Veterinary Anatomy Chapter 6 Part 2

Questions and Answers

What is the primary function of the dig.superf muscle?

Flexion of the digits (correct)

Abduction of the digits

Extension of the digits

Adduction of the digits

The N.ulnaris nerve innervates the flexor carpi ulnaris muscle.

True

What structure is responsible for preventing excessive extension of the carpus and digits?

Suspensory apparatus of the fetlock

Which muscle is responsible for the extension of all the digits?

M.extensor digitorum communis Signup and view all the answers

The ____ muscle acts as a stabilizer for the shoulder joint.

supraspinous Signup and view all the answers

Match the following nerves to their corresponding muscle functions:

Suprascapular nerve = Shoulder stabilizer muscles Musculocutaneous nerve = Elbow flexors Radial nerve = Elbow extensors Median nerve = Carpal flexors Signup and view all the answers

The M.extensor carpi ulnaris is responsible for the extension of the carpus.

False Signup and view all the answers

What is the primary function of the M.flexor carpi radialis?

Flexion of the carpus Signup and view all the answers

The M.extensor digitorum lateralis extends the _____ digits.

lateral Signup and view all the answers

Match the following muscles with their respective origins:

M.extensor carpi radialis = Lateral epicondyle M.flexor carpi radialis = Medial epicondyle M.flexor digitorum superficialis = Medial epicondyle M.extensor digitorum communis = Lateral epicondyle Signup and view all the answers

Study Notes

Muscles of the Carpal and Digital Joints

Located on the antebrachium; involved in extension and flexion of the carpal and digital joints.
Extensors are found craniolaterally, while flexors are positioned caudomedially on the antebrachium.

Key Extensor Muscles

M.extensor carpi radialis
- Originates from the lateral epicondyle.
- Inserts on the proximal part of metacarpals II and III.
- Primarily responsible for carpal extension.
- Innervated by the radial nerve.
M.extensor digitorum communis
- Positioned laterally to the extensor carpi radialis.
- Extends all digits; inserts on P3 of all digits.
- Innervated by the radial nerve.
M.extensor digitorum lateralis
- Lateral to the extensor digitorum communis.
- Extends lateral digits; inserts on P1 of digits IV and V.
- Innervated by the radial nerve.
M.extensor carpi ulnaris
- Located caudal to the extensor digitorum lateralis.
- Insertion on the proximal end of metacarpal V or accessory carpal bone in other species.
- Functions in carpal flexion; innervated by the radial nerve.

Key Flexor Muscles

M.flexor carpi radialis
- Situated caudal to the radius.
- Flexes the carpus; inserts on the proximal part of metacarpals II and III.
- Innervated by the median nerve.
M.flexor digitorum superficialis
- Located caudally on the antebrachium.
- Covers other flexor muscles; inserts on P2 of digits II - V.
- Responsible for flexion of the digits; innervated by the ulnar nerve.
M.flexor digitorum profundus
- Deep to the flexor digitorum superficialis; consists of three parts.
- Inserts on P3 of all digits.
- Functions to flex the digits; innervated by the ulnar nerve.
M.flexor carpi ulnaris
- Originates from the medial epicondyle.
- Inserts on the accessory carpal bone.
- Primarily flexes the carpus; innervated by the ulnar nerve.

Short Muscles of the Digital Joints

Located in the metacarpal region; activate individual digits.
Mm.interossei
- Originates from the metacarpal bones and inserts on the proximal sesamoid bones.
- Innervated by the ulnar nerve.

Passive Stay Apparatus of the Horse

Enables horses to stand for extended periods by fixing joints.
Front limb supports 55-60% of body mass; reliance on extrinsic muscles like M.serratus ventralis.
Key structures preventing joint flexion include lacertus fibrosus and collateral ligaments, along with powerful M.triceps brachii.
Overextension is prevented through flexor tendons, accessory ligaments, and suspensory apparatus of fetlock and pedal joints (e.g., M.interosseus medius).

Summary of Muscles and Nerves

Shoulder Joint: Stabilized by infraspinous, supraspinous, and subscapular muscles; innervated by suprascapular and subscapular nerves.
Elbow Joint: Extensors innervated by the radial nerve; flexors innervated by the musculocutaneous nerve.
Carpus & Digits: Extensors found on craniolateral antebrachium (radial nerve) and flexors on caudomedial antebrachium (median & ulnar nerves).

Foot Pads

Composed of densely cornified epidermis, devoid of hair, and frequently contact the ground.

Description

Explore the detailed anatomy of the thoracic limb in this quiz, focusing on the muscles of the carpal and digital joints. Learn about the functions of extensor and flexor muscles located on the antebrachium, and their anatomical positioning. This knowledge is essential for students in veterinary science and anatomy.