REVIEW OF ANATOMY OF SPINE UNDERLYING INTERVERTEBRAL DISC REPAIR

NOSE CERVICAL SPINE IS LOCATED IN CENTER OF NECK SURROUNDED BY CERVICAL SPINE IS LOCATED IN CENTER OF NECK SURROUNDED BY MANY STRUCTURES THAT ARE ESSENTIAL, SMALL AND READILY DAMAGED THESE SLIDES REVIEW THE ANATOMY OF VERTEBRAE, STRUCTURE OF THE NECK AND SPINAL CORD TO APPRECIATE THE TECHNIQUE OF CERVICAL DISC REPAIR CERVICAL SPINE IS LOCATED IN CENTER OF NECK SURROUNDED BY MANY STRUCTURES THAT ARE ESSENTIAL, SMALL AND FRAGILE NOSE BODY OF CERVICALVERTEBRA INTERVERTEBRAL DISC

{ ANATOMY OF TYPICAL VERTEBRA BODY VERTEBRAL ARCH 1. BODY – anterior, solid transmits weight 2. VERTEBRAL ARCH – posterior, surrounds vertebral canal, spinal cord; consists of a) PEDICLES – project from body b) LAMINAE – unite to form arch posteriorly anterior NOSE BODY TRANSVERSE PROCESS-LATERAL { PEDICLE VERTEBRAL ARCH LAMINA SPINOUS PROCESS - POSTERIOR 3. TRANSVERSE AND SPINOUS PROCESSES - projections from arch for muscle, ligament attach

LATERAL VIEW OF VERTEBRA NOSE JOINTS BETWEEN VERTEBRAE PERMIT MOVEMENTS HOWEVER, CAN POTENTIALLY DAMAGE SPINAL NERVES Sup. Vertebral Notch Inf. Vertebral Notch 2. Spinal nerves leave vertebral canal via INTERVERTEBRAL FORAMINA - between vertebrae; bordered by – Superior and Inferior Vertebral Notches 1. Location of Intervertebral Discs between bodies

VERTEBRA IN DIFFERENT REGIONS ARE SPECIALIZED Cervical (neck) - 7 vertebrae (C1-C7) Thoracic (chest) - 12 vertebrae (T1-T12) Lumbar (lower back) - 5 vertebrae (L1-L5) Sacral (pelvis) - 5 fused vertebrae (S1-S5) Coccygeal (tail) - 3-5 vertebrae (Co1-Co3) Vertebral column functions like structural support column Most weight is supported at base of column (lumbar and sacral vertebrae are large) Cervical vertebrae are relatively small

CERVICAL VERTEBRA - small and highly mobile NOSE – body is small Foramen Transversarium - in transverse process (C1-C7) for Vertebral artery & veins ant. BODY TRANSVERSE PROCESS post. SPINOUS PROCESS – bifid (divided) for Ligamentum nuchae ARTICULAR FACETS - angled superiorly & medially - PERMIT CONSIDERABLE MOVEMENT lat. view

VERTEBRAE ARE STABILIZE BY BEING LINKED BY LIGAMENTS, INTERVERTEBRAL DISCS 1. ANTERIOR LONGITUDINAL LIGAMENT -Strong band joins bodies on anterior side Adjacent vertebrae held tightly together (protect spinal cord) Anterior view

VIEW FROM INSIDE VERTEBRAL COLUMN On post. Side of bodies LOOK ANTERIOR LOOK POSTERIOR 2. POSTERIOR LONGITUDINAL LIGAMENT- weaker, narrower band on posterior side of bodies 3. LIGAMENTA FLAVA - yellow elastic bands connecting laminae

FUNCTION OF INTERVERTEBRAL DISC STRUCTURE/ FUNCTION OF INTERVERTEBRAL DISC Intervertebral discs function as shock absorbers; there are strong but undergo degeneration with age (begins at about age 20) a) Nucleus pulposus-inner gelatinous core b) Anulus fibrosus - collagen fibers & fibrocartilage

MRI OF 'SLIPPED DISK' FROM SNELL'S TEXTBOOK POSTERIOR ANTERIOR HERNIATION OF NUCLEUS PULPOSUS

DAMAGE TO INTERVERTEBRAL DISCS Postero-lateral POSTERIOR LONGITUDINAL LIGAMENT post lateral ANTERIOR LONGITUDINAL LIGAMENT Typically in Postero-Lateral Direction, lateral to Posterior Longitudinal Ligament (Anterior Longitudinal Ligament is broad and strong) Disc herniation can lead to nerve compression at intervertebral foramen

Ventral rami of spinal nerves: DAMAGE TO CERVICAL INTERVERTEBRAL DISCS CAN PRODUCE SYMPTOMS IN UPPER EXTREMITY Ventral rami of spinal nerves: C5 LOWER CERVICAL SPINAL NERVES FORM BRACHIAL PLEXUS C6 C7 C8 T1 DAMAGE TO SPINAL NERVES CAN PRODUCE SENSORY AND MOTOR LOSS

SENSORY LOSS - DERMATOME MAP THUMB = C6 LITTLE FINGER = C8 Dermatomes of upper extremity: C6 - thumb C7 - middle finger C8 - little finger Questions: What is the level of a herniated disc that would produce numbness of thumb? Little finger?

NUMBERING OF CERVICAL SPINAL NERVES LEVELS OF SPINAL NERVES Spinal nerves - arise from/project to spinal cord; there are 31 spinal nerves (8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal). Note: Cervical spinal nerves 1-7 (C1-C7) exit above corresponding vertebrae; Spinal nerve C8 exits below vertebra C7; All other spinal nerves exit below corresponding vertebrae. CONVENTION FOR NAMING LEVELS Cervical (C1-C8) Thoracic (T1-T12) Spinal nerves C1-C7 above vertebra Lumbar (L1-L5) Sacral (S1-S5) C8 and all others below vertebra Coccygeal (Co1) SPINAL NERVE C6 ARISES ABOVE VERTEBRA C6

CLINICAL TESTING OF STRETCH REFLEX: TENDON TAP TESTING OF SPINAL NERVE DAMAGE - STRETCH REFLEXES Ia sensory neuron CLINICAL TESTING OF STRETCH REFLEX: TENDON TAP Alpha motor neuron TENDON TAP 1- Tendon tap elicits twitch because it excites almost all muscle spindles simultaneously 2- Use stretch reflexes to test nerve function at different spinal levels

REFLEXES USED FOR CLINICAL TESTS Nerve compressions can produce reduced spinal reflexes; also muscle weakness

NECK CONTAINS A NUMBER OF VITAL STRUCTURES SPINAL CORD TRACHEA COMMON CAROTID ARTERY ESOPHAGUS INTERNAL JUGULAR VEIN INTERVERTEBRAL DISC

ANT. LAT. POST. ANATOMY OF NECK: NECK IS COMPARTMENTALIZED 1. Posterior Compartment -Vertebrae and muscles which support and move head & neck 2. Anterior Compartment- Viscera and rostral continuation GI & Respiratory Systems 3. Lateral Compartment- Blood vessels & nerve Plane of section ANT. LAT. POST. HORIZONTAL SECTION THROUGH NECK: NOTE VERTEBRAE ARE IN CENTER OF NECK

LOCATION OF STRUCTURES IN NECK: COMPARTMENTALIZED BY FASCIA NOSE Pretracheal layer Plane of section Carotid Sheath Prevertebral Layer- surrounds vert. column & muscles back of neck, prevertebral, lateral vertebral and suboccipital m. Pretracheal Layer- surrounds trachea, esophag. & thyroid continues to mediastinum Carotid Sheath- surrounds common & int carotid, int jugular and X (not: Symp. Chain) LOCATION OF INTERVERTEBRAL DISC Prevertebral layer

DISCS ARE POSTERIOR TO PREVERTEBRAL MUSCLES ACT - FLEX NECK/HEAD INN - CERVICAL VENTRAL RAMI 2. Longus capitis O - Trans processes C3-C6 I - Occipital bone 1. Longus colli muscle - O- Trans processes Lower cervical vertebrae I - Bodies upper cervical vertebrae Colli = neck in Latin View of anterior side of Cervical Vertebrae with structures of Anterior and Lateral Compartments removed

HOW IS DAMAGE TO CERVICAL INTERVERTEBRAL DISC REPAIRED? SEE DR. LECLERCQ'S LECTURE INTERVERTEBRAL DISC