Functional Anatomy 1 - Lecture 1b

Anatomical Position

The standard position of the body used as a reference point in anatomy; the individual stands upright, facing forward, with arms at the sides and palms facing forward.

frontal (coronal) plane

An anatomical plane that divides the body into anterior and posterior sections

Sagittal Plane

Divides the body into left and right sections, can be anywhere on the body

transverse (axial) plane

Divides the body superiorly and inferiorly

Median sagittal plane

sagittal plane always midline

Anteroposterior (AP) axis

axis of the frontal plane

Mediolateral (ML) axis

axis of the sagittal plane

Vertical axis

axis of the transverse plane

superficial

nearer to surface

intermediate

between a superficial and a deep structure

deep

farther from surface

medial

nearer to median plane

lateral

farther from median plane

posterior (dorsal)

nearer to back

superior (cranial)

nearer to head

anterior (ventral)

nearer to front

distal

farther from trunk or point of origin (ex: of a limb)

proximal

nearer to trunk or point of origin (ex: of a limb)

plantar

inferior foot surface (sole)

dorsal

superior foot surface (dorsum)

palmar

anterior hand (palm)

dorsal (hand)

posterior hand (dorsum)

inferior (caudal)

nearer to feet

bilateral

both sides of the body

unilateral

one side of the body

ipsilateral

towards same side of reference structure

contralateral

away from/opposite side of reference structure

flexion/extension

movement in the sagittal plane rotating around a medial/lateral axis

abduction/adduction

movement in the frontal plane rotating around the AP axis

abduction

moving away from midline

adduction

moving toward midline

internal/external rotation

movement in the transverse plane rotating around a superior/inferior (longitudinal) axis

sagittal plane joint motions

a. flexion and extension of upper limb at shoulder joint and lower limb at hip joint

b. flexion and extension of forearm at elbow joint and of leg at knee joint

c. flexion and extension of vertebral column at intervertebral joints

d. flexion and extension of hand at wrist joint

e. dorsiflexion and plantarflexion of foot at ankle joint

frontal plane joint motions

abduction

adduction

lateral bending

transverse plane joint motions

rotation of the head, neck, lower limb

lateral and medial rotation

circumduction

a combination of flexion, extension, abduction, adduction

ipsilateral rotation

ex: muscle on right side rotating to right

contralateral rotation

ex: muscle on left rotating to the right

supination

forearm rotates palm upward

pronation

forearm turns palm of hand downwards

eversion of foot

turns sole outward, away from midline

inversion of foot

turns sole of food inward, toward the midline

opposition

brings pad of thumb into direct contact with pads of other fingers on same hand, essential for fine motor skills

reposition

returns thumb back to neutral, resting anatomical position

thumb movements

Axial Skeleton

skull, vertebrae, ribs

Appendicular Skeleton

clavicle, scapula, pelvis, upper extremities, lower extremities

fibrous joints

• bones united by fibrous tissue

• variable amount of movement within different types

• no joint capsule

  • direct connection between bones via fibrous tissue

• examples: sutures, gomphosis (tooth), syndesmosis (radioulnar)

suture

the apposed bony surfaces are united by fibrous tissue, permitting no movement, fibrous joint

ex: coronal

gomphosis

teeth, no movement, fibrous joint

syndesmosis

partially moveable, bones connected by interosseous membrane, fibrous joint

cartilaginous joints

bones are united by hyaline cartilage or fibrocartilage

no joint cavity or joint capsule, direct connection via tissue

2 types: synchondrosis, symphyses

hyaline cartilage

firm, lots of collagen, same cartilate that makes articular cartilage

fibrocartilage

flexible yet tough

synchondrosis

primary, hyaline cartilage, not to be confused with synarthroses

ex: head of femur

hyaline cartilage unites bone

growth plate - epiphyseal plate

• permit growth of the bone, convert to solid bone after puberty

• used to assess boney maturity

costochondral joints

• between the anterior end of rib and costal cartilage

symphysis

secondary, fibrocartilage

ex: intervertebral disc

fibrocartilage unites bone

slightly movable joints that provide strength with flexibility

intervertebral discs or pubic symphysis

synovial joints

most common joint type in body

diarthroses - allow most motion

joint capsule

• fibrous outer layer blends with periosteum, synovial membrane

joint cavity

• synovial fluid secreted by synovial membrane

articular (hyaline) cartilage

• covers articulating surfaces of the bone

reinforced with ligaments

diarthroses

allow most motion

synovial fluid

a viscous fluid

• nourishes cartilage

• lubricates joint surface

reinforcing ligaments

often are thickened parts of the fibrous capsule

connect bone to bone

some are intracapsular ligaments - located internal to the joint capsule

• ACL, PCL

some are extracapsular ligaments - located outside the joint capsule

• LCL, MCL

synovial joints are richly supplied with sensory nerves

in fibrous capsule and ligaments

proprioception

detect pain

monitor stretching of the capsule

synovial joints have a rich blood supply

• synovial membrane and ligaments (not the cartilage)

• extensive capillary beds produce basis of synovial fluid

some synovial joints contain an articular disc

• temporomandibular joint, wrist, and knee joint

• joints whose articulating bones have different shapes

• help to increase joint congruency

plane (gliding) joint

• articular surfaces are flat planes

• small gliding movements

  • intertarsal and intercarpal joints

  • scapulothoracic joint

  • movements are non-axial

  • gliding does not involve rotation around any axis

• joints of hand, wrist, foot

hinge joint

• cylindrical (convex) end of one bone fits into a trough (concave surface) on another bone

• angular movement in one plane

• elbow, ankle, knee, interphalangeal

• movement is uniaxial (only flexion/extension)

  • strong lateral ligaments, bony structure

pivot joints

• classified as uniaxial - rotating bone only turns around its long axis (only rotation)

• examples

  • joint between atlas and axis (atlanto-axial joint)

  • proximal radioulnar joint

  • pronation and supination of forearm

condyloid joint

• biaxial: movement occurs around 2 axes

  • wrist joint (radio/ulnar articulation with carpals)

  • MCP

  • MTP

• one bone is concave, one is convex

• allows

  • abduction/adduction (frontal plane)

  • flexion/extension (sagittal plane)

  • no rotation

• similar to, but more restrictive than ball in socket joint

saddle joint

• each articular surface has concave and convex surfaces

• biaxial joints

• allows flexion, extension, adduction, abduction, circumduction

• no axial rotation

• 1st carpometacarpal joint

  • allows opposition of the thumb

ball-and-socket joints

• spherical head of one bone fits into round socket of another

• classified as multiaxial

  • shoulder and hip

  • sacrifice stability for mobility

factors influencing stability of synovial joints

• articular surfaces

  • shapes of articulating surfaces determine movements possible

• ligaments

  • the more ligaments, usually stronger and more stable

  • what joint relies heavily on ligaments for support/function? knee and shoulder

• muscle tone

  • helps stabilize joints by keeping tension on tendons

mobile

the more stable a joint, the less ____ it is

stable

the more mobile a joint, the less ____ it is

sheath

tendinous movement over joint

bursa

between bone and muscle, skin, tendons, or ligaments

fat pad

between joint/bone and tendons

articular disc, labrum

improve joint congruency, help shock absorption

osteokinematics

movements are described by the actual direction that the bones move and the axis about which they move

• flexion of the forearm in the sagittal plane around the medial/lateral axis of the elbow

arthrokinematics

the movement of the joint may be different than the motion of the axial bones

• relationship of the movement between the two joint surfaces

• ex: roll, glide, slide