Muladhara or root chakra is represented as a yellow square, with 4 red petals (According to Wikipedia).  

This is the first chakra known as the root chakra  (Muladhara) and is located at the base of the pelvic bone. It  relates to our survival instincts,and to our sense of  grounding and connection of our bodies to Mother Earth.  Ideally this chakra brings us the foundations of health and  the development of spirituality by the stimulation of the  kundalini (soul energy) (Debbie Creagh).

This chakra relates to the physical functions of the Adrenal Cortex, Hormone Cortisone, Skeletal  System, Spine and the balance of Blood Cells including the sex organs such as the prostate and  the ovaries, cervix and Reproductive System.  

Congestion of this chakra can lead to symptoms such as sluggishness, tiredness, weight  problems, skin, bone, teeth and back problems (Lee Wei-Dei).

 (Citing Siam Reiki materials)

The First Chakra – The Base Chakra

Swadhisthana, is symbolized by a white lotus within which  is a crescent moon, with six orange petals (According to Wikipedia).  

This is the second chakra and known as the Sacral Chakra  (Svadhisthana) and is located in the abdomen and lower  back. It’s related to emotions, connecting us to others  through love at a deeper spiritual level with possible soul connections (Debbie Creagh).

This chakra relates to the physical functions of the Small and Large Intestines, Appendix,  Testicles, Ovaries, and inter-relationships with mammary glands in the breasts.  

Congested energy in this chakra can lead to Sexual problems, back problems, problems with  reproductive organs, spleen, and urinary system (Lee Wei-Dei).

(Citing Siam Reiki materials)

Manipura is symbolised by a downward pointing triangle  with ten petals (According to Wikipedia).

This chakra is the third chakra known as the solar plexus. It  relates to our personal power, self-identity, ego, as well as  our metabolism. It’s one of the first chakras to be affected  when an emotional situation occurs (Debbie Creagh).

This chakra relates to the physical functions of the Stomach, Liver, Large Intestine and Small  Intestine, Pancreas, Outer Adrenal Glands, Heart, Lungs and Sympathetic Nervous system.  Congestion of this chakra can lead to symptoms such as Arthritis, diabetes, digestive disorders,  ulcers, problems with the stomach, liver, colon and intestine. It can also cause anorexia or  bulimia, pancreatitis, gallstones, allergies (Lee Wei Dee).

(Citing Siam Reiki materials)

Anahata, is symbolised by a circular flower with twelve  green petals (According to Wikipedia).

This chakra is the fourth chakra and called the heart chakra  (Anahata). It is related to love, self-acceptance, compassion.  A healthy fourth chakra allows us to love deeply, feel  compassion, have a sense of acceptance socially. A  congested heart chakra can lead to feelings of rejection,  jealousy, loneliness and difficulties in relationships (Debbie Creagh).

This chakra relates to the phyiscal functions of the Thymus Gland, Nerves, Heart, Para sympathetic Involuntary Muscles. Congestion of this chakra therefore can result in problems of  the heart, lungs, breast, arms, asthma, as well as allergies and problems with the immune system (Lee Wei-Dei).

(Citing Siam Reiki materials)

Vishuddha is depicted as a silver crescent within a white  circle, with 16 light or pale blue, or turquoise petals ( Accordimg to Wikipedia).

This chakra is the fifth chakra and called the throat chakra (Vishuddha). It relates to  communication, self-expression, identity and creativity (Debbie Creagh). 

This chakra relates to the physcal functions of lungs, vocal apparatus, Larynx, Throat, Thyroid  Gland, Para- Thyroid Gland and Lymphatic System. Congestion in this chakra can result in  symptoms such as stammering, laryngitis, swollen glands and ear problems (Lee Wei-Dei).

(Citing Siam Reiki materials)

Ajna is symbolisedby a lotus with two petals, and corresponds  to the colors violet, indigo or deep blue.  

Ajna (along with Bindu), is known as the third eye chakra and  is linked to the pineal gland which may inform a model of its  envisioning. The pineal gland is a light sensitive gland that  produces the hormone melatonin which regulates sleep and  waking up. Ajna’s key issues involve balancing the higher &  lower selves and trusting inner guidance. Ajna’s inner aspect  relates to the access of intuition. Mentally, Ajna deals with  visual consciousness. Emotionally, Ajna deals with clarity on  an intuitive level (According to Wikipedia).

This chakra is the sixth chakra and known as the third eye or Ajna. It is related to physic and  intuitive abilities so allows us to see clairvoyantly and communicate telepathically when  activated (Debbie Creagh).  

This chakra relates to the phyiscal functions of the Pineal Gland, Pituitary Gland, muscles of the  eyes and brain functions. Congestion of this chakra therefore can result in Poor Vision, Sinus &  Nose Problems, headaches, seizures, learning disability, nerve problems, neurological problems (Lee Wei-Dei).

 (Citing Siam Reiki materials)

The Sixth Chakra – The Third Eye Chakra

Sahasrara, which means 1000 petalled lotus, is  generally considered to be the chakra of pure  consciousness, within which there is neither  object nor subject. When the female kundalini Shakti energy rises to this point, it unites with  the male Shiva energy, and a state of liberating  samadhi is attained (According to Wikipedia).

This is chakra seven or the crown chakra (Sahasrara) which relates to our self-knowledge,  consciousness and pure awareness. It is our connection to the greater world beyond. When  developed, this chakra brings us knowledge, wisdom, understanding and spiritual truths (Debbie Creagh). 

This chakra relates to the physical functions of the Brain, Nervous, Spinal Cord, Nerve Fibers,  Pituitary gland. Therefore, some of these symptoms can occur when this chakra is congested:  Migraine, Brain Tumor, Amnesia, Coma, sensitivity to light/ Sound (Lee Wei-Dei).

 (Citing Siam Reiki materials)