General - The back

Question 1

Functions

Answer 1

Support
Movement
Protection of the nervous system

Question 2

Support function

Answer 2

The bodies weight
Transmit forces through the pelvis to the lower limbs
Carry and position the head
Brace and help maneuver the upper limbs
Holds the vertebral column which is positioned at the midline and has many curvatures:
Primary curvature is concave anteriorly, reflecting the original shape of the embryo and is retained in the thoracic and sacral regions in adults.
Secondary curvatures are concave posteriorly form the cervical and lumbar regions and bring center of gravity into a vertical line, allowing the body weight to be balanced on the vertebral column in a way that expends the least amount of energy to maintain an upright bipedal stance.

Question 3

Movement function

Answer 3

Muscles of the back consist of extrinsic and intrinsic groups
Extrinsic muscles of the back move the upper limbs and the ribs
Intrinsic muscles of the back maintain posture and move the vertebral column. Movements include flexion(anterior bending), extension, lateral flexion, and rotation.
Movement between two vertebrae is limited but is additive along the length of the vertebral column.
Freedom of movement and extension are limited in the thoracic region relative to the lumbar part of the vertebral column.
Muscles in more anterior regions flex the vertebral column.
The first two vertebrae and the associated muscles in the cervical region are specifically modified to support and position the head flexing and extending in a nodding motion C1. rotation of the head as C1 moves on vertebra C2

Question 4

Protection of the nervous system function

Answer 4

The vertebral column and the associated soft tissues of the back contain the spinal cord and proximal parts of the spinal nerves.
More distal parts of the spinal nerves pass into all other regions of the body including certain regions of the head.

Question 5

Movement of the spinal cord segments

Answer 5

Intrinsic muscles of the back maintain posture and move the vertebral column. Movements include flexion(anterior bending), extension, lateral flexion, and rotation.
Movement between two vertebrae is limited but is additive along the length of the vertebral column.
Freedom of movement and extension are limited in the thoracic region relative to the lumbar part of the vertebral column.
Muscles in more anterior regions flex the vertebral column.
The first two vertebrae and the associated muscles in the cervical region are specifically modified to support and position the head flexing and extending in a nodding motion C1. rotation of the head as C1 moves on vertebra C2

Question 6

Primary curvature

Answer 6

is concave anteriorly, reflecting the original shape of the embryo and is retained in the thoracic and sacral regions in adults.
Thoracic Curvature
Sacral/coccygeal curvature

Question 7

Secondary curvature

Answer 7

are concave posteriorly from the cervical and lumbar regions and bring center of gravity into a vertical line, allowing the body weight to be balanced on the vertebral column in a way that expends the least amount of energy to maintain an upright bipedal stance.
Cervical curvature
Lumbar curvature

Question 8

Curvature reasons

Answer 8

The Primary curvature reflects the original shape of the embryo and is concave anteriorly backward C shaped in the thoracic and sacral regions. The Secondary curvature is for the center of gravity in the body in the cervical and lumbar regions; these are shaped like regular C’s and are likely there to offset the primary curvature for an even distribution.