Yoga Anatomy

• Useful Terms
• Motions
• Muscles
  • Four major functions of muscles
  • Muscle origins \& insertion
  • Three operating groups of muscle
  • Three types of muscle contractions
  • Connective tissue
• Skeletal
  • Spine
  • Skeleton
    • Categorizations of skeleton bones
• Special Bones
• Joints
  • Categorization of joints
  • Torque
• Nervous System
  • Neurons
  • Autonomic nervous system

Useful Terms

• Superior & Inferior: higher & lower
• Anterior & Posterior: front & back
• Dorsal & Ventral: front & back
• Medial & Lateral: towards & away from the midline
• Proximal & Distal: closer & further away from the origin
• Superficial & Deep: external & internal

Motions

• Flexion & Extension: decreasing & increasing the angle betwen two body parts, e.g. elbow
• Abduction & Adduction: movement away & towards the midline, e.g. arm, hip, finger and toes
• Eversion & Inversion: Tilting of the foot so the sole faces away from / towards the midline.
• External & Internal Rotation: movement of limbs away from / towards the midline.
• Elevation & Depression: movement in a superior / inferior direction
• Pronation & Supination: inward & outward rolling of foot and arms
• Dorsiflexion & Plantarflexion: hand or foot pointing upward / downward
• Circumduction: circular movement of the limbs

Muscles

Four major functions of muscles

• Energize the body
• Protect internal organs
• Generate movement
• Maintain posture

Muscle origins & insertion

• Origin: the point on the immobile bone where the muscle attaches
• Insertion: the point on the bone which is moved by the action of the muscle

Three operating groups of muscle

• Agonists: these muscles cause the movement to occur. aka primer movers
• Antagonists: these muscles act in opposition to the movement generated by the agonists and are responsible for returning a limb to its initial position.
• Synergists: these muscles assit in performing the same set of joint motion as the agonists by neutralizing extra motion from the agonists, aka neutralizers or fixators

Three types of muscle contractions

• Concentric: muscles shorten while generating force, overcoming resistance.
• Eccentric: muscle lengthens while generating force but resistance is greater than force generated.
• Isometric: musle generates force without changing the length

Connective tissue

• Fascia: the most superficial layer of the muscles and connects the musle to each other
• Tendon: connects muscle to bone
• Ligament: connects bone to bone

Skeletal

Spine

The spine column is comprsied of 33 vertebrae for infant and 26 verterbrae for aduts (some bones are fused)

• 7 cervical vertebrae (neck/head): C1 - C7
• 12 thoracic vertebrae (shoulder/trunk): T1 - T12
• 5 lumbar vertebrae (lower back): L1 - L5
• 5 sacral vertebrae (sacrum): fused as one in adult
• 4 coccygeal vertebrae (tailbone): fused as one in adult

Skeleton

The skeleton of an adult is made up of approx. 206 bones

• Axial skeleton: skull, spine and rib cage
• Appendicular skeleton: limbs and shoulder & hip joint

Categorizations of skeleton bones

• Long bones: for leverage
• Flat bones: for protection
• Short bones: weight bearing

Special Bones

• Ribs: Human have 24 ribs (12 pairs)
• Sternum: aka breastbone, a long flat bone in the center of the chest
• Clavicle: aka collarbone, a long bone between the shoulder blade and the sternum; the only long bone in the body that lies horizontally
• Scapula: aka shoulder blade, a triangular bone that connects upper arm bone with the clavicle
• Femur: aka highbone, the strongest and the longest bone in th ebody
• Patella: aka kneecap
• Tibia: main bone of the leg, second largest bone
• Fibula: aka calf bone, located on the lateral side of the tibia, the slenderest of all the long bones
• Humerus: the long bone in the upper arm
• Radius & Ulna: two large bones in the lower arm
• Tarsals: aka ankle bones
• Phalanges: aka toe/finger bones

Joints

Joints, aka articulation, are spaces where two bones meet.

Categorization of joints

• Fibrous joints: aka synarthrotic joints, are immobile or extremely limited in movement
  • Connected by dense connective tissue consisting mainly of collagen
  • e.g. skull
• Cartilaginous joints: aka amphiarthrotic joints, are limited in movement
  • Connected by cartilage
  • e.g. pelvis girdle
• Synovial joints: diarthrotic joints, are most mobile and make up 80% of joints in the body
  • Connected with a fibrous joint capsule filled with syovial fluid
  • Falls into one of four categories
    • Hinge, e.g. fingers and toes, ankle, elbow and knee joints
    • Ball and socket, e.g. hip and shoulder joints
    • Pivot, e.g. neck
    • Gliding, e.g. wrist

Torque

• The force applied to the joint by the bones

Nervous System

• Central nervous system
  • Brain
  • Spinal cord
• Peripheral nervous system
  • Cranial nerves
  • Spinal serves

Neurons

• Sensory neurons - carry messages received from outside stimuli to the brain
• Motor neurons - carry messages to the muscles
• Interneurons - carry messages from one neuron to another

Autonomic nervous system

• Parasympathetic nervous system: regulates “rest and digest” functions
• Sympathetic nervous system: controls “fight or flight” responses