MJM 2

Movement of the back

- The extrinsic muscles- move upper limbs and the ribs - The intrinsic muscles- Maintain posture and move the vertebral column

Vertebral foramen and canal

- Vertebral arch and posterior surface of vertebral body forms the walls of the vertebral foramen - The succession of vertebral foramina form the vertebral canal Vertebral canal allows for passage of Meningeal vessels and spinal cord

Interspinous and supraspinous

- Adjacent spinous processes are united by weak almost membranous interspinous ligaments - Also joined by strong fibrous supraspinous ligaments - Supraspinous ligament merges superiorly with nuchal ligament

Long ligaments

- Anterior longitudinal ligament - Posterior longitudinal ligament - Supraspinous

Longissimus

- The longissimus muscle is situated between the iliocostalis and spinalis. It is the largest of the three columns. It can be divided into three parts - thoracic, cervicis and capitis. Attachments: - Arises from the common tendinous origin, and attaches to the lower ribs, the transverse processes of C2 - T12, and the mastoid process of the skull. Innervation: - Posterior rami of the spinal nerves. Actions: - Acts unilaterally to laterally flex the vertebral column. Acts bilaterally to extend the vertebral column and head.

Semispinalis

- The semispinalis is the most superficial of the deep intrinsic muscles. Much like the intermediate muscles, it can be divided by its superior attachments into thoracic, cervicis and capitis. Attachments: - Originates from the transverse processes of C4-T10. The fibres ascend 4-6 vertebral segments, attaching to the spinous processes of C2-T4, and to the occipital bone of the skull. Innervation: - Posterior rami of the spinal nerves. Actions: Extends and contralaterally rotates the head and vertebral column

Serratus Posterior Inferior

- The serratus posterior inferior is broad and strong. It lies underneath the latissimus dorsi. Attachments: - Originates from the thoracic and lumbar spines (usually T11 - L3). - The fibres pass in a superolateral direction, attaching to ribs 9-12. Innervation: - intercostal nerves. Actions: - Depresses ribs 9-12.

Serratus Posterior Superior

- The serratus posterior superior is a thin, rectangular shaped muscle. It lies deep to the rhomboid muscles on the upper back. Attachments: - Originates from the lower part of the ligamentum nuchae, and the cervical and thoracic spines (usually C7 - T3). - The fibres pass in an inferolateral direction, attaching to ribs 2-5. Innervation: - Intercostal nerves. Actions: - Elevates ribs 2-5.

Spinalis

- The spinalis muscle is located medially within the erector spinae. It is the smallest of the three muscle columns. It can be divided into the thoracic, cervicis and capitis (although the cervicis part is absent in some individuals). Attachments: - Arises from the common tendinous origin, and attaches to the spinous processes of C2, T1-T8 and the occipital bone of the skull. Innervation: - Posterior rami of the spinal nerves. Actions: - Acts unilaterally to laterally flex the vertebral column. Acts bilaterally to extend the vertebral column and head.

Nunchal ligament

- The strong medial ligament of the neck - Composed of thickened fibroelastic tissue extending Span - From external occipital protuberance and posterior border of foramen magnum - To the spinous processes of the cervical vertebrae Function - Shortness of the C3-C5 spinous processes, ligament substitutes for bone in providing muscular attachment

Intermediate layer of the deep muscles of the back

- There are three intermediate intrinsic back muscles - the iliocostalis, longissimus and spinalis. Together these muscles form a column, known as the erector spinae. - The erector spinae is situated posterolaterally to spinal column, between the vertebral spinous processes and the costal angle of the ribs. All three muscles can be subdivided by their superior attachments (into lumborum, thoracic, cervicis and capitis). They also all have a common tendinous origin, which arises from: - Lumbar and lower thoracic vertebrae. - Sacrum. - Posterior aspect of iliac crest. - Sacroiliac and supraspinous ligaments.

General structure of verterae

- Vertebral body- The superior and inferior aspects of the vertebral body are lined with hyaline cartilage. Adjacent vertebral bodies are separated by a fibrocartilginous intervertebral disc. - Vertebral arch- lateral and posterior parts of the vertebral foramen Consists of two pedicles which attach the vertebral arch to the vertebral body Two laminae- flat sheets of bone that extend from each pedicle to meet in the midline and form the roof of the vertebral arch - A spinous process- projects posteriorly and inferiorly - A transverse process- extends posterolaterally - Superior and inferior articular processes- project from the region where the pedicles join the laminae - Vertebrae allows for protection of nervous tissue, attachment of ligament and muscle, allows for movement

Intervertebral foramen

- Vertebral notches formed above and below and contribute to forming the intervertebral foramina - Give passage to spinal nerve roots and accompanying vessels and contain the spinal ganglia

Scoliosis

A lateral curvature of the spine, usually of unknown cause.

Splenius Cervicis

Attachments: - Originates from the spinous processes of T3-T6 vertebae. - The fibres ascend, attaching to the transverse processes of C1-3/4. Innervation: - Posterior rami of the lower cervical spinal nerves. Actions: - Rotate head to the same side. Note: The two splenius muscles can also act together to extend the head and neck.

Rhomboid Major

Attachments: - Originates from the spinous processes of T2-T5 vertebrae. - Attaches to the medial border of the scapula, between the scapula spine and inferior angle. Innervation: - Dorsal scapula nerve. Actions: - Retracts and rotates the scapula.

Kyphosis

Excessive thoracic curvature, causing a hunchback deformity.

Posterior longitudinal ligament

Much narrower and weaker - Runs within vertebral canal along with posterior aspect of vertebral bodies - Attached mainly to IV discs - Partially attached to posterior edges of vertebral bodies from C2 to sacrum Function - Prevents hyperflexion of the vertebral column - Prevents posterior herniation of IV discs - Well innervated with pain nerve ending

Curvatures of the spine

Primary - Concave anteriorly - reflects original shape of the embryo, retained in the thoracic and sacral regions in adults - Kyphoses Secondary - Concave posteriorly - Form in the cervical and lumbar regions and bring the centre of gravity into a vertical line, allows the body weight to be balanced - Lordoses

Short ligaments

Provide support when spine is flexed - Ligamentum flavum - Supraspinous (strong) - Interspinous (weak) - Articular ligament

Joints of vertebral bodies

Secondary cartilagenous, designed for weight bearing and strength - Articulating surfaces of adjacent vertebrae are joined by IV discs and ligaments - The IV discs between the bodies of adjacent vertebrae provide strong attachment between them - Discs also have resilient deformability which allows them to serve as shock absorbers

What does a lumbar puncture needle have to pass through?

Skin, subcutaneous tissue, supraspinous ligament, infraspinous ligament, ligamentum flavum, dura matter, extradural space (internal vertebral venous plexus/fat), arachnoid mater, subarachnoid space (CSF). DO NOT GO TO PIA MATER.

Spinal cord vs vertebral levels

Spinal levels C=same T= +1 L= +1 or 2

Tectorial membrane

Strong superior continuation of posterior longitudinal ligament - Runs across median atlanto-axial joint through foramen magnum to central floor of cranial cavity - Runs from body of C2 to internal surface of occipital bone - Covers alar ligaments and transverse ligaments of atlas

Rhomboid Minor

Superior to the major Attachments: - Originates from the spinous processes of C7-T1 vertebrae. - Attaches to the medial border of the scapula, at the level of the spine of scapula. Innervation: - Dorsal scapula nerve. Actions: - Retracts and rotates the scapula.

Multifidus

The multifidus is located underneath the semispinalis muscle. It is best developed in the lumbar area. Attachments: - Has a broad origin - arises from the sacrum, posterior iliac spine, common tendinous origin of the erector spinae, mamillary processes of lumbar vertebrae, transverse processes of T1-T3 and articular processes of C4-C7. - The fibres ascend 2-4 vertebral segments, attaching the spinous processes of the vertebrae. Innervation: - Posterior rami of the spinal nerves. Actions: - Stablises the vertebral column.

Where does the spinal cord end?

The spinal cord typically ends between L1 and L2 in most adults.

Atlanto-axial joints

Three atlanto-axial articulations - Two lateral atlanto-axial joints (lateral masses of C1 and superior facets of C2) - Median atlanto-axial joint between dens of C2 and anterior arch and transverse ligament of atlas - Median is a pivot joint, lateral are plane-type synovial - The dens is held by the transverse ligament of the atlas Function - Permits head to be turned side to side

Basic organisation of a spinal nerve

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Latissimus dorsi

The latissimus dorsi originates from the lower part of the back, where it covers a wide area. Attachments: - Has a broad origin - arising from the spinous processes of T6-T12, iliac crest, thoracolumbar fascia and the inferior three ribs. - The fibres converge into a tendon that attaches to the intertubercular sulcus of the humerus. Innervation: - Thoracodorsal nerve. Actions: - Extends, adducts and medially rotates the upper limb

Levator Scapulae

The levator scapulae is a small strap-like muscle. It begins in the neck, and descends to attach to the scapula. Attachments: - Originates from the transverse processes of the C1-C4 vertebrae and attaches to the medial border of the scapula. Innervation: - Dorsal scapular nerve. Actions: - Elevates the scapula.

Minor Deep Intrinsic Muscles:

Interspinales: Spans between adjacent spinous processes. Acts to stablise the vertebral column. Intertranversari - Spans between adjacent transverse processes. Acts to stablise the vertebral column. Levatores costarum - Originates from the transverse processes of C7-T11, and attaches to the rib immediately below. Acts to elevate the ribs.

Deep muscles of the deep back

The deep intrinsic muscles are located underneath the erector spinae. They are a group of short muscles, associated with the transverse and spinous processes of the vertebral column There are three major muscles in this group - the semispinalis, multifidus and rotatores.

Function and innervation of the zygapophyseal joints

- Permit gliding movements between articular processes - Shape and disposition of articular surfaces determine the type of movement possible - Zygapophysial joints innervated by articular branches of posterior rami of spinal nerves. - Each posterior ramus supplies two adjacent joints - Therefore, each joint supplied by two spinal nerves

Ligamenta flava

- Laminae of adjacent vertebral arches bound by broad fibrous tissue called ligament flava - Extends almost vertically from the lamina above to the lamina below - Form alternating sections of the posterior wall of the vertebral canal Function - Resist separation of vertebral laminae by arresting abrupt flexion of the vertebral column - Therefore prevents injury to the IV discs - Preserves the normal curvatures of the vertebral column - Also assists with straightening the column after flexing

Structure of the back

- Skin - Subcutaneous tissue - Deep fascia - Muscles - Ligaments - Vertebral column - Ribs - Spinal cord and meninges - Segmental nerves and vessels - Extradural space (internal vertebral venous plexus, some fat)

C1 and C2

- C1 fuses into the body of C2 - C1 is ring shaped and composed of 2 lateral masses interconnected by an anterior arch and a posterior arch - Each lateral mass articulates above with an occipital condyle of the skull and below with the superior articular process of vertebra C2 - The superior articular surfaces are concave - Inferior surfaces are flat - The atlano-occipital joint allows the head to nod up and down on the vertebral column - The posterior surface of the anterior arch has an articular facet for the dens, projects superiorly from the vertebral body of the axis - The dens is held in position by a strong transverse ligament of atlas posterior to it and spanning the distance between the oval attachment facets on the medial surfaces of the lateral masses of the atlas. - The dens acts a pivot that allows the atlas and the attached head to rotate on the axis, side to side. - The transverse process act as levers for muscle action- muscles that move the head at the atlano-axial joints. - There is not IV disk between C1 and C2

Access to the spinal dural sac allows other important clinical procedures. Summarise these.

- Epidural Anaesthesia: pain relief in childbirth - lumbar puncture/spinal tap: obtain CSF - cisternography: radiography of the basal cistern of the brain after subarachnoid injection of a contrast medium - myelography: patient is positioned on his/her side and asked to flex the neck and bring the knees up to his/her chest (in a fetal position). Alternatively, the patient may be asked to sit with his/her head and shoulders forward flexed forward. A spinal needle is inserted and a small amount of contrast material is injected into the CSF followed by acquisition of x-rays or CT image. - lumbar drain: catheter can be placed through the lumbar puncture needle into the space that contains the CSF in order to continuously drain CSF for treatment/diagnosis of various conditions

Lordosis

- Excessive lumbar curvature, causing a swayback deformity.

Alar ligaments

- Extend from sides of dens to lateral margins of foramen magnum - short rounded cords attach cranium to C2 vertebra - Serve as check ligaments to prevent excessive rotation at the joints

Lumbar puncture

- Get patient to bend forwards and hug their knees to open up space between L3-L4 - Allows for insertion in a reasonably safe region, between spinal processes and below the spinal cord (L1/L2) - Used to get a sample of CSF - Use iliac crest to find safe region - Cant give to people with raised intracranial pressure Draining the fluid in the spine would lower the pressure and would not be able to hold the weight of the fluid in the head= medulla oblongata would get compressed Raised intracranial pressure can be caused by tumours, heamatoma etc

Intertransverse ligaments

- Intertransverse ligaments connect adjacent transverse processes - Consists of scattered fibres in the cervical region and fibrous cords in the thoracic region - In the lumbar region, thin and membranous

IC discs

- Join vertebral bodies - Tough fibrous of annulus fibrosis: Pass obliquely to give torsional strength, peripheral, attaches to a thin cartilage - plate on body of the vertebrae above and below it. - Gelatinous nucleus pulposus : Shock absorber. Becomes broader when compressed ad thinner when tensed or stretched. - Compression and tension occur simultaneously in the disc during movement of the vertebral column. Avascular, nourishment by diffusion from blood vessels at periphery of annulus fibrosus and vertebral arteries. Account for about 1/4 of the length of the spine and account for its curvatures thickness depends on the region and the range of movement needed in that part of the spine

Anterior longitudinal ligament

- Strong, broad fibrous band - Covers and connects anterolateral aspects of vertebral bodies and IV discs - Extends from pelvic surface of sacrum to anterior tubercle of atlas and occipital bone Function - Maintains stability of intervertebral joints - Limits extension of vertebral column

Thoracic region

- Supports thorax - Articular facet (demi-facets) on the transverse process for articulation with the ribs - Spinous processes directed posteroinferiorly

Joints between the vertebral arches

- Synovial articulations between superior and inferior articular processes of adjacent vertebrae - Accessory ligaments unite the laminae, transverse processes and spinous process and help stabilize the joints

Deep muscles

- The deep muscles develop embryologically in the back, and are thus described as intrinsic muscles. - The superficial and intermediate muscles do not develop in the back, and are classified as extrinsic muscles. Thoracolumbar fascia covers the deep muscles of the back and trunk.

Iliocostalis

- The iliocostalis muscle is located laterally within the erector spinae. It is associated with the ribs, and can be divided into three parts - lumborum, thoracis, and cervicis. Attachments: - Arises from the common tendinous origin, and attaches to the costal angle of the ribs and the cervical transverse processes. Innervation: - Posterior rami of the spinal nerves. Actions: - Acts unilaterally to laterally flex the vertebral column. Acts bilaterally to extend the vertebral column and head.

'Uncovertebral' joints

- The lateral margins of the upper surfaces of typical cervical vertebrae are elevated into crests or lips termed unicate processes - These may articulate with the body of the vertebra to form small -uncovertebral synovial joints

Innervation of the back

- The posterior branches of spinal nerves innervate the intrinsic muscles of the back and adjacent skin.

Rotatores

- The rotatores are most prominant in the thoracic region Attachments: - Originates from the vertebral transverse processes. The fibres ascend, and attach to the lamina and spinous processes of the immediately superior vertebrae. Innervation: - Posterior rami of the spinal nerves. Actions: - Stablises the vertebral column, and has a proprioceptive function.

Cervical vertebrae

- The vertebral body is short in height and square shaped when viewed from above and has a concave superior surface and a convex inferior surface - Each transverse process is trough shaped and perforated - Spinous process is short and bifid - The vertebral foramen is triangular

Intermediate muscles

- two muscular sheets in the superior and inferior regions of the back - Fibres attach to the ribs - Respiratory group

Cervical Spondylosis

A decrease in the size of the intervertebral foramina, usually due to degeneration of the joints of the spine. The smaller size of the intervertebral foramina puts pressure on the exiting nerves, causing pain.

Superficial muscles of the deep back: spinotransversales Splenius Capitis

Attachments: - Originates from the lower aspect of the ligamentum nuchae, and the spinous processes of C7 - T3/4 vertebrae. - The fibres ascend, attaching to the mastoid process and the occipital bone of the skull. Innervation: - Posterior rami of spinal nerves C3 and C4. Actions: - Rotate head to the same side.

Atlanto-occipital joint

Between lateral masses of atlas and occipital condyles - Permit flexion and extension - Permit sideways tilting of the head - Also connected by anterior and posterior atlanto-occipital membranes - This prevents excessive movement

What might be the result of a fracture between C6 and C7 vertebrae? What functions might be lost/retained?

C7 nerve root compressed. • Axillary nerve (C5, C6) - shrug shoulders, flexion, extension and rotation of shoulder (teres minor, deltoid, long head of triceps brachii) • Ulnar nerve (C8, T1) - can hold a card (the interossei muscles are primarily concerned with movements, like spreading fingers apart and bringing them together (abduction and adduction of fingers). Ulnar nerve is intact so a person is able to hold a card with sufficient force and the examiner cannot pull out the card held between any two fingers. In ulnar nerve injury or palsy, the card cannot be held tightly and slips out easily from between the fingers. Functions lost: • Radial nerve (C5-T1) - weakness in extension of arm and forearm • Median nerve (C6-T1) - Musculocutaneous (C5, C6, C7) - weakness of biceps brachii (flexor at elbow and supination

Clinical correlation of IV disc

Clinical correlation Annulus fibrosis not as thick posteriorly - This causes nucleus pulposus to sit more posteriorly - Therefore, prolapsed disc more likely posteriorly Old age - Nucleus pulposus shrinks in old age - This results in a shrink in height - The spine begins to return to the neonatal C shape Overall, this means the annulus fibrosis assumes a greater role in taking vertical load

where do spinal nerves exit?

Each spinal nerve exists the vertebral canal laterally through an intervertebral foramen: The superior and inferior margins are formed by notches in adjacent pedicles. The posterior margin is formed by the articular processes of the vertebral arches and the associated joint. The anterior border is formed by the intervertebral disc between the vertebral bodies of the adjacent vertebrae

Fractures of vertebrae

Fractures - Rare - Occur following serious injury - Commonly at junction between relatively flexible and inflexible regions of spine - Includes cervicothoracic and thoracolumbar regions - One vertebrae and those above it shear away from the spinal column below - Spinous process above needs to be broken to pull vertebrae out

Describe the symptoms of a person with a C7 accessory rib might complain of?

May compress spinal nerves C8 and T1/ inferior trunk of the brachial plexus supplying the upper limb. May compress subclavian artery = ischaemic muscle pain in the upper limb Tingling and numbness may occur along the medial border of the forearm. Thoracic outlet syndrome

7 processes

Seven processes arise from the vertebral arch: - One median spinous process projects posteriorly - Two transverse processes project posterolaterally - Four articular processes, two superior and two inferior. Form zygapophysial (facet) joints. The spinous and transverse processes allow for attachments for deep back muscles and act as levers

What might be the result of a fracture between T12 and L1 vertebrae? What functions might be lost/retained?

T12 nerve root compressed/ cauda equine damaged. Upper thoracic spine (T1 to T10) is stabilized by the ribs & facet orientation, and is less suseptible to trauma; At T12-L1 junction, however, there is a fulcrum of increased motion. acute hyperflexion + rotation • when a person is thrown from a moving vehicle, thoracolumbar frx dislocation frequently occurs; • lap seat belt may be associated with characteristic throracolumbar flexion distraction type of injury • traumatic paraplegia: sustain vertebral injury at skeletal thoracolumbar junction where conus medullaris lies, & several lumbar roots are descending to exit through the appropriate foramen - conus medullaris and descending roots of the cauda equina; • middle of T-spine is a vascular watershed area, & vascular insult can lead to cord ischemia The spinal cord terminates at T12/L1 1. bladder & bowel signs 2. decrease movement & sensation in lower extremities

Superficial muscles of the back

The superficial back muscles are situated underneath the skin and superficial fascia. They originate from the vertebral column and attach to the bones of the shoulder - the clavicle, scapula and humerus. All these muscles are therefore associated with movements of the upper limb.

Trapezius

The trapezius is a broad, flat and triangular muscle. The muscles on each side form a trapezoid shape. It is the most superficial of all the back muscles. Attachments: - Originates from the skull, ligamentum nuchae and the spinous processes of C7-T12. - The fibres attach to the clavicle, acromion and the scapula spine. Innervation: - Motor innervation is from the accessory nerve. It also receives proprioceptor fibres from C3 and C4 spinal nerves. Actions: - The upper fibres of the trapezius elevates the scapula and rotates it during abduction of the arm. - The middle fibres retract the scapula and the lower fibres pull the scapula inferiorly.

Types of joints in the vertebral column

The two major types of joints between vertebrae are: - Symphyses (IV discs) between vertebral bodies - Synovial joints between articular processes A typical vertebra has a total of six joints with adjacent vertebrae: 4 synovial joints and two symphyses- each symphyses includes an IV disc.

Lumbar region

Weight bearing region of body - Large vertebral body - Spinous process horizontal and square, strong - Articular facets lie in sagittal plane

What would a myelogram allow you to see?

• x-ray of the spinal canal and its nerves • to detect whether there is a compression of the spinal cord or nerve roots • injection of contrast medium into the cervical or lumbar spine, followed by several X-ray projections. • there are any unusual indentations or abnormal shapes in the spinal cord. Anything that is pushing into the nerves shows up as an indentation into the spinal sac. • This indentation could be from a herniated disc, a tumour, or an injury to the spinal nerve roots. • Patients who have heart pacemaker, metal valve or defibrillator/cochlear implant/aneurysm clip (a metal clip on an artery)/ joint replacements or large metal implants/ an intra-uterine contraceptive device or coil/ shrapnel or gunshot wounds/a body piercing/metal fragments anywhere in your body/some medication patches/tattoos that have been done using a metallic ink • does not show the soft tissues • only the bones and the spinal fluid where the dye has mixed with the fluid. • Radiation is less ionising than CT