Back and Vertebral Column Flashcards
Back
Formed by the posterior part of the trunk. Described as the region inferior to the neck and superior to the gluteal region.
Back consists of…
Skin, Muscles, Intervertebral disks, Vertebrae, Ribs, Spinal Cord and Meninges
Vertebral Column: Vertebrae
33 vertebrae. 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 4 coccygeal
Curvatures of vertebral column (Primary Curvatures)
Develop during the fetal period. Caused by vertebral shape.
Primary Curvatures
Thoracic kyphosis and Sacrococcygeal kyphosis
Curvatures of vertebral column (Secondary Curvatures)
Develop after birth. Caused by changes in intervertebral discs; vital for upright position and bipedal locomotion.
Secondary Curvatures
Cervical lordosis and Lumbar lordosis
Vertebral Column functions
Protect the spinal cord and the spinal nerves.
Support Weight.
Provide a rigid and flexible axis for the body.
Vital for posture and locomotion.
Provides for the pivot head.
Vertebrae consist of…
Vertebral Body
Pedicles
Lamina
Vertebral arch
Transverse vertebral process
Spinous process
Articular processes
Vertebral Body
Oval segment of bone that forms the anterior part of the vertebra.
Costovertebral joint
Pedicles
Connects the lamina to the vertebral body to form the vertebral arch.
Lamina
Provides roof for the spinal canal and protects the back of the spinal cord
Vertebral arch
Includes a pair of pedicles and a pair of laminae
Supports 2 traverse processes, 1 spinous process and 4 articular processes
Transverse vertebral process
Site of attachment for muscles and ligaments of the spine; point of articulation of the ribs in thoracic spine.
Costo-transverse joint
Spinous process
Bony projection of the back of the vertebra that enables muscle and ligament attachment of the spine
Articular processes
Serve the purpose of fitting with an adjacent vertebra through the articular facet.
Cervical vertebrae
Vertebral Body: Presence of the ucinate process
Vertebral Foramen: Large and triangular
Transverse process: Foramina transversarii
Spinus process: Short and bifid (C3-C6) Expect in vertebra prominens (C7)
Foramina Transversarii
Allow the vertebral artery to pass from the thoracic inlet to the head.
Atypical Cervical Vertebrae C1
Atlas
Lack of vertebral body and spinous process
Composed of two arches: Anterior arch, Posterior Arch
Transverse process: Arise from the lateral mass
Transverse ligament of atlas
Atypical Cervical Vertebrae C2
Axis
Presence of Dens
Superior articular facets
Dens (Odontoid process)
Enables movements in transverse plane (Say no)
Superior articular facets
Allow the rotation of the atlas
Together C1 and C2
C1 carries the cranium and rotates on C2
Thoracic vertebrae
Body: Heart Shape, 2 or 4 costal facets for articulation with the heads of the ribs.
Vertebral foramen: Circular and smaller than the foramen in cervical and lumbar vertebrae.
Transverse process: Long and strong
Articular process: Superior and inferior facets to articulate between vertebrae. Superior and inferior costal facets.
Spinous process: Pointed, long, and slope posteriorly. Tip to extend to the level of the vertebral body below.
Lumbar Vertebrae
Body: Kidney Shape
Vertebral Foramen: Triangular and larger than the foramens in the thoracic vertebrae and smaller than in cervical vertebrae.
Transverse process: Short and slender
Articular process: Superior and inferior facets to articulate between vertebrae. Mammilary process.
Spinous process: Short and sturdy, thick broad and hatched shaped (flat)
Sacrum
Five fused sacral vertebrae
Sacrum composed of…
Sacral canal
Sacral foramina
Sacral promontory
Median Sacral Crest
Sacral Canal
Continuation of the vertebral canal
Contains the cauda equina
Cauda Equina
Bundle of spinal nerves root inferior to L1
Sacral foramina
Allows the exit of the posterior and anterior rami of the spinal nerves
Coccyx
Usually forms by the fusion of the 4 rudimentary coccygeal vertebrae. Co1 often fuses with the sacrum.
Intervertebral Disc
The disc accounts 20-25% of the height of the vertebral column
Intervertebral Disc consist of:
Anulus fibrous
Nucleus pulposus
Anulus fibrosus
Outer fibrous part, composed of concentric lamellae of fibrocartilage
Nucleus pulposus
Core of the IV disc: gelatinous central
Pulpy nuclei are about 88% water
Their semifluid nature is responsible for much of the flexibility and resilience of the IV disc and of the vertebral column as a whole
Cervical Spinal Nerves
Consists of 8 spinal nerves even though there isn’t an 8th cervical vertebrae
Spinal Cervical Nerves will exit the cervical spine…
Through the intervertebral foramen
Cervical spinal nerves will exit…
Above their corresponding vertebrae
Ligaments of the vertebral column
Anterior longitudinal ligament
Posterior longitudinal ligament
Ligamentum flava
Interspinus ligament
Supraspinous ligament
Anterior longitudinal ligament
Strong, broad fibrous band that covers and connects anterolateral aspects of the vertebral bodies and IV discs
Prevents hyperextension of the vertebral column, maintaining stability of the joints between the vertebral bodies
Only ligament that limits extension
Posterior longitudinal ligament
Narrow weaker ligament
Runs within the vertebral canal along the posterior aspect of the vertebral bodies
Weakly resist hyper flexion of the vertebral column and helps prevent of redirect posterior herniation of the nucleus pulposus
Ligamentum flava
Bind the lamina of the adjoining vertebrae together
Interspinus ligament
Connect adjoining spinous processes, attaching from the rot of the apex of each processes
Supraspinous ligament
Connect adjoining tips of spinous processes form the C7 to the sacrum and merge superiorly with the nuchal ligament of the back of the neck
Superficial Muscles of the back
Trapezius
Latissimus dorsi
Rhomboid major
Rhomboid minor
Trapezius
Triangular muscles cover the posterior aspect of the neck and the superior half of the back
Innervation: Accessory Nerve XI
Action:
Descending fibers elevate the scapula
Middle fibers retract the scapula
Ascending fibers depress the scapula and lower the shoulder
Latissimus dorsi
Innervation: Thoracodorsal Nerve
Action:
Acts directly on the glenohumeral joint and indirectly on the pectoral girdle.
Levator Scapulae
Innervation: Dorsal scapular nerve
Action: Elevates the scapula
Rhomboids
Innervation: Dorsal scapular nerve
Action: Retracts the scapula
Intermediate Extrinsic Muscles of the Back: Intermediate Layer
Serratus posterior superior
Serratus posterior inferior
Intermediate Layer
More likely proprioceptive rather than motor in function muscles
Designated as superficial respiratory muscles
Serratus posterior superior
Lies deep to the rhomboid muscles
Innervation 2th-5th intercostals
Action Propioreception of the elevation of the ribs
Serratus posterior inferior
Lies deep to the latissimus dorsi muscle
Innervation: Anterior rami T9-T12 thoracic spinal nerves
Action: Propioreception of the depression of the ribs
Intrinsic muscles of the back
Splenius capitis
Splenius cervicis
Erector spinae
Transversospinalis muscle group
Interspinales
Intertransversarii
Levatores costarum
Intrinsic muscles of the back (Superficial Layer)
Splenius capitis
Splenius cervicis
Splenius capitis
Splenius cervicis
Innervation: Posterior rami of spinal nerves
Action: Laterally flexes the neck and rotates the head to the side of the active muscle
Intrinsic muscles of the back (Intermediate Layer)
Erector spinae (Iliocostalis, Longissimus and Spinalis)
Erector spinae
Innervation: Posterior rami of spinal nerves
Action:
Unilaterally- Flex laterally the vertebral column
Bilaterally - Extend the vertebral column
Intrinsic muscles of the back (Deep Layer)
Transversospinalis group: Semispinalis, Multifidus, Rotatores
Transversospinalis group: Semispinalis
Innervation: Posterior rami of spinal nerves
Action: Extended the head and the thoracic and cervical vertebral regions
Transversospinalis group: Multifidus
Innervation: Posterior rami of spinal nerves
Action: Stabilized the vertebra under local movement of vertebral column
Transversospinalis group: Rotatores
Innervation: Posterior rami of spinal nerves
Action: Stabilized the vertebrae and assist with local extension and rotatory movements of the vertebral column
Intrinsic muscles of the back (Minor Deep Layer)
Interspinales
Intertransversarii
Levatores costarum
Interspinales
Innervation: Posterior rami of spinal nerves
Action: Extension and rotation of vertebrae
Intertransversarii
Innervation: Anterior and Posterior rami of spinal nerve
Action: Aid in lateral flexion of vertebral column acting bilaterally
Levatores costarum
Innervation: Posterior rami of C8-T1 spinal nerves
Action: Elevates the ribs assisting respiration
Clinical Correlation: Laminectomy
Surgical excision of one or more spinous processes and the adjacent supporting vertebral laminae in a particular region of the vertebral column
Often performed to relieve pressure on the spinal cord or nerve roots caused by a tumor, herniated IV disc, or bony hypertrophy
Clinical Correlation: Fracture and Dislocation of Atlas
Jefferson or burst fracture
Compression to the lateral masses by the occipital condyles drive them apart, fracturing one or both of the anterior or posterior arches
Itself does not necessarily result in spinal cord injury,
because the dimensions of the bony ring actually increase.
Spinal cord injury is more likely to happen if the transverse
ligament has also been ruptured
Clinical Correlation: Herniation of Nucleus Pulposus
(Herniation of IV Disc)
Protrusion of the gelatinous nucleus pulposus into or through the anulus fibrosus
Herniations of the nucleus pulposus usually extend posterolaterally
Can be damaged by violent rotation
Clinical Correlations: Abnormal curvatures of the vertebral
column
Excessive thoracic kyphosis
Excessive lumbar lordosis
Excessive thoracic kyphosis (humpback or hunchback)
Characterized by an abnormal increase in the thoracic curvature; the vertebral column curves posteriorly
Can result from osteoporosis in older women
Excessive lumbar lordosis (clinically
shortened to lordosis)
Characterized by an anterior tilting of the pelvis with increased extension of the lumbar vertebrae
Associated with weakened trunk musculature, especially the anterolateral abdominal muscles
Obesity in both sexes can also cause
Clinical Correlations: Scoliosis
Characterized by an abnormal lateral curvature that is accompanied by rotation of the vertebrae
The spinous processes turn toward the cavity of the abnormal
curvature, and when the individual bends over, the ribs rotate posteriorly (protrude) on the side of the increased convexity.
