Is it Hock, Stifle, or Back Pain? How to Tell the Difference

Hind limb lameness in horses is frequently attributed to the hock, stifle, or back, and distinguishing between these regions can be challenging even for experienced professionals. These areas are biomechanically linked, meaning pain in one structure often alters movement elsewhere, leading to overlapping clinical signs.

For horse owners, this overlap can make it difficult to determine whether a horse’s resistance, stiffness, or performance decline is due to joint pain, muscular discomfort, or compensatory movement patterns. Understanding the anatomy, function, and typical clinical signs of each region can help guide appropriate veterinary evaluation and avoid misinterpretation of symptoms.

Anatomical Overview: How These Regions Differ

The Hock (Tarsus)

The hock is a complex joint system located in the lower hind limb, composed of six small bones and four joints. Its primary function is to:

• Transmit force from the hindquarters

• Provide propulsion

• Absorb repetitive impact during movement

Most hock motion occurs in the upper joint, while the lower joints move very little and primarily absorb stress.

Study the hock with: Tarsus Flashcards

The Stifle

The stifle is the largest joint in the horse’s body and is anatomically comparable to the human knee. It is formed by:

• The femur

• Tibia

• Patella

• Multiple ligaments and menisci

The stifle plays a major role in:

• Weight bearing

• Limb stabilization

• Initiating forward motion

Unlike the hock, the stifle relies heavily on soft tissue structures, making it prone to ligament and meniscal injury.

Study the Stifle with: Equine Joint Anatomy Flashcards

Interactive Horse Skeleton Map

Bones of The Horse Flashcards

The Back (Thoracolumbar and Lumbosacral Region)

The equine back includes:

• The thoracic and lumbar spine

• The lumbosacral joint

• Associated muscles and ligaments

Rather than producing propulsion, the back functions to:

• Transfer force from the hind limbs to the forehand

• Stabilize the rider’s weight

• Allow controlled flexibility

Back pain often reflects muscle dysfunction, joint restriction, or altered biomechanics, rather than a single focal injury.

Study the equine back with: Equine Vertebrae Infographic Poster

Interactive Horse Skeleton Map

Bones of The Horse Flashcards 

How Pain in Each Region Typically Presents

Hock Pain: Common Characteristics

Hock pain most often develops gradually and is frequently bilateral, which can mask obvious lameness.

Typical signs include:

• Shortened hind limb stride

• Reduced push-off power

• Stiffness, especially when starting work

• Difficulty with collection or engagement

• Resistance to transitions

Hock pain often appears as a performance problem rather than overt lameness, particularly in early stages.

Stifle Pain: Common Characteristics

Stifle pain more often produces visible gait abnormalities, though subtle cases do occur.

Common signs include:

• Inconsistent hind limb lameness

• Toe dragging or stumbling

• Difficulty picking up or maintaining a lead

• Problems backing up

• Episodes of sudden worsening, especially with ligament involvement

Stifle issues may appear  and can worsen on circles or uneven footing.

Back Pain: Common Characteristics

Back pain frequently presents as behavioral or rideability issues, rather than classic lameness.

Common signs include:

• Resistance to saddling or mounting

• Hollowing or bracing through the topline

• Reluctance to bend or move laterally

• Bucking, rearing, or tail swishing under saddle

• Poor tolerance of rider weight

Back pain may exist without visible lameness on the ground.

Key Differences in Gait and Posture

Hock Pain

• Reduced impulsion

• Stiff, mechanical movement

• Difficulty engaging hindquarters

• Often worse with collected work

Stifle Pain

• Inconsistent stride length

• Catching or locking sensation

• Dragging of the toe

• Difficulty stabilizing the limb

Back Pain

• Shortened stride behind without clear asymmetry

• Reluctance to step under the body

• Altered posture under saddle

• Increased tension through the topline

Why These Conditions Are Commonly Confused

Several factors contribute to diagnostic confusion:

• The reciprocal apparatus mechanically links the stifle and hock

• Pain in one region alters loading in another

• Horses often develop compensatory movement patterns

• Bilateral disease reduces obvious asymmetry

• Behavioral signs may overshadow physical ones

As a result, a horse with hock pain may appear to have back pain, and a horse with stifle pain may be misdiagnosed as having hock arthritis.

Diagnostic Challenges and Veterinary Evaluation

Accurately identifying the source of hind limb discomfort typically requires:

• Careful gait evaluation

• Targeted flexion tests

• Diagnostic nerve or joint blocks

• Imaging such as radiographs or ultrasound

No single sign is diagnostic on its own. Localization often depends on systematic exclusion of potential pain sources.

Summary Comparison Table

Feature	Hock Pain	Stifle Pain	Back Pain
Onset	Gradual	Variable	Often gradual
Laterality	Often bilateral	Often unilateral	Often bilateral
Visible lameness	Subtle	More obvious	Often absent
Performance issues	Very common	Common	Very common
Behavior under saddle	Mild–moderate	Variable	Common
Swelling	Sometimes	Rare	No

Key Takeaways

• Hock, stifle, and back pain can look very similar on the surface.

• Performance decline is often the earliest sign of hind limb pain.

• Back pain frequently reflects underlying limb issues.

• Accurate diagnosis requires veterinary assessment and imaging.

• Early evaluation improves long-term outcomes and management options.