Elbow joint and muscles of the proximal forelimb Flashcards
What region of the forelimb are the radius and ulna located in?
Antebrachium
What type of bones are the radius and ulna?
long bones
which bone is weight bearing out of the radius and the ulna?
Radius
What is the function of the ulna?
Provides leverage
True/False?
The radius is longer than the ulna?
FALSE
(Ulna is the longest!)
What part of the radius is the articular surface for the elbow joint?
Head
What part of the radius is the articular surface for the carpus?
Distal end
If you get a fracture to both the radius and ulna which is the most important to stablise and why?
Radius
- It provides the main weight bearing facility
What part of the ulna is palpable?
olecranon process
What is the name for the beak shaped process that fits into the ulna fossa of the humerus?
Anconeal process
What part of the ulna is the articular surface fot the elbow joint?
Trochlea notch
What parts of the ulna does the radius sit between?
Medial and lateral coronoid processes
What ligament runs from the lateral to medial coronoid processes and holds the radius in place?
Annular ligaments
What is the name for the distal end of the ulna?
Styloid process
(also present in radius)
Where is the ulna in relation to the radius (proximally)?
Ulna is the most medial projection
Where is the ulna in relation to the radius (distally)?
Ulna is the most lateral projection
How many centres of ossification does the radius have?
3
How many centres of ossification does the ulna have?
4
What are the centres of ossification of the ulna?
- olecranon process
- Anconeal process
- Body
- Distal epiphyses
True/ False?
The anconeal process growth plate should already be closed when the animal is born?
True
(should not be seen on a radiograph- open growth plate is pathological!)
What would happen if the ulna stopped growing but the radius continued to grow?
Limb pushed in a medial direction
What ligaments attach to the styloid process?
collateral ligaments of the carpal joint
What are specific features seen in the radius and ulna of a cat?
- Radius and ulna are a similar diameter (no tapering to a point like in dogs)
- Olecranon process is sqaure
True/false?
The radius and ulna are already fused in the ruminant.
False
(2 complete bones that fuse as the animal ages)
True/false?
There is no rotation of the radius and ulna in larger animals.
True
Give specific features of the radius and ulna in the horse.
- Proximal ulna present and fused to the radius
- Body of the ulna is absent
- Distal ulna fused with radius
- no rotation
What are the 3 components of the elbow joint?
- Trochlea of the humerus
- Trochlea notch of the ulna
- Head of the radius
What are the palpable landmarks of the elbow joint?
- Medial and lateral epicondyles
- Olecranon process
Where do the collateral ligaments of the elbow joint originate and insert into?
Humeral epicondyles to the radius and ulna
What part of the humerus does the anconeal process engage with?
ulna fossa
If the elbow is hyperextended what is more likely to occur dislocation or a fracture and why?
Dislocation of the ulna because the anconeal process is no longer engaging with the ulnar fossa of the humerus when the limb is flexed.
What is osteochondrosis?
- Developmental disease
- Erosion of articular cartilage and subchondral bone
What is oesteoarthritis?
- Degenerative joint disease
- New bone formation
What developmental conditions could lead to elbow dysplasia?
-Osteochondrosis
- Ununited anconeal process
- Fragmented medial coronoid process
- Elbow incongruity
Where is the O and I of the deltoideus muscle?
O- Spine of scapula
I - lateral aspect of humerus
Where is the deltoideus muscle located?
Caudolateral aspect of the limb
How many heads does the deltoideus muscle have?
2
What is the function of the deltoideus muscle?
Shoulder flexor
(crosses caudal to shoulder joint)
What nerve supplies the deltoideus muscle?
Axillary nerve
What is the O and I of the teres major muscle?
O - caudal border of the scapular
I- Medial humerus
Where is the teres major located?
Caudomedial aspect of the limb
What is the function of the teres major?
shoulder flexor
(crosses caudal to the shoulder joint)
What nerve supplies the teres major?
Axillary nerve
How many heads does the triceps brachii have?
4
Where is the O of the long head of the triceps brachii muscle?
Caudal border of the scapula
Where is the O of the 3 smaller heads of the triceps brachii?
Shaft of humerus
Where do all heads of the triceps brachii muscle insert into?
Olecranon process of the ulna
Where is the triceps brachii muscle located?
Caudal aspect of the limb
What are the functions of the triceps brachii muscle?
- Shoulder flexor
- Elbow extensor
What nerve supplies the triceps brachii muscle?
Radial nerve
Where is the biceps brachii muscle located?
Cranial- medial aspect of the limb
Where is the origin and insertion of the biceps brachii muscle?
O- supraglenoid tubercle
I - Proximal radius
What is the function of the biceps brachii muscle?
- Shoulder extensor (cranial to shoulder)
- Elbow flexor (cranial to elbow)
What nerve supplies the biceps brachii muscle?
musculocutaneous nerve
What is the biceps brachii muscle deep to?
Pectorals and brachiocephalic
What animal has a lacertus fibrosis?
horse
What is the lacertus fibrosis?
Fibrous extension from the distal end of the biceps brachii to the 3rd metacarpal of the horse.
Contributes to long standing time
Where is the lacertus fibrosis located in relation to the carpus?
Dorsal to the carpus
What is the function of the lacterus fibrosis?
Carpal extensor
Where is the O and I of the brachialis muscle?
O- humerus
I - radius
What muscle wraps around the humerus?
Brachialis
What is the function of the brachialis muscle?
Elbow flexor
(crosses cranial to elbow joint)
What nerve supplies the brachialis muscle?
Musculocutaneous nerve
What muscles provide shoulder collateral support?
infraspinatous
supraspinatous
subscapularis
