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Spinal Anatomy - Part 1

When addressing conditions of the spine, it is important to understand the anatomy of the spine. This is the first in a series of blogs about the spine, and begins by discussing the structure of the spine and how the spinal column functions.

The human spine consists of 33 bones, which are stacked upon each other. It is often referred to as the Spinal Column, which supports the body and allows standing, bending, and twisting. The secondary purpose is to protect the spinal cord. Muscles, bones, tendons and ligaments work together to support the spine, and the central nervous system communicates instructions to the body and relays nerve impulses. If the spine is injured, strained, or affected by disease, it can reduce functionality and cause pain.

S-Shaped Curve of the Spine

The spine is not a straight structure, in fact, when viewed from the side it is shaped more like an S. The upper portion, called the cervical spine, and the lower, or lumbar, portion have a slight concave curve. The thoracic and sacral areas are convex. The shape of the spine is benefiecial becuase it functions like a shock absorber to help withstand impact and maintain balance. There is range of motion along the entire spinal column.

The body’s natural spinal curves are supported by muscles and by maintaining proper posture. Remaining conscious of good posture enables the body to walk, sit, and stand in a way that reduces stress upon the spine. The same is true when carrying heavy objects, working at a desk, or exercising. Excess weight, weak muscles, certain injuries or abnormal conditions can tug at the spine and cause loss of alignment, which leads to pain and loss of mobility.

Abnormal conditions of the spine include:

  • Lordosis or sway back - a curve of the lumbar spine
  • Kyphosis - affects the thoracic spine, and is sometimes referred to as “hunchback”. Kyphosis often affects senior women.
  • Scoliosis - causes the spine to curve from one side to the other, resembling an S from the front or back

Muscles of the spine

The extensors and flexors are the two major muscle groups which involve the spine. Extensors grant the ability to stand and lift and are secured to the back of the spine. Flexors are in the front of the spine; they include the abdominal muscles. It is important to keep these muscles strong as they control the arch in the back. Carrying weight in the midsection can put undue stress and strain on the spine, leading to pain and even injury.

What are the Vertebrae?

There are 33 bones which interlock within the spinal column. Divided into regions, each one is assigned a number to identify it from the others. Each region has the ability to perform specific functions, but the sacrum and the coccyx are fused and not movable. Functions of each region are:

  • Cervical - The cervical spine supports the weight of the head. It allows the head and neck to turn, nod, or shake the head from side to side. There are seven vertebrae and are numbered C1 thorough C7.
  • Thoracic - The mid-section of the back, the Thoracic spine, has a limited range of motion as its main purpose is to hold the rib cage steady so it can protect major organs like the lungs, and heart. These vertebrae are numbered T1 through T12.
  • Lumbar - The lower back has a big job, as it supports the weight of the body. These vertebrae, numbered L1 through L5, are larger in size to help bear heavy loads.
  • Sacrum - Five Sacral vertebrae are fused toether, and connect the spine to the iliac (hip bones). The structure of the sacrum and the iliac is referred to as the “Pelvic Girdle”.
  • Coccyx - Commonly called the “Tailbone”, the coccyx has four fused bones and serves to attach ligaments and muscles to the pelvic floor.

Though vertebrae are designed with unique purpose and features, they all contain three elements:

  • The body: A drum shaped bone to withstand and contend with compression
  • Vertebral Arch: A bridge shaped bone, which arches to protect the spinal column
  • Processes: Structures which extend from the bone, serving to attach muscles

Dr. Badlani is dedicated to educating our patients about their condition, to provide a complete understanding of the spine and how they can help heal themselves with exercise, therapy, and all, including minimally invasive, surgical and non-surgical options. Contact us today for a full evaluation if you are experiencing back pain or discomfort.