Muscle / Ligament

Origin / where the muscle starts

Insertion point; where the muscle starts

Action

Comment

Massester; cheek muscle

Opens and closes the jaw. Allows chewing.

Brachiocephalicus Wide strap like muscle

Base of the skull behind the jaw

Below the point of shoulder to the humerus

Moves the head from side to side, pulls the scapula forward, raises it in collection, swings the foreleg forward.

Well developed for good movement. Too strong a rein contact stops free forward movement.

Sternocephalic

Jowl

Sternum

Moves the head and neck.

Over developed in ewe or bull necked horses, difficult to get into a relaxed shape.

Rhomboideus

Nuchal ligament

Scapula

Lifts shoulder and the forehand. Pulls the scapula forward.

Splenius

Behind the poll

Beginning of the Trapezius

Turns and extends the neck.

Makes up the top line if well developed.

Trapezius; flat sheet like muscle.

Occipital bone

Spines of the 7th cervical and all the Thoracic vertebrae

Lifts shoulder and forehand

If this is well developed the horse is working in a good outline.

Nuchal ligament

Poll

Withers

Helps muscles in the neck support the head

Deltoid

Scapula

Humerus

Flexes shoulder joint

If over developed it wil load the shoulder

Supraspinatus

Below the Trapezius

Point of shoulder

Maintains the shoulder in extension

Latissimus dorsi

Lower Thoracic vertebrae

Back of the humerus

Flexes the shoulder and pulls the foreleg back.

Triceps

Flexes the shoulder and extends the elbow

Biceps

Flexes the elbow and extends the shoulder

Pectoral

Helps pull the foreleg foreward.

Triceps Brachii

Extends the elbow joint

Biceps Brachii

Flexes the elbow joint

Extensor Carpus

Extend the knee

Flexor Carpus

Flexes the knee

Digital Extensor

Extends the toe and knee

Digital flexor

Flexes the toe and knee and extend the elbow.

Muscle or ligament

Origin; where it starts

Insertion point; where it finishes

Action

Comment

Spinalis Dorsi

Beneath thoracic part of Trapezius

4th cervical vertebrae

Lumbar muscles or Longissimus dorsi

Ilium

Vertebrae along the sine and the last 4 cervical vertebrae

Extends the spine and raises and supports the head, neck . Main muscle used in rearing, kicking, jumping and aids turning

Longest and strongest muscle, rider sits on them

Intercostal muscles

Spaces between ribs

Aids breathing

External and internal abodominal oblique

Attach to ribs and pelvic bones

Supports the internal organs

Supraspinous ligament

Poll

Sacrum

Supports head and neck, traction force aids support in weak thoracic lumbar area.

Spreads out, attaching to spines of the cervical vertebrae, Called nuchal ligament in the withers and neck area.

Muscle or ligament

Origin; where it starts

Insertion point; where it finnishes

Action

Comment

Superficial gluteal

Croup

Bottom of the hip attached to the sacrum

Flex and extend the hip, pulls hindleg toward the body, used for rearing, galloping and kicking

More developed in a dressage horse.

Biceps femoris

Behind gluteals

Bottom of the high attached to the patella and tibia

Maintains hip joint in extension

Main muscles over the hindquarters, part of the hamstring group, well developed in eventers, race horses.

Semitendinosis

Behind biceps femoris

Back of the hindquarters

Extends the hip and hock joints

Part of the hamstring group, well developed in eventers and race horses.

Semi membranosus

Part of hamstring group, well developed in race horses /eventers.

Gastrocnemius

Rear of the femur

Point of hock

Maintains hip extension

Peroneus tertius

Femur

Cannon bone

With superficial digital muscle moves the stifle and hock.

Achillies tendon

Gastrocnemius

Over point of hock

Sacrosciatic ligament

Sacrum and coccygeal vertebrae

Pelvic bone