Musculoskeletal System Flashcards
What is a joint
-place where 2 or more bones make contact- articulation
- structural classification:
• fibrous: bones joined by dense fibrous connective tissue
• cartilaginous: bones joined by cartilage
• synovial: bones not directly joined (allows movement- limited by shape of synovial joint eg. Shoulder joint)
Joint functional classification
- synarthrosis: no movement eg. Sutures, synchondrosis, synostosis
- amphiarthrosis: little movement eg. Distal tibiofibular, pubic symphysis
- diarthrosis: free movement eg. Synovial joints
Synovial joint (true joints)
- articular surface+ cartilage
- articular capsule lined by synovial membrane
- articular space filled with synovial fluid (allows frictionless movement)
- ligament that strengthen the capsule
- muscle layers increase stability
- additional devices (bursae, menisci, labrum)
Continuous joints
- home ends linked by fibrous or cartilaginous tissue
Shapes of synovial joint
- pivot, hinge, plane: uniaxial eg atlantoaxial, elbow, AC
- condyloid, saddle: biaxial eg MCP, carpomeyacarpal
- ball and socket: multiaxial eg hip
Osteoarthritis
- common in older individuals
- more common in females
- usually affects weight bearing joints (knees,hips)
- stiffness and pain, reduced mobility
Increased risk: - overused
-prior injury. RA, gout - obesity
- family history
Muscle tissue
- skeletal= voluntary- MSK
- cardidiac= involuntary- heart
- smooth= involuntary- viscera, blood vessels, iris
Voluntary: contract under bodies control
Involuntary: contract without internal stimulation
Functions of the muscular system
- locomotion, stability, posture, protection, respiration ( skeletal muscle)
- circulation ( cardiac and smooth muscle)
- digestion, urination, childbirth, vision (smooth and skeletal muscle)
- temperature regulation ( smooth and skeletal)
Skeletal muscle
- consists of bundles of muscle fibres ( muscle cells)
- muscle fibres are grouped into muscle fascicles - group forming one or more heads or bellies
- usually connect to bone or other structures by tendon (round) or apineurosis (flat sheet)
- The range of a movement depends on the fibre length – muscles can contract by about 30% of their length
- The strength of the muscle depends on the number of fibres
Skeletal Muscle Classification
- flat muscles – parallel fires often with an apineurosis
- Pennate muscles – featherlike (Penna= feather, wing)
• unipennate, bipennate, multipennate - fusiform muscles- spinal shaped with a round, thick belly (or bellies) and tapered ends
- convergent muscles – arise from a broad area and converge to form a single tendon
- Quadrate muscles have four equal sides
- circular or sphincteral muscles- surround the body opening or orifice
Layers of the body- limbs
- feel fascia forms compartments surrounding muscles
Extrinsic and intrinsic back muscles
Extrinsic: act in structures outside of the back (appendicular skeleton)
- innervated by anterior rami of spinal nerves
Intrinsic: act in stuffier within the back
- innervated by dorsal rami of spinal nerves
Surface features of the dorsum (back)
- trapezius
- latissimus dorsi
- rhomboids
- levator scapulae
Posterior Axioappendicular Muscles
- superficial
•trapezius (1) and latissimus dorsi (2) - deep
• levator scapulae (3) and rhomboids (maj and min) (4)
Trapezius- attachments
Origins
- superior nuchal line
- nuchal ligament
- C7-T12 spinous processes
Insertion
- descending: later third of clavicle
- horizontal: acromion of the scapula
- ascending: spine of scapula
Trapezius actions: on shoulder girdle
Descending: keep shoulder girdle up, tilts the scapula for arm elevation
Horizontal and ascending: depress and pull scapular medially
Trapezius action on head and neck
Descending: with fixed shoulder, contra lateral rotation (unilateral action) or extension (bilateral action)
Trapezius action on vertebral column
- flattens the thoracic kyphosis
Nerve supply ( trapezius)
- cranial nerve XI accessory
Tilting of the scapula
- serratus anterior: forward pulling, tilting
- trapezius: elevation, depression, medial pulling, titling
Latissimus dorsi
Line of origin
- spinous processes t7- t12
-thoraco- lumbar apineurosis
- dorsal surface of sacrum
- dorsal 1/3 of the iliac crest
Additional origins
- 10th-12th ribs
- inferior angle of the scapula
Insertion
- humerus: floor of intertubercular sulcus
Latissimus dorsi action
On arm- adduction, internal (medial) rotation, extension
On trunk- elevation
On shoulder girdle
- depression, pulls the scapula medially
Nerve supply
- thoraco-dorsal nerve from brachial plexus
Rhomboids (major and minor)
Origin: Minor: spinous processes of C6-C7 + major: spinous processes of T1-T4
Insertion: medial margin of scapula, minor: root of scapular spine, major: below scapular spine
Action on shoulder girdle
- retract scapula, rotate glenoid inferiorly, fix scapula to trunk
Nerve supply
- dorsal scapular nerve from brachial plexus
Levator scapulae
Attachments
- vertebrae c1-c4 transverse processes
- scapula: superior angle
Action on shoulder girdle
- elevates scapula and rotates glen our inferiority
Action on vertebral column
- with fixed shoulder girdle it extends the neck
Nerve supply
- dorsal scapular nerve from brachial plexus
