Vertebral column: Anatomy, curvature and movements
- primary spinal curves
- The thoracic and sacral curves, which are concave anteriorly, are present at birth and are called the primary spinal curve.
- secondary spinal curves
- The lumbar and cervical curves both are concave posteriorly and supporting the body in an upright position when children begin to sit up and stand. Because these curves are not present at birth is called secondary spinal curves.
curvature and movements
- It is defined as the abnormal inward curvature of lumber spine.
- It is occurred due to weakened abdominal muscles and anterior pelvic tilt.
- Causes of lordosis
Causes of lordosis include
- Congenital spinal deformity
- The weakness of the abdominal muscles
- Poor postural habits
- Overtraining in sports requiring repeated lumbar hyperextension
- Obesity causes to reduced range of motion of the entire spine and pelvis, and obese individuals resultingly display increased anterior pelvic tilt and an associated increased lumbar lordosis.
- Osteoporosis a condition in which vertebrae become fragile and can be easily broken.
curvature and movements
- It is defined as the abnormal outward curvature of the thoracic spine.
- It is estimated that kyphosis is 8% in the general population.
- Causes of kyphosis
- Congenital kyphosis (abnormal vertebral development in utero)
- Postural kyphosis (poor posture)
- Scheuermann’s disease; it is the condition in which vertebrae is misshaped.
- Spine infection
- Spine tumors
- It is sideways curvature of the spine which occurs during growth just before puberty.
- Scoliosis appears as a C- or an S-curve involving the thoracic spine, the lumbar spine, or both.
- Nonstructural scoliotic curves are flexible and are corrected with lateral bending.
Causes of scoliosis
- Doctors don’t know what is the main causes of scoliosis.
- The term is used idiopathic which means the cause is unknown.
- Idiopathic scoliosis is most commonly diagnosed in children between the ages of 10 and 13 years but seen in any age.
- There are less common types of scoliosis which may be caused by:
- Neuromuscular conditions, such as cerebral palsy or muscular dystrophy
- Birth defects affecting the development of the bones of the spine
- Injuries or infections of the spine
MOVEMENTS OF THE SPINE
- The spine allows motion in all three planes of movement.
- Flexion, Extension, and hyperextension
- The ROM for flexion/ extension of the motion segments is considerable in the cervical and lumbar regions.
- It is important that not to confuse spinal flexion with hip flexion/ anterior pelvic tilt.
- Flexion, Extension, and hyperextension motions occur during an activity such as touching the toes.
- The ROM for spinal hyperextension is considerable in the cervical and lumbar regions.
- Lateral Flexion and Rotation
- The largest range of motion (ROM) for lateral flexion occurs in the cervical region.
- Spinal rotation occurs in the transverse plane which is again freest in the cervical region of the spine.
MUSCLES OF THE SPINE
- The muscles of the neck and trunk are named in pairs because one on the left and the other on the right side of the body.
- These muscles can cause lateral flexion and rotation of the trunk when they act unilaterally.
- Trunk flexion or extension when they acting bilaterally.
- Anterior Aspect
- The major anterior muscle is eight pairs of hyoid muscles and the prevertebral muscles, including the rectus, capitis anterior, rectus capitis lateralis longus capitis and longus Colli.
- Bilateral tension development by these muscles results in flexion of the head, although the main function of the hyoid muscles appears to be to move the hyoid bone during the act of swallowing.
- Unilateral tension development in the prevertebral muscle contributes to lateral flexion of the head toward the contracting muscles or to the rotation of the head away from the contracting muscles, depending on which other muscles are functioning as neutralizers.
- When Tension development in the internal muscle obliques causes rotation of the spine toward the same side.
- Tension development by the external obliques muscle results in rotation toward the opposite side.
- If the spine is fixed than the internal obliques muscle produces pelvic rotation toward the opposite side, with the external obliques producing rotation of the pelvis toward the same side.
- These muscles form the major part of the abdominal wall which protects the internal organs of the abdomen.
- Posterior Aspect
- The splenius capitis and splenius cervicis are the primary cervical extensors.
- Bilateral tension development in the four suboccipitals—the rectus capitis posterior major and minor and the obliquus capitis superior and inferior—assist.
- When these posterior cervical muscles develop tension on one side only, they laterally flex or rotate the head toward the side of the contracting muscles.
- The erector spinae group includes the spinalis, longissimus, and iliocostalis muscles.
- The muscles of the erector spinae group are the major extensors and hyper extensors of the trunk.
- All posterior trunk muscles contribute to extension and hyperextension when contracting bilaterally and to lateral flexion when contracting unilaterally.
- Lateral Aspect
- Muscles on the lateral aspect of the neck include the prominent sternocleidomastoid, the levator scapulae, and the scalenus anterior, posterior, and Medius.
- Bilateral tension development in the sternocleidomastoid may result in flexion of the neck or extension of the head, with unilateral contraction producing lateral flexion to the same side or rotation to the opposite side.
- The levator scapulae can also contribute to lateral flexion of the neck when contracting unilaterally with the scapula stabilized.
- The three scalenes assist with flexion and lateral flexion of the neck.
- In the lumbar region, the quadratus lumborum and psoas major are large. These muscles function bilaterally to flex and unilaterally to laterally flex the lumbar spine.
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