Horse Anatomy: The Lower Legs

Lower leg anatomy is critical for understanding horse biomechanics and injuries.

Spine of Scapula: Important for muscle attachment and forelimb movement.
Carpal Bones: Comprise the wrist area, include multiple carpal bones.
Scapular Cartilage: Crucial for flexibility and movement of shoulder joint.
Scapula: Shoulder blade, connecting forelimb to the trunk.
Knee: Joint connecting the lower leg to the upper leg.
Splint Bones: Second (medial) and fourth (lateral) metacarpals, provide support to the limb.
Olecranon: Bony prominence of the ulna contributing to elbow joint structure.
Uina: A bone in the forearm leading to the carpal bones.
Radius: Main bone of the forearm that connects to the carpal bones.
Accessory Carpal: A small bone contributing to the carpus.
Cannon Bone: Dominant bone of the lower leg, known as the third metacarpal.
Pastern Bones: Group includes long pastern (first phalanx), middle pastern (second phalanx), and short pastern (third phalanx).
Coffin Bone: Also known as the distal phalanx.
Navicular Bone: Positioned near the coffin bone; important for joint function.

Proximal Sesamoids: Pair of sesamoid bones located at the fetlock joint.
Fetlock Joint: Joint between the cannon bone and proximal phalanx.
Pastern Joint: Joint connecting the long pastern to the short pastern.
Coffin Joint: Joint between the short pastern bone and coffin bone.
Distal Sesamoid: Often hidden from view due to the distal phalanx, important for joint mechanics.

Recognize the accessory carpal bone and rows of carpal bones in various views:
- Lateral View Left Carpus: Displays anatomical arrangement of carpal bones including the radial, intermediate, third, second, and ulnar carpals.
- Medial View Left Carpus: Similar to lateral, but from the medial perspective, essential for understanding carpals and metacarpals arrangement.

Long Head of Triceps Brachii: Participates in extension of the foreleg.
Lateral Head of Triceps Brachii: Contributes to extension; partially cut in diagrams for visibility.
Brachialis: Aids in elbow flexion.
Biceps Brachii: Important for flexion of the forearm.
Pectoralis Brachii Descendens: Contributes to forelimb movement.

Anconeus: A small muscle involved in elbow extension.
Ulnar Head: Part of the triceps, also extends the forelimb.
Deep Digital Flexor: One of the primary flexors, has three heads of origin.
Flexor Carpi Radialis: Flexes the carpus, originates from the humerus.
Extensor Carpi Radialis Lateralis: Extends the carpus, attached to the lateral side.
Common Digital Extensor: Extends digits and carpus; originates from the humerus.
Extensor Retinaculum: Connective tissue that holds tendons in place.

Extensor Carpi Radialis: Attaches humerus to metacarpus; crucial for carpal extension.
Common Digital Extensor Muscle/Tendon: Extends from humerus down to coffin bone; aids multiple joints (elbow, knee, fetlock, pastern, coffin).
Lateral Digital Extensor Tendon: Works with common digital extensor; extends digits and carpus.

Flexor Carpi Ulnaris: Inserts onto accessory carpal bone, responsible for carpal flexion.
Ulnaris Lateralis: Flexes carpus; originates on the lateral humerus and attaches to accessory carpal bone.
Superficial Digital Flexor Muscle/Tendon: Flexes carpus, fetlock, and pastern joints; runs down back of leg.
Deep Digital Flexor Muscle/Tendon: Multiple origins (humeral, ulnar, radial); attaches to coffin bone and is responsible for flexion of fetlock, pastern, and coffin joints.

Carpal Arthrosis: A degenerative joint condition affecting the carpus, characterized by pain and reduced mobility.
Muscle Dynamics: Discusses which muscles counteract body weight and gravity to prevent carpal arthrosis.
Fatigue Factor: Explores the role of fatigue in exacerbating carpal arthrosis.
At-Risk Horse Types: Identifies types of horses more susceptible to carpal arthrosis based on usage, conformation, and training.

Suspensory Ligament: Provides support to the fetlock joint, originating at the back of the cannon bone, it branches to surround the fetlock joint, attaching to the coffin bone.
Distal Check Ligament: Connects to the deep digital flexor tendon to provide stability.
Proximal Check Ligament: Supports the superficial digital flexor tendon, attaching above the carpus.

Describes the arrangement of extensor branches of suspensory ligaments and digital flexor tendons.
Key Structures:
- Short Pastern: Second phalanx.
- Coffin Bone: Third phalanx, main structural support of hoof.
- Long Pastern: First phalanx.

Common Digital Extensor Tendon: Contributes to extension and stabilization of lower limbs.
Distal Sesamoidean Ligaments: Provide critical support to the fetlock joint.
Navicular Bursa and Bone: Important for cushioning and functioning of the deep digital flexor tendon.

Hoof Components:
- Coffin Bone: Central structural component of the hoof, also known as third phalanx.
- Hoof Wall: The exterior of the hoof that protects internal structures.
- Digital Cushion: Shock-absorbing structure beneath the frog.
The hoof wall is made of horn-like tissue, attaching to the coffin bone via laminae structures.
- Sensitive Laminae: Softer structure allowing nutrient exchange, crucial for hoof health.
- Insensitive Laminae: Harder structure supporting the hoof wall.

Bone/Joint Injuries include:
- Carpal arthrosis
- Sesamoid bone injuries
- Condylar fractures
- Buck shins
- Ringbone/side bone
- Coffin bone fractures
- Splints
- OCD lesions
Soft Tissue Injuries include:
- Bowed tendon
- Deep digital flexor tendon injury
- Suspensory ligament injury
- Impar ligament injury
- Check ligament injury

Task: Research a famous horse with an injury. Create a PowerPoint slide detailing:
- Horse’s name
- Reason for fame
- Details of the injury (how it occurred, recovery process).
Submission: Due on February 6, 2026, at 8:00 am, in the ELC assignment folder.