Anatomy of Immature Bone | Anatomy of Joints

Previously we discussed basics of orthopedics, in this part, we will discuss quickly on Anatomy of an Immature long bone and Anatomy of Joints.

Anatomy of Immature Long Bone

A bone consists of four parts: Epiphysis, Growth plate in between epiphysis and metaphysis, Metaphysis and Diaphysis. We will discuss in detail the following:

Functional Classification of Epiphysis

Pressure Epiphysis

It is an intra-articular weight bearing epiphysis

Traction Epiphysis

It is an extra-articular epiphysis for Traction or Pull or Attachment to soft tissues, mainly tendons

Atavistic Epiphysis

E.g. – Coracoid process of scapula

Aberrant Epiphysis

Occasional epiphysis, e.g. – Head of first metacarpal

Layers of Growth plate (Physis)

The mnemonic for layers of Growth plate or Physis is as follows:

Real People Have Carrier Options

  1. Reserve Zone / Resting Zone- contains chondrocytes that store glycogen or lipids
  2. Proliferative Zone- determines height and width of bone
  3. Hypertrophic Zone / Maturation Zone
  4. Zone of Calcification
  5. Zone of Ossification

Key points to remember

Reserve zone
  • Gaucher’s disease
Proliferative zone
  • Achondroplasia (dwarfism)
  • Gigantism
  • Laron’s syndrome- Hereditary dwarfism and Truncal obesity
Hypertrophic zone
  • Cartilage converted to bone
  • Maturation occurs with Calcium incorporation
  • Most common layer for trauma or injury
Zone of Calcification
  • Rickets
Zone of Ossification
  • Vascularity (metaphyseal vascular invasion)


  • Special bone- Spongy, Soft or Cancellous
  • Highly vascular
  • Vessels dilated, Tortuous and End arteries
  • Hair pin loop of vessels
  • Most common site for acute hematogenous osteomyelitis

Anatomy of Joint

Functional classification of Joint:

  1. Fibrous joint- Synarthrosis- Non-motile
  2. Cartilaginous joint- Amphiarthrosis- Somewhat motile
  3. Synovial joint- Diarthrosis- Highly motile
Feature Fibrous Joint Cartilaginous Joint Synovial joint
Other name Synarthrosis Amphiarthrosis Diarthrosis
Types Suture

E.g. – Cranial vault skull


E.g. – Inferior tibio-fibular joint


E.g. – Tooth and socket joint

1st degree- Synchondrosis or Syncedrosis

E.g. – Costochondral joint

2nd degree- Symphysis

E.g. – Pubic symphysis

Hinge joint

E.g. – Elbow joint

Ellipsoid joint

E.g. – Wrist joint

Condylar joint

E.g. – Knee joint and temporomandibular joint

Ball and socket joint

E.g. – Hip and shoulder joint

Pivot joint

E.g. – Atlantoaxial joint

Saddle joint

E.g. – 1st carpo-metacarpal joint

Gliding joint

E.g. – Inter-carpal joint

Related Articles


Please enter your comment!
Please enter your name here