Muscles and Joints (Extrinsic back) Flashcards
Define a joint:
The place where 2 or more bones make contact - articulation
What are the 3 structural classifications of joints? Give a breif overview and an example of each:
Fibrous - bones joined by dense connective tissue (e.g. sutures)
Cartilaginous - bones joined by cartilage (e.g. IVDs)
Synovial - bones that are not directly joined, allows movement (limited by shape of synovial joint) (e.g. shoulder joint)
What are the 3 functional classifications of joints? Give examples for each:
Synarthrosis - no movement (e.g. sutures, sunchondrosis, synostosis)
Amphiarthrosis - little movement (e.g. distal tibiofibular, pubic symphysis)
Diarthrosis - free movement (e.g. synovial joints)
What is a continuous joint?
A joint where the two bones are linked by fibrous or cartilaginous tissue
What is the structure of a synovial joint? (Draw it)
Articular surfaces, articular cartilage, articular space filled with synovial fluid, articular capsule lined by synovial membrane, ligaments strengthening the capsule, muscle to increase stability, other additional devices
What are the different shapes of synovial joints
Uniaxial:
- Pivot: rounded process of bone fits in bony ligamentous socket permitting rotation (e.g. atlanto-axial joint)
- Hinge: permits flexion and extension only (e.g. elbow joint)
- Plane: permits gliding or sliding movements (e.g. acromioclavicular joints)
Biaxial:
- Condyloid: permit flexion and extention, abduction and adduction and circumduction (e.g. metacarpophalangeal joint)
- Saddle: saddle- shaped heads permit movement in 2 different planes (e.g. carpometacarpal joint)
Multiaxial:
- Ball and socket: rounded head fits into concavity permitting movement on several axes (e.g. hip)
What are the 3 types of Muscle?
Skeletal, Cardiac, Smooth
Location of skeletal striated muscle?
Composes gross named muscles attached to skeleton and fascia of limbs, body wall and head/neck
Appearance of cells in skeletal striated muscle?
- Large, very long, unbranched, cylindrical fibres
- Transverse straiation
- Arranged in parallel bundles
- Multiple, peripherally located nuclei
Type of activity of skeletal striated muscle?
- Intermittent contraction above a baseline tonus
- Acts mainly to produce movement rhough shortening or controlled relaxation
Stimulation of skeletal muscle?
Voluntary or reflective by somatic nervous system
Location of cardiac muscle?
Heart and portions of adjacent great vessels
Appearance of cells in cardiac muscle?
- Branching and anastamosing shorter fibres
- Transverse striations running parallel and connected end to end by complex junctions
- Single central nucleus
Type of activity of cardiac muscle?
- Strong, quick, continous rythmic contractions
- Pumbs blood from heart
Stimulation of cardiac muscle
Involuntary
Intrinsically stimulated and propogated
Rate and strength of contraction modified by autonomic nervous system
Location of smooth muscle
Walls of hollow viscera and blood vessels, iris and ciliary body of the eye
Attached to hair follicles of skin
Appearance of cells in smooth muscle?
Single or agglomerated (gathered in clusters) cells
Small spindle shaped fibres without striations
Single central nucleus
Type of activity of smooth muscle?
- Weak, slow, rythmic or sustained contraction
- Mainly acts to propel substances (peristalsis, vascular pulsation) and to restrict flow (vasoconstrinction, sphincteric activity)
Stimulation of smooth muscle?
Involuntary by autonomic or enteric nervous systems
Functions of Muscular System
Skeletal muscle only: Locomotion, stablity, posture, protection, respiration
Combination of muscles: circulation, digestion, urination, childbirth, vision, temperature regulation
What does the range of movement and strength of a muscle depend on?
Range of movement dependent on fibre length (can contract to 30% of their length)
Strength of muscle depenent on number of fibres
List and describe the 6 muscle classifications:
Flat muscles: parallel fibres often with aponeurosis (e.g. external oblique)
Pennate muscles: feather-like, can have unipennate (e.g. extensor digitorum longus), bipennate (e.g. rectus femoris) and multipennate (e.g. deltoid)
Fusiform: spindle shaped with a round thick belly and tapered ends (e.g. biceps brachi)
Convergent: arise from a broad area and converge to form a single tendon (e.g. pectoralis major)
Quadrate: four equal sides (e.g. rectus abdominis)
Circular/ sphincteral muscles: surround a body opening or orifice (e.g. orbicularis occuli)
What type of muscle is the biceps brachii? Where does it originate and insert? What movement does it cause?
- Fusiform muscle with two heads
- Originates: long head at supraglenoid tubercle and short head at the coracoid process
- Inserts at the radial tuberosity
- Crosses sholder and elbow so can cause flexion at both joints (and supination of forearm)
What are the 4 layers of the body?
Skin (epidermis, dermis)
Subcutaneous tissue/ superficial fascia (adipose tissue)
Deep pascia - forms compartments surrouding muscles in the limbs
Muscle
Define the two catagories of back muscle and state the nerve group supplying them:
Extrinsic back muscles:
- act on structures outside the back (appendicular skeleton)
- innervated by anterior rami of spinal nerves
Intrinsic back muscles:
- act on structures within the back
- innervated by dorsal rami of spinal nerves
What are the 4 Posterior Axioappendicular Muscles? Divide them into 2 catagories:
Define: group of muscles arising from the axial skeleton which act upon the pectoral girdle (extrinsic back muscles)
Superficial:
- Trapezius
- Latissimus Dorsi
Deep:
- Levator Scapulae
- Rhomboids (major and minor)
What are the origins and insertions of the trapezius?
Origins:
- superior nuchal line
- nuchal ligament
- C7 to T12 spinous processes
Insertions:
- Descending: lateral third clavicle
- Horizontal: acromion of scapula
- Ascending: spine of scapula
What are the actions of the trapezius on the shoulder girdle, head/neck and vertebral column?
Action on shoulder girdle:
- Descending muscles keep shoulder girdle up and tilts scapula for arm elevation
- Horizontal and ascending muscles depress and pull scapula medially
Actions on head and neck:
- Descending muscles: with fixed shoulder lead to contralateral rotation (looking to side) or extension
Actions on vertebral column: flattens thoracic kyphosis
What is the nerve supply to the trapezius muscle?
Cranial nerve XI Accessory (+ cervical pl.)
What are the origins and insertions of the latissimus dorsi?
Origins:
- spinous processes T7-T12
- Thoraco-lumbar aponeurosis
- Dorsal surface of sacrum
- Dorsal 1/3 of the iliac crest
- 10th-12th rib
- Inferior angle of scapula (variable)
Insertions:
- Humerus: floor of intertubercular sulcus
Actions of the latissimus dorsi:
On arm:
- adduction
- internal (medial) rotation
- extension
On trunk:
- elevation (with arm fixed on a bar)
On shoulder girdle:
- depression
- Pulls scapula medially
Nerve supply of latissimus dorsi
Thoraco-dorsal nerve from brachial plexus
Origins and insertion of rhomboid major and minor:
Origins
- Minor: spinous processes C6-C7
- Major: spinous processes T1-T4
Insertions:
- Medial margin of scapula
-Minor: root of scapular spine
- Major: below scapular spine
Action of Rhomboids:
On shoulder Girdle:
- retract scapula
- rotate glenoid inferiorly
- Fix scapular to trunk
Nerve supply of rhomboids:
Dorsal scapular nerve from brachial plexus
Attachments of Levator scapulae
- Vertebrae C1-C4 transverse processes
- Scapula superior angle
Actions of levator scapulae
On shoulder girdle:
- elevates scapula and rotates glenoid inferiorly
On vertebral column:
- with fixed shoulder girdle it extends the neck
Nerve supply to levator scapulae
Dorsal scapular nerve from brachial plexus
