musculoskeletal system

vertebral column curvatures

• primary C-shaped curvature, primary curvatures are kyphotic

• secondary “lordotic” curves develop in cervical and lumbar regions, in opposition to the C-curve

atypical curvatures

major anatomical landmarks of typical vertebra

• vertebral body

• vertebral arch

• spinous & transverse processes

• articular processes

vertebral body

• eight bearing

• articulate superiorly and inferiorly

• epiphyseal ring (dotted circle), helps ith attachment to intervertebral disk

vertebral arch

• pedicles (1) + lamina (2)

• forms vertebral foramen

• protects spinal cord

spinous and transverse processes

• levers for muscle attachment

• levers for ligamentous attachment

• spinous (in the middle), transverse (sides)

articular processes

• projections (yello) ith articular facets (blue)

• articulate superiorly (big yello) and inferiorly (small yello), hich connect beteen vertebra

• blue: smooth surface for articulation, surface here the bones connect: articular facet.

cervical vertebrae

• transverse processes have extra holes

thoracic vertebrae

• long spinous process hich projects donards

lumbar vertebrae

• large vertebral body

• thick spinous process

sacrum

• fused vertebrae

vertebral foramen

vertebral canal

• multiple foramen in a ro form a canal

vertebral notch

• incomplete hole

intervertebral foramen

• a foramen created from to vertebrae stacked together

• inferior notch of upper vertebra + superior notch of loer vertebra = foramen

• spinal nerve roots leave through these foramen

intervertebral joints

• vertebral body + disk + vertebral body

• secondary cartilaginous joints (fibrocartilaginous)

disks in aging

• loer is in a younger adult, here it appears more atery

• disk dries out over time

• disk bulges are more likely in younger population here the atery substance can move out and cause herniations

annulus fibrosus

• attaches to epiphyseal ring

• - keeps the vertebra together

• concentric lamellae of collagen

nucleus pulposus

• pushes compressive force in all directions to spread the load, shock absorber

• surrounded by annulus fibrosus

• keeps the vertebra apart

• gelatinous consistency, deforms but not compressible

layers of annulus fibrosus

• concentric lamellae of collagen

• permits movement in all directions

• resists excessive rotation

• some layers are going in diffrent directions to limit tisting - if e tist too far, some layers ill get taught

zygapophyseal joints

• plane synovial joints

• movement dependent on the orientation of the articular surfaces involved, differs along the vertebral column

• beteen superior and inferior articular processes hich have articular surfaces or “facets” on them

thoracic vs lumbar plane joints

• thoracic more specialised for coronal movement

• lumbar for sagittal movement (flexing and extending in the lumbar region)

longitudinal ligaments

• thick at the front, smaller at the back

interspinous ligament

• beteen spinous processes

supraspinous ligament

• superficial to spinous processes

ligamentum flavum

• project from lamina

• extra elastin tissue hich assists us in big movements

extrinsic muscles of the back

• attach to and act on the upper limb

• trapezium and rhomboid

• major and minor

• lattisimus (broadest) and dorsi (back)

• levator (elevate) and scapulae (shoulder blade)

• superficial

trapezium vs rhomboid

intrinsic muscles of the back

• primarily attach to and act on the back

  • erector spinae

  • transversospinalis

erector spinae

• prime movers of the back, particularly in the sagittal plane

• concentrically extend the trunk

• eccentrically control trunk flexion (e.g. sloly bending over)

• commonly implicated ith postural issues

transversospinalis

• deep to the erector spinae

• short muscles

• control more fine movements at vertebral segments

• important in rehabilitation for improving smaller segmental movements

• multifidus is the name of these muscles in the lumbar spine

bony framework of upper limb

• attaches to anterior aspect of axial skeleton

• distinct pattern of 1 proximal (arm) and 2 distal bones (forearm)

• pentadactyl hand

• thumb is rotated 90 degrees in relation to the hand

shoulder girdle

• clavicle (collar bone)

• scapula (shoulder blade)

clavicle

• less smooth on the inferior vie as there are ligaments and muscles that attach

• long bone

• provides the only upper limb articulation between the appendicular and axial skeletons

• projects underlying neurovasculature

key features of the clavicle

• sternal (one end to sternum) and acromial (one end to acromion) ends

• distinct S curvature

• roughened inferior surface

acromial end vs sternal end

acromial end is usually flatter (left), sternal end is more like a circle (right)

scapula

• large and flat, good for muscles to anchor onto (significant muscle attachment)

• flat bone

key features of the scapula

• bony ridge is called the spine of the scapula

• processes: acromion and coracoid

• acromion is on the top right of the posterior view, top left of lateral view

• coracoid is the other smaller bit that sticks out

• fossae for muscle attachment

• glenoid fossa

glenoid fossa

• flat surface for bone attachment, here the humerous attaches

• flat surface on lateral vie

clavicular joints

• sternoclavicular

  • acromioclavicular

sternoclavicular joint

• rolling your shoulders hile keeping your humerous still

• intra-articular disk

• from clavicle to first rib: costoclavicular ligament

• saddle joint: shrugging up and don to forwards and back is similar in ROM

• strong capsule

why does the sternoclavicular joint have to be strong?

• the only synovial joint that is connecting the appendicular skeleton to the axial skeleton

movement of the sternoclavicular joint

• elevation and depression

• pro- (shoulder pushing forards) and retraction (shoulders back, chest out)

acromioclavicular joint

• plane joint

• strong coracoclavicular ligament but weak capsule

• coracoclavicular ligament comes off the coracoid process and attaches to the inferior surface of the clavicle

  • acromioclavicular ligament is quite weak - injury often occurs here

neurovasculature near the clavicle

key features of the humerus

• head (1)

• neck - anatomical (2) and surgical (3)

• tubercles - greater (4) and lesser (5)

• bicipital/intertubecular groove (6)

• epicondyles - lateral (7) and medial (8)

• condyles - capitulum (9) and trochlea (10)

head

• smooth surface (1)

neck

• anatomical = clear demarcated line in beteen the smooth and rough surface on the head (2)

• surgical = here fractures normally happen (3)

tubercles

• greater (4)

• lesser (5)

• sites for attachments of muscles

• greater tubercule looks smaller but actually continues around the lateral aspect to the posterior aspect

bicipital/intertubecular groove

• 6

epicondyles

• lateral (7) and medial (8)

• muscle attachment

condyles

• capitulum (9): lateral forearm bone attachment

• trochlea (10): medial forearm bone attachment

glenohumeral joint

• triaxial

• ball and socket

• incongruent tissues - the articular surfaces don’t fit ell together

• large humeral head + shallow glenoid fossa

• loose joint capsule = unstable joint (loose bit toards the bottom extends hen you reach out to the side)

supportive features of the glenohumeral joint

• specialised fibrocartilage

• muscles

• ligaments

muslces of the glenohumeral joint

• rotator cuff (blend into the capsule)

• long head of biceps brachii

ligaments of the glenohumeral joint

• glenohumeral & coracohumeral (both blend into capsule)

fibrocartilage of the glenohumeral joint

• glenoid labrum

• extra rim - continues past the glenoid fossa to deepen the socket

ulna and radius

• ulna has a big divot here it connects to the trochlea

• radius has a disk at the top, allowing rotation

• long bones

• connected via interosseous membrane

articulations of the ulna and radius

• synovial joints ith humerous = flexion and extension

• x2 synovial joints ith each other, one at each end = rotation

• radius ith carpal bones (rist)

olecranon process

trochlear notch

tuberosities of the ulna and radius

radial notch

• for the radius to fit into on the ulna - head of the radius articulates here

ulnar notch

• here the ulna bone articulates on the radius

styloid process

• bony projections

elbo joint

• hinge joint

• strong collateral ligament support to prevent medial and lateral movements

• collateral = ligaments going don laterally

movement in the elbo joint

• the ulnar bone is the primary bony contact, only hen e get into flexion the radius has a bit more articulation

• humero-ulnar shares synovial cavity ith proximal radio-ulnar joint

proximal radioulnar joint

• pivot joint

• radial head —> radial notch on the ulna

• annular ligament encircles the radial head

distal radioulnar joints

• ulnar head —> ulnar notch on the radius

supernation

uncrosses the forearm bones, palm upards

pronation

crosses the forearm bones, palm donards

bone groups of the rist and hand

• metacarpals and phalanges are long bones

• carpals are short bones

sesamoid bone

• encapsulated by tendons, e.g. patella, there are also some in the fingers

radiocarpal joint

• ulna does not make a direct bony articulation, there is an articular disk in beteen

• joint is the articulation beteen the radius and the lunate and scaphoid

• condyloid

• ulnar and radial deviation = movement of the rist in the coronal plane toards either of the bones

• complex ligamentous support

scaphoid fractures

• scaphoid has a unique blood supply, fractures can lead to bony necrosis

• can occur from a fall on an outstretched hand (FOOSH)

joints of the hand

• 8 carpal bones and 5 metacarpal bones

• thumb is 1st digit, pinky is 5th

• intercarpal joints: here the carpals join ith each other, plane joints

• carpometacarpal joints

carpometacarpal joints

• 1st CMC joint - saddle joint

  • vital for the unique functions of the thumb and the most degenerative joint in the body

  • unique movement: opposition - moving to touch the thumb to the pad of the pinky finger, specific muscle associated ith this movement

• 2nd-5th - plane joints

interphalangeal joints

• only one on the first digit

• 2 each on the other digits (proximal and distal)

• 14 phalanges

• hinge joints

• commonly subluxated or dislocated

metacarpophalangeal joints

condyloid joints

axio-appendicular muscles

• includes the extrinsic back muscles

• serratus anterior

• pectoralis major (superficial, attaches to humerous) and minor (deeper, attaches to scapula)

scapulohumeral muscles

• rotator cuff muscles

• deltoid and teres major

rotator cuff muscles

• attach to the head of the humerus, to the greater and lesser tubercules, rapping around the glenohumeral joint for support

• supraspinatus (above the spine of the scapula)

• infraspinatus

• teres minor

• subscapularis

ho do the rotator cuff muscles relate to the joint capsule?

• they blend ith the joint capsule to compress the humeral head into the glenoid fossa

movements of the rotator cuff muscles

• abduction (supraspinatus)

• external rotation (infraspinatus and teres minor)

• internal rotation (subscapularis)

deltoid and teres major

• attach more distally on the humerus than the rotator cuff

anterior vie of the deltoid and teres major

deltoid

• triangle

• broad fan from humerus to the scapula and clavicle

  • produces shoulder flexion, abduction and extension

teres major

• larger than teres minor

• attaches more anteriorly to the humerus

• internal rotation at the shoulder

upper limb compartments and deep fascia

• muscles are separated into compartments largely by intermuscular septa

• deep fascia can be specialised

intermuscular septa

• commonalities beteen muscles ithin these compartments: share a nerve, collective movements

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specialised deep fascia

• interosseous membrane: in beteen bone

• retinacula: hold don tendons, creates pulley system

• aponeurosis: broad sheet of connective tissue

arm anterior compartment

• biceps brachii (long head and short head)

• coracobrachialis (connects to coracoid process)

• brachialis

• all cross over the anterior aspect of at least one joint and produce flexion

long head of biceps brachii

• tendon enters the glenohumeroid joint

hat muscle is responsible for supination?

• the biceps brachii as it attaches to the radius

brachialis

• just causes flexion and extension

arm posterior compartment

triceps brachii

triceps brachii

• all aspects of the triceps brachii cross over the posterior aspect of at least one joint (the elbo) to attach onto the olecranon process and produce extension

• if it crosses the back of the shoulder, it causes shoulder extension, if it crosses the back of the elbo, it causes elbo extension

forearm muscles - anterior compartment

• superficial, intermediate and deep

• the medial epicondyle of the humerus provides attachment for the superficial and intermediate muscle groups

• if the muscle attaches to the carpals/metacarpals = rist flexor

• attaches to digits = finger flexor

• distal attachment into radius = pronator

forearm muscles - posterior compartment

• musculature attaches to lateral epicondyle of the humerus

grip strength

• extensors allo rist flexors to be at a good length to contract (not too shortened)