Joints of the Forelimb PDF

Joints of the forelimb  Forelimb articulations No true articulations with the body Limb is attached to body by muscles - synsarcosis These muscles referred to as the extrinsic muscles of the forelimb – Superficial pectoral – Deep pectoral –...

Joints of the forelimb  Forelimb articulations No true articulations with the body Limb is attached to body by muscles - synsarcosis These muscles referred to as the extrinsic muscles of the forelimb – Superficial pectoral – Deep pectoral – Brachiocephalicus – Omotransversarius – Trapezius – Rhomboideus – Latissmus dorsi – Serratus ventralis  Joints of the forelimb A. Shoulder joint B. Elbow joint C. Carpal articulations D. Metacarpo- phalangeal articulations E. Proximophalageal articulations F. Distalphalangeal articulations Horse Ox  Shoulder Joint Ball and socket type – Glenoid cavity and humerus head Head of the humerus is more extensive than the glenoid cavity Loose joint capsule Gleno-humeral ligaments – Attaches the supraglenoid tubercle to the tuberosities of the humerus Collateral ligaments absent – Compensated by tendons of subscapular (medial) and infraspinatus (lateral)  Shoulder joint Muscles that are attached around the joint act as ligaments – Supraspinatus – Infraspinatus – Subscapularis – Biceps brachii Transverse humoral ligament All movements possible but chiefly flexion and extension Due to these muscles and the head of the humerus is twice larger, so the clinical luxation or dislocation is rare Shoulder joint Synovial sheath of bicipital tendon – Discrete in horse and ox – Bicipital bursa in horses Infraspinatus bursa Bursa: Def: A sac-like dilatation between two different tissues Function: Reduce friction Structure: Consists of fibrous capsule lined by a synovial membrane Location: May be between the following: A- skin and bone B- tendon and bone C- muscle and bone D- ligament and bone Bicipital Bursa: it presents in the shoulder joint between the bicipital tendon and bicipital groove in the horse and ruminants but the bursa communicates with the joint capsule in the pig and carnivores. It may be inflamed causing lameness Injection of shoulder joint: In carnivores: direct the needle medially just caudal to the end of the acromion In large animals: in similar manner just cranial to the tendon of the infraspinatus muscle. To take mediolateral radiograph of the humeral joint: pull the limb cranially and ventrally to a marked degree to avoid superimposing the joint  Cubital articulation ( elbow joint) Ginglymus- extension and flexion but limited by collateral ligaments and biceps brachii muscle Joint capsule thin caudally forms a pouch in the olecranon fossa Supported laterally by collateral ligaments Supported caudally by tendon of muscles that attach to the olecranon process Structure: I- Bones: 3 bones (distal end of the humerus as well as the proximal ends of radius & ulna ( head of radius and trochlear notch of ulna) II- Joint capsule III- Ligaments: collateral ligaments A- Medial (ulnar) collateral ligament: between medial humeral epicondyle and medial tuberosity of the radius & ulna (1- long superficial part & 2- short deep part) B- Lateral (radial) collateral ligament: between lateral humeral epicondyle and lateral tuberosity of the radius. This ligament is divided in carnivores into a cranial and a caudal (ulnar) part. - In carnivores: radial annular ligament (around the humerus head) and olecranon ligament extends from medial epicondyle to ulna. Clinical Significance Clinical: Capped elbow (olecranon bursitis): False subcutaneous bursa between the skin and the olecranon tuberosity due to repeated trauma (acquired bursitis) by the shoe of the affected limb either during locomotion or when laying down (shoe boil) Luxation is rarely occurs medially because the enlarged medial epicondyle of the humerus prevents the radius and ulna from dislocating in the medial side. Injection of the cubital joint in carnivores, ox and horse by directing the needle between the olecranon tuberosity and lateral epicondyle of the humerus.  Radioulnar articulation A- Motion: No movement B- Structure: I- Bones: 2 convex facets on ulna and 2 corresponding facets on radius II- Joint capsule: enclosed in the elbow joint capsule III- Ligaments (3 for proximal one and 1 for distal one). 1.Annular ligament of the radius: around the radial head and attaches distally to radial notch of ulna. 2.Interosseous ligament of antebrachium--- in proximal half of interosseous space 3. Interosseous membrane of the antebrachium: joints the ulna with radius in dog 4. Radioulnar ligament: between the radial trochlea and styloid process of ulna. - The proximal and distal radioulnar joints ossify in case of the horse and ruminants  Ginglymus Composite joint – Radio-ulnar-carpal joint – Intercarpal joint – Carpometacarpal joint 1- Knee (carpal) joints -It consists of 4 joints (composite joint) -A- Motion: act together as ginglymus joint ( extension and flexion & limited amount of gliding). -Most movement occurs at joint (1), considerable movement at joint (2) and no movement at joint (3).  Bones: -1- Antebrachiocarpal (ulnocarpal & radiocarpal) joint: between the distal end of the radius & ulna (carpal articular surface of the radius and first row of carpal bone (radial, intermediate, ulnar and accessory carpal bones) Hinge in horse, cochlear in ox and ellipsoidal in dog. -2- Middle carpal joint: between the proximal and distal rows of the carpal bones. It also includes the accessory carpal (intercarpal) joints. Complex hinge joint -3- Carpometacarpal joint: between the distal row of the carpal bone (1st , 2nd, 3rd and 4th carpal bones) and the proximal surface of the metacarpal bones Plane joint -4- Intercarpal joints: between the carpal bones in the same row Joint capsule: - A- Fibrous joint capsule: -Is common to the 4 joints and forms the extensor retinaculum (dorsal carpal ligament) dorsally and the carpal palmar ligament palmarly -The carpal palmar ligament is the dorsal boundary of the carpal canal (for SDFT and DDFT) and it then continues distally as the inferior check ligament of DDFT (carpal head of the DDFT) B- The synovial joint capsule: The synovial membrane forms three sacs corresponding to the joints: 1- Antebrachicarpal: doesn’t communicate with the two distal compartments 2- Midcarpal 3- carpometacarpal --- communicate with each other in horse and dog.  Carpal joints Joint capsule – Heavily reinforced by fibrous layer Dorsal carpal ligament – Strengthened by EXTENSOR RETINACULUM – Canals for extensor tendons Palmar carpal ligament – Closely attached to the carpal bones – Enforced by FLEXOR RETINACULUM – Forms the dorsal wall of the carpal canal – Continued distally to form the ACCESSORY LIGAMENT blends with the deep digital flexor tendon in horses Carpal canal Structures passing through the carpal canal - Ulnar and median nerve - Arteries and veins - Tendons and synovial sheaths of the superficial and deep digital flexors  Carpal joints Long medial and lateral collateral ligaments Main movements are flexion and extension Intermetacarpal joints – Intercarpal bones are joined by short interosseous ligaments  Phalangeal joints Each digit has – Metacarpophalange al /fetlock joint – Proximal interphalangeal /pastern joint – Distal interphalangeal/coff in joint  Phalangeal joints Metacarpophalangeal /fetlock Proximal interphalangeal joint /pastern joint Hinge joint – Saddle joint Joint capsule – Joint capsule – form dorsal and palmar pouches Dorsal and palmar pouches Ligaments – Ligaments – Collateral ligaments Medial and lateral collateral – Sesamoidean ligaments ligaments – Present in dog and horse Proximal sesamoidean ligaments – Palmar ligaments – Replaced by INTEROSSEOUS Present in dogs, ruminants and muscle in dogs or SUSPENSORY pig LIGAMENT in ox and horses – Movement Middle sesamoidean ligaments flexion and extension Distal sesamoidean ligaments – Interdigital ligaments Distal interphalangeal/coffin Movement joint – flexion and extension – Same as pastern joint  Fetlock ox Proximal sesamoidean ligament/Suspensory ligament – Support fetlock proximally – Originates in distal carpal bones – end extend on palmar surface of metacarpal bones – divide into 4 branches at distal third of metacarpus – Middle part – Lateral and medial branch – Strong branch Sesamoid ligaments: group of ligaments attach to the proximal sesamoid bones to form the part of the stay apparatus or brace a- Proximal ----- Suspensory ligament (interosseous m) : arises from the proximal part of the 3rd metacarpal (metatarsal) bone, distal row of carpal (tarsal) and planter tarsal ligament and inserts into the abaxial surface of the proximal sesamoid bones. A branch passes to the dorsal surface of the proximal phalanx where it joins the common digital extensor tendon. In the young the tendon has some striated muscle but becomes completely tendinous in adult life. The tendon supports the fetlock and prevents excessive dorsal flexion of the joint when the foot in the ground. The dorsal branch limits flexion of the joint. It Prevents deep flexor tendon from flexing the joint as a result of tension on it (deep flexor), when limb is on the ground and joint is extended.  B- Middle sesamoidean ligaments: 1- Intersesamoidean ligament: is a mass of fibrocartilage in which the sesamoid bones are partially embedded, it forms transverse connection between the two proximal sesamoid bones 2- Collateral sesamoidean ligaments (lateral and medial): each arises from the abaxial surface of the corresponding sesamoid bone and insert into the 3rd metacarpal (metatarsal) bone and first phalanx  B- Middle sesamoidean ligaments: 1- Intersesamoidean ligament: is a mass of fibrocartilage in which the sesamoid bones are partially embedded, it forms transverse connection between the two proximal sesamoid bones 2- Collateral sesamoidean ligaments (lateral and medial): each arises from the abaxial surface of the corresponding sesamoid bone and insert into the 3rd metacarpal (metatarsal) bone and first phalanx  Fetlock joint ox Middle sesamoidean ligament Middle and lateral palmar ligaments – Interdigital intersesamoidean ligament – Collateral sesamoidean ligaments Proximal and distal inter digital ligaments – Prevent abnormal separation of two digits  Pastern joint ox Collateral ligaments Axial ligament Palmar ligaments Central Axial Abaxial Additional bands from digital fascia insert to first phalanges  Coffin joint ox Distal interdigital ligaments Distal ligament of coffin joints Axial and abaxial collateral ligaments Distal sesamoidean ligaments  Fetlock joint horse Collateral ligaments Proximal sesamoidean ligament/suspensory ligament – from distal row of carpal bones – Passes between splint bones – Above fetlock divide 2 branches to insert proximal sesamoids Middle sesamoidean ligaments – Palmar ligament – Medial and lateral collatera; ligaments  Fetlock joint horse Distal sesamoidean ligaments Straight sesamoidean ligaments Y – attach to the bases of the sesamoid bones and to the proximal end of the middle phalanx Oblique sesamoidean ligaments V – attach to the sesamoid bones and to the proximal end of the proximal phalanx Cruciate sesamoidean ligaments X – arise on the bases of the sesamoid bones, cross and attach to the proximal ends of the proximal phalanx  Pastern joint horse Collateral ligaments Palmar ligaments – Central pair – Axial – Abaxial ligamnets Lateral palmar ligaments  Coffin joint horse Composite joint Medial and lateral Collateral ligaments Distal sesamoidean ligaments Collateral sesamoidean ligament  Ligaments of the cartilages of distal phalanx Chondroungulocompedal ligaments Lateral and medial chondrocoronal ligaments Lateral and medial chondroungular collateral ligaments Lateral and medial chondrosesamoidean ligaments Cruciate chondroungular ligaments Chindropulvinal ligament  Stay apparatus of the forelimb (Suspensory apparatus and ckeck appratus) It is a system of muscles, tendons and ligaments in equine limbs. It allows horse to lock joints in his limb with no muscular effort. This mechanism explains how equine species can sleep while standing: The structures are: 1- Tendons of biceps brachii muscle 2- lacertus fibrosus tendon 3- Extensor carpi radialis tendon 4- Thoracic part of serratus ventralis muscle 5- Long head of triceps brachii muscle 6- SDFT& superior check ligament 7- DDFT& inferior check ligament 8-Suspensor ligament and its extensor branches 9- Common digital extensor tendon 10- Distal sesamoidean ligaments Indication of joint blocks 1- Localize areas of lameness within a limb 2- Desensitize areas of a limb for surgical procedures