T2 Anatomy Slides (10) PDF

T2 Anatomy The vertebral column (The spine) - Plate: 162 the vertebral column is a series of bones called vertebrae (sing. vertebra) which are held together to give support for the spinal cord and the nerves arising from it there are a total of 33 vertebrae but only 24 of them are mov...

T2 Anatomy The vertebral column (The spine) - Plate: 162 the vertebral column is a series of bones called vertebrae (sing. vertebra) which are held together to give support for the spinal cord and the nerves arising from it there are a total of 33 vertebrae but only 24 of them are moveable from top to bottom, it is divided into the: cervical spine (7 vertebrae) thoracic spine (12 vertebrae) lumbar spine (5 vertebrae) sacrum (5 fused vertebrae) coccyx (4 fused vertebrae) each vertebra is numbered from top to bottom Intervertebral discs - Plate: 164 between the vertebrae are fibrocartilagenous discs called intervertebral discs key function in weight bearing a disc is named for the 2 vertebrae that it sits between there is no disc between C1 and C2 Intervertebral discs cont. - Plate: 164 Annulus fibrosis: each disc has a fibrous outer layer called the annulus fibrosis Nucleus pulposus: the annulus surrounds the inner substance which is called the nucleus pulposus disc innervation: aneural, except in the peripheral 1/3rd blood supply: avascular Analogy of IVD’s - jelly donuts Curves of the spine - Plate: 162 cervical (lordotic) thoracic (kyphotic) lumbar (lordotic) sacral (kyphotic) the thoracic and sacral curves are termed primary (bc they develop during the fetal period) the cervical and lumbar are termed secondary (bc they develop when the infant starts lifting their head and walking) General characteristics of a vertebra - Plate: 164 Each vertebra consists of a(n): body - large, heavy anterior part of the vertebra (vertebral bodies get larger as you progress inferiorly) vertebral arch - this part encloses the vertebral foramen pedicles: the arch is formed anteriorly by 2 pedicles which project posteriorly from both sides of the superior part of the vertebral body laminae: as the pedicles project posteriorly, they meet 2 laminae spinous process: the laminae meet posteriorly to form a spinous process (SP) articular processes: four articular processes also arise from the arch: there are superior and inferior articular processes on the right and on the left (total: 4) General characteristics of a vertebra - Plates: 163 & 164 articular facet: on each process is an articular facet: the inferior facets of one vertebra articulate with the superior facets of the next lower vertebra (articular joints: a.k.a. zygapophysial joints) pars interarticularis: this is the area between the superior and inferior articular processes (the most common fracture site) transverse processes: two transverse processes (TVPs) also arise from the arch – they project laterally intervertebral foramen: there are notches on the pedicles (superior and inferior vertebral notches) – the vertebral notches of 2 adjacent vertebrae form an almost complete ring called the intervertebral foramen The cervical spine - Plates: 26 - 30 upper cervical spine: C1 & C2 lower cervical spine: C3 – C7 Upper Cervical Spine (C1, C2) C1 and C2 are atypical vertebrae The upper cervical spine - Plate: 26 C1 (the atlas) varies significantly from a typical vertebra designed to support the occipital region of the skull anterior arch articular facet for dens 2 lateral masses superior articular surface the TVPs are projections from the lateral masses PLATE 29: transverse foramen allows passage of the vertebral artery groove for vertebral artery The upper cervical spine cont. Plate: 26 C1 (the atlas) continued posterior arch vertebral foramen tubercle for transverse ligament of atlas transverse ligament of atlas – connects the 2 lateral masses and divides the vertebral foramen into a posterior portion for passage of the spinal cord and an anterior portion which accommodates the dens of the axis – there is a thin layer of cartilage on the anterior surface inferior articular surface NO VERTEBRAL BODY NO SPINOUS PROCESS The upper cervical spine cont. - Plate: 26 & 28 C2 (the axis) dens (a.k.a. the odontoid process) anterior articular facet TVP inferior articular facet for C3 superior articular facet for atlas posterior articular facet spinous process (bifid) C2-C6 SPs are bifid The lower cervical spine (C3 - C7) - Plates: 27, 28 & 29 SP (bifid from C2-C6) C7 SP – vertebra prominens lamina vertebral foramen pedicle TVP - the anterior and posterior tubercles are connected by a small strut of bone to form the TVP body area for articulation with uncinate process of C4 (next lower vertebra) transverse foramen The lower cervical spine cont. - Plates: 27, 28 & 29 inferior articular process and facet superior articular process and facet groove for spinal nerve (C4 used as an example) uncinate process -- upward bony projections on the posterolateral rims of the vertebral body these upward projections articulate with the next higher vertebra these are called the uncovertebral joints (a.k.a. joints of Lushka) these joints provide stability in the cervical spine prevent excessive lateral translation note on C6 that the anterior tubercle is called the carotid tubercle The lumbar spine - Plate: 164 possess the characteristics of a typical vertebra massive vertebral bodies the largest vertebra is L5 SPs are broad, thick, prominent, and horizontal landmark: a horizontal line drawn between the tops of the iliac crests landmarks L4 SP The sacrum and coccyx - Plate: 166 5 fused vertebrae and IVDs base: the top part, the WIDEST part apex: the pointed inferior edge this applies to both the sacrum and the coccyx (more detail to come soon to a slideshow near you) The sacrum - Plate: 166 lumbosacral articular surface – this is the articulation between L5 and the sacrum (with the L5-S1 disc in between) superior articular processes (with facets) ala (pl. alae) – the ‘wings’ of the sacrum promontory anterior & posterior sacral foramina apex: the bottom part pelvic surface is concave, dorsal surface is convex The sacrum cont. - Plate: 166 sacral canal sacral hiatus sacral cornu (horn) median sacral crest - fused remnants SPs lateral sacral crest – fused remnants of TVPs auricular surface coccyx 4 (varies 3-5) fused vertebrae The joints of the pelvis - Plate: 167 Lumbosacral joint L5 articulates with S1 cartilaginous (IVD) Supporting ligaments: Iliolumbar ligament TVPs of L4 and L5 to posterior iliac crest key stabilizer of L5 limits lateral flexion The joints of the pelvis cont. - Plate:167 Sacrococcygeal joint apex of sacrum articulates with the base of the coccyx Sacroiliac (SI) joints auricular surface of the sacrum articulates with the auricular surface of the ilium synovial limited gliding and rotational movements are available The joints of the pelvis cont. - Plate: 338 & 167 Anterior/Posterior Sacroiliac ligaments ilium to sacrum Interosseous Sacroiliac ligaments lies just anterior (deep) to the posterior SI ligaments Of note… the sacrotuberous and sacrospinous ligaments are accessory ligaments to the SI joints Symphysis pubis adjacent pubic bones with disc in between refer to T1 notes The thoracic cage - Plates: 203 & 192 The thorax surrounds and protects the heart and lungs and some of the abdominal organs The bony thorax consists of: 12 thoracic vertebrae (and their IVDs) 12 pairs of ribs the sternum manubrium body aka Gladiolus xiphoid process all ribs articulate posteriorly with the vertebral column and most articulate anteriorly with the sternum (directly or indirectly) The thoracic spine - Plate: 163 normal characteristics of a vertebra costal demi-facets on the vertebral body costal facets on the TVPs note the SP that points down and back The Sternum - Plate: 192 The Manubrium jugular (a.k.a. sternal) notch on either side of the jugular notch is an articular facet (clavicular notch) where the manubrium articulates with the clavicle The Body aka gladiolus manubriosternal joint (sternal angle) (a.k.a. angle of Louis) a landmark for rib 2 along th e side of the body are costal notches for the articulation of costal cartilage The Xiphoid the thin process inferior to the body The ribs - Plate: 192 ribs 1-7 are called ‘true’ ribs they have a direct connection with the sternum via their own costal cartilage ribs 8-12 are called ‘false’ ribs they have an indirect connection with sternum (via the 7th ribs costal cartilage) 11 and 12 are also called floating ribs because they are unattached anteriorly Typical ribs - Plate: 193 ribs 2-10 ‘typical’ ribs have the following characteristics: a head, neck, tubercle and shaft Head - 2 facets (superior and inferior) articulate with 2 vertebral bodies Neck - between the head and the tubercle Tubercle - articular facet (articulates with a TVP) Shaft Rib angle Costal groove (for the costal nerve) Costal facets - Plate: 193 2 costal demi facets on the vertebral body: superior and inferior the superior costal demi facet articulates with the head of the rib of the same number (ie. the superior costal demi facet on T4 articulates with rib 4) the inferior costal demi facet articulates with the head of the inferior rib the inferior costal demi facet on T4 articulates with rib 5 the transverse costal facet articulates with the tubercle of the rib of the same number the transverse costal facet on T4 articulates with the tubercle of rib 4 another way to look at this is that the head of rib 5 articulates with the vertebral body of _____ at its ____________________ costal demi facet and the vertebral body of ____ at its___________________ costal demi facet, and the articular facet on the tubercle of the rib articulates with the transverse costal facet of _____ Atypical ribs - Plates: 193 & 192 ribs 1, 11, 12 articulate with only 1 vertebral body (the numerically corresponding vertebra) Rib 1 many structures cross and/or attach to it scalene tubercle – where anterior scalene muscle attaches grooves for subclavian artery and vein Ribs 11 & 12 floating ribs small facet on the head of the rib no neck, no tubercle Summary for ribs and vertebral bodies Typical Ribs 2-10 articulates with the numerically corresponding vertebral body, the IVD and the vertebra above Typical Vertebral Bodies 2-9 has 2 demi facets for articulation with 2 different ribs superior demi facet articulates with the rib of the same number inferior demi facet articulates with the rib just inferior Summary or ribs and vertebral bodies cont. Atypical Ribs 1, 11, 12 not connected to a disc articulate with the numerically corresponding vertebral body only 1 does articulate with corresponding TVP, 11 & 12 do not Atypical Vertebral Bodies 1, 10, 11, 12 T1 has complete superior facet and demi-facet inferiorly T10-12 have only one facet surface on each side Summary of vertebral characteristics Cervical uncinate processes bifid SPs transverse foramen oblique facet orientation Thoracic two costal demi-facets on the body (per side) costal facets on TVPs SPs that point down facet orientation tends to be in the frontal/coronal plane Lumbar large bodies large SPs projecting horizontally facet orientation tends to be in the sagittal plane Relationship of scapula and thorax - Plate: 192 superior angle landmarks rib 2 root of the spine of the scapula landmarks rib 3 inferior angle landmarks rib 7 or 8 Vertebral articulations The vertebrae from C2-S1 articulate with one another at joints between their bodies and between their articular processes (with facets) Intervertebral Joints designed for strength and weight bearing cartilaginous joints adjacent vertebrae are connected by IVDs Craniovertebral joints - Plate: 30 & 29 No IVDs Atlanto-Occipital joint superior articular facets on the lateral masses of C1 articulate with the occipital condyles of the skull synovial condyloid Available Movements flexion of head on neck extension of head on neck lateral flexion of the head on the neck Ligaments Atlanto-occipital membrane Craniovertebral joints cont. - Plates: 30 & 29 Atlanto-Axial joint (dens) the articular facet (for the dens) of C1 articulates with the dens (anterior) of C2 C1 rotates on it synovial pivot joint Available Movements rotation Ligaments of the craniovertebral joints - Plate: 30 Transverse ligament of the atlas holds the dens of C2 against the anterior arch of C1 Cruciate/Cruciform ligament bands travel from transverse ligament superiorly to the occipital bone and inferiorly to the body of C2 Alar ligaments dens to lateral margins of foramen magnum Apical ligament dens to anterior margin of foramen magnum Posterior Longitudinal ligament (PLL) - Plate: 30 travels/is anchored to the posterior aspect of the vertebral bodies and IVDs from sacrum to C2 checks hyperflexion of the spine prevents posterior protrusion of the IVD the most superior part is the tectorial membrane which attaches onto the occiput Anterior Longitudinal ligament - Plate: 29 travels/is anchored to the anterior aspect of the vertebral bodies and IVDs from sacrum to occiput checks hyperextension of the spine stabilizes intervertebral joints Facet joints - Plates: 29 & 192 The inferior articular facet of one vertebra articulates with the superior articular facet of the next inferior vertebra synovial plane Orientation of the Facet Joints cervical facets: oblique (higher anteriorly) thoracic facets: more in the frontal plane lumbar facets: more in the sagittal plane Facet joints cont. Available movements flexion extension rotation (right, left) lateral flexion (right, left) Factors Affecting ROM size and shape of IVDs angle of the facet joints laxity of ligaments/joint capsules Ligaments of the spine - Plates: 29 & 168 Ligamenta Flava (Ligamentum flavum) (Yellow ligament) lamina to lamina from sacrum up to C1 helps preserve normal curves helps return spine to normal position after flexion Interspinous ligaments between SPs limit flexion preventing excessive forward flexion Ligaments of the spine cont. - Plates: 29 & 168 Supraspinous ligaments posteriorly along tips of SPs from C7 to sacrum limits flexion Ligamentum Nuchae aka Nuchal ligament from C7 to back of the skull thickening of the interspinous/supraspinous ligaments The sternoclavicular joint - Plate: 408 the only ‘bony’ articulation between the upper limb and the axial skeleton clavicle articulates with manubrium and costal cartilage of 1st rib synovial saddle joint surfaces are separated by a fibrocartilagenous articular disc which acts as a shock absorber for forces along clavicle Available Movements elevation/depression protraction/retraction rotation Ligaments of the sternoclavicular joint - Plate: 408 Costoclavicular ligament first rib to sternal end of clavicle checks all movements of the clavicle except inferior Interclavicular ligament connects the 2 SC joints across the manubrium Sternoclavicular ligament anterior and posterior Joints of the sternum - Plate: 408 & 192 Manubriosternal joint manubrium articulates with the body of the sternum cartilaginous some movement during respiration Xiphisternal joint body of the sternum articulates with the xiphoid process cartilaginous Joints of the thorax - Plate: 193 Chondrosternal joints cartilages of first 7 ribs and costal notches on lateral borders of sternum rib 1 and manubrium: cartilaginous ribs 2-7: synovial Ligaments radiate sternocostal ligaments Costochondral joints cartilaginous lateral end of each costal cartilage fits into a cup-shaped anterior end of its associated rib no ligaments – supported/bound together by periosteum Joints of the thorax cont. - Plate: 193 Interchondral joints the adjacent borders of the costal cartilages articulate synovial supported by interchondral ligaments Joints of the thorax cont. - Plate: 193 Costovertebral joints the head of the rib articulates with the facets on the side of the vertebral body the superior facet of the head articulates with the inferior facet of the superior vertebral body the inferior facet on the head articulates with the superior facet on the vertebral body of the same number plane synovial Ligaments Radiate ligament head of the rib to the 2 vertebral bodies and disc in between Joints of the thorax cont. - Plate: 193 Costotransverse joints facet on the tubercle of the rib articulates with the costal facet on the associated TVP synovial plane Ligaments Costotransverse ligaments Superior neck of a rib to the next superior TVP Lateral tubercle of a rib to the associated TVP The layers of back musculature - Plates: 180, 181 & 182 Superficial layer (extrinsic) connect the upper limb to the trunk trapezius (upper, middle, lower) latissimus dorsi levator scapula rhomboid major (minor) The layers of back musculature cont. Plates: 180, 181 & 182 Intermediate layer (intrinsic) 2 muscles on the posterior thorax accessory muscles of respiration serratus posterior superior serratus posterior inferior The layers of back musculature cont. Plates: 180, 181 & 182 Deep muscles (intrinsic) maintain posture and move the spine/head 3 layers (superficial, intermediate, deep) The layers of back musculature cont. Plates: 180, 181 & 182 (1) Superficial layer (of the deep muscles) splenius capitis splenius cervicis (2) Intermediate layer (of the deep muscles) 3 columns of muscles collectively called the erector spinae (a.k.a. paraspinals) medial to lateral, they are… (a) spinalis (b) longissimus (c) iliocostalis The layers of back musculature cont. Plates: 180, 181 & 182 (3) Deep layer (of the deep muscles) (a) superomedial fibre direction found in the groove between the spinous and transverse processes (the laminar groove) attach from the transverse processes to the spinous processes (of more superior vertebrae) collectively called the transversospinalis muscles from superficial to deep, they are… 1. semispinalis (capitis, cervicis, thoracis) 2. multifidus 3. rotatores (b) vertical fibre direction 1. interspinales 2. intertransversarii Intermediate layer (intrinsic) - Plate: 181 serratus posterior superior deep to rhomboids (sharing the same fibre direction) superficial to the erector spinae medial attachment: SPs of C7-T3 lateral attachment: superior borders of ribs 2-5 action: elevates ribs 2-5, during inspiration serratus posterior inferior deep to latissimus/thoracolumbar fascia superficial to the erector spinae medial attachment: SPs of T11 – L2 lateral attachment: lower 4 ribs action: draws ribs down and back during forced expiration Deep layer (Intrinsic) - Plates: 180 & 181 & 36 Superficial layer (of the deep muscles) splenius capitis inferior attachment: SPs of C4 – T2 superior attachment: mastoid process and lateral superior nuchal line action: unilateral contraction: ipsilateral rotation of the head and neck action: bilateral contraction: extension of the head and neck splenius cervicis inferior attachment: SPs of T3 – T5 superior attachment: C1 – C4 TVPs (posterior tubercles) action: unilateral contraction: ipsilateral rotation action: bilateral contraction: extension of the neck Deep layer (Intrinsic) - Plates: 180 & 181 Intermediate layer (of the deep muscles) these muscles arise inferiorly from the thoracolumbar fascia and spread out in a superolateral direction they are subdivided into 3 columns of muscles on either side of the spine and each column has 3 segments from medial to lateral, they are the spinalis, the longissimus and the iliocostalis Actions of the group: unilateral: lateral flexion of the vertebral column bilateral: extension of the vertebral column Deep layer (Intrinsic) - Plates: 180 & 181 Intermediate layer (of the deep muscles) Spinalis very thin the shortest column sit in the laminar groove (beside the SPs) attach to SPs (i) thoracis (ii) cervicis (iii) capitis Deep layer (Intrinsic) - Plates: 180 & 181 Intermediate layer (of the deep muscles) Longissimus longest column most visible and palpable attach to TVPs (i) thoracis (ii) cervicis (iii) capitis Deep layer (Intrinsic) - Plates: 180 & 181 Intermediate layer (of the deep muscles) Iliocostalis attach to angles of the ribs (i) lumborum (ii) thoracis (iii) cervicis Deep layer (Intrinsic) - Plates: 182 Deep layer (of the deep muscles) Superomedial fibre direction (transversospinalis) Semispinalis covers ½ of the spinal column skips 3-6 vertebrae attaches superiorly to the occipital bone between the superior and inferior nuchal lines largest mass in the posterior neck Actions bilateral: extension of the head and neck unilateral: contralateral rotation of the neck Deep layer (Intrinsic) - Plates: 182 Deep layer (of the deep muscles) Superomedial fibre direction (transversospinalis) Multifidus from S4 – C2 (skipping 1-3 vertebrae) the only muscle whose fibres run across the posterior sacrum Actions bilateral: extension of the spine, stabilization unilateral: contralateral rotation Deep layer (Intrinsic) - Plates: 182 Deep layer (of the deep muscles) Superomedial fibre direction (transversospinalis) Rotatores deepest in the laminar groove longus: skips 1 vertebra brevis: attaches to next highest vertebra Actions bilateral: stabilization unilateral: contralateral rotation Deep layer (Intrinsic) - Plates: 182 Deep layer (of the deep muscles) Vertical fibre direction Interspinales paired muscles on either side of cervical and lumbar SPs action: extension Intertransversarii attach TVPs of adjacent vertebrae of cervical and lumbar spine action: lateral flexion The suboccipital muscles - Plates: 181 & 184 4 small muscles deep to semispinalis capitis lay directly over the Atlanto-axial joint mainly postural, but help to move the head positioned to move the upper cervical spine independently of the lower cervical spine deepest in the area The suboccipital muscles The suboccipital muscles - Plates: 181 & 184 Rectus capitis posterior major inferior attachment: SP of C2 superior attachment: inferior nuchal line action (unilateral contraction): ipsilateral rotation of the head action (bilateral contraction): extend the head on the neck The suboccipital muscles - Plates: 181 & 184 Rectus capitis posterior minor inferior attachment: posterior arch of C1 (posterior tubercle) superior attachment: inferior nuchal line action(bilateral contraction): extend the head on the neck also attaches to the dura mater which may result in headaches by disruption of normal cerebrospinal fluid flow (CSF) and therefore the function of the vertebral artery and the suboccipital nerve The suboccipital muscles - Plates: 181 & 184 Obliquus capitis inferior inferior attachment: SP of C2 superior attachment: TVP of C1 action (unilateral contraction): ipsilateral rotation of the head at the AA joint key muscle for rotation of C1 The suboccipital muscles - Plates: 181 & 184 Obliquus capitis superior inferior attachment: TVP of C1 superior attachment: between superior and inferior nuchal lines action (unilateral contraction): lateral flexion of the head on the neck action (bilateral contraction): extend the head on the neck The suboccipital triangle Boundaries: the most lateral 3 suboccipital mm. define the triangle inferolateral border: obliquus capitis inferior superolateral border: obliquus capitis superior superomedial border: rectus capitis posterior major floor: posterior atlanto-occipital membrane roof: semispinalis m. Contents: vertebral artery suboccipital nerve The looking reflex The looking reflex: the head wants to follow where the eyes look. The clinical application: rolling the eyes upward generates a small contraction in the suboccipital muscles and rolling them downward will help them relax. Anterolateral neck muscles - Plates: 36 & 37 Pre-vertebral: Rectus capitis anterior inferior attachment: lateral mass of C1 superior attachment: occiput action: flexes head on the neck Anterolateral neck muscles cont. - Plates: 36 & 37 Rectus capitis lateralis inferior attachment: TVP of C1 superior attachment: occiput action: flexes head on the neck action: laterally flexes head on neck Anterolateral neck muscles cont. - Plates: 36 & 37 Longus colli (a.k.a longus cervicis) inferior attachment: body of T3 superior attachment: anterior tubercle of C1 additional attachments to the bodies and TVPs of the cervical spine action: flexion of the neck Anterolateral neck muscles cont. - Plates: 36 & 37 Longus capitis inferior attachment: TVPs of C3-6 superior attachment: occiput action: flexion of the head AND neck Anterolateral neck muscles cont. - Plates: 36 & 37 Lateral Neck muscles: Anterior scalene superior attachment: anterior tubercles of C3-6 TVPs inferior attachment: rib 1 (scalene tubercle) action (bilateral contraction): flexion of the neck action (unilateral contraction): ipsilateral lateral flexion of the neck action: elevates 1st rib during forced inhalation action (unilateral contraction): contralateral rotation of the neck (weak) Anterolateral neck muscles cont. - Plates: 36 & 37 Middle scalene superior attachment: posterior tubercles of C2-7 TVPs inferior attachment: rib 1 (posterior to subclavian artery) action (unilateral contraction): ipsilateral lateral flexion action: elevates 1st rib during forced inhalation action (unilateral contraction): contralateral rotation of the neck (weak) Anterolateral neck muscles cont. - Plates: 36 & 37 Posterior scalene superior attachment: posterior tubercles of C4-6 TVPs inferior attachment: rib 2 action (unilateral contraction): ipsilateral lateral flexion action: elevates rib 2 during forced inhalation Anterolateral neck muscles cont. - Plates: 36 & 37 Sternocleidomastoid (SCM) superior attachment: mastoid process inferior attachment: sternum (sternal head) inferior attachment: clavicle (clavicular head) action: contralateral rotation of the head and neck action: ipsilateral lateral flexion of the head and neck action: flexion of the neck (if the head/neck is in neutral or flexed) action: extension of the head (if the head is already extended) action: assists with inspiration The anterior cervical triangle - Plate: 36 base: mandible lateral border: SCM medial border: midsagittal plane of the neck contents: muscles, arteries, veins, lymph nodes, viscera The posterior cervical triangle - Plate: 36 base: clavicle anterior border: SCM posterior border: trapezius floor (superior to inferior): 1. splenius capitis 2. levator scapula 3. posterior scalenes 4. middle scalenes 5. anterior scalenes 6. omohyoid contents: blood vessels and nerves Surface anatomy of the neck - Plates: 77, 35 & 22 Larynx just inferior to where the pharynx splits into the trachea and the esophagus voice production Adam’s apple – formed by the thyroid cartilage thyroid gland: anterior to the trachea, inferior to the thyroid cartilage trachea: cartilaginous rings hyoid bone: anterior neck superior to the thyroid cartilage (part of the larynx) The hyoid muscles - Plates: 69, 35, 36 & 32 Suprahyoids superior to the hyoid bone connect the hyoid to the skull mylohyoid geniohyoid stylohyoid digastric general action (superior attachments fixed): elevate the hyoid bone general action (hyoid fixed): assist in depressing (lowering) the mandible The suprahyoids - Plates: 69, 35, 36 & 32 mylohyoid superior attachment: mandible (jaw bone) inferior attachment: hyoid bone geniohyoid superior attachment: mandible inferior attachment: hyoid bone stylohyoid superior attachment: styloid process of the temporal bone (part of the skull) inferior attachment: hyoid bone The suprahyoids cont. - Plates: 69, 35, 36 & 32 digastric (anterior belly) superior attachment: inferior border of the mandible (jaw bone) inferior attachment: intermediate tendon to hyoid (via a connective tissue loop) digastric (posterior belly) superior attachment: mastoid process (medial side) inferior attachment: intermediate tendon to hyoid (via a connective tissue loop) The infrahyoids - Plates: 69, 35, 36 & 32 Infrahyoids inferior to the hyoid bone sternohyoid sternothyroid thyrohyoid omohyoid general action: depress the hyoid bone The infrahyoids - Plates: 69, 35, 36 & 32 sternohyoid superior attachment: hyoid bone inferior attachment: manubrium sternothyroid superior attachment: thyroid cartilage inferior attachment: manubrium thyrohyoid superior attachment: hyoid bone inferior attachment: thyroid cartilage The infrahyoids - Plates: 69, 35, 36 & 32 omohyoid (superior belly) two bellies connected by an intermediate tendon superior attachment: hyoid bone inferior attachment: intermediate tendon omohyoid (inferior belly) superior attachment: intermediate tendon inferior attachment: superior border of the scapula near the suprascapular notch Regions of the abdomen - Plate: 251 the abdomen is the area between the diaphragm and the pelvis the abdomen is typically divided into 4 quadrants the dividing lines are based on the mid-sagittal plane and the transumbilical plane (the transverse plane passing through the umbilicus or belly button) the quadrants are: RUQ: right upper quadrant LUQ: left upper quadrant RLQ: right lower quadrant LLQ: left lower quadrant Muscles of the abdomen - Plates: 252, 253 & 254 Anteriorly, they are… rectus abdominis external oblique internal oblique transversus abdominis Posteriorly, they are… psoas major quadratus lumborum The anterior wall of the abdomen - Plates: 252 & 253 Rectus abdominis superior attachment: costal cartilages of ribs 5-7, xiphoid process inferior attachment: pubic symphysis and pubic crest right and left sides are separated by the linea alba action: flexes the vertebral column (trunk) action: stabilizes the pelvis during leg-lowering action: compresses viscera The anterior wall of the abdomen cont. - Plate: 252 External oblique most superficial superior/lateral attachment: ribs 5 – 12 inferior/medial attachment: linea alba (via abdominal aponeurosis), pubic tubercle, anterior ½ of the iliac crest fibre direction: anteriorly and inferomedially action (unilateral contraction): rotates column to contralateral side action (unilateral contraction): ipsilateral lateral flexion action (bilateral contraction): trunk flexion action (bilateral contraction): stabilizes the pelvis during leg-lowering action (bilateral contraction): compress and support viscera The anterior wall of the abdomen cont. - Plate: 253 Internal oblique inferior/lateral attachment: anterior ½ of the iliac crest superior/medial attachment: linea alba (via abdominal aponeurosis), ribs 10-12 (inferior borders) deep to external oblique fibre direction: anteriorly and superomedially action (unilateral contraction): rotates column to ipsilateral side action (unilateral contraction): ipsilateral lateral flexion action (bilateral contraction): trunk flexion action: (bilateral contraction): stabilizes the pelvis during leg lowering action (bilateral contraction): compress and support viscera The cremaster muscle - Plate: 253 The cremaster muscle is an expansion of the internal obliques Only developed in biological males. Contraction of this muscle raises the testes. Light stroking on the medial thigh can initiate the cremaster reflex. The anterior wall of the abdomen cont. - Plate: 254 Transversus abdominis lateral attachment: inner iliac crest, lower 6 costal cartilages, thoracolumbar fascia medial attachment: linea alba (via abdominal aponeurosis) deep to internal oblique fibre direction: medial - lateral action (bilateral contraction): compress and support viscera The anterior wall of the abdomen cont. the external obliques, internal obliques, and transversus abdominis overlap/cross each other in such a way that they protect and strengthen the abdominal wall they contract to compress the abdominal contents Loose ends Fascia of the Abdomen - Plates: 252, 253, 254 & 255 The rectus sheath the aponeurotic attachments of the external oblique, internal oblique and transversus abdominis form a sheath of connective tissue which encases the rectus abdominis muscle medially, they reconnect to form the linea alba The linea alba runs vertically from the xiphoid process to the symphysis pubis the 2 rectus abdominis muscles are separated by the linea alba The linea semilunaris the lateral border of the rectus abdominis and its sheath Bruce Lee’s abs Arnold’s abs The Posterior Wall - Plate: 265 Psoas major (review T1 notes) Quadratus lumborum (QL) superior attachment: medial ½ of rib 12, TVPs of lumbar vertebrae inferior attachment: iliac crest, iliolumbar ligament action (bilateral contraction): extends the lumbar spine action (bilateral contraction): fixes 12th rib during forced expiration action (bilateral contraction): stabilizes lumbar spine action (unilateral contraction): ipsilateral lateral flexion or ‘hip hike’ QL TrPs Muscles of respiration - Plate: 195, 196 & 197 The Intercostals arranged in 3 layers in the spaces between adjacent ribs (the intercostal space) from superficial to deep: external, internal, innermost each group (external, internal, innermost) has 11 pairs of muscles external intercostals (superior att. fixed) superior attachment: ribs 1-11 inferior attachment: ribs 2-12 Muscles of respiration - Plates: 195, 196 & 197 Internal intercostals superior attachment: ribs 1-11 inferior attachment: ribs 2-12 (inferior att. fixed) fibre direction: (right angles (90o) to the external intercostals) Innermost intercostals same as internal intercostals separated from the internal intercostals by the neurovascular bundle Actions external intercostals: quiet and forced inspiration (through elevation of the ribs) internal/innermost intercostals: forced expiration all intercostals: keep the intercostal spaces rigid Muscles of respiration - Plates: 182 & 195 Levator costarum 12 pairs superior attachment: TVPs of C7-T11 inferior attachment: ribs (immediately inferior) action: elevate the ribs during inspiration Subclavius medial attachment: 1st rib and its costal cartilage lateral attachment: middle 1/3rd of the inferior surface of the clavicle action: anchors, depresses and draws the clavicle medially The (thoracic) diaphragm - Plates: 200, 201 & 196 the principle muscle of respiration a dome-shaped muscle that divides the thoracic cavity and abdominal cavity pierced by structures passing between the thorax and abdomen the top of the dome sits at approximately the 4th intercostal space (during expiration) and the 6th intercostal space (during inspiration) it is divided into a muscular component and a tendinous component The (thoracic) diaphragm - Plates: 200, 201 & 196 The Muscular Component the muscle attaches inferiorly onto the… posterior surface of the xiphoid internal surfaces of lower 6 ribs (and their costal cartilages) upper lumbar vertebrae via 2 muscular crura medial arcuate ligaments (upper lumbar vertebral bodies to TVPs – travels over psoas) lateral arcuate ligaments (L1 TVP to 12th rib – travels over QL) The (thoracic) diaphragm - Plates: 200 & 201 The Central Tendon the muscular fibres converge radially into a strong aponeurotic tendon called the central tendon has a C-shaped appearance with a central, left and right ‘leaflet’ The diaphragm The diaphragm cont. Action with contraction, the diaphragm moves inferiorly so that it is flattened Innervation phrenic nerve (C3, 4, 5) C3, C4, C5 keep the diaphragm alive Respiration Inspiration contraction of the diaphragm causes inferior movement of the central tendon as it flattens it increases the vertical dimension of the thoracic cavity (increased thoracic volume) inspiration is assisted by the contraction of the intercostals the ribs are raised and moved laterally which increases the transverse dimension of the thorax (increased thoracic volume) this is called the “bucket-handle movement” The bucket handle movement Respiration cont. as the ribs are raised, the anterior parts of the ribs and the sternum move anteriorly which increases the anterior-posterior dimension of the thorax (increased thoracic volume) – this is called the pump-handle movement The pump-handle movement Respiration cont. these increases in the vertical, transverse, and AP dimensions create a negative pressure in the lungs which results in air being drawn in (inspiration) this same contraction decreases the vertical dimension of the abdomen and increases the pressure this is important for normal blood and lymphatic circulation summary: with inspiration, the thoracic volume increases which decreases thoracic pressure AND the abdominal volume decreases which increases abdominal pressure Respiration cont. Expiration the diaphragm relaxes and moves superiorly this, with the elastic recoil of the lungs decreases the thoracic volume and increases the thoracic pressure air flows out normally, this is a passive process Respiration cont. Apical Breathing the diaphragm remains relatively relaxed accessory muscles of respiration lift the chest up and out this is an inefficient means of respiration (Singultus = hiccup) The pelvic diaphragm - Plates: 339 - 343 The Perineum the region below the pelvic cavity floor: skin roof: pelvic diaphragm The pelvic diaphragm - Plates: 339 - 343 Pelvic Diaphragm levator ani muscles (two) coccygeus muscles (two) levator ani anterior attachment: back of pubis, spine of ischium posterior attachment: anococcygeal ligament, lower sacrum & coccyx coccygeus lateral attachment: pelvic surface of the ischial spine and sacrospinous ligament medial attachment: lateral margin of coccyx and S5 Actions of the pelvic diaphragm: supports the pelvic viscera, helps maintain control of bodily functions The skull - Plates: 11 & 16 the skeleton of the head cranium: the part of the skull that contains the brain (often used interchangeably with skull – consists of the frontal, occipital, sphenoid, ethmoid, temporal and parietal bones calvaria: the dome-like superior portion of the cranium facial skeleton (facial bones): the bones that make up the face suture: the line of union in an immobile articulation (Taber’s) The mandible - Plate: 24 U-shaped bone forms the skeleton of the lower jaw and the inferior part of the face coronoid process mandibular notch head (condyle) neck ramus angle (of the mandible) body (of the mandible) base (of the mandible) mental foramen mental protuberance The mandible - Plate: 24 lingula mandibular foramen mandibular canal digastric fossa mylohyoid line pterygoid tuberosity (roughened area on the inner aspect of the angle of the mandible) The skull - Plates: 11 & 13 The Frontal bone superciliary arch (ridge where your eyebrows are) glabella supraorbital foramen orbital surface – the frontal bone forms the roof of the eye sockets The Parietal bones superior temporal line inferior temporal line The skull - Plates: 13 The Temporal bones zygomatic process articular tubercle mastoid process temporal fossa styloid process (of the temporal bone) mandibular fossa external acoustic meatus the temporal bone houses structures related to hearing and balance within the temporal bone is the tympanic cavity which houses the 3 ossicles (bones of the middle ear) called the malleus, incus, stapes – they help in the transmission of sound Bones of the middle ear (temporal) - Plate: 105 & 106 Incus = Anvil Malleus = Hammer Stapes = Stirrup The skull - Plates: 11, 13, 15, 17 & 18 The Sphenoid bone wedge-shaped bone anterior to the temporal bones body greater wings lesser wings sella turcica (Turkish saddle) - houses the pituitary gland pterygoid process – there is a medial plate and a lateral plate The sphenoid The sphenoid The skull - Plates: 11, 13, 15, 16, 17 & 18 Occipital bone external occipital protuberance (inion) foramen magnum occipital condyles superior nuchal line inferior nuchal line Nasal bones bridge of the nose The skull - Plates: 11, 13, 15 & 17 The Maxillae skeleton of the face between the mouth and the eyes frontal process zygomatic process orbital surface alveolar processes infraorbital foramen – exit of the infraorbital nerve palatine process The Zygomatic bones cheek bones anterolateral and infra orbital margins temporal process (of the zygomatic bone) The skull - Plates: 11, 15 & 18 The Ethmoid bone separates the nasal cavity from the brain located at the roof of the nose between the orbits crista galli – a ridge of bone projecting superiorly - attachment for the falx cerebri (arched fold of dura mater which separates the right and left hemispheres of the brain and descends in the longitudinal fissure) cribriform plate perpendicular plate – forms the posterior and superior part of the nasal septum The ethmoid - posterior and lateral views The ethmoid - superior view Sutures of the skull - Plate: 13 & 16 Sutures coronal suture sagittal suture bregma: meeting point between the coronal and sagittal sutures squamous suture - joint between temporal and parietal bones lambdoid suture lambda: meeting point of the lambdoid and sagittal sutures pterion: connection between the sphenoid, temporal, frontal and parietal bones The orbital socket - Plate: 11 The Orbit eye socket cone-shaped cavity made of many bones optic canal posterior wall - sphenoid floor - maxillae roof - frontal lateral wall - zygomatic medial wall - ethmoid The facial sinuses - Plates: 50 & 51 The Sinuses frontal (2) sphenoidal (2) ethmoidal (2) maxillary (2) (largest) the air travelling through the sinuses is either warmed or cooled to within 1 degree of body temperature there are short, thick hairs called vibrassae which help to move particulate matter - (dust etc) The facial sinuses The temporomandibular joint - Plates: 25 The Temporomandibular Joint (TMJ) the head/condyle of the mandible articulates with the mandibular fossa and articular tubercle of the temporal bone synovial modified hinge The Articular Disc there is a fibrocartilagenous disc that sits between the head of the mandible and the temporal bone (the 2 articulating surfaces) it is connected to the joint capsule (the capsule is quite loose and thin) follows the movements of the mandible attached to the disc posteriorly is the retrodiscal pad which helps maintain the proper positioning of the disc The temporomandibular joint - Plates: 25, 55 & 56 Ligaments the joint is supported by the capsule the capsule thickens laterally to form the lateral (temporomandibular) ligament stylomandibular ligament sphenomandibular ligament Available Movements depression: opening the mouth elevation: closing the mouth protraction/protrusion: anterior translation of the mandible retraction/retrusion: posterior translation of the mandible deviation: movement from side to side The muscles of mastication - Plates: 55 & 56 Temporalis superior attachment: temporal bone (fossa) inferior attachment: coronoid process and anterior ramus action: elevation of the mandible action: retraction of the mandible (more horizontal/posterior fibres) The muscles of mastication - Plates: 55 & 56 Masseter note: superficial and deep fibres superior attachment: inferior border of the zygomatic arch inferior attachment: angle of the mandible action: elevation of the mandible action: (superficial fibres) protraction of the mandible action (deep fibres): retraction of the mandible (from a protracted position) The muscles of mastication - Plates: 55 & 56 Lateral pterygoid note: superior head and inferior head anterior attachment: greater wing of the sphenoid (superior head) and lateral surface of the lateral pterygoid plate (inferior head) posterior attachment: neck of the mandible (inferior head), articular disc (superior head) action: protraction of the mandible action: translational (anterior/posterior) control of the articular disc (superior head) action: depression of the mandible (inferior head) (once translation occurs) action: contralateral deviation of the mandible The muscles of mastication - Plates: 55 & 56 Medial pterygoid anterior attachment: medial surface of the lateral pterygoid plate inferior attachment: pterygoid tuberosity (inner surface of the angle of the mandible) action: elevation of the mandible action: protrusion of the mandible action: contralateral deviation of the mandible Hyoids action (hyoid fixed): assist in depression of the mandible Action summary Depression hyoids lateral pterygoid (inferior head) (once translation occurs) Elevation temporalis masseter medial pterygoid lateral pterygoid (superior head) (eccentric control of disc return) Protrusion masseter (superficial fibres) lateral pterygoid medial pterygoid Action summary Retrusion temporalis (posterior fibres) masseter (deep fibres) Deviation contralateral pterygoids Biomechanics of the TMJ Depression (opening the mouth) beginning to midrange of motion is primarily anterior sagittal rotation of the head of the mandible in the mandibular fossa midrange to end range is primarily anterior translation of the head of the mandible from the fossa onto the articular tubercle as the translation occurs, the articular disc is pulled anteriorly by the superior head of the lateral pterygoid to maintain joint surface congruency muscles activated include: digastric, mylohyoid, geniohyoid and, when translation occurs, the inferior head of the lateral pterygoid Biomechanics of the TMJ Elevation (closing the mouth) posterior translation of the mandibular head from the articular tubercle to the fossa followed by posterior sagittal rotation of the mandibular head in the mandibular fossa as the mouth closes, the disc is pulled back into position by elastic fibres that attach to the back of the disc – the movement is controlled (eccentrically) by the superior head of the lateral pterygoid muscles activated include: masseter, medial pterygoid, temporalis, superior portion of lateral pterygoid Biomechanics of the TMJ Deviation muscles activated include: contralateral medial pterygoid, contralateral lateral pterygoid Protraction medial pterygoid, masseter, lateral pterygoid Retraction temporalis, and deep fibres of masseter TMJ cont. Close packed position maximal occlusion Resting position teeth 2-5mm apart with the tip of the tongue resting behind the front teeth on the roof of the mouth Muscles of facial expression Muscles of facial expression - Plates: 31 OCCIPITOFRONTALIS occipitalis (2 bellies): superior nuchal line 🡪 epicranial aponeurosis frontalis (2 bellies): skin near the eyebrows 🡪 epicranial aponeurosis action: occipitalis anchors the aponeurosis so that the frontalis can pull the eyebrows up ORBICULARIS OCULI sphincter of the eye – contraction closes the eyelids also helps to empty the lacrimal (tear) sac (tearing) Corrugator supercilii draws eyebrows inferiorly and medially Muscles of facial expression - Plates: 31 Levator labii superioris raises upper lip Levator labii superioris aleque nasi raises lip dilates nostrils Zygomaticus minor raises upper lip Muscles of facial expression - Plates: 31 ZYGOMATICUS MAJOR draws the angle of the mouth superolaterally ORBICULARIS ORIS sphincter of the mouth fibres are derived from other muscles closes the lips protrudes lips compresses lips against teeth MENTALIS raises and protrudes lower lip Muscles of facial expression - Plates: 31 Depressor labii inferioris draws lip inferiorly and slightly laterally Depressor anguli oris depresses the corner of the mouth BUCCINATOR compresses cheek against molar teeth when chewing (keeps the food where the teeth can grind it) helps with whistling (forceful blowing) Muscles of facial expression - Plates: 31 PLATYSMA retracts and depresses angle of the mouth Auricularis anterior draws ear up and forward Auricularis superior draws ear up Auricularis posterior draws ear back Muscles of facial expression summary Occipitofrontalis = Surprise Orbicularis oculi = Squinting & winking Corrugator supercilii = Frowning Levator labii superioris = Snarling Levator labii superioris aleque nasi = Stank face Zygomaticus minor = Elvis Zygomaticus major = Smiling Orbicularis oris = Kissing & whistling Mentalis = Pouting Depressor labii inferioris = Yikes Depressor anguli oris = Sad Platysma = Creature from the black lagoon Nerves of the upper limb - Plates: 36, 37, 419-423, 436, 452, 463-469 Median Axillary Radial Musculocutaneous Ulnar The brachial plexus - Plate: 36, 37, 419 & 420 The brachial plexus is a bundle of nerves that exit the intervertebral foramen from C5 - T1. They travel between the anterior and middle scalenes, deep to the clavicle and over the first rib, deep to pec minor and through the axilla to become the terminal branches. These are all potential areas for impingement. (See TOS) This braiding of nerves accounts for all of the sensory and motor control to the entire upper limb. Interruption of this nerve supply via muscular spasm, trauma, compression, tumours, etc can lead to severe functional impairment. Thoracic outlet syndrome (TOS) - Plate: 37 Thoracic outlet syndrome is compression/interruption of the brachial plexus, subclavian artery, and subclavian vein. Symptoms may include: paresthesia (ie. numbness, tingling etc) of the entire upper limb bluish discoloration of the affected arm arm fatigue during activity weak pulse or lack of pulse coldness of the arm/hand swelling Thoracic outlet syndrome Common causes: Cervical ribs Pregnancy Repetitive strain (especially with overhead activity or sports) Postural fault Trauma Fractures (cervical, clavicular, etc) Heavy bags/backpacks Shoulder dislocations surgery Terminal branches of brachial plexus - Plates: 423, 466 The Median nerve Travels with the brachial artery through the arm Passes into the anterior forearm through the cubital fossa Deep to the flexor retinaculum at the wrist (via the carpal tunnel) Provides motor innervation to all of the muscles in the superficial, intermediate and deep layers of the anterior forearm EXCEPT, flexor carpi ulnaris and the medial half of flexor digitorum profundus. In the hand it gives off motor supply to the thenar eminence and lateral lumbricals The sensory area of supply is the lateral palm and lateral 3 ½ digits (thumb, index, middle finger and lateral half of the ring finger Median, radial and ulnar sensory nerve patterns Median nerve damage The presentation is determined by the level of injury The more proximal the injury, the more severe the impairment With injury above or at the elbow, there would be a loss of pronation, and weak wrist flexion. You may notice ulnar deviation as flexor carpi ulnaris would be unopposed Wasting of the thenar eminence resulting in loss of opposition Inability to flex the MCP’s or extend the PIP’s and DIP’s (lumbricals) Ape hand deformity Hand of benediction The carpal tunnel - Plate: 452 Structures passing through the carpal tunnel: The median nerve 4 tendons of FDS 4 tendons of FDP 1 tendon of FPL Carpal tunnel syndrome Causes: Trauma/swelling at the wrist Diabetes Pregnancy Tendonitis Rheumatoid arthritis Wrist fracture Positional fault Idiopathic Carpal tunnel syndrome Common signs and symptoms: Parasthesia (feelings of tingling, numb, burning, shooting, electric etc… associated with interruption of nerve supply) into the lateral 3 ½ digits Weakness The axillary nerve - Plate: 468 & 414 The axillary nerve Travels through the quadrangular space of the posterior shoulder It wraps around the surgical neck of the humerus Provides motor supply to the deltoids, teres minor, and the long head of triceps brachii Sensory innervation to the “regimental badge” area, around the deltoid tuberosity Quadrangular space Regimental badge Axillary nerve damage Typical causes include: Inferior shoulder dislocations Direct trauma/fracture to the proximal humerus Improper use of crutches Breech births (Erb’s palsy C5, C6 nerve roots) Axillary nerve damage Typical presentation may include: Loss of abduction of the shoulder (between 15 - 90 degrees) Weakness with flexion, extension and lateral rotation Loss of sensation over the “regimental badge” Flat shoulder deformity Flat shoulder deformity Erb’s Palsy The radial nerve - Plate: 468 & 469 Travels through the triangular interval Spiraling around the humerus in the radial groove Motor innervation to the lateral and medial heads of triceps brachii, and the superficial and deep compartments of the posterior forearm (including brachioradialis and the supinator) Sensory supply to the posterolateral aspect of the arm and posterior forearm as well as the posterior hand and lateral 3 ½ digits Triangular interval Radial sensory nerve pattern Radial nerve damage Typical presentation may include: Loss of elbow extension Loss of wrist and finger extension (Finger/wrist drop) Weak supination Numbness in the sensory distribution pattern “Saturday night palsy” Finger/wrist drop Saturday night palsy The musculocutaneous nerve - Plate: 465 Travels through the axilla and pierces the muscles of the anterior arm Motor supply to biceps brachii, brachialis, and coracobrachialis Sensory innervation to the anterolateral forearm It presents with frequent irregularities in its pathway Sensory and motor supply of the musculocutaneous nerve Musculocutaneous nerve damage This nerve may be compressed through hypertrophy of biceps brachii and brachialis, and can be trapped between the 2 muscles, especially for serious weightlifters or body builders It can also be compromised by stretch injuries and dislocations of the GH joint, or during surgery You will likely observe weakness with elbow flexion and supination and/or sensory loss to the anterolateral forearm The ulnar nerve - Plate: 463 & 467 The ulnar nerve is notorious for being the largest unprotected nerve in the human body. It is most superficially exposed between the olecranon and the medial epicondyle. Compression at this point is known as “hitting your funny bone”. This is because of the association to the word humorous and the arm bone, the humerus. It provides no motor or sensory supply to the arm, as it passes through this region. In the forearm, it innervates flexor carpi ulnaris, the medial half of flexor digitorum profundus and the remaining muscles of the hand which are not supplied by the median nerve. (hypothenar eminence, dorsal and palmar interossei, medial 2 lumbricals etc) It provides sensory innervation to the 5th digit and the medial half of the 4th digit. In the forearm the ulnar nerve travels between the 2 heads of flexor carpi ulnaris and down the medial forearm to enter the hand superficial to the flexor retinaculum and deep to the hook of the hamate (tunnel of Guyon) Ulnar nerve damage Injuries to the ulnar nerve are common, due to its superficial exposure, posterior to the medial epicondyle. Long haul biking can cause compression at the Tunnel of Guyon. Severe injury may result in a condition called “ulnar claw”. The presentation is extension at the MCP and flexion of the PIP’s and DIP’s. In the present day, with excessive cell phone use and video games, flexor carpi ulnaris can show high MRT in the majority of the population, which results in compression of the ulnar nerve. Ulnar claw Nerves of the lower limb - Plates: 529 - 533 Sciatic Common peroneal Superficial peroneal Deep peroneal Tibial Femoral Obturator The lumbar plexus - Plate: 486, 487 & 488 Exits the intervertebral foramen from T12 - L4 Travels through psoas to exit the pelvis either deep to the inguinal ligament, through the greater sciatic notch or through the obturator foramen Branches of the lumbar plexus supply sensory and motor innervation to the entire lower limb Injuries at the spinal level can lead to severe functional impairment including paraplegia and altered gait The sciatic nerve - Plate: 531 The sciatic nerve is the largest nerve fibre in the body and is comprised of the tibial and common peroneal nerves wrapped in one sheath. It exits the pelvis through the greater sciatic notch, passing deep to piriformis and down the posterior thigh. It gives motor innervation to the hamstrings and the posterior fibres of adductor magnus. It does not have any sensory supply to the thigh, but it’s branches do in the leg and foot. Just above the level of the popliteal fossa, the sciatic nerve branches into the tibial and common peroneal nerves which supply the leg and foot with both motor and sensory function. The sciatic nerve cont. Sciatic nerve damage/impingement/compression Interruption to the sciatic nerve can lead to severe pain and dysfunction. This is most often caused by disc herniation, spondylolisthesis, spasm in musculature (ie. piriformis pain syndrome), or a stenosis (narrowing of the intervertebral foramen). Obesity and pregnancy weight gain can both be possible factors causing “sciatica” due to additional weight compressing the IVD’s and bulging them into nerve roots. Forward flexion will often increase the symptoms, while extension exercises can help alleviate discomfort. Pain is often described as shooting, burning, or electric and the patient may have difficulty controlling the affected limb. Motor dysfunction typically presents with weightbearing on the affected side. The sciatic nerve cont. The tibial nerve - Plate: 532 The tibial nerve originates just above the level of the popliteal fossa and travels down the posterior leg, into the foot through the tarsal tunnel (between the medial malleolus and the calcaneus) It gives motor supply to all muscles in the superficial and deep posterior crural compartments of the leg. In the foot it gives motor information to the layers of the sole of the foot as well as sensory supply. Tarsal tunnel syndrome Compression of the tibial nerve as it passes through the tarsal tunnel (between the medial malleolus and the calcaneus). Symptoms present as numbness, tingling, shooting pain etc into the sole of the foot. Common causes include: RA, prolonged eversion, pes planus, direct trauma, tendonitis etc The common, superficial and deep peroneal nerves - Plate: 533 It is only called the common peroneal nerve from the area where it bifurcates above the popliteal fossa, until it wraps around the neck of the fibula, where it is most superficially exposed. It branches into the deep peroneal nerve which innervates the muscles of the anterior compartment of the leg, and the superficial peroneal nerve which innervates the muscles of the lateral compartment of the leg. The deep peroneal nerve also gives sensory supply to the web space between the 1st and 2nd toes on the dorsum of the foot. The superficial peroneal nerve provides sensation to the anterolateral leg and the majority of the dorsum of the foot, with the above noted exception. The obturator nerve - Plate: 530 Exits the pelvis through the obturator foramen. It gives motor supply to the adductor muscles with the exception of pectineus (femoral n) and the posterior fibres of adductor magnus (sciatic n). It also provides sensation to the majority of the skin on the medial aspect of the thigh. This nerve is most commonly injured during abdominal or pelvic surgeries. This can cause loss of sensation on the medial thigh and difficulty with gait, due to the lack of adduction. There may be observable abduction and external rotation with damage. The femoral nerve - Plate: 529 The femoral nerve provides motor information to the anterior thigh, including the quadriceps, pectineus, sartorius, and iliacus. It passes deep to the inguinal ligament and through the femoral triangle. Sensation to the anteromedial thigh and medial leg comes from branches of the femoral nerve. There is a branch called the lateral femoral cutaneous nerve (LFCN) that has a clinical relevance in massage therapy. Meralgia parasthetica Compression of the LFCN as it exits the pelvis, deep to the inguinal ligament, just medial to the ASIS. Characterized by burning, sometimes excruciating pain over the anterolateral thigh. Some people report the feeling of multiple bee stings. Populations affected include, pregnant people, police officers, construction workers, former hipsters, and the obese. It often presents with an anterior pelvic tilt. Find the cause - treat the cause. During massage, firm pressure often feels better than superficial techniques. Hip extension can exacerbate symptoms. Meralgia parasthetica