PED101: 2011

Anatomical Directions

The anatomical position

Important things to note:

1.Standing

2.Feet together

3.Arms to side

4.Head, eyes and palms facing

In order to explain the positioning of bones, organs, muscles and the like on the human body, anatomists have agreed on a standardised position for the human body in all cases. This is known as the anatomical position.

Lateral vs Medial

LateralLateral

MedialMedial

Lateral: Further away from the midline of the body. E.g. Little toe is on the lateral aspect of the foot.

Medial: Nearer the midline of the body. E.g. The big toes is on the medial aspect of the foot.

Superior vs InferiorSuperior

Inferior

Superior: Above or on top of. Towards the top of the body (head). E.g. The cervical vertebrae are superior to the thoracic vertebrae.

Inferior: Below or beneath. Towards the bottom of the body (feet). E.g. Thoracic vertebrae are inferior to the cervical vertebrae.

Proximal vs Distal

DistalProximal

Distal: Further away from the body – usually refers to limbs. Towards the end of the limb. E.g. Wrist is distal to the elbow.

Proximal: Nearer the body – usually refers to limbs. Closer to the top of the limb. E.g. Elbow is proximal to the wrist joint.

Anterior

Anterior: On the front of the body or limb. E.g. The chest is on the anterior of the body.

Posterior

Posterior: On the back of the body or limb. E.g. The buttocks are on the posterior of the body.

The skeleton is divided into two sections:

• Axial skeleton – consists of the central core of the body (head, ribs, spine & sternum)

• Appendicular skeleton – encompasses all of the bones in the limbs (arms/legs, hands/feet, pelvis, scapula & clavicle)

• There are 206 bones in the human adult body

• At birth, a human has over 300 bones but they fuse together as they develop through a process called ossification.

• Adult human bones account for 14% of the body's total weight.

• Your thigh bone (femur) is stronger than concrete.

Cranium

Mandible

Ribs

Clavicle

Sternum

Radius

Ulna

Femur

Tibia

TarsalsMetatarsals

Fibula

Patella

Phalanges

MetacarpalsCarpals

Pelvis

Vertebrae

Humerus

Scapula

Phalanges

The Joints

Flexion

Bending or decreasing the angle between two joints. E.g. Arm bending at the elbow.

Flexion - Sequence of events

Extension

• Straightening or increasing the angle between two joints. E.g. Hip – moving the leg backward. Knee – straightening the knee.

Inversion vs Eversion

Inversion: Movement of the sole of the foot inward.

Eversion: Movement of the sole of the foot outward.

Dorsiflexion vs Plantarflexion

Dorsiflexion: Movement of the top of the foot upward, closer to the shin.

Plantarflexion: Movement of the sole of the foot downward.

Abduction vs Adduction

Abduction: Moving a limb or part of a limb away from the midline of the body. E.g. Moving limbs outwards on a star jump.

Remember: Aliens abduct people by taking them away.

Adduction: Moving a limb or part of a limb towards the midline of the body. E.g. bring limbs back together in a star jump.

Remember: ‘Add’ to the midline

Circumduction

A combination of flexion, extension, abduction and adduction. E.g the armstroke in butterfly.

Rotation

Twisting of a limb about its long axis.

Pronation vs Supination

Pronation: Movement of the hand into a palm down position. E.g. Turning a card face down.

Supination: Movement of the hand into a palm-up position. E.g. Turning a card over in cards.

Medial and Lateral Rotation

Movements

Joint

Ligaments

Types of Joints

Types of Joints

Types of Joints

Anatomy of the Knee

Knee Joint

http://www.arthroscopy.com/sp05001.htm

Knee Joint

http://www.arthroscopy.com/sp05001.htm

Cross-Sectional View of Right Knee

http://www.arthroscopy.com/sp05001.htm

Anatomy of the Shoulder

Hip Joint

Muscles

Muscle types

There are three main types of muscles in the body. They are:

1.Skeletal (striated)

2.Smooth

3.Cardiac

Skeletal Muscle

Seen from under the microscope, skeletal muscle fibers show a pattern of cross banding, which gives rise to the other name: striated muscle.

Skeletal (striated) muscles move your bones. These are the muscles that we can see and feel. Skeletal muscles attach to the bones through tendons. They come in pairs -- one muscle to move the bone in one direction and another to move it back the other way. Skeletal muscles are voluntary muscles. Meaning, that you think about contracting them and your nervous system tells them to do so. Skeletal muscles can perform two types of contractions: short single contractions (twitch) and long, sustained contraction (tetanus).

Smooth Muscle

Smooth muscles are found in the internal organs (digestive system, blood vessels, bladder, airways and, the uterus). Smooth muscle has the ability to stretch and maintain tension for long periods of time. Smooth muscles move involuntarily. You do not have to think about movement for movement to occur.

Cardiac Muscle

Cardiac muscle is found only in your heart. Cardiac muscle is also an involuntary muscle. It can stretch in a limited way, like smooth muscle, and contract with the force of a skeletal muscle. Cardiac muscle is a twitch muscle.

Skeletal, Smooth & Cardiac Muscles

Skeletal

Smooth

Cardiac

Our muscles

Trapezius

Deltoid

Pectoralis MajorTriceps

BicepsLatissimus Dorsi

Gluteus MaximusAbdominals

Hamstrings

Quadriceps

GastrocnemiusTibialis anterior

Soleus

Iliopsoas

How muscles work

Muscle create movement by pulling on bones. They are attached to bones via tough cords called tendons and most muscles reach from one bone to another across a joint.

But..Muscles can only pull, and not push so they need

to work in pairs. While one muscle works (pulls) the other relaxes to allow the movement. When it’s time to move in the other direction, they switch jobs. The muscle that is pulling is called the agonist, and the muscle that is relaxing is called the antagonist.

(Pulling)

(Relaxing)