RA week 8 Flashcards

Question

trapezius muscle function? Innervation?

Answer 1

rotate scapula so glenoid cavity points more superiorly, allowing greater degree of abduction of upper limb retract scapula (middle fibres) Innervation = spinal accessory (XI)

Answer 2

extension, adduction + medial rotation of arm important in things like climbing innervation = thoracodorsal nerve (C6, C7, C8)

Answer 3

bottom right is showing muscular attachment of latissimus dorsi in anterolateral aspect of humerus tendon comes from posteriorly to wrap around anteriorly at bicipital groove

Answer 4

rhomboid major + minor levator scapulae

Answer 5

major = sp. processes T2-5 to → medial border scapula (spine to inf. angle) minor = nuchal ligament, sp. processes C7, T1 to → medial end of spine of scapula (so divided at level of spine of scapula) innervation = dorsal scapular nerve (C4, C5) retract the scapula

Answer 6

largely located within the neck from posterior tubercles transverse processes C1-C4 to → medial border of scapula above spine function = elevates scapula innervation = cervical nerves C3, C4 + dorsal scapular nerve (C4, C5)

Answer 7

secondary muscles of respiration: serratus posterior superior serratus posterior inferior

Answer 8

superior = nuchal ligament, spinous processes C7-T3 to → superior borders ribs 2-4 innervation = intercostal nerves 2-5 assists in raising upper ribs inferior = sp. processes T11-L2 to → inferior borders ribs 8-12 near angle innervation = anterior rami T9-T12 function = assist in lowering lower ribs

Answer 9

Deep back muscles (muscles of back proper) * maintain posture and control movements of VC * divided into superficial, intermediate + deep layers * all supplied by **posterior rami of spinal nerves**

Answer 10

* superficial = splenius mucles (only found within cervical region) * intermediate = errector spinae group * deep = many small muscles

Answer 11

splenius capitis (looks a bit like a bandage) + cervicis nuchal ligament and sp. processes C7-T4 to → * capitis → mastoid process and lateral ⅓ sup. nuchal line * cervicis → tubercles of transverse processes C1-C4

Answer 12

Erector spinae muscles arranged in 3 columns from lateral to medial: iliocostalis, longissimus, spiinalis common porximal attachment = posterior iliac crest, posterior sacrum + SI ligaments, sp processes of sacral + lower lumbar vertebrae, supraspinous ligament

Answer 13

lumborum, thoracic, cervicis parts common proximal attachment → angles of lower ribs, cervical transverse processes

Answer 14

thoracis, cervicis, capitis parts common proximal attachment → ribs (between tubercles + angles), thoracic and cervical transverse prcoesses, mastoid process

Answer 15

thoracis, cervicis, capitis parts common proximal attachment → upper thoracic sp. processes + cranium often poorly developed

Answer 16

semispinalis multifidus rotatores levator costarum interspinale intertransversari

Answer 17

thoracic, cervicis and capitis parts transverse processes C4-T12 → occipital bone (capitis), thoracic + cervical sp. processes (thoracic + cervicis)

Answer 18

multifidus: * thickest in lumbar region * fibres pass superomedially from transverse processes → to sp. processes 2-4 vertebrae above rotatores: * well developed in thoracic region (i.e. rotation most possible in thoracic region) * fibres pass superomedially from transverse process → to junction of lamina + transverse process 1-2 vertebrae above both are important in rotational movements of the VC

Answer 19

thickest in lumbar region

Answer 20

levator costorum = in thoracic region raises ribs transverse process → upper border rib Interspinale = well developed in cervical and lumbar regions between adjacent spinous processes Intertransversari = well developed in cervical + lumbar regions between transverse processes of vertebrae

Answer 21

thoracolumbar fascia extends from transverse processes towards anterior abdo wall muscles also muscles of posterior abdo wall posterior aspect of middle thoracolumbar fascia = intrinsic muscles of back

Answer 22

anterior longitudinal ligament posterior longitudinal ligament

Answer 23

anterior longitudinal ligament posterior longitudinal ligament (run almost entire length of VC)

Answer 24

anterolateral aspect of vertebral bodies skull base → sacrum 3 layers of dense collagen fibres * deep fibres bind adjacent vertebrae together * superficial fibres span multiple segments **limits extension** (it is the only ligament that does this)

Answer 25

found within vertebral canal on posterior aspect of VBs much narrower than anterior longitudinal ligament C2 → sacrum attached mainly to IV discs + vertebral margins fat + vessels located between ligament + bone surface functions = limits flexion (weakly) + **prevents herniation of IV disc**

Answer 26

ligamenta flava interspinous ligaments supraspinous ligaments intertransverse ligaments nucal ligament

Answer 27

singular = ligamentum flavum connect laminae of adjacent vertebrae made up of strong elastic fibres functions: helps maintain curvatures **reinforce wall of vertebral canal posteriorly** **limit flexion**

Answer 28

singular = ligamentum flavum connect laminae of adjacent vertebrae made up of strong elastic fibres functions: helps maintain curvatures **reinforce wall of vertebral canal posteriorly** **limit flexion**

Answer 29

Interspinous ligaments * connect adjacent spinous processes * thin, weak, membranous supraspinous ligament * joins tips of spinous processes * C7 → sacrum (isn't found above C7 due to nuchal ligament) * tough, cord-like intertransverse ligaments * between adjacent transverse processes * cervical = scattered fibres * thoracic = fibrous * lumbar = membranous Interspinous + supraspinous limit flexion

Answer 30

thickened fibroelastic tissue external occipital protuberance, posterior border foramen magnum, spinous processes C1-C7 continuous with supraspinous ligament functions: **muscle attachment** **limits flexion**

Answer 31

foramen magnum → L1/L2 (medullary cone) cervical enlargement C4-T1 (nerves to UL) lumbosacral enlargement L1-S3 (nerves to LL) cervical spinal nerves named after vertebrae below (exception C8) - emerge above vertebrae of the same number T1 - Co1 named after vertebrae above - emerge below vertebrae of same number

Answer 32

cauda equina = lumbar + sacral roots extend below end of spinal cord filum terminale = remnant of caudal part of spinal cord extends from tip of conus medularis to coccyx

Answer 33

at 3 months spinal cord and VC will be same length by 5 months much more rapid growth of VC than spinal cord - root of 1st sacral nerve has had to lengthen in newborn, spinal cord ends at level of L3 - growth continues in childhood so ends at L1/L2 blue indicates the pia covering the spinal cord meninges attached to sacrum so as spinal cord moves upwards = thin remnant of pia called filum terminale

Answer 34

continuous with meninges covering the brain * spinal dura mater (superficial, toughest) * spinal arachnoid mater * spinal pia mater (deep) meningeal coverings will extend along initial portion of the spinal nerve

Answer 35

tough outer covering attached to coccyx inferiorly by filum terminale lateral extensions of spinal dura cover nerve roots as dural root sheaths

Answer 36

epidural space contains internal vertebral venous plexuses + epidural fat

Answer 37

delicate membrane lining dura (looks like spider web hence the name) arachnoid trabeculae connect arachnoid to pia subarachnoid space contains CSF enlarged around conus medullaris to form **lumbar cistern** (L2-S2) - this is where you would do a lumbar puncture i.e. below level of spinal cord

Answer 38

can see dural root sheath when open dura (right) can see spider web-y arachnoid mater pia mater not visible as distinct layer but as shiny surface of spinal cord

Answer 39

covers spinal cord, nerve roots + spinal blood vessels denticulate ligaments - run on either side of spinal cord between posterior + anterior nerve roots found between ant + post roots of spinal nerve, will pierce through arachnoid and anchor in the dura suspend cord in dural sac

Answer 40

anterior spinal artery (x1) posterior spinal artery (x2) run longitudinally from medulla oblongata to conus medullaris supported by medullary segmental arteries (from trunk i.e. intercostal/lumbar arteries) radicular arteries supply nerve roots

Answer 41

3 anterior + 3 posterior spinal veins drain into medullary (segmental) and radicular veins join internal vertebral venous plexuses in epidural space

Answer 42

midline sagittal section through VC can see internal vertebral venous plexus in epidural space receives blood from vertebral bodies + spinal cord will anastomose with anterior internal venous plexus + posterior

Answer 43

Photograph A shows the posterior body wall after removal of the skin from the back. Some superficial fascia and fat are still adherent to the muscles. Photograph B shows the same individual with the majority of this fatty tissue removed to expose the superficial muscles of the back. The scapulae can also be identified, though they are still covered in connective tissue and muscle at this stage of the dissection. This photograph shows the large trapezius muscles that attach to the occipital bone of the skull, to the scapula and to the vertebra. It has fibres that run in several different orientations which allows it to elevate, depress, retract and rotate the scapula relative to the body wall. Trapezius is the odd one out of the superficial muscle layer as it is innervated by a cranial nerve – CNXI the spinal accessory nerve. Latissimus dorsi is the other prominent superficial muscle of the back. Photograph C shows the large, thin muscle sheet of latissimus dorsi as it passes between the lumbosacral fascia, around the lateral surface of the thorax and abdomen before inserting into the humerus. Although the muscle forms a thin sheet, it has a relatively large surface area allowing the weight of the body to be raised upwards towards the arms during chin-ups or climbing. Latissimus dorsi is innervated by a nerve from the brachial plexus – the thoracodorsal nerve.

Answer 44

Photograph A shows trapezius lying between the vertebrae and the scapula. These fibres of trapezius act to retract the scapula (pull it towards the midline). If these fibres are sectioned, then the rhomboid muscles are visible. This is shown in photograph C – rhomboid major and immediately above it rhomboid minor pass between the vertebrae and the scapula. They also act to retract the scapula. During dissection, these muscles often appear as one sheet of muscle, with very little gap between the inferior border of rhomboid minor and the superior surface of rhomboid major. The rhomboids are innervated by the dorsal scapular nerve from the brachial plexus.

Answer 45

Photograph A shows latissimus dorsi, if this muscle is sectioned and reflected then a much smaller muscle can be seen. Photograph B shows the thin and fibrous serratus posterior inferior muscle highlighted by a red plastic strip. Serratus posterior inferior is innervated by the anterior rami of T9 to T11 and the subcostal nerve (T12). Serratus posterior superior is not shown here but is innervated by T2 to T5 intercostal nerves. This means than none of the superficial muscles of the back are innervated by dorsal rami nerves – even though they are on the dorsal (posterior surface) of the body. The next layer of muscles – the intermediate muscles of erector spinae and the small deep muscles of the back are supplied by nerves from the dorsal rami, as is the skin of the back. As you dissect down to the erector spinae you may find branches of the dorsal rami piercing through the muscle to reach the superficial fascia and skin. This is shown in photograph C where the nerves have been highlighted by a red plastic strip.

Answer 46

This slide shows the intermediate muscle layer of the back – the erector spinae. These muscles appear to be one interconnected mass but can be divided into 3 muscle blocks. Each muscle can also be given the term ‘capitis’, ‘cervicis’, ‘thoracis’ or ‘lumborum’ depending on which part of the vertebral column it is related to. Photograph A shows iliocostalis (shown by the red plastic strip), the most lateral of the erector spinae. Photograph B shows longissimus and photograph C spinalis (shown by the red plastic strip). All of the muscles extend the back and help to control flexion of the trunk. All of the erector spinae are innervated by the dorsal rami of the spinal nerves.

Answer 47

Trapezius is the most superficial muscle that covers the posterior surface of the neck. If it is reflected then splenius capitis becomes visible (as shown in photograph A). On the same level as splenius capitis but in a more inferior position in the neck is splenius cervicis (shown by the red plastic strip in photograph B). If splenius capitis and cervicis are reflected then semispinalis capitis becomes visible (as shown in photograph C). There are deeper muscles in the suboccipital triangle of the neck posterior to semispinalis muscle but these muscles will be described later during dissection of the head and neck. The splenius capitis and cervicis and semispinalis capitis muscles act to extend the head or neck and allow lateral flexion of the neck, they are innervated by the dorsal rami nerves.

Answer 48

This slide shows the deeper muscles of the back. Multifidus is shown by the red plastic strips in photographs A and B – it is easier to identify in the lumber region (photograph B) as there is more muscle mass in this area. There are many deep muscles such as the interspinales(between the spinous processes of the vertebrae) and intertransversarii (between the transverse processes of the vertebrae). These are very small, as is rotatores(shown in photograph C) and levatorescostarum(shown in photograph D) and are not as easy to identify as the other muscles of the back. They act to provide small movements that assist in lateral flexion, rotation or extension of the back and are supplied by the dorsal rami nerves.

Answer 49

Photograph A shows the right side of the back with much of the muscular tissue removed. If the posterior bony parts of the vertebral canal are removed (a laminectomy) the duralsheath surrounding the spinal cord can be seen. This is shown in photograph B. Photograph C shows the dura mater surrounding the spinal nerves as they exit the spinal canal (shown by red plastic strips).

Answer 50

If the dura is opened, then the neural tissue becomes visible. Photograph A shows the thin, shiny arachnoid lying inferior to the dura, the pia mater adheres to the nerves themselves. The spinal cord and nerves have become soft and pink/purple in colour due to the Thielembalming fluid. A spinal nerve can just be seen passing away from the cord in photograph A. Photograph B shows the end of the spinal cord, which in adults is at vertebral level L1 to L2. The cord splits into the nerves of the cauda equina at this level and the end of the cord can be seen to form a medullary cone as it does so.