tendonous sheet of tissue over the top of the cranium.
- Galea aponeurotica
This term is used to refer to any broad, flat tendon in the body.
An important muscle of the neck area. Important for its action of moving the head and for the fact that the distance between the lateral margins of the two of these muscles marks the widest part of the neck.
Located on the front of the neck region. It outlines the vicinity in which the common carotid artery and the internal jugular vein are located.
Anterior Cervical Triangle
The medline of the neck.
Medial Boundary of The Anterior Cervical Triangle
The inferior margin of the mandible.
Superior Boundary of The Anterior Cervical Triangle
The anterior border of the sternocleidomastoideus.
Lateral Boundary of The Anterior Cervical Triangle
- Pectoralis Major
- Internal and External Intercostals
- Phrenic Muscle (Diaphragm)
- Rectus Abdominus
- External and Internal Oblique
- Psoas Major
- Latissimus Dorsi
- Erector Spinae
Located in the anterior chest area and is involved in moving the upper arm.
- Comes from the Latin word for "breast"
"Betwen the ribs." Important for their involvement in the expansion and contraction of the thoracic area which occurs during breathing.
Internal and External Intercostals
Extremely important in the breathing process. A dome-shaped sheet of muscle which forms the floor of the throacic cavity, or the roof of the abdominal cavity.
- During Breathing: Flattens out and enlarges the size of the thoracic cavity, which helps draw air into the lungs.
Phrenic Muscle (Diaphragm)
- Esophageal Orifice
- Vena Caval Orifice
- Aortic Orifice
Openings in the Diaphragm
The center of the diaphragm is composed of this sheet of tendon.
These muscles tend to be arranged in several layers, with the muscle fibers of each layer running at different angles.
- This makes for a strong, supportive structure to enclose and protect the abdominal organs.
Often categorized by their general location:
- Posterior Abdomen
Abdominal Muscle Categories
One of the anteromedial muscles and runs from the sternum and rib cage straight down to the pubic bone.
Run at angles down the anterior lateral part of the abdomen, with the transverse muscles underneath them.
External and Internal Oblique
An important posterior abdominal muscle. Runs from the lumbar vertebrae down to the femur. Involved with moving the femur and serves as an anatomical guide along the medial border for the external iliac artery and vein.