Anatomy of the back, spine and spinal cord Flashcards
Functions of the back.
- maintenance of posture.
- movement of limbs and trunk.
What do the skin “dimples” found on the surface anatomy indicate?
The positions of the posterior superior iliac spines.
Name the 3 parts of the trapezius muscle.
- Descending (superior).
- Transverse (middle).
- Ascending (inferior).
Low back pain may be due to strain of which muscle(s)?
Erector spinae
Name the extrinsic muscles of the back.
- Levator scapulae.
- Rhomboid.
- Trapezius.
- Latissimus dorsi.
Where do the extrinsic back muscles attach?
The pectoral girdle.
What is the function of the extrinsic back muscles?
To move the upper limb.
Trapezius extends superiorly into the neck to attach to what?
The occipital bone.
Latissimus dorsi extends superiorly into the neck to attach to what?
Cervical vertebrae.
Function of the intrinsic back muscles?
- Maintaining back posture.
- Movement of spine.
- Spine support.
Name the intrinsic muscles of the back.
- Erector spinae (superficial).
- Transverospinalis (deep).
NB both extend superiorly into neck.
Describe the positioning of the erector spinae muscles.
3 vertical muscle groups found laterally on either side of the spine.
Where do erector spinae muscles attach inferiorly?
Via a common tendon to the sacrum and iliac crest.
Where do erector spinae muscles attach superiorly?
Individual muscle fibres attach (via tendon) to:
- a rib (between rib angles and tubercles) OR
- a transverse process of a vertebra OR
- a spinous process of a vertebra.
Where is transverospinalis located?
Within the grooves between the transverse and spinous processes of vertebrae.
Individual muscle fibres of Transversospinalis attach between?
- A vertebra and the skull.
- A vertebra and a rib.
- One vertebra and another vertebra.
- The sacrum and a vertebra.
Describe the anatomical relationship of Transversospinalis in relation to the laminae and articular processes?
Transversospinalis is found superficially.
How do intrinsic back muscles receive nerve supply?
- Segmentally - dermatome/myotome pattern.
- Via POSTERIOR rami branches of the cervical, thoracic and lumbar regions.
Muscles of the anterolateral abdominal wall (superficial to deep)?
- External oblique.
- Internal oblique.
- Transversus abdominis.
Muscles of the posterior abdominal wall?
- Psoas major.
- Quadratus lumborum.
If erector spinae contracts bilaterally what happens to the spine?
Extension.
If erector spinae contracts unilaterally what happens to the spine?
Lateral flexion.
What muscles are involved in flexion of the spine?
- Psoas major.
- Rectus abdominis.
How many vertebrae in the adult vertebral column?
33 vertebrae,
- C7
- T12
- L5
- S5
- 4 coccygeal -> one coccyx.
What part of the vertebral column do spinal nerves pass through?
Intervertebral foraminae.
What part of the vertebral column does the spinal cord pass through?
Vertebral foraminae.
Which curvatures of the adult spine are described as lordosis?
Cervical and lumbar.
Therefore thoracis and sacral will be kyphosis.
What type of joint is found between the articular processes of adjacent vertebrae?
Facet joints.
- May be affected by arthritis.
What is found between the bodies of adjacent vertebrae?
Intervertebral discs.
- Can herniate.
Pain signals from facet joints and discs of the spine are transmitted via what?
Posterior rami.
Where within the spine are intervertebral discs not found?
- C1-C2.
- Fused sacrum/coccyx.
What proportion of the spine’s length is made up of intervertebral discs?
20-25%.
The outer fibrous ring of an intervertebral disc is known as?
Annulus fibrosus.
- Made up of fibrocartilage.
The inner soft pulp of an intervertebral disc is known as?
Nucleus pulposus.
NB in newborns, can be 90% water. Functions to provide flexibility and protection.
This is a short ligament connecting adjacent laminae posterior to the spinal cord.
Ligamentum flavum.
This is a narrow, weak ligament that prevents over-flexion of the spine. (Little disc support).
Posterior longitudinal ligament.
This is a broad, strong ligament that prevents over-extension of the spine and provides strong support for the intervertebral disc.
Anterior longitudinal ligament.
Anterior longitudinal ligament attaches to?
Anterior aspects of ALL vertebral bodies and intervertebral discs.
Posterior longitudinal ligament attaches to?
Posterior aspects of ALL vertebral bodies and intervertebral discs.
A strong, fibrous ligament connecting the tips of spinous processes.
Supraspinous ligament.
A weak, membranous ligament connecting the superior and inferior surfaces of adjacent spinous processes.
Interspinous ligament.
What does C1 (Atlas) have in place of a body and spinous process?
Posterior and anterior arch.
Special feature of C2?
Odontoid process projecting superiorly.
Where are the Atlanto-occipital joints found?
Between the occipital condyles and superior articular facets of the atlas.
What type of joint are the Atlanto-occipital joints?
Synovial joints with a loose capsule.
What movements occur at the Atlanto-occipital joints?
- Flexion & extension of the neck.
- Some lateral flexion and rotation of the neck.
Why might the spinal cord be unharmed in a dislocation of the cervical vertebra?
Due to the large vertebral canal in this area.
What type of joints are the Atlanto-axial joints?
Synovial.
How many articulations in the Atlanto-axial joints?
3.
- 2 between inferior articular facets of atlas and superior articular facets of axis.
- 1 between anterior arch of atlas and odontoid process of axis.
What main movement occurs at the Atlanto-axial joints?
Rotation.
What is found in place of intervertebral foraminae in the sacrum?
The anterior and posterior sacral foraminae.
What is the inferior end of the sacral canal?
The sacral hiatus.
- A palpable structure.
What is found within the sacral canal?
Cauda equina and meninges.
In caudal anaesthesia, where is local anaesthetic injected?
Into the sacral hiatus.
What is caudal anaesthesia attempting to anaesthetise?
The sacral spinal nerve roots of the cauda equina.
Where does the spinal cord begin?
Foramen magnum.
The spinal cord is continuous with which structure?
The medulla oblongata.
Where does the spinal cord end?
Around L1/L2.
Can end from T12 - L3
What name is given to the tapered end of the spinal cord?
Conus medullaris.
Where does the spinal cord lie and what is it surrounded by?
- In the spinal canal.
- 3 layers of meninges and epidural fat.
Procedure used to access the spinal canal for the posterior exposure of the spinal cord and/or spinal roots.
Laminectomy.
Why might a laminectomy be performed?
To relieve pressure on the spinal cord or nerve roots.
What might cause pressure on the spinal cord or nerve roots?
- Tumours.
- Herniated disc.
- Bone hypertrophy.
Removal of one or more spinous processes and the adjacent lamina.
Laminectomy.
