Anatomical terms for direction
In studying anatomy , you need to understand directional terms. A phrase “the longissimus cervicis muscle is located posteriorly and ventral to the splenius muscle” simply means the longissimus cervicis is below the splenius muscle. These terms do not need to be memorized, but it’s a good idea to keep them handy.
Directional Terms
Distal – farther from trunk or center of body
Proximal – closer to trunk
Lateral – away from midline
Medial – closer to midline
Anterior – front side in/towards the front (caudal)
Posterior – back side in anatomical position anatomical position (ventral) (dorsal)
Superior – closer to head
Inferior – farther from head (cranial) (caudal)
Superficial – closer to surface
Deep – farther from surface
Palmar- palm/bottom of forefeet
Plantar – bottom of foot
Dorsal – top of foot /back
Body Planes
Sagittal — vertical plane that divides the body into RIGHT and LEFT parts
Frontal — vertical plane that divides the body into ANTERIOR and POSTERIOR parts
Transverse — horizontal planes that divides the body into CRANIAL and CAUDAL parts
Body Planes & Axes
Sagittal plane rotations occur about a medial-lateral (ML) axis
Frontal Plane rotations occur about an anterior-posterior (AP) axis
Transverse lane rotations occur about a longitudinal axis
Movement of joints
Sagittal Plane Joint Movements
Flexion = decrease angle between 2 segments
Extension = increase angle between 2 segments
Dorsiflexion = point toes up (towards shin)
Plantar flexion = point toes down
Frontal Plane Joint Movements
Elevation = move shoulder girdle superiorly
Depression = move shoulder girdle inferiorly
Valgus = “knock-kneed”
Varus = “bow-legged”
Transverse Plane Joint Movements
Abduction = move away from midline in transverse plane (also called horizontal extension) horizontal
Adduction = move towards midline in transverse plane (also called horizontal flexion)
Medial rotation = anterior surface rotates medially (also called inward or internal rotation)
Lateral rotation = anterior surface rotates laterally (also called outward or external rotation)
Supination = rotate palm up
Pronation = rotate palm down horizontal
Muscles, tendons, ligaments
Muscles attach to bones either directly or through tendinous attachments.
Ligaments attach bone to bone
Tendons attach muscle to bone or other structures such as the eyeball.
An easy way to remember this- The Achilles tendon attaches the gastrocnemius (calf muscle) to the calcaneus (heel bone). Ligaments hold bone to bone and provide stabilization.
Origin & Insertion
Origin: the place a muscle begins- it is usually located proximal or closer to the body, and functions as an anchor when the muscle contracts.
Insertion– the opposite end of the muscle and attaches to the movable part of the joint- usually more distal to the body. When the muscle contracts (shortens), the joint moves.
Action– the movement a muscle produces.
For instance, the muscle in the diagram to the left is the ulnaris lateralis This is the equine foreleg (human equivalent of the elbow) and the ulnaris lateralis flexes the lower leg. It originates on the lateral side of the humerus, and it inserts into the carpal bone and on the proximal side of the lateral splint bone (two lower arrows). This muscle flexes the carpus and extends the elbow.
HANDS ON: If you run your hand down a horse’s foreleg, the bony prominence felt just behind the knee is the accessory carpal bone.
