Bones and ligaments thoracic limb

Question 1

What are the three skeletal components of a general pectoral girdle?

Answer 1

Scapula, Clavicle (if present), Coracoid

Question 2

What is the name of this part of the scapula? At what angle of the scapula is this located?

Answer 2

Glenoid cavity/fossa, ventral angle

Question 3

What is the name of this part of the scapula? What is the process at the distal end called?

Answer 3

Spine of the scapula, acromion process.

“The spine is the most prominent feature of the bone. It begins at the dorsal border as a thick, low ridge and becomes thinner and wider toward the neck. In all dog breeds the free border is slightly thickened, and in some it is everted caudally. The distal end is a truncated process, the acromion.”

Question 4

What muscles attatch to the spine of the scapula and the acromion process?

Answer 4

Deltoideus: acromial part origin acromion process; scapular part origin spine of the scapula via the aponeurosis

Omotransversarius: origin acromion process/distal end of spine of the scapula

Trapezius: cervical part insertion spine of scapula including acromion; thoracic part insertion proximal third of the spine of the scapula into an aponeurosis

Question 5

Name this part of the scapula on the lateral surface.

Answer 5

Supraspinous fossa

Question 6

What muscle attaches to the supraspinous fossa in the lateral surface of the scapula?

Answer 6

Origin of the supraspinatus muscle

Question 7

Name this part of the lateral surface of the scapula.

Answer 7

Infraspinous fossa

Question 8

What muscle attaches at the infraspinous fossa of the scapula?

Answer 8

Origin of the infraspinatus

Question 9

Name this region on the medial (costal) surface of the scapula. What muscle has its origin here?

Answer 9

Subscapular fossa, subscapularis

Question 10

A small proximal and cranial rectangular area on the medial (costal) surface of the scapula, the _____ _____ or _______ _______, serves as insertion for the serratus ventralis muscle.

Answer 10

A small proximal and cranial rectangular area on the medial (costal) surface of the scapula, the serrated face or facies serrata, serves as insertion for the serratus ventralis muscle.

Question 11

Name this area of the scapula. What muscle has its origin here?

Answer 11

Supraglenoid tubercle (cranial to the glenoid cavity), biceps brachii

Question 12

Name this area of the scapula. What two muscles have their origins here?

Answer 12

Infraglenoid tubercle.

Teres minor origin: Infraglenoid tubercle, distal third of caudal margin of scapula

Triceps brachii (long head) origin: Distal 2/3rd of caudal border of scapula; Infraglenoid tubercle (tendinous)

Question 13

Name and describe this part of the scapula. What muscle arises here?

Answer 13

Coracoid Process: The supraglenoid tubercle shows a slight medial inclination on which a small tubercle, the coracoid process, can be distinguished.

Origin of the coracobrachialis

Question 14

Comparative: scapula

What is this structure and in what common animals is it found?

Answer 14

Scapular cartilage at the dorsal margin.

Horse, ruminants, pig

Question 15

Comparative: What is the structure labelled here on the spine of the scapula of a pig? What other domestic/production animals is it found in?

Answer 15

tuber spinae scapulae

hore, pig, cat

Question 16

The acromion process of the spine of the scapula is absent in ____ and _____. The acromion extends ventrally in carnivores (_______ process) and extends caudally in cats (________ process - pictures). Rabbits possess the both processes of acromion.

Answer 16

The acromion process of the spine of the scapula is absent in horses and pigs. The acromion extends ventrally in carnivores (hamate process) and extends caudally in cats (suprahamate process). Rabbits possess the both processes of acromion.

Question 17

In the dog model, the infraspinous and supraspinous fossae are of roughly equal size. In horses and ruminants, the _______ fossa is larger.

Answer 17

In the dog model, the infraspinous and supraspinous fossae are of roughly equal size. In horses and ruminants, the infraspinous fossa is larger.

Question 18

Label the muscles that attach at these regions of the scapula.

Answer 18

Question 19

Label the muscles that attach at these regions of the scapula.

Answer 19

Question 20

Label these components on the humerus of the dog

Answer 20

Question 21

Label these structures on the humerus of the dog

Answer 21

Question 22

Label these structures on the humerus of the dog

Answer 22

Question 23

The ______ of the humerus articulates with the scapula at the __________ joint.

Answer 23

The head of the humerus articulates with the scapula at the glenohumeral joint.

Question 24

The _________ groove begins at the cranial end of the articular area of the head of the humerus. It lodges the tendon of origin of the _____ _______ and is deflected toward the median plane by the _______ tubercle, which forms the craniolateral part of the proximal extremity.

Answer 24

The intertubercular groove begins at the cranial end of the articular area of the head of the humerus. It lodges the tendon of origin of the biceps brachii and is deflected toward the median plane by the greater tubercle, which forms the craniolateral part of the proximal extremity.

Question 25

Where on the proximal humerus do these muscles have their insertions? Supraspinatus: Infraspinatus: Teres minor:

Answer 25

**Supraspinatus**: Proximomedial aspect of greater tubercle of humerus **Infraspinatus**: Distal aspect of greater tubercle of humerus, Joint capsule of shoulder **Teres minor**: Crest of greater tubercle of humerus/tricipital line

Question 26

In the horse and large ruminant: * Humerus is short and **\_\_\_\_\_\_\_** * Greater and Lesser Tubercle have **\_\_\_\_** and **\_\_\_\_\_\_** parts * Intertubercular groove * Divided by **\_\_\_\_** ridge (ruminants) - see picture (cow) * Divided by a **\_\_\_ \_\_\_\_\_** ridge in horses * Intermediate **\_\_\_\_\_** present

Answer 26

In the horse and large ruminant: * Humerus is short and **compressed** * Greater and Lesser Tubercle have **cranial** and **caudal** parts * Intertubercular groove * Divided by **low** ridge (ruminants) - see picture (cow) * Divided by a **well developed** ridge in horses * Intermediate **tubercle** present

Question 27

The structure around the rim of the glenoid fossa is called the **\_\_\_\_ \_\_\_\_\_**. It is made of **\_\_\_\_\_\_\_** tissue.

Answer 27

The structure around the rim of the glenoid fossa is called the **glenoid labrum**. It is made of **fibrocartilaginous** tissue.

Question 28

Internal to the joint capsule, the shoulder joint capsule is strengthened by: * **\_\_\_\_\_\_** Glenohumeral Ligament * **\_\_\_\_\_\_** Glenohumeral Ligament * **\_\_\_\_\_\_\_\_** humeral ligament Label these on the following diagram.

Answer 28

Internal to the joint capsule, the shoulder joint capsule is strengthened by: * **Lateral** Glenohumeral Ligament * **Medial** Glenohumeral Ligament * **Transverse** humeral ligament

Question 29

Label the following parts of the ulna: * Oleacranon * Oleacranon tuberosity * Anconeal process * Medial and lateral coranoid processes * Trochlear notch * Radial notch * Ulnar tuberosity * Styloid process

Answer 29

Question 30

Label the following parts of the radius: * Head * Fovea capitis * Articular circumfrence * Radial tuberosity * Trochlea * Articular Facet for Ulna * Articular facet for carpal bones * Styloid Process

Answer 30

* Head * Fovea capitis * Articular circumfrence * Radial tuberosity * Trochlea * Articular Facet for Ulna * Articular facet for carpal bones * Styloid Process

Question 31

In the ruminant (see picture from ox lateral and medial radius and ulna): * In young animals ulna and radius separated by **\_\_\_\_\_\_\_\_** membrane, which ossifies with age * Ulna extends distally to **\_\_\_\_\_\_** * Radius shaft is **\_\_\_\_\_** craniocaudally * Deeply excavated fovea **\_\_\_\_\_** with ridges * Ulna projects above the radius * Olecranon has **\_\_\_\_\_** and **\_\_\_\_\_** parts

Answer 31

In the ruminant (see picture from ox lateral and medial radius and ulna): * In young animals ulna and radius separated by **interosseous** membrane, which ossifies with age * Ulna extends distally to **carpus** * Radius shaft is **flattened** craniocaudally * Deeply excavated fovea **capitis** with ridges * Ulna projects **above** the radius * Olecranon has **cranial** and **caudal** parts

Question 32

In the horse (see picture horse radius and ulna): * Distal 1/3rd ulna **\_\_\_\_\_\_** * Radius and Ulna distinctly curved proximally * Radius **\_\_\_\_\_\_** end greatly widened * **\_\_\_\_\_** is the weight-bearing bone

Answer 32

In the horse (see picture horse radius and ulna): * Distal 1/3rd ulna **absent** * Radius and Ulna distinctly curved proximally * Radius **proximal** end greatly widened * **Radius** is the weight-bearing bone

Question 33

The three articulations that make up the elbow joint are....

Answer 33

1. **humeroulnar joint**: trochlear notch of the ulna articulates with the trochlea of the humerus 2. **humeroradial joint**: fovea capitis on the head of the radius articulates with the capitulum and the trochlea of the humerus 3. **proximal radioulnar joint:** Caudal border (articular circumference) of the head of the radius articulates with the radial notch of the ulna

Question 34

The ligaments that stabilise the elbow joint laterally and medially are the lateral and medial **\_\_\_\_\_\_\_** ligaments.

Answer 34

The ligaments that stabilise the elbow joint laterally and medially are the lateral and medial **collateral** ligaments.

Question 35

The ______ ligament at the proximal radioulnar joint is a fibro-ossesous ring from medial to lateral parts of the ________ process of the ulna. It allows the radius to rotate against the ulna, which is fixed by the \_\_\_\_\_\_.

Answer 35

The **annular ligament** at the proximal radioulnar joint is a fibro-ossesous ring from medial to lateral parts of the **coronoid** process of the ulna. It allows the radius to rotate against the ulna, which is fixed by the **humerus**.

Question 36

Name this ligament at the elbow joint

Answer 36

Medial collateral ligament

Question 37

In the horse (and ruminant) the **\_\_\_\_\_** collateral ligament has two limbs as the **\_\_\_\_ \_\_\_\_** muscle is absent. The **\_\_\_\_\_\_\_** collateral ligament is singular. These are shown in this diagram of the medial and lateral elbow of a horse.

Answer 37

In the horse (and ruminant) the **medial** collateral ligament has two limbs as the **pronator** **teres** muscle is absent. The **lateral** collateral ligament is singular.

Question 38

**Proximal articular surfaces of the radius and ulna:** The **\_\_\_\_ \_\_\_\_\_\_** on the head of the radius articulates with the **\_\_\_\_\_\_\_** and the **\_\_\_\_\_\_\_** of the humerus. The **\_\_\_\_\_\_\_** notch of the ulna articulates with the **\_\_\_\_\_\_** of the humerus. The caudal border (articular circumference) of the head of the radius articulates with the **\_\_\_\_\_\_** notch of the ulna.

Answer 38

**Proximal articular surfaces of the radius and ulna:** The **fovea capitis** on the head of the radius articulates with the **capitulum** and the **trochlea** of the humerus. The **trochlear** notch of the ulna articulates with the **trochlea** of the humerus. The caudal border (articular circumference) of the head of the radius articulates with the **radial** notch of the ulna.

Question 39

What is the articular surface of the humerus called where it joins to the radius and ulna, and what is this joint called?

Answer 39

Capitulum (radius) and trochlea (ulna) of the humeral head. Elbow joint.

Question 40

The interosseous border of the ulna articulates with the **\_\_\_\_\_\_** by a thick ligament.

Answer 40

The interosseous border of the ulna articulates with the **radius** by a thick ligament.

Question 41

**Distal articular surfaces of radius and ulna:** The articular circumference of the ulna articulates with the **\_\_\_\_\_\_** notch of the radius. The styloid process of the ulna articulates with the **\_\_\_\_\_** and **\_\_\_\_\_** carpal bones. The distal surface of the radius articulates with the **\_\_\_\_\_\_\_\_\_\_** carpal bone.

Answer 41

**Distal articular surfaces of radius and ulna:** The articular circumference of the ulna articulates with the **ulnar** notch of the radius. The styloid process of the ulna articulates with the **ulnar** and **accessory** carpal bones. The distal surface of the radius articulates with the **intermedioradial** carpal bone.

Question 42

Label these areas on the radius and ulna.

Answer 42

1. oleacranon tuber 2. anconeal process 3. trochlear notch 4. lateral coronoid process 4' medial coronoid process 5. articular circumference for articulation with the radius 6. styloid process of the ulna 7. ulnar notch 8. styloid process of the radius 9. head of the radius

Question 43

What muscles attach to the Olecranon tuberosity of the ulna?

Answer 43

triceps brachii i Flexor carpi ulnaris (ulnar head) o anconeus i

Question 44

Name the seven carpal bones. In what direction are the distal row numbered?

Answer 44

PROXIMAL ROW: Intermedioradial Carpal (merging of radial carpal and intermediate carpal bones), Ulnar Carpal, Accessory Carpal. DISTAL ROW: First, second, third, fourth carpal bones (numbered medial to lateral)

Question 45

What are the three main joints of the carpus? What is a fourth type of joint that can also be found there?

Answer 45

* *Antebrachiocarpal** Joint = Proximal: Between radius/ulna and proximal row * *Middle Carpal** Joint: Between proximal and distal row * *Carpometacarpal** Joint =Distal: Between distal row and metacarpal bones **Intercarpal Joint**: Between two carpal bones

Question 46

The antebrachiocarpal joint compartment [**communicates/does not communicate**] with the middle carpal joint compartment. The middle carpal and carpometacarpal joint compartments [**communicate/do not communicate**] between the distal row of carpal bones.

Answer 46

The antebrachiocarpal joint compartment **does not communicate** with the middle carpal joint compartment. The middle carpal and carpometacarpal joint compartments **communicate** between the distal row of carpal bones.

Question 47

What is the carpal canal? What passes through it? What two ligaments are involved?

Answer 47

Canal for structures to pass through on the palmar side of the carpus. Deep Flexor Tendons of the digits, Blood vessels (Radial and Ulnar), Nerves (Median and Ulnar). Palmar carpal ligament and Flexor Retinaculum.

Question 48

Name the digital bones of the manus. In what direction are they numbered?

Answer 48

proximal and distal phalanx I; proximal, middle, and distal phalanges II - IV. Medial to lateral.

Question 49

What is a retinaculum?

Answer 49

A band of thickened deep fascia around tendons that holds them in place

Question 50

What type of joint is the shoulder joint and what movements occur here?

Answer 50

Spheroidal ball and socket (but functions as a hinge joint) Flexion and extension (also limited adduction/abduction)

Question 51

At the elbow joint, the **\_\_\_\_\_** and **\_\_\_\_\_** tendons cover the distal portion of the medial collateral ligament. The origin of the **\_\_\_\_ _____ \_\_\_\_\_\_** covers the lateral collateral ligament.

Answer 51

At the elbow joint, the **biceps** and **brachialis** tendons cover the distal portion of the medial collateral ligament. Origin of the **lateral digital extensor** covers the lateral collateral ligament.

Question 52

What type of joint is the elbow and what movements can occur here?

Answer 52

Mostly a hinge joint (flexion and extension) Also some rotational movement at the radioulnar joint (pronation/supination of the lower limb).

Question 53

Describe the communication of synovial fluid between joint space compartments at the elbow.

Answer 53

All compartments communicate with one another

Question 54

What ligament unites the radius and the ulna proximally?

Answer 54

**Annular ligament**: Fibro-osseous ring from medial to lateral parts of coronoid process allows radius to rotate against ulna which is fixed by humerus

Question 55

Describe how the radius and the ulna differ in the horse.

Answer 55

Distal 1/3rd ulna absent; Radius and Ulna distinctly curved proximally; Radius proximal end greatly widened; Radius weight-bearing bone.

Question 56

What is the name, origin, and insertion of this ligament of the carpus? dorsolateral : palmar

Answer 56

**Medial Collateral Ligament** Origin * Radial (medial) styloid process Insertion * Intermedioradial carpal bone

Question 57

What is the name, origin, and insertion of this ligament of the carpus? dorsolateral : palmar

Answer 57

**Lateral Collateral Ligament** Origin * Ulnar (lateral) styloid process Insertion * Ulnar carpal bone

Question 58

Name and describe these ligaments of the carpus? dorsolateral : palmar

Answer 58

**Antebrachial Ligaments** * Connect radius and ulna to intermedioradial carpal bone

Question 59

Name and describe these ligaments of the carpus. dorsolateral : palmar

Answer 59

Carpometacarpal ligaments * Connect carpal bones to metacarpal bones

Question 60

Name and describe these ligaments of the carpus. dorsolateral : palmar

Answer 60

Intercarpal ligaments * Connect adjacent carpal bones to each other

Question 61

Name these ligaments of the carpus. dorsolateral : palmar

Answer 61

Accessory Carpal Ligaments * Accessorioulnar ligament * Accessoriocarpoulnar ligament * Accessoriometacarpal ligament

Question 62

What type of joint is the carpus and what movements can occur here? At which joint does most movement occur?

Answer 62

Composite Joint: hinge: mostly flexion and extension Most movement occurs at the antebrachiocarpal joint.

Question 63

Describe the communication of synovial fluid between joint space compartments at the carpus.

Answer 63

The antebrachiocarpal joint compartment does not communicate with the middle carpal joint compartment. The middle carpal and carpometacarpal joint compartments communicate between the distal row of carpal bones.

Question 64

Describe how the carpal bones in the horse differ to those of the dog. Why does this difference occur?

Answer 64

Intermediate and radial carpal bones are not fused (dog = intermedioradial) Distal carpal bone I is situated palmar to carpal bone II. Articular surface at antebrachiocarpal joint different because horse ulnar bone dissipates halfway down the shaft of radius so radial is only articular surface. At Carpometacarpal joint the articular surface is also different due to the reduction of all but metacarpal bone III.