BioMech Exam 2 Flashcards
Types of joints
bony joint, fibrous, cartilaginous, synovial
Bony joint
synarthrosis- an immovably fixed joint between bones connected by fibrous tissue
ex. metopic synostosis- premature fusing of the metopic suture have a triangular shape to the forehead. They have a noticeable ridge along their foreheads. Their eyes that appear too close together.
fibrous
synarthrosis
ex. suture- immovable joint
cartilaginous
slight mobility
amphiarthrosis- slightly movable joint
joints where bones are connected by cartilage, a flexible but tough connective tissue
Two types: Synchondrosis, Symphysis
ex. pubic symphysis- joins your left and right pelvic bones and holds it in place
Synchondrosis
primary cartilaginous joint that connects bones with hyaline cartilage. Synchondroses can be temporary or permanent.
Symphysis
secondary cartilaginous joint that connects bones with fibrocartilage. Symphyses are slightly moveable joints that allow for a small range of motion.
example is the pubic symphysis, where the pubic bones of the pelvis are joined together.
gomphosis
a fibrous mobile peg-and-socket joint.
ex. The roots of the teeth fit into their sockets in the mandible and maxilla
synovial
Joint in body that allow long range of motion
space between bones
fluid between bones
diarthrotic- a joint that is freely movable and allows for a wide range of motion. Diarthroses are also known as synovial joints, and are the most common and movable type of joint in the body.
ex. hinge, ball and socket, knee, hip, etc…
Joint positions
Close-packed and loose-packed
close packed joint position
maximum contact between surfaces
maximum compression possible
forces travel through joint as if it does not exist
ex. elbow
loose-packed joint position
all other joint positions
less contact area between surfaces
diarthrotic
a joint that is freely movable and allows for a wide range of motion.
Examples of diarthrotic joints
Head of humerus and scapula to make ball and socket joint (humeroscapular)
Humerus and Ulna to make hinge joint (humeroulnar)
Carpal and metacarpal to make saddle joint (carpometacarpal I)
Radius and Ulna to make pivot joint (radioulnar)
Carpal bones to make gliding joint (intercarpal)
Metacarpal bone and phalanx to make Condyloid joint (metacarpophalangeal)
Joint postitions
Close-packed position and Loose-packed position
Close-packed position
Position maximum contact between surfaces
maximum compression possible
Forces travel through joint as if it did not exist
Loose-packed position
All other joint positions
Less contact area between surfaces
Osteokinematics
Movement you can see
ex. flexion, extension
under voluntary control
passive range of motion (PROM)
Arthrokinematics
The movement of joint surfaces. Arthrokinematics differs from Osteokinematics - in general Osteokinematics means joint movement and Arthrokinematics joint surface motion.
Types of Arthrokinematic Motion
- Spin
- Distraction and traction
- Compression
- Roll
- Glide/slide
Spin
*Rotation of a movable joint surface on a fixed adjacent surface
*A single point on one joint rotates on a single point on another joint
surface
Roll
*Rolling of one joint surface on another
*Multiple points along one joint surface contact multiple points on
another joint surface
Glide/Slide
*Linear movement of a joint surface parallel to the plane of an adjoining
joint surface
*A single point on a joint surface contacts multiple points on another
joint surface
Roll- Slide dynamics
The Convex-Concave Rule
The Concave-Convex Rule
The Convex-Concave Rule
A convex joint surface will move on a fixed concave surface
in the opposite direction as the moving body segment
The Concave-Convex Rule
A concave joint surface will move on a fixed convex surface
in the same direction as the moving body segment
How to keep integrity of convex-concave joint?
joint subluxation or dislocation would result were a convex surface to roll on a fixed concave surface without gliding at the same time.
Roll and glide must occur simultaneously, and must occur in opposite
directions.
Connective tissue prevents rolling off plateau. Glide/slide allows joint to stay intact since connective tissue pulls it into opposite direction
How to keep integrity of concave-convex joint?
Joint surfaces would gap in some areas and impinge in others were a concave surface to roll on a fixed convex surface without gliding at the same time.
To preserve joint integrity, roll and glide must occur simultaneously, and in the same direction.
Open kinetic chain
distal segment is mobile
lower resistance
increased acceleration forces
increased distraction of the joint capsule
Closed kinetic chain
distal segment is fixed
higher resistance
lower acceleration forces
increased opposite compression of the joint capsule
Ex. Walking, standing. Resistance is body weight. Compression pushes joints together
What causes large range of motion of the shoulder complex?
multi-joint structure
poor bony structure
moderate ligamentous restraint
scapulohumeral cooperative action
Structures of shoulder
Clavicle
Shoulder girdle
Scapula
Glenoid fossa
Glenoid labrum
Clavicle
- “S”-shaped bone articulating with scapula and sternum
connects upper extremity to thorax
protects brachial plexus (network of nerves) and vascular structures
Serves as attachment site for shoulder and neck muscles (connect to the skull)
Shoulder girdle
- An incomplete bony ring in the upper extremity
Scapula
- Flat, triangular bone on the upper posterior thorax
Glenoid fossa
- “Socket” for shoulder joint
Glenoid labrum
- Ring of fibrocartilage around rim of glenoid fossa
- Deepens socket for shoulder joint
Joints of shoulder
Sternoclavicular joint
acromioclavicular joint
scapulothoracic joint
glenohumeral joint
Sternoclavicular joint motions
frontal plane= elevation and depression
sagittal plane= posterior rotation
horizontal plane= protraction and retraction. moving scapula
Joint is end of clavicle near the sternum
Where will clavicle fracture on sternoclavicular joint?
Middle of S-shaped curve
sternoclavicular joint dislocation?
pops forward or backwards and hits the blood vessels (subclavian veins and arteries)
anterior dislocation (forward) caused by hard blow to the shoulder from falling on an outstretched hand
posterior is when front of clavicle is hit and puts clavicle behind the sternum
scapulothoracic joint
serratus anterior attaches to outside of ribs and inserts on the inside of the scapula (medial border) Keeps scapula against back
Damage to muscle/nerve causes muscle to be paralyzed and scapula is winged
On scapula towards back
acromioclavicular joint
Between clavicle toward shoulder (lateral end) and acromion on scapula
acromion
bony process on scapula that develops separately and fuses with the scapula
Movement of acromioclavicular joint
frontal plane = upward and downward rotation of scapula. Big movement
horizontal plane (transverse) = small rocking left and right on a persons back
sagittal plane = forward (not much b/c ribs are there) and backward (lifts off a lil bit)
AC ligament
between acromion and clavicle
coracoclavicular ligament
Connects the clavicle to the coracoid process of the scapula.
trapezoid and conoid
Grades of AC damage
grade 1: AC/ligament sprain
grade 2: AC and coracoclavicular
grade 3: all of them
Glenohumeral joint
head of humerus and glenoid of scapula
Connective tissue is passive restraint. Neg pressure holds it together which provides stability
Labrum
cartilage that helps keep ball of joint in place
missing labrum parts would cause
The absence of anterior superior labrum would, in theory, concentrate forces in the superior labrum and the area of insertion of the biceps tendon, which could predispose the patient to a SLAP lesion and other intra-articular lesions.
However, some authors have suggested that its presence may create overload to the other structures of the shoulder that restrain movements such as the biceps tendon and rotator cuff. Its presence needs to be considered in athletes who present with repetitive shoulder pain that is attributed to rotator cuff lesions and SLAP lesions.
glenoid labrum
group of connective tissue that make glenoid deeper
Ways to check for dislocated shoulder
finger between process and head of humerus
More fingers = less intact the joint is
Have someone hold something and see if it falls
Coracohumeral ligament
from humerus to coracoid process
superior glenohumeral ligament
12 o’clock
like a tendon
Middle glenohumeral ligament
3 oclock fibers pan out, not as tight bundles
Less like a tendon
Inferior glenohumeral ligament
ligament structure anterior and posterior band with pouch in-between
Catches humerus when shoulder is dislocated
Posterior capsule
provides zero restraint
Holds nothing in place because glenoid does not sit, it tips forward
Back bony ridge of glenoid does the restraint
Allows capsule space to have negative pressure
Roles of muscle
Attach scapula to trunk
attach humerus to trunk
attach scapula to humerus
Rotator cuff muscles do this!
Trapezius
Helps attach scapula to trunk
Latissimus dorsi
Attaches humerus to trunk
Either moves the humerus or keep the scapula in place
Scapulohumeral rhythm
Coordination of scapular and humeral movements
enables much greater range of motion (ROM) of the shoulder
Happens at the expense of stability
Rotator cuff muscles
small muscle mass
deal with large external muscles (create unwanted shear)
provide joint compression, restraint in anterior, posterior and superior aspects
SITS muscles
The subscapularis
The infraspinatus
The teres minor
The supraspinatus
supraspinatus
Attaches from top of scapula to upper end of humerus
Rotate and lift your arm
subscapularis
attaches middle of scapula to lower part of humeral head
Hold arm outstretched
infraspinatus
bottom of scapula to humerus behind the supraspinatus
rotation of arm
Teres minor
Attaches to outside edge of scapula and attaches to humerus beneath infraspinatus
Turn and rotate arm
Layers of rotator cuff
- Outer most layer. Down toward joint capsule. Ligaments
- Tendons for larger muscles that will move the arm.
- Tendons for the rotator cuff and tendons for large muscles at 45 degrees
- Unknown layer. Structures in outermost layer blending into this layer
- Joint capsule
Regions of the spine
Cervical region, cervicothoracic junction, thoracic region, thoracolumbar junction, lumbar region, lumbosacral junction, sacrococcygeal region, sacrum, coccyx
Primary curves of spine
thoracic and sacral curves
Through development two more curves are added.
Secondary curves of spine
cervical curve, thoracic curve, lumbar curve, sacral curve
cervical curve develops as baby lifts head (3 months)
lumbar curve develops as baby stands up and bears weight (9 months) Forms because head is above pelvis
Weight bearing of the spine
It increases as you go down the spine from cervical to sacral regions
Cervical vertebrae
C1 = atlas (allows nodding movement)
C2 = axis (allows turning movement)
C1 atlas
Allows nodding movement
opisthion is posterior side (back of skull)
basion is anterior side (towards the front of skull)
Open mouth, atlas is straight back behind the throat
Foramen magnum
Opening in the base of the skull that connects the spinal chord to the brain
Ocular occipital angle
Head is tilted up
Anterior side is raised
Angle is about 20-30 degrees in humans
Children’s migraines
Children with not well developed axis has migraines from blood vessel issues
Fuses around 7 years of age
