Anatomy of the back

Question 1

What are the 4 curvatures of the vertebral column and what is their function?

Answer 1

Primary (foetal) kyphoses: thoracic + sacral
Secondary lordoses (childhood -> crawling to walking): cervical + lumbar.
Bipedalism, shock absorption, flexibility.

Question 2

What are the anterior and posterior ligaments to bodies of the vertebral column and what are their functions?

Answer 2

Reinforce and stabilise joints, limit range of movement.
Post. longitudinal ligament, ligamentum flava -> resists hyperflexion.
Ant. longitudinal ligament -> resists hyperextension.

Question 3

What is the clinical significance of the ligaments?

Answer 3

Injury to anterior longitudinal ligament following whiplash

Question 4

What are the functions and properties of intervertebral joints?

Answer 4

Weight bearing + strength
Secondary cartilaginous -> fibrocartilage -> intervertebral discs -> shock absorbers -> nucleus pulposus (semi fluid core), annulus fibrosus (outer – strong) -> thickness increases down vertebral column.

Question 5

What is the clinical significance of intervertebral discs?

Answer 5

Disc protrusion/NP herniation can impinge on nerves

Question 6

What are the facet joints and its properties?

Answer 6

Joints between vertebral arches, synovial. movement depends on joint angle:
Cervical -> slight slope -> flexion, extension, rotation
Thoracic -> near vertical -> rotation only
Lumbar -> wrapped -> flexion, extension only

Question 7

How are the muscles of the back divided?

Answer 7

Extrinsic (move upper limbs/ribs) -> superficial + intermediate.
Intrinsic muscles (postural/move vertebral column) -> deep.
Separated by thoracolumbar fascia.

Question 8

What are the superficial muscles of the back and what is their function?

Answer 8

Trapezius, latissimus dorsi,
Behind trapezius -> levator scapulae, rhomboids
Attach upper limb to trunk

Question 9

What is the origin, insertion and action of the trapezius muscle?

Answer 9

Origin: cervical + thoracic spinal processes.
Insertion: spine + acromion of scapula, lateral portion of clavicle.
Action: rotates scapula

Question 10

What is the origin, insertion and action of the latissimus dorsi?

Answer 10

Origin: thoracolumbar fascia
Insertion: intertubercular sulcus
Action: adducts/extends/medially rotates arm

Question 11

What is the origin, insertion and action of the levator scapulae?

Answer 11

Origin: upper cervical vertebrae
Insertion: superior angle of scapula
Action: elevates scapula

Question 12

What is the origin, insertion and action of the rhomboids (major and minor)?

Answer 12

Origin: lower cervical to fifth thoracic spinous process
Insertion: medial border of scapula
Action: retracts scapula

Question 13

What are the deep muscles?

Answer 13

3 layers:
Splenius –> most superficial (in neck)
Erector spinae –> main group
Multifidus –> Very deep

Question 14

What are the 3 muscle blocks of the erector spinae muscles and what is their location, origin, insertion and action?

Answer 14

Within groove between spinous processes + angles of ribs.
Extend/laterally flex/rotate vertebral column
Origin: erector spinae aponeurosis
Spinales -> to spinous processes
Longissimus -> to transverse processes
Iliocostalis -> to ribs

Question 15

What is the organisation and action of the multifidus?

Answer 15

Transverse processes to spinous processes segmentally for whole length of vertebral column.
Extend/rotate/stabilize vertebral column

Question 16

What is the nerve supply of the intrinsic and extrinsic muscles?

Answer 16

Extrinsic: ant. primary ramus (mainly cervical rami)
Intrinsic: post. primary ramus