20 Sept 2015

Musculoskeletal System Anatomy

What is Medical Coding?

      Medical coding is one of the processes in US healthcare, Any patient receives health care services in a physician's office/hospital outpatient/inpatient facility/ambulatory surgical centre, etc. It's the responsibility of the physician to document all the services provided to that patient. 

      After that, the medical coder will abstract the information from the medical record and assign the most appropriate universally accepted codes (CPT & ICD 10 CM), then create a claim to be paid, whether by a Medicare or Medicaid or commercial payer or by the patient itself.

What does a medical coder do?

     Using codebooks [CPT (Current procedural terminology), ICD-10-CM (International Classification of Disease, Tenth Revision,  Clinical Modification ) and HCPCS II (Healthcare common procedure coding system II)] the medical coder assigns appropriate codes for the procedures performed by the physicians to the respective patients. 

     In addition to assigning codes, the medical coder may be involved in a wide variety of coding-related activities. The coder may audit and rework on denied claims. The coders may also educate the physicians about the coding updates. 

     To begin, coders must have a strong knowledge of human anatomy, medical abbreviations and medical terminology. Also, it is must know how to use CPT, ICD-10-CM along with its guidelines.   

What is the role of Human anatomy in Medical Coding?

     Medical coding is the process of converting the medical procedures and diagnosis found in the medical records into numerical (universally accepted CPT / ICD codes).

     As I mentioned above medical coders are going to deal with the patient's medical record in their routine work. The medical record is all about the documentation of a patient's health conditions.

     To be a successful medical coder the basic knowledge of human anatomy and physiology is the must. (Physiology is the branch of biology dealing with the functions and activities of living organisms and their parts). 

What is Anatomy?

       Anatomy is the branch of biology, the study of the structure of organisms and their parts. 

      The anatomy is divided into the macroscopic and microscopic anatomy. 

Macroscopic anatomy or gross anatomy - is the examination of the body parts using unaided eyesight. 

Microscopic anatomy involves the use of optical instruments in the study of the tissues of various structures, known as histology and also in the study of cells.

Human anatomy deals with anatomical structures of the human body, including cells, tissues, organs, and organ systems. 

Cells: Cells are the basic units of life.

Tissues: A group of similar cells working together is called a tissue, for eg, Nervous tissue, connective tissue, and muscle tissue: Muscle tissue is made up of lots of muscle cells. All the cells in a tissue are the same and perform the same job (Muscle contraction and relaxation).

Organs: A group of tissues forms together is called an organ, for eg, Liver, stomach, kidney, spleen, lungs and Heart: Heart is made up of cardiac muscle tissue.

Organ Systems: when a group of organs working together to do some similar function is called organ systems,

All of our organ systems put together and made the human body.  There are 11 organ systems in Human Body which are given below,

   1.  Skeletal system

        2.  Muscular system

        3.  Nervous system

        4.  Circulatory system

        5.  Excretory system

        6.  Respiratory system

        7.  Digestive system

        8.  Endocrine system

        9.  Lymphatic system

      10.  Reproductive system

      11.  Integument system


The skeletal system includes all of the bones and joints in the body. Totally 206 bones form the skeletal system.

The bone is made up of many cells, protein fibres, and minerals. The skeleton providing support and protection for the soft tissues those make up the rest of the body.

The skeletal system also provides attachment points for muscles to allow movements at the joints. The ligaments and tendons all hold the bones together. 

New blood cells are produced by the red bone marrow inside the bones.

The skeletal system divided into Axial and Appendicular,  

The Axial Skeleton – 80 bones

    1. Skull Bones with hyoid – Totally 29 bones

            Facial bones – 14 bones.

               Inferior nasal concha (2)

               Lacrimal bones (2)
               Zygomatic bones (2)
               Maxilla (2)
               Nasal bones (2)
               Palatine bones (2)

           Cranial bones – 8 bones
               Ethmoid Bone
               Frontal Bone
               Occipital Bone
               Sphenoid Bone
               Parietal Bones – (2)
               Temporal Bones – (2)

           Ossicles – 6 bones

               Stapes – (2)
               Malleus – (2)
               Incus – (2)

          Hyoid - 1 bone


    2.  Rib Cage – 12 pairs

              True ribs        – 1st to 7th  ribs
               False ribs       – 8th  to 10th  ribs
               Floating ribs   – 11th  & 12th  ribs

         Sternum - 1 bone

    3.  Vertebral Column – 26 bones

                Cervical spine       – 7 bone

                Thoracic spine      – 12 bones

                Lumbar spine        – 5 bones

                Sacral spine           – 5 bones fused to join together as a single bone

                Coccyx                     – 1 or 2 bones


     The Appendicular skeleton – 126 bones


1. Upper Extremity – (Right side – 32 and Left side – 32 = Totally 64 bones in both side)

    Pectoral girdle – 2 bones


    Arm – 1 bone  


    Forearm – 2 bones


    Carpal – 8 bones


    Metacarpals – 5 bones

    Phalanges – 14 bones

2. Lower extremity - (Right side – 31 and Left side – 31 = Totally 62 bones in both side)

    Pelvic girdle – 1 bone


         Thigh – 1 bone

    Knee Cap – 1 bone


     Leg – 2 bones

     Tarsal’s – 7 bones
                 Medial cuneiform
                 Lateral cuneiform
                 Intermediate cuneiform

     Metatarsals – 5 bones

     Phalanges – 14 bones


There are five types of bones in the human body:

       1. Long,

       2. Short,
       3. Flat,
       4. Irregular, and
       5. Sesamoid

Long Bones - 
Femur, Humerus, Ulna, Radius, Tibia and Fibula even the Metacarpals, Metatarsals and Phalanges are considered as long bones, due its shape of having a body (shaft), having a hard outer and spongy inner surface containing bone marrow,  two ends with growth plates/epiphysis and both ends (upper & lower) are covered with cartilage.  

Short Bones – 
Carpals & Tarsals, Generally for support and stability.

Flat Bones – 
Scapula, Sternum, Skull bones and Ribs, Generally to protect vital organs.

Irregular bones – 
Vertebrae, Sacrum and mandible

Sesamoid bones – 
Patella, Usually short and irregular embedded in a tendon. 


Meeting point or Junction between two bones forms joint/Articulation. 

Joints are classified based on their structure and function.

Three Major Types of Joints:

   1.  Fibrous
         2.  Cartilaginous 
         3.  Synovial

FIBROUS JOINTS (Immovable joints / Synarthrosis)

  Bones are held together by fibrous connective tissues.

  Fibrous Joints are further classified into three types,

       1. Sutures              -
Skull Bones
       2. Syndesmoses  - Tibia and fibula & Radius and ulna (Slightly moveable)   
       3. Gomphoses      - Tooth and maxilla or mandible.

CARTILAGINOUS JOINTS (Slightly moveable joints / Amphiarthrosis)

 The articulating end of two bones made up of cartilage. But there is no synovial cavity and synovial fluid.

  Cartilaginous joints are further classified into two types,

       1. Synchondroses –
First sternocostal joints. (Immovable)
       2. Symphyses          - Pubic symphysis.

SYNOVIAL JOINTS (Movable joints / Diarthrosis)

     Bones forming the joint is surrounded by an articular capsule and joints include a synovial cavity with synovial fluid.  

 Synovial Joints are further classified into six types, 

     1. Ball and socket – Shoulder & Hips (All direction movements)

     2. Condyloid -
Radiocarpal Wrist (Flexion, Extension, Abduction and Adduction)
     3. Gliding/plane - Intercarpal & Acromioclavicular (sliding movements)

     4. Hinge -
Elbow & Knee (Flexion and Extension in one plane)  

     5. Pivot -
Atlanto-axial, Radioulnar (Rotation movements)         

     6. Saddle - Carpometacarpal (Flexion, Extension, Abduction and Adduction)   



   Body planes are used to transect the human body, in order to describe the location of structures and the direction of movements. Three-body planes are, 

     The sagittal plane is a plane parallel to the sagittal suture. It divides the body into left and right. 

     The coronal plane or frontal plane divides the body into dorsal and ventral (back and front, or posterior and anterior) portions.

    The transverse plane or axial plane divides the body into cranial and caudal (head and tail) portions.

    Common conditions related to Skeletal System:

Osteoporosis: The bones become weak and prone to fracture.

Osteopenia: Bone mineral density is lower than normal.

Osteomalacia: Softening of your bones, often caused by a vitamin D deficiency

Paget’s disease: Excessive breakdown and formation of bone, followed by disorganized bone remodelling.

Bone tumor: An abnormal (neoplastic) growth in the bone may be benign or malignant

Osteomyelitis: Inflammation of bone due to infection

Scoliosis, kyphosis, and Lordosis: Deformity of the vertebral column

Fracture: A break in the bone, The two major classifications are open (compound) and closed (Simple).  

     Greenstick fracture: 

     Transverse fracture: 

     Oblique fracture: 

     Spiral fracture: 

     Comminuted fracture: 

     Impacted fracture: 

     Avulsion fracture:

Arthritis: Inflammation of one or more joints and cause pain and stiffness in the affected area. There are two major classifications are,

Osteoarthritis is a chronic degenerative joint disease. Breakdown of cartilage and underlying bone.

Rheumatoid Arthritis, also a chronic disease, the autoimmune disease is characterized by inflammation of the lining of the joints.


1.    Head                    - Cephalo / Cranio

2.    Neck                    - Cervico

3.    Chest                    - Thoraco / Pectoral

4.    Hand                    - Chiro

5.    Joint                     - Arthro

6.    Wrist                    - Carpo

7.    Finger / toe       - Dactylo

8.    Rib                        - Costo

9.    Bone                    - Osteo

10.  Foot                     - Podo

11.  Big toe                - Hallux

12.  Vertebra            - Spondylo

13.  Ankle                  - Tarso       

14.  Arm                     - Brachi

15.  Cartilage            - Chrondro

16.  Spinal cord       - Myel/o 

17.  Straight              - Orthr/o



1. ACL - Anterior cruciate ligament

2. AKA - Above the knee amputation

3. DJD - Degenerative joint disease

4. Fx / # - Fracture

5. IPJ – Interphalangeal joint

6. LCL - Lateral collateral ligament

7. MCL - Medial collateral ligament

8. ORIF - Open reduction and internal fixation

9. PCL - Posterior cruciate ligament

10. PET - Positron emission tomography

11. PIP - Proximal interphalangeal (joint)

12. RA - Rheumatoid arthritis

13. RCL - Radial collateral ligament

14. TMJ - Temporomandibular joint

15. UCL - Ulnar collateral ligament


The Muscular System 

      There are more than 600 muscles in the human body. The muscular system helps in maintains posture, strength, balance and movement of the body (at joints)

       A. Cardiac Muscles Muscles found in the heart, is involuntary.


       B. Smooth Muscles - Smooth muscle is responsible for the contraction of hollow organs, such as blood vessels, the gastrointestinal tract, the bladder, or the uterus


       C. Skeletal Muscles - are attached to bones by tendons and they produce all the movements of body parts in relation to each other - is under voluntary control.

List of some important muscles of the human body:

CHEST - Pectoralis major, 

                 External and Internal Intercostal muscles, 

                 Diaphragm (Major muscle for respiration)

ABDOMEN - Transversus abdominis, 

                          Rectus abdominis 

                          Oblique (External and Internal)

BACK -  Trapezius, 

                Latissimus dorsi 

                Erector spinae. 


A.   Shoulder - Deltoid, 

                             Rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis)

B.    Arm -   Anterior compartment - Biceps, Brachialis

                       Posterior compartment – Triceps


A.   Thigh:  

        Anterior compartment: 

        Posterior compartment: Hamstring

B. Leg: 

        Anterior compartment: 
 Tibialis anterior, 

                                                           Extensor digitorum, 

                                                           Extensor hallucis longus

        Posterior compartment:  Gastrocnemius, 



Common Diseases of the Muscular System:


1. Myasthenia gravis - is a chronic autoimmune neuromuscular disease characterized by varying degrees of weakness of the skeletal (voluntary) muscles of the body


2. Duchenne muscular dystrophy - is caused by an absence of dystrophin, a protein that helps keep muscle cells intact


3. Rotator Cuff Tear - is a tear of one or more of the tendons of the four rotator cuff muscles of the shoulder.


4. Talipes – Clubfoot, the front half of the foot turns inwards and downwards


5. Tendonitis - is an inflammation or irritation of a tendon.


6. Rhabdomyolysis - is a condition in which damaged skeletal muscle breaks down rapidly.


7. Myotonia - an inability to relax the voluntary muscle after the vigorous effort.


8. Muscle strain - A strain is an injury to a muscle in which the muscle fibres tear as a result of overstretching.


9. Muscle cramp - is a strong, painful contraction or tightening of a muscle that comes on suddenly and lasts from a few seconds to several minutes



1.  Muscle                   - My/o

2.  Diaphragm          - Phreni

3.  Tendon                  - Ten/o

4.  Movement            -  kinesi/o



1. AROM - Active range of motion

2. DTR - Deep tendon reflex

3. EMG - Electromyogram

4. PROM - Passive range of motion; premature rupture of membranes

5. ROM - Range of motion

6. SLR - Straight leg raising


Test Your Knowledge: Click the below link, 

             A. Terminology Quiz 

             B. Anatomy Quiz A

             C. Anatomy Quiz B

            D. Anatomy Quiz C  

            E. Anatomy Quiz D

            F. Anatomy Quiz