Back, Spine and Spinal Cord Flashcards
What are the two main functions of the back?
Maintenance of posture and movement of the trunk and limbs
Lower back pain may be due to strain of which muscle?
Erector spinae
What are the names of the three parts of the trapezius muscle and where do they lie?
Descending (superior), transverse (middle), ascending (inferior)
What are the 4 extrinsic back muscles?
Levator scapulae, rhomboids, trapezius and latissimus dorsi
Extrinsic back muscles attach the back to where?
Pectoral girdle
The extrinsic back muscles allow movement of where?
The upper limb
Are the extrinsic back muscles involved in the maintenance of posture?
No
The trapezius muscle extends superiorly into the neck to attach to where?
Occipital bone
The latissimus dorsi extends superiorly into the neck to attach to where?
Cervical vertebrae
What are the two groups of intrinsic back muscles?
Erector spinae and transversospinalis
Which group of intrinsic back muscles is more superficial?
Erector spinae
Which group of intrinsic back muscles is more deep?
Transversospinalis
Both groups of intrinsic back muscles extend superiorly into where?
The neck
What are the functions of the intrinsic back muscles?
Maintenance of posture and movement of the spine
The erector spinae is made up of how many muscle groups?
Three
Where is the erector spinae muscle group located in relation to the spine?
Lateral
Where does the erector spinae attach inferiorly?
A common tendon attaches to the sacrum and iliac crest
Where does the erector spinae attach superiorly?
Individual muscle fibres attach via a tendon to either a rib, a transverse process of a vertebra or a spinous process of a vertebra
Where is the transversospinalis muscle group located?
Within the grooves between transverse and spinous processes
Individual muscle fibres of the transversospinalis muscle can attach between a vertebrae and what other structures?
The skull, a rib, another vertebrae, the sacrum
Describe the nerve supply of intrinsic back muscles?
This is segmental - i.e. as per the dermatome/myotome pattern
Are the intrinsic back muscles supplied by anterior or posterior rami?
Posterior rami
What is the nerve supply to the levator scapulae?
Dorsal scapular nerve
What is the nerve supply to the rhomboids?
Dorsal scapular nerve
What is the nerve supply to the trapezius?
Spinal accessory nerve
What is the nerve supply to the latissimus dorsi?
Thoracodorsal (long scapular) nerve
What muscles are responsible for extension of the spine?
Erector spinae and transversospinalis
Bilateral contraction of the erector spinae muscle results in what movement?
Extension
Unilateral contraction of the erector spinae muscle results in what movement?
Lateral flexion
What muscles are responsible for flexion of the spine?
Psoas major and rectus abdominus
How many vertebrae are there? How is this divided?
33: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, 4 coccygeal
Describe the variations in size of the vertebrae?
They get bigger as you descend as they bear more weight, and then get smaller again once weight has been transferred to the hips
The vertebral foraminae combine to form what two structures?
Vertebral canal and intervertebral foramina
What structure passes through the vertebral canal?
Spinal cord
What structures pass through the intervertebral foramina?
Spinal nerves
What are the names of the two lordosis’ in the spine?
Cervical and lumbar
What are the names of the two kyphosis’ in the spine?
Thoracic and sacral
What structures attach to the spinous processes of vertebrae?
Muscles and ligaments
What structures attach to the transverse processes of vertebrae?
Muscles, ligaments and ribs
What is the role of the articular processes of a vertebrae?
To allow mobility by forming synovial facet joints with adjacent vertebrae
What is the role of the vertebral foramen?
Convey and protect the spinal cord
What is the role of the vertebral arch? What is it formed of?
Protects the spinal cord, formed of 2 lamina and 2 pedicles
What joints of the back are affected by arthritis?
Facet joints
Pain signals from the back will be transmitted through where?
Posterior rami
Where in the vertebral column are intervertebral discs not found?
Between C1 and C2, and in the fused sacrum/coccyx
Describe the movement provided by intervertebral discs?
Each disc allows a small amount of movement which has a summative effect providing a large amount of movement
What is the role of the ligamentum flavum?
This is a short ligament, responsible for connecting adjacent laminae posterior to the spinal cord
What does the posterior longitudinal ligament attach to?
The posterior aspect of all vertebral bodies and intervertebral discs
Which is stronger, the anterior or posterior longitudinal ligament?
Anterior (broad and strong whereas the posterior is narrow and weak)
What is the role of the posterior longitudinal ligament?
Prevents over flexion of the spine
What does the anterior longitudinal ligament attach to?
The anterior aspect of all vertebral bodies and intervertebral discs
What is the role of the anterior longitudinal ligament?
Prevents over extension of the spine
Describe the strength/material of a supraspinous and interspinous ligament?
Supraspinous = strong, fibrous / interspinous = weak, membranous
What is the role of the supraspinous ligament?
To connect the tips of spinous processes
What is the role of the interspinous ligament?
To connect the superior and inferior surfaces of adjacent spinous processes
What structure do cervical vertebrae possess that other vertebrae do not?
Transverse foraminae
What structures pass through the transverse foraminae in cervical vertebrae?
Vertebral arteries
What is unique about C1 atlas?
Does not have a vertebral body or spinous process
What structure does C2 axis possess that other vertebrae do not?
An odontoid process projecting superiorly
What is C7 vertebrae known as and why?
Vertebrae prominens as it is the first palpable spinous process
Where do the atlanto-occipital joints connect between?
The occipital condyles and superior articular facets of atlas
What type of joints are the atlanto-occipital joints?
Synovial joints with a loose capsule
What movements do the atlanto-occipital joints allow?
Flexion and extension of the neck and a little lateral flexion and rotation
Why may spinal cord damage not always occur in a dislocation of a cervical vertebrae?
Because the vertebral canal in this area is larger
How many articulations form the atlanto-axial joint? What type of joint is this?
3 - it is a synovial joint
Where are the 3 articulations which form the atlanto-axial joint?
2x between the inferior articular facets of atlas and superior articular facets of axis, and 1x between the anterior arch of atlas and odontoid process of axis
What is the main movement that the atlanto-axial joint is responsible for?
Rotation
What are found in the sacrum instead of intervertebral foraminae?
Anterior and posterior sacral foraminae
What structures are found in the sacral canal?
Cauda equina and meninges
Where is anaesthetic injected in caudal anaesthesia? What nerves are anaesthetised?
Sacral hiatus / the sacral spinal nerve roots of the cauda equina
Where does the spinal cord begin? It is continuous with what other structure?
Foramen magnum / medulla oblongata
Where does the spinal cord end? What is this known as? What does it become after this?
L1/L2 / conus medullaris / cauda equina
What is the spinal cord surrounded by?
3 layers of meninges and epidural fat
What is a laminectomy?
Removal of one or more spinous processes and the adjacent lamina
What layers do you have to pass through to perform a laminectomy?
Skin, superficial fascia, deep fascia, intrinsic muscles, ligaments (flavum, supraspinous, interspinous)
