MasseterThe cheek muscle. It closes the jaws for chewing.
BrachiocephalicusA long strap from the head to the arm. It draws the front leg forward.
SternocephalicusA narrow muscle from the breastbone to the lower jaw.
SpleniusA flat, triangular muscle on the upper side of the neck.
TrapeziusA thin triangle over the withers. Its neck part and chest part both end on the shoulder blade.
Serratus ventralisA fan-shaped muscle in a neck part and a chest part. The chest part has a saw edge.
DeltoideusA muscle from the shoulder blade to the upper arm. It flexes the shoulder joint.
Triceps brachiiThe large muscle between shoulder blade and elbow.
Pectoralis descendensA short, thick muscle from the breastbone to the arm. It draws the leg inward.
Extensor carpi radialisThe muscle on the front of the forearm. It straightens the knee.
Common digital extensorA slim forearm muscle. Its tendon runs down the front of the leg to the foot.
Back and hind leg 8
Latissimus dorsiA wide triangle from the back to the arm. It helps pull the body forward.
Longissimus dorsiThe long muscle of the back, from the hip to the neck.
Gluteus mediusA very large muscle of the croup. It straightens the hip.
Tensor fasciae lataeA triangle from the point of the hip toward the stifle. It flexes the hip.
Gluteus superficialisA small triangle behind the tensor. It flexes the hip.
Biceps femorisA large curved muscle from the croup to the stifle and leg.
SemitendinosusA long muscle down the back of the thigh. It straightens the hip and hock.
SemimembranosusThe muscle behind and inside the semitendinosus. It straightens the hip.
Lower leg: tendons and ligaments 6
Common digital extensor tendonThe tendon down the leg's front. It ends on the last bone of the foot.
Suspensory ligamentA thick band behind the cannon bone. It supports the fetlock.
Check ligamentA short band from the back of the knee. It joins the deep flexor tendon halfway down.
Deep digital flexor tendonThe tendon between the suspensory ligament and the outer tendon. It ends on the last bone of the foot.
Superficial digital flexor tendonThe tendon at the very back of the leg. It ends on the pastern.
Distal sesamoidean ligamentsShort ligaments from the sesamoid bones down to the pastern bones.
How this list was compiled: Every name checked on 2026-10-02 in two sources. S. Sisson, The Anatomy of the Domestic Animals (1914, public domain), the muscles of the horse and the ligaments and tendons of the digit, https://archive.org/details/anatomyofdomesti00siss. Wikipedia, Muscular system of the horse, Limbs of the horse and Stay apparatus, https://en.wikipedia.org/wiki/Muscular_system_of_the_horse. F. Gamucci and others, Animals 2022 (open access), for the English name descending pectoral, https://europepmc.org/article/PMC/PMC8944866. Licence: own work
The drawing: Drawn for this site on 2026-10-02 from plain geometry; nothing traced. Licence: own work
How it works
This horse muscle anatomy quiz covers the muscles that lie just under the skin on a horse's left side. It works as an equine muscle anatomy quiz in three views: front half, back half and lower leg.
Read the full guide
Front half and back half
Start at the masseter on the cheek. Straps run down the neck, a triangle sits over the withers, and the largest patch behind the shoulder ends at the elbow. On the back half, one long muscle follows the back, a wide triangle covers the chest, and the croup and thigh carry the big muscles that drive the horse forward.
Lower leg
The third view is the lower leg. From the knee down the drawing shows tendons and ligaments around pale bones. Show me the labels first writes every name on the drawing.
On the lower leg, count back from the bone: suspensory ligament, deep flexor tendon, superficial flexor tendon.
Questions and answers
Which muscle pulls a horse's front leg forward?
The brachiocephalicus. It is the long strap down the side of the neck, from the head to the upper arm, and it draws the front leg forward.
Which muscles straighten a horse's hip?
The gluteus medius on the croup, with the semitendinosus and semimembranosus down the back of the thigh. They straighten the hip joint as the hind leg pushes.
What does the suspensory ligament do in a horse?
It supports the fetlock. The ligament starts at the top of the cannon bone, runs down behind it and ends on the sesamoid bones, so the joint does not sink too far under the horse's weight.
What is the check ligament in a horse?
It is the accessory ligament of the deep digital flexor tendon: a short band from the back of the knee that joins that tendon about halfway down the cannon bone.