Back and Vertebral Column

Question 1

Curvatures

Answer 1

Cervical = 2 (concave posteriorly)
Thoracic = 1 (convex posteriorly)
Lumbar = 2
Sacral = 1

Question 2

Abnormal Spinal Vertebrae

Answer 2

Lordosis: anatomic term for a posteriorly concave curve
Kyphosis: anteriorly concave curve
Scoliosis: lateral curve

Question 3

General Vertebrae Features

Answer 3

From most posteriorly to anteriorly:

1. Spinous Process:
   - projects posteriorly
   - site of attachment for muscles and ligaments
2. Articular Process:
   - facilitates and restricts movement
   - projects vertically and forms synovial joints and corresponding parts of adjacent vertebrae
   - contains superior and inferior articular processes and facets
3. Vertebral Arch (b/w articular processes)
   - protects spinal cord
4. Lamina:
   - connects transverse and spinous process to form the posterolateral part of vertebral arch
5. Transverse Processes:
   - attachment points for muscles and ligaments
   - extends posterolaterally
6. Pedicle:
   - joins the vertebral body anteriorly and forms lateral part of vertebral arch
7. Vertebral Body
   - main weight-bearing structure of vertebrae
   - large mass of bone

Intervertebral Foramen:
- formed b/w 2 articulating vertebrae by the inferior vertebral notch (of superior vertebrae) and superior vertebral notch of inferior vertebra

Question 4

Regional Specialisations of Vertebrae

Answer 4

Cervical Vertebrae:

• triangular vertebral foramen
• horizontal articular facets
• presence of foramen transversarium

Thoracic Vertebrae:

• circular vertebral foramen
• heart-shaped columnar bodies
• vertical articular facets
• presence of costal facets where ribs articulate

Lumbar Vertebrae:

• triangular smaller vertebral foramen
• massive columnar body

Question 5

Intervertebral Discs

Answer 5

Secondary cartilaginous joints b/w vertebral bodies
- made up of outer annulus fibre (concentric layers of fibrocartilage) that surrounds the nucleus pulposus

Annulus Fibre: keeps vertebrae tog and contains nucleus

Nucleus Pulposus: keeps vertebrae apart and absorbs shock

Question 6

Posture’s influences on intervertebral discs

Answer 6

1. Recumbent (lying down)
   - not a lot of force
2. Standing
   - weight of body is directed through the vertebral column and is evenly distributed through discs
3. Flexion at the Lumbar Spine
   - anterior part of disc is compressed, therefore force is directed through disc posteriorly

Disc Prolapse: when nucleus penetrates through annulus
Bulge < Herniation < Severe Extrusion

Question 7

Synovial Joints of Vertebral Arches (Zygapophysial/Facet Joints)

Answer 7

formed by the INF. ARTICULAR PROCESS on sides of vertebrae articulating in a SYNOVIAL JOINT with the SUPERIOR ARTICULAR PROCESS of the VERTEBRA BELOW.

• allow sliding and gliding movement

Question 8

Ligaments of the Vertebral Column

Answer 8

hold bones together and restrict movement

1. Anterior and Posterior Longitudinal Ligaments:
   from deepest to most superficial:
   LIGAMENTUM FLAVUM: connects laminae of adjacent vertebrae

POSTERIOR LONGITUDINAL LIGAMENT: runs along posterior surface of vertebral bodies

ANTERIOR LONGITUDINAL LIGAMENT: runs along the anterior surface of vertebral bodies

2. Interspinous and Supraspinous Ligaments:
   INTERSPINOUS: runs in a sagittal plane b/w spines of adjacent vertebrae

SUPRASPINOUS: runs along posterior surface of vertebral spine

Question 9

Intervertebral Foramen

Answer 9

lateral foramen formed b/w 2 vertebrae

Formed by a notch from one pedicle aligned with a matching notch on adjacent vertebrae

Ant wall:
- vertebral bodies and intervertebral discs

Post:

• zygapophysial joints
• articular processes

Sup. and Inf. Walls:
- vertebral notches of pedicles

Question 10

Muscles of the Back

Answer 10

Extrinsic Muscles: superficial that act on upper limb

From most superior –> inferior:
1. TRAPEZIUS: moves scapula up and down away from ribs

2. DELTOID: (shoulder muscle)
3. LATISSIMUS DORSI: big, flat muscles on lower back that attach to the humerus
4. THORACOLUMBAR FASCIA: flattened tendon that attaches the latissimus dorsi to hip bones

Intrinsic Muscles: attach vertebrae to other vertebrae to control posture and vertebral movement - ALL INNVERVATED BY PRIMARY DORSAL RAMI
- Erector Spinae Muscles: responsible for extension of vertebral column

From medial –> lateral:

1. SPINALIS (medial column of erector spinae)
2. LONGISSIMUS: middle column
3. ILIOCOSTALIS: most lateral column

Transversospinalis: group of muscles responsible for rotation and extension of vertebral column

Question 11

Muscles involved in Movement

Answer 11

FLEXION:

• rectus abdominis & Psoas major = key agonists
• erector spinae muscles act eccentrically to stabilise during flexion

EXTENSION:
- bilateral concentric contraction of the erector spinae muscles

LATERAL:
- unilateral action of ESM

ROTATION:

• transversospinalis
• unilateral action of ESM and internal/external obliques