2. Vertebra, Sacrum, Skull, Pelvis + Upper Limb - Anatomy Lecture
Start from the skin on the midline of the back and work anteriorly naming all of the structures until you get to the posterior longitudinal ligament.
1. Skin, superficial fascia, 2. supraspinous ligament 3. spinous process 4. ligamentum flavum 5. epidural space, dura mater, arachnoid mater, subarachnoid space, pia mater, spinal cord, meninges and spaces again, epidural space, 6. PLL.
Osteoporosis
A condition in which the body's bones become weak and break easily. Bone quality is normal but quantity is deficient
Purpose of Intervertebral Discs
Anulus Fibrosis + Nucleus Pulposus work as shock absorbers Longitudinal compression: squeezes the nucleus outward, this distributes the force across the whole vertebra Variable compression allows: distribute tension across whole body when uneven pressure is applied - flexion-extension movements in sagittal plane - lateral flexion in coronal plane
Atlas
C1 - Atlas (holds head) - no vertebral body (Dens of axis in location where body would be) - Small posterior tubercle (instead of spinous process) Superior articular facet: concave surface that meets the convex condyles on the inferior surface of the occipital bone. - curves work with the ligaments that hold the skull, atlas and axis together prevent transverse rotation between the skull and atlas - Though flexion and extension is allowed Inferior Articular Facet: flat facet that meets moderately flat facets of axis - this geometry allows a lot of rotation (head rotation of 90* right and left - half of that occurs here) Transverse Process: Large and protrude further laterally than other cervical v. - acting as levers for muscle action. - Transverse foramen present
The Axis
C2 - Axis Odontoid Process (Dens): prominent midline process that serves as axis of rotation for the atlas in transverse plain - Anterior facet of Dens: articulates with anterior tubercle of atlas Spinous Process: Largest of cervical vertebrae helping to provide stable base for nodding, head-shaking and tilting movements that occur in the Occipito-atlanto-axial complex Superior Articular Facet: articulate with inferior articular facets of the atlas to allow much range of motion in rotation Inferior Articular Process and facet: Connects to C3 - similar to bones below it. Transverse Process: smaller than other 6 cervical vertebrae w Transverse Foramen
Variation in Vertebral Number
Cervical (C1-7): Fusion Thoracic: Extra Ribs Lumbar: Fusion of 5 with sacrum Hemivertebrae: vertebrae on only one side
Cervical Vertebrae Features
Cervical Vertebrae Features 1. Vertebral Body: short in height and square shaped (viewed from above) - Concave superior surface, convex inferior 2. Transverse Process: transverse foramen 3. Spinous process: short and bifid 4. Lamina: thin 5. Vertebral Foramen: triangular
Degnerative Disc Disease Example:
Degenerative Disc Disease at C5/C6 vertebral unit Osteophytes: bone growths (whiter) Diminished height of disc Instability indicated by posterior shift + abnormal curvature
Disc Herniation
Disc protrusion + Herniation Tears in anulus fibrosis allow the nucleus pulposus to migrate outward. Radial tears in anulus fibrosis allow nucleus pulposusto herniate
Does C7 usually have a transverse foramen? Do any of the vertebrae superior to C7 not have transverse foramina?
Does C7 usually have a transverse foramen? Yes Do any of the vertebrae superior to C7 not have transverse foramina? No, they all have transverse foramina.
Each rib articulates in __ places on ___ bones.
Each rib articulates in 3 places on 2 bones (thoracic vertebrae) 1. Costal Transverse Joint: Costal Facet of transverse process (same rib/bone) 2. Superior demifacet of its own vertebrae 3. Inferior demifacet of its the next vertebrae superiorly (above it)
Fossa: Foramen: Process: Tuberosity + Tubercle: Facet:
Fossa: indentation (in bone or soft tissue) Foramen: hole (should go all the way through something) Process: protrudes outward (vertebrae have spinous and transverse processes) Tuberosity/Tubercle: Bumps - Tuberosity = large, tubercle = small (process generally larger) Facet: surface where one bone contacts another bone to form a joint
Herniation of Intervertebral Disc
Herniation of Intervertebral Disc Anulus Fibrosus tear through which the nucleus pulposus can exit into the vertebral canal or intervertebral foramen to impinge on neural structures - Radial tears in anulus fibrosis allow nucleus pulposusto herniate Common cause of back pain. Most common location: Lateral part of vertebral canal - medial to the pedicle
If the Transverse ligament of atlas ruptures or avulses away from its bone attachments, what displacement of bones occurs? How does affect the relationship between the skull and atlas? Between the skull and axis?
If the Transverse ligament of atlas ruptures or avulses away from its bone attachments, what displacement of bones occurs? The skull, foramen magnum and atlas glide anteriorly. How does affect the relationship between the skull and atlas? It does not. The skull is anterior. Between the skull and axis? The result is that the dens compresses the spinal cord.
In a lumbar vertebral unit, do the laminae of the two bones contribute to the intervertebral foramen?
In a lumbar vertebral unit, do the laminae of the two bones contribute to the intervertebral foramen? No
In a thoracic or lumbar vertebral unit, does the pedicle of one bone, both bones, or neither bone contribute to the intervertebral foramen?
In a thoracic or lumbar vertebral unit, does the pedicle of one bone, both bones, or neither bone contribute to the intervertebral foramen? Both
In the L4-L5 vertebral unit. Where exactly does the ligamentum flavum attach?
In the L4-L5 vertebral unit. Where exactly does the ligamentum flavum attach? From the inferior edge of a lamina to the superior edge of the lamina of the next inferior vertebra.
sacral apex
Inferior portion of sacrum that connects to coccyx below.
Injuries of Cervical Spine
Injuries of Cervical Spine 1. Hyperextension: Whipflash, when the head extends back much farther than it normally would 2. Fractures: Dens of axis, traumatic spondylolisthesis (anterior slippage of vertebral body), and atlas Example (Photo): Hangman's Fracture - Pt hit dashboard. Hypertension caused traumatic spondylolithesis of C2 (axis) with fracture of vertebral arch of C2 and tearing of ligaments between C2 and C3
Intervertebral Disc
Intervertebral Disc: located between vertebral bodies - Symphyses between vertebral bodies - Outer anulus fibrosus surrounding central nucleus pulposus Anulus Fibrosus: Limits rotation of vertebra. - outer set of fibrocartilage rings of a disc give it strength. - degeneration can lead to herniated disc Nucleus Pulposus: Fills center of intervertebral disc - Inner core of soft material is mostly acelluar (Gelatinous) - Provides shock absorption by distributing force outward as well as longitudinally
Intervertebral Foramina
Intervertebral foramina: hole between two bones (vertebrae) Spinal Nerve: travels through intervertebral foramen - At all levels of the spinal column Anterior Ramus of Spinal Nerve: lower cervical spine, anterior ramus of spinal nerve rests in the gutter (between anterior and posterior tubercles of transverse process) Problems: impinge upon spinal nerves or branches - fractures of posterolateral part of vertebral body, of Superior articular process, and tubercles of transverse
Pelvic Fracture
It is not possible to break one side of the bony ring on your pelvis without breaking the other. If you fracture one side a second fracture should always be expected
Where are the inferior articular facets found on thoracic vertebrae?
Lamina Interior Articular Processes are very small so facet is mostly found on the lamina
Path of Spinal nerve (Cervical Spine)
Left C5 transverse process gutter shown. Shape and angle of superior vertebral notch on superior side of pedicle indicate path of spinal nerve as it leaves the neural canal and goes out into the tissues of neck. Shape and angle of Gutter indicate path of anterior ramus.
Ligament
Ligament: connective tissue that Connects bone to bone Reinforces joints
Ligamentum Flavum
Ligamenta Flava: connects the laminae of adjacent vertebrae - thin broad, elastic tissue - Posterior surface of vertebral canal Resist separation of the laminae in flexion. Assist in extension back to the anatomical position
List two features of the atlas that are shared with other cervical vertebrae.
List two features of the atlas that are shared with other cervical vertebrae. 1. Transverse Process 2. Transverse Foramen
List two features of the atlas that distinguish it from the other cervical vertebrae. Which features does the atlas not have that other cervical vertebra do?
List two features of the atlas that distinguish it from the other cervical vertebrae. 1. Posterior Arch (highlighted in picture 2. Anterior Tubercle (front area that articulates w/ Dens) No vertebral Body + No Spinous Process
List two features of the axis that distinguish it from the other cervical vertebrae.
List two features of the axis that distinguish it from the other cervical vertebrae. 1. Dens 2. Large bifid spinous process
Anterior and Posterior Longitudinal Ligaments
Longitudinal Ligaments: Anterior and Posterior surfaces of vertebral bodies and extend along most of the vertebral column. Anterior Longitudinal Ligament: attached superiorly to base of skull and extends inferiorly to attach to anterior surface of sacrum. - attached to vertebral bodies and intervertebral discs Posterior Longitudinal Ligament: Lines posterior surface of vertebral bodies, but is lining the anterior surface of the vertebral canal (made up of vertebral foramen) - tectorial membrane: C2 to base of skull (upper part)
Lower Cervical Spine
Lower Cervical Spine is Less specialized. Each lower segment allows - Rotation - Lateral Flexion - Flexion and extension But not as much of any movement as the rotation that can occur at the atlanto-axial joint complex.
Lumbar Spine
Lumbar Spine: 5 Vertebrae - Features for stability and weight baring (transmission of weight to lower limbs) Body: Large Articulate Processes: Large - Facet joints on vertebral arch (Lumbar) have an interlocking arrangement to help with weight baring Spinous Process: shape of ax blade Transverse Process: thin blades homologous to ribs - but there are no ribs so more movement is possible than thoracic spine
The typical way to injure a ligament is to stretch it too much. Name a ligament that can be injured by severe flexion of the lumbar spine. Name the ligament on Anatomy study list 1 2 that can be injured by repetitive excessive extension of the lumbar spine.
Name a ligament that can be injured by severe flexion of the lumbar spine. Supraspinous Ligament or Posterior longitudinal Ligament. Name the ligament on Anatomy study list 1 2 that can be injured by repetitive excessive extension of the lumbar spine. Anterior longitudinal ligament
Name the principal soft tissue structure that occupies the transverse foramen of C5. Is that structure present in the transverse foramen of C7?
Name the principal soft tissue structure that occupies the transverse foramen of C5. Vertebral Artery Is that structure present in the transverse foramen of C7? No
Nuchal Ligament
Nuchal Ligament: Binds the skull to the vertebral column - Continuous with supraspinous ligament Helps to stabilize head and allows shoulders and head to be more independent. Allows improved balance during running
Occipito-atlanto-axial complex
Occipito-atlanto-axial complex: Atlas + Axis Occipital bone of skull relates closely to first 2 vertebrae in the way they connect and biomechanics C1 - Atlas (holds head) - no vertebral body (Dens of axis in location where body would be) - Small posterior tubercle (instead of spinous process) C2 - Axis - Dens: prominent midline process that serves as axis of rotation for the atlas in transverse plain - Large spinous process (in comparison to small posterior tubercle of atlas) **no intervertebral disc between C1 and C2
Cervical Vertebrae
Occipito-atlanto-axial complex: Atlas + Axis Occipital bone of skull relates closely to first 2 vertebrae in the way they connect and biomechanics C1: Atlas C2: Axis C3 to C7 look very similar - C3,4,5: extremely similar - C6 + C7 almost the same All cervical vertebrae give stability and allow movement in very similar ways
Sacral Hiatus
Opening at inferior end of sacrum on posterior side Used as a route to administer an epidural anesthetic
Osteophytes
Osteophytes: when bone experiences excess tension for an extended period of time it responds by forming more bone - Often where ligaments attach to bone Expect to find where you have spinal trauma
Vertebral Differences: Arch Features
Pedicle (circle): Anchors vertebral arch to body Lamina (double arrow): meet posteriorly at base of spinous process right and left lamina meet to make spinous process Spinous Process (single arrow): Posterior protrusion Transverse Process (*): Lateral protrusion 1. Cervical: - Pedicle: Not very obvious - Lamina: right and left flat "sheet"s that meet to make spinous process - Spinous Process: small - Transverse Process: very small 2. Thoracic: - Pedicle: distinct - arch meets vertebral body - Lamina: right and left flat "sheet"s that meet to make spinous process 3. Lumbar: - Lamina: right and left (not as flat) that meet to make spinous process
Relative to the height (superior to inferior dimension) of the two vertebrae in the vertebral unit, are cervical, thoracic and lumbar discs tall or short? Which are tallest?
Relative to the height (superior to inferior dimension) of the two vertebrae in the vertebral unit, are cervical, thoracic and lumbar discs tall or short? Cervical: Medium Tall Thoracic: Short. Whole disc is often called thin Lumbar: Tall (Tallest)
Rib 6 articulates with transverse process and superior costal demifacet of vertebrae ? Rib 6 also articulates with inferior costal demifacet on inferior part of vertebral body of ?
Rib 6 articulates with transverse process and superior costal demifacet of vertebrae T6 Rib 6 also articulates with inferior costal demifacet on inferior part of vertebral body of T5
Sacrum
Sacrum: bone formed from five vertebrae fused together near the base of the spinal column Sacral Canal: Holds the cauda equina Anterior Sacral Foramina: anterior ramus leave Posterior Sacral Foramina: posterior ramus leave **bone in photo has condition where sacrum articulates with transverse process of L5 (extra contact limits movement of 2 bones)
How many cervical, thoracic and lumbar vertebrae are there? What areas make up the vertebral column?
Spine: gives stability and allows mobility of trunk/neck 7 Cervical: between skull and rib 12 Thoracic: Rib cage attached 5 Lumbar: weight baring 5 Sacrum segments Coccyx: tail bone
supraspinous ligament
Supraspinous ligament: Connects tips of spinous processes (C7 to sacrum) continuous with ligamentum nuchae (C7 to skull)
The epidemiology matches the anatomy quite well. Given the amount of material in them, are cervical discs very likely to herniate? Thoracic discs? Lumbar discs?
The epidemiology matches the anatomy quite well. Given the amount of material in them, are cervical discs very likely to herniate? Thoracic discs? Lumbar discs? Cervical: not really Thoracic: no, but sometimes Lumbar: yes
Thoracic Spine
The thoracic spine contains 12 vertebrae each connected to a pair of ribs. - thoracic spine curve is convex posteriorly (concave anteriorly) - Long spinous process (shape not related to ribs, all other characteristic features relate to ribs)
Thoracic Features related to Ribs
Thoracic Features related to Ribs 1. Transverse Process: long and sturdy to provide a stable anchor point distal to rib neck 2. Superior Costal Demifacet: contact point for rib head with same number as vertebrae 3. Inferior Costal Demifacet: contact point for head of rib that is numbered inferior to the vertebrae
What holds axis and atlas together?
Transverse Ligament of Atlas: posterior to dens of the axis - Completes ring around dens and prevents atlas from gliding anteriorly relative to axis. (if it did whole head would go with it) Ligament: sturdy connective tissue to prevent too much movment from occuring
Damage to transverse Ligament of Atlas
Transverse Ligament of Atlas: prevents anterior glide of C1 (head + atlas would fall forward off of axis) Ligament Damaged or Dens Malformed: anterior displacement of the atlas and skull can occur, causing compression of the spinal cord against the dens Down Syndrome: common malformations of atlanto-axial complex. - Automobile accident or spinal injury must handle pt very carefully
Transverse Foramina
Transverse foramina: ONLY present in Cervical Spine - Lies in the center of the transverse process - Anterior part of transverse process joins vertebral body directly and separately from pedicle - Cervical vertebrae have then lamina
Joints between vertebrae
Two types of joints between vertebra: 1. Symphyses: between vertebral bodies 2. Synovial Joints: between articular processes Typical vertebra has 6 joints - 4 synovial: 2 above/2below - 2 symphyses: 1 above/ 1 below
Lumbar Vertebra: Facets
Typical Lumbar Vertebrae Superior Articular Process (with concave facet): - lines show how vertebrae above's inferior facets attach, this limits rotation and lateral flexion. - Facets do allow flexion and extension Superior process is on the lateral side of joint with facets facing medially , while the inferior process (of the vertebra above) lies medially with its facets pointed out lateral - Bascially vertebra above sits in the middle and vertebra below on the outside for each joint
Typical Thoracic Vertebrae
Typical Thoracic Vertebrae 1. Spinous Process: Very long and inferiorly projected - palpating tip of spinous process of T6, transverse process directly lateral to that will be part of T7 2. Superior Articular Process + Facet: Facets mounted on moderately prominent articular processes 3. Interior Articular Processes: very small so facet is mostly found on the lamina 4. Inferior vertebral notch: forms most of intervertebral foramen that houses the spinal nerve
Vertebra and Cancer
Vertebra are common site of metastatic disease (secondary spread of cancer cells) - cancer can destroy mechanical properties of the bone
Vertebral Artery
Vertebral Artery: branches from subclavian a. at the root of the neck. - Passes through transverse foramen of C6-1 - Then through foramen magnum of occipital bone on way to the brain + spinal cord
Vertebral Differences: Body + Arch
Vertebral Body: Located anterior Vertebral Arch: forms vertebral foramen posteriorly (called neural arches) 1. Cervical: Body is small relative to Arch 2. Thoracic: Body elongated from anterior to posterior - Arch has long transverse processes on right and left side (ribs) - Arch has long spinous process on midline 3. Lumbar: Body is "bean" shaped in superior view - good for load bearing (larger) 4. L5: Particularly stout transverse process to allow strong ligaments to anchor to the ileum of the hip bone
Vertebral Canal
Vertebral Canal: Combination of the vertebral foramina of two or more consecutive vertebrae. - contains the spinal cord Runs from foramen magnum to the sacral hiatus
Vertebral Fracture
Vertebral Column Stability Regions: 1. Anterior Column: Vertebral bodies and anterior longitudinal Ligament 2. Middle Column: vertebral body and posterior longitudinal ligament 3. Posterior Column: ligamenta flava, ligamenta nuchae (in cervical), supraspinous l. (rest). Injury based on how many columns: 1 Column: stable just needs rest 2 Columns: unstable requiring fixation and immobilization 3 Columns: significant neurological event and requires fixation to prevent further extension
Vertebral Unit
Vertebral Unit: two contiguous vertebrae and the soft tissue structures that connect them (disc + other ligamentous structures, short muscles) - Lets us discuss movements and stability. Photo: two consecutive vertebral units - Spinous process of most superior is shorter and not as angled so T3 - T5
What elements of bone would a dissector have to remove to show this view? Name part of the atlas that as been "cut"? Name part of other cervical vertebrae that has been "cut"? Name parts of bone that have been "cut" in thoracic region? Name part of lumbar vertebrae that as been "cut" Name part of sacrum that has been "cut"
What elements of bone would a dissector have to remove to show this view? Vertebral bodies and pedicles Name part of the atlas that as been "cut"? Lateral Masses Name part of other cervical vertebrae that has been "cut"? Pedicle Name parts of bone that have been "cut" in thoracic region? Transverse proccess and rib + costotransverse joint Name part of lumbar vertebrae that as been "cut". Pedicles Name part of sacrum that has been "cut": Body
What is one cause of increased back pain in the morning or after lying recumbent for several hours?
What is one cause of increased back pain in the morning or after lying recumbent for several hours? Discs absorb water when one lies recumbent, and water is squeezed from them when one stands or moves. So you are a little taller when you get up in the morning. The distension that is caused by that rehydration is painful to some people.
What is the posterior longitudinal ligament posterior to?
What is the posterior longitudinal ligament posterior to? Vertebral bodies.
Let's consider the upper cervical spine for another obvious key principle of ligaments: torn or lax ligaments allow excess movement that can have serious consequences. What ligament connects the right lateral mass to the left lateral mass of C1?
What ligament connects the right lateral mass to the left lateral mass of C1? Transverse ligament of atlas
What parts of a vertebral unit are connected by an intervertebral disc?
What parts of a vertebral unit are connected by an intervertebral disc? Vertebral bodies.
What structure is immediately anterior to the Transverse ligament of atlas? And then what structure is immediately anterior to that?
What structure is immediately anterior to the Transverse ligament of atlas? Dens And then what structure is immediately anterior to that? Anterior Tubercle of Atlas
Which individual vertebra has the largest vertebral body?
Which individual vertebra has the largest vertebral body? L5
Which type of vertebra (cervical, thoracic, lumbar) has the largest vertebral bodies?
Which type of vertebra (cervical, thoracic, lumbar) has the largest vertebral bodies? Lumbar
Which vertebrae have long spinous processes?
Which vertebrae have long spinous processes? Thoracic
Why are radial tears of the annulus fibrosis more serious than circumferential tears?
Why are radial tears of the annulus fibrosis more serious than circumferential tears? Deep radial tears form a channel for the nucleus pulposus to herniate into or through the annulus.
Spina Bifida
a congenital defect that occurs during early pregnancy when the spinal canal fails to close completely around the spinal cord to protect it tow sides of vertebral arches fail to fuse resulting in open vertebral canal
Lordosis
abnormal anterior curvature of the lumbar spine (sway-back condition)
Scoliosis
abnormal lateral curvature of the spine
Sacral Promontory
anterior lip of the base (superior end) of the sacrum
sacrococcygeal joint
cartilaginous joint between the sacrum and coccyx
Sacral Canal
continuation of the vertebral canal in the sacrum central canal transmitting the dorsal and ventral roots of spinal nerves S1 to S6 and the coccygeal spinal nerve.
Kyphosis
excessive outward curvature of the spine, causing hunching of the back. abnormal curvature of thoracic region
Coccyx
four vertebrae fused together to form the tailbone
the posterior longitudinal ligament is anterior to some very important things. Just to verify that you understand what I mean, name one of those important anatomical structures.
the posterior longitudinal ligament is anterior to some very important thing Spinal cord, meninges.
sacral base
top of sacrum
