There are three types of muscle tissue to be found in your body: smooth, which is found in the hollow internal organs; cardiac which is found in your heart; and skeletal which is attached to your bones and controls movement. All of your muscles have names that are derived from Greek and Latin. Muscles are named according to one or more of their characteristics: size, shape, location, action, number of attachments and fiber direction.
Major Muscles of the Arms
Biceps brachii, meaning two attachment sites on the arm, is the main muscle on the front of your upper arm. The biceps bend your elbow, turn your palm up toward the sky and also weakly flex your shoulder. Your triceps brachii, meaning three attachment sites on the arm, is located on the back of your upper arm and straightens your elbow and extends your shoulder.
Major Muscles of the Shoulders
A complex ball and socket joint, the shoulder is affected by numerous muscles. The deltoids, named after their triangular shape, cap your shoulders like football pads. Your pectoralis major, or pecs for short, make up your chest and, along with your latisimus dorsi, or lats, the large muscles located on the side up your back, attach your arms onto your body. Your rhomboids and trapezius muscles, again named because of their shape, make up your upper back and control your shoulder girdle.
Major Muscles of the Spine
Keeping your spine upright and controlling the movements of your back is the job of a group of muscles collectively referred to as your core. Your core consists of the rectus abdominus muscle located on the front of your torso, your erector spinea running up your spine and your obliques, which run around your waist. Surrounding your midsection like an old-fashioned girdle is your transverse abdominus, literally meaning "around your abdominals."
Major Muscles of the Hip
The biggest muscle in your body is the gluteus maximus, which is essentially your butt. Along with your hamstring muscles, your glutes work to extend your leg backward when you are walking or running. Drawing your leg in toward the midline of your body is the job of your inner thigh or adductor muscles, of which there are three: longus, brevis and magnus. The opposite of your adductors is your abductors on the outside of your hips, which lift your leg out to the side. Bending your hip forward is the job of the hip flexors. Consisting of the iliacus and psoas major muscles, the hip flexors run from the top of your thigh bone and through your pelvis to attach onto your lumbar spine.
Major Muscles of the Knee
Made up of four individual muscles: vastus lateralis, vastus intermedius, vastus lateralis and rectus femoris, your quadriceps are located on the front of your thigh and are responsible for straightening your knee. On the opposite side of your leg, your semi membranosis, semi tendonosis and biceps femoris; collectively known as your hamstrings, bend your knee. The quadriceps and hamstrings work together in walking, running and jumping movements and, along with the adductor and abductor muscles, make up the bulk of your thigh girth.
Major Muscles of the Ankle
Your calf muscles are made up of your gastrocnemius, soleus and tibialis posterior and are responsible for plantar flexion or pointing your toes away from you. Located on the rear of your lower leg, these powerful muscles are particularly well developed in ballet dancers and gymnasts. Pulling your toes up toward your shins in a movement called dorsi flexion is the job of your tibialis anterior, which is located on the front of your lower leg.
References
- "Principles of Anatomy & Physiology, Ninth Edition"; Sandra R. Grabowski & Gerald J. Tortora; 2000
- "Yoga Anatomy"; Leslie Kaminoff, Sharon Ellis, and Amy Matthews, 2007
- "Bodybuilding Anatomy"; Nick Evans M.D; 2006
