Ligament

Fibrous bands that connect adjacent bones, supporting the joints are known as ligaments. They consist of type 1 collagen fibers and elongated fibroblasts mainly. 

Mechanical role of ligaments is reflected in their composition.They are tough but also flexible at the same time, so normal movements can be made easy. 

Types of ligament-

  1. According to their composition-
  • Made up of collagen fibers. These are inelastic and unstretchable. Most of the ligaments of the body are of this type, for example deltoid ligament of foot.
  • Made up of elastin fibers predominantly. These are elastic and stretchable. Only a few ligaments are made of elastin fibers for example ligamenta flava and ligament auditory ossicles.
  1. According to their relation to the joint-
  • Intrinsic ligament
  • Extrinsic ligament

Morphology-

Ligaments are considered as degenerated tendons example- Tibial collateral ligament is a degenerated tendon of adductor magnus muscle. 

As they do not have tone, they are always reinforced and supported by muscles to provide sole defense to joints example- if there is excessive strain on the medial collateral ligament, the supporting vastus medialis muscle will be activated to reduce stress on the ligament and the medial compartment of the knee joint.

Difference between tendon and ligament-

In order to resist bone separation fibers are oriented in a range of directions in ligaments whereas collagen fibers align with tension in the adjacent muscle in the tendon. 

Blood and nerve supply-

The blood vessels and nerves of the joints ramify on its ligaments to supply them.

Due to rich nerve supply they act as an important reflex mechanism.

Functions-

  • Maintain joint stability
  • They are important reflex organs which accounts for their sensory function.
  • Reinforce joint capsule.
  • Protection from injury as they have the ability to withstand excessive stress over the joint.
  • Assist in joint movement with reduced load and stress on the prime mover muscle group.

Injury to ligament-

Injury to ligaments is also known as sprain.

Problems in healing of the ligament-

  • Due to poor vascularity healing is delayed.
  • As they do not have specialized cells to mimic the original tissue, repair always takes place by scar formation.
  • As healing takes place with excessive fibrous tissue formation, results in lengthening of the ligament causing permanent laxity or loosening of joints.
  • Continuous pull on the injured ligament during the early sessions of passive range of motion exercises may give rise to periosteal irritation and serofibrinous exudates- leading to organization of fibrous adhesions and finally resulting in painful stiffness of the related joint.

Classification of extent of injuries to the ligaments-

Grade 1 injury-

They are easy to deal with instant application of RICE protocol.

Test-

  • Passive stress test
  • Separation of the joint surface up to 5mm.
  • Partial loss of function due to pain.

Clinical features-

  • Localized pain and tenderness.
  • Slight swelling may be present.

Treatment- 

Grade 2 injury-

Ligament is partially torn or detached from its bony attachment.

Test-

  • Passive stress tests are extremely painful.
  • Separation of the joint surface between 5mm and 10mm.

Clinical features-

Moderate localized pain and tenderness.

Treatment-

Grade 3 injury-

Due to sudden violent injury, injured muscle is totally out of action in this type.

Test-

  • Passive stress test is impossible
  • Marked joint instability
  • Joint separation more than 10mm

Clinical features-

  • Profuse swelling with marked localized tenderness.
  • Unremitting pain and discomfort to the whole limb.

Treatment-

Reference-

  • B.D. Chaurasia ( Human anatomy)
  • Susan Standring (Gray’s Anatomy)
  • Jayant Joshi and Prakash Kotwal ( Orthopedics and applied physiotherapy)
  • J. Maheshwari and Vikram A. Mhaskar ( Essential orthopedics)