Difference between revisions of "Bovine Forelimb - Anatomy & Physiology"
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==Structures of the Proximal Forelimb and Shoulder== | ==Structures of the Proximal Forelimb and Shoulder== | ||
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===Radius and Ulna=== | ===Radius and Ulna=== | ||
| − | These are complete bones in the ox but are entirely fused. There is a proximal and distal '''interosseous | + | These are complete bones in the ox but are entirely fused. There is a proximal and distal '''interosseous spac'''e which are the only two places where the shafts are seperated. The ulna's proximal end is caudal to the radius and it's distal end forms the '''lateral styloid process''', distal to the radius and articulating with the ulnar carpal bone. |
==Joints of the Proximal Forelimb== | ==Joints of the Proximal Forelimb== | ||
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===Metacarpal bones=== | ===Metacarpal bones=== | ||
| − | These are covered in detail in the [[Bovine | + | These are covered in detail in the [[Bovine Phalanges - Anatomy & Physiology|bovine phalanges]] section. |
==Joints of the Distal Forelimb== | ==Joints of the Distal Forelimb== | ||
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3. The '''carpometacarpal joint''' between the distal carpal bones and the proximal metacarpals. | 3. The '''carpometacarpal joint''' between the distal carpal bones and the proximal metacarpals. | ||
| − | The joint is a synovial joint, | + | The joint is a synovial joint, comprised of a common outer fibrous capsule and three inner synovial pouches, one for each joint. '''Collateral ligaments''' extend from the radius to the metacarpal bones on the medial and lateral aspect of the carpus. The carpal canal houses both the deep digital flexor tendon, and the deep branch of the superficial digital flexor. |
==Muscles of the Forelimb== | ==Muscles of the Forelimb== | ||
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These muscle are responsible for joining the forelimb to the trunk, forming a synsarcosis rather than a conventional joint. Collectively, they act to transfer the weight of the body to the forelimbs as well as stabilize the scapula. | These muscle are responsible for joining the forelimb to the trunk, forming a synsarcosis rather than a conventional joint. Collectively, they act to transfer the weight of the body to the forelimbs as well as stabilize the scapula. | ||
| − | + | '''Trapezius''': Accessory n. | |
| − | + | ||
| − | + | Origin: mid-dorsal raphe and supraspinous ligament. | |
| − | + | ||
| − | + | Insertion: spine of the scapula. | |
| − | + | ||
| + | Body: two parts, cervical and thoracic separated by aponeurosis. | ||
| − | + | Action: raises scapula against the trunk and swings cranially to advance the limb. | |
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| − | ''' | + | '''Brachiocephalic m.''': Accessory n. |
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| − | + | The two parts are separated by the clavicle, where it exists. | |
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| − | + | Origin: occipital bone, nuchal ligament and the mastoid process. | |
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| − | + | Insertion: deltoid tuberosity and fascia of the limb. | |
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| − | + | Actions: advances the limb and extends the shoulder joint when limb is in motion. Draws the head and neck ventrally when the limb is fixed. | |
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| − | + | '''Omotransversarius''': Accessory n. | |
| − | + | ||
| + | Origin: transverse processes of the atlas. | ||
| + | |||
| + | Insertion: acromion and spine of scapula. | ||
| − | + | Action: advancing the limb. | |
| − | + | '''Latissimus dorsi''': local branch of brachial plexus | |
| − | + | The broadest muscle of the back. | |
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| − | + | Origin: thoracolumbar fascia. | |
| − | + | Insertion: teres tuberosity of the humerus. | |
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| − | |||
| − | |||
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| − | + | Actions: antagonist to the brachiocephalic m. The cranial fibers strap the scapula to the chest. It retracts the free limb and flexes shoulder joint. It draws the trunk forward over the fixed limb. | |
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| − | + | '''Pectoral mm.''': brachial plexus | |
| − | + | Two superficial parts, cranial and caudal, these aren't very distinct in the ox. | |
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| − | + | Origin: cranial sternum. | |
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| − | ''''' | + | Insertion: |
| − | + | 1. cranial ('''descending'''), crest of the humerus distal to the deltoid tuberosity. | |
| + | 2. caudal ('''transverse'''): covers elbow joint to insert on the medial fascia of the forearm. | ||
| + | Action: adduct the forelimb and assist in protraction and retraction. | ||
| + | '''Serratis ventralis''': branch of the brachial plexus. | ||
| − | + | Origin: C4 to 10th rib. | |
| + | Insertion: medial scapula and scapular cartilage. | ||
| + | Action: supporting the weight of the trunk. It is reinforced by strong fascia. The cervical portion can retract the limb and the caudal portion can advance the limb. | ||
| − | + | '''Rhomboids''': brachial plexus, | |
| − | + | Origin: nuchal ligament. | |
| − | + | Insertion: dorsal border and adjacent scapula. | |
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| − | + | Action: retracting the limb, may also raise the limb. | |
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| − | === | + | ===Intrinsic Musculature=== |
| + | ====Muscles of the Shoulder==== | ||
| − | + | These muscles are grouped: | |
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| − | + | ==1. Lateral== | |
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| − | + | '''Supraspinatus ''' and '''Infraspinatus''': Suprascapular n. of the brachial plexus. | |
| − | + | Origin: the fossae of the scapula. | |
| − | + | Insertion: both tubercles of the humerus. | |
| − | + | Action: brace the shoulder. | |
| − | : | ||
| − | ''' | + | Clinical significance: bursa between the tendon of the infraspinatus and lateral tubercle of the humerus can be the site of inflammation. |
| − | : | + | |
| + | ==2. Medial== | ||
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| + | '''Supscapularis''': Subscapular n. from the brachial plexus. | ||
| + | |||
| + | Origin: Deep surface of the scapula. | ||
| + | |||
| + | Insertion: medial tubercle of the humerus. | ||
| − | + | Action: braces medial shoulder joint, potential adductor. | |
| − | : | ||
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| − | ''''' | + | '''Coracobrachialis''': Musculocutaneous n. of the brachial plexus. |
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| − | + | Origin: medial supraglenoid tubercle. | |
| − | : | ||
| − | + | Insertion: proximal shaft of the humerus. | |
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| − | + | Action: fixator. | |
| − | + | ==Caudal (Flexors)== | |
| − | ''''' | + | '''Deltoids''': Axillary n. of the brachial plexus. |
| − | : | ||
| − | + | Origin: Two heads of origin; the caudal border and spine of the scapula and the acromion. | |
| − | : | ||
| − | + | Insertion: deltoid tuberosity on the humerus. | |
| − | |||
| − | + | Action: Flexor of Shoulder. | |
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| − | ''''' | + | '''Teres Major''': Axillary n. of the brachial plexus. |
| − | : | ||
| − | == | + | Origin: dorsal part of the caudal scapula. |
| + | |||
| + | Insertion: teres tuberosity midway down humerus. | ||
| + | |||
| + | '''Teres Minor''': Axillary n. of the brachial plexus. | ||
| + | |||
| + | There are no defined extensors of the shoulder. Those involved (brachiocephalic m., biceps brachii, supraspinatus, and ascending pectorals) have other, more primary roles. | ||
| + | |||
| + | ====Muscles of the Elbow==== | ||
| + | ''Extensors'': Radial n. from the brachial plexus | ||
| + | *'''Triceps brachii''': Three heads,the medial branch is the most developed | ||
| + | **Long head: caudal margin of the scapula | ||
| + | **Lateral, medial, and accessory heads: shaft of the humerus | ||
| + | **Insertion: olecranon, proteced by tricipital bursa against the bone and subcutaneous bursa against the skin | ||
| + | *'''Tensor fasciae antebrachii''' | ||
| + | **Overlies triceps extending from scapula to olecranon | ||
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| − | ''' | + | ''Flexors'': Musculocutaneous n. from the brachial plexus |
| + | *'''Biceps brachii''' | ||
| + | **Origin: supraglenoid tubercle of the scapula | ||
| + | **Insertion: medial tuberosity of proximal radius and adjacent ulna | ||
| + | **Runs through the intertubercular groove of the humerus | ||
| + | *'''Brachialis''' | ||
| + | **Origin: proximocaudal humerus | ||
| + | **Insertion: spirals to insert next to biceps | ||
| − | ''' | + | ====Muscles of the Carpal and Digital Joints==== |
| + | ''Extensors'': Radial n. from the brachial plexus | ||
| + | *Craniolateral position on the forearm | ||
| + | *Almost all originate from the lateral epicondyle of the humerus | ||
| + | *'''Extensor carpi radialis''': most medial, inserts on 2nd/3rd metacarpal bone | ||
| + | *'''Ulnaris lateralis''': most lateral, inserts on accessory carpal bone | ||
| + | *'''Extensor carpi obliquus''': aka '''abductor pollicis longus''' | ||
| + | **Origin: cranial radius | ||
| + | **Insertion: most medial metacarpal bone | ||
| + | *Last two may also serve in medial deviation of the foot | ||
| + | *'''Common Digital Extensor''' | ||
| + | **Insertion: extensor process of the distal phalanx of each digit | ||
| + | *'''Lateral Digital Extensor''' | ||
| + | **Insertion: dorsal proximal phalanges | ||
| + | *'''Medial Digital Extensor''' | ||
| + | **Insertion: middle and distal phalanges | ||
| − | ''' | + | ''Flexors'': Median or Ulnar n. of the brachial plexus |
| + | *Caudal position on the forearm | ||
| + | *Originate from the caudal medial epicondyle of the humerus | ||
| + | *'''Flexor carpi radialis''': most medial, inserts on upper 2nd/3rd metacarpal bone | ||
| + | *'''Flexor carpi ulnaris''': most lateral, inserts on the accessory carpal bone | ||
| + | *'''Superficial Digital Flexor''' | ||
| + | **Insertion: palmar surface of middle phalanges | ||
| + | *'''Deep Digital Flexor''' | ||
| + | **Passes through carpal canal before branching and continues to palmar distal phalanges | ||
| + | ''Interosseus muscles'' | ||
| + | *This is covered in more detail in the [[Bovine Phalanges - Anatomy & Physiology|bovine phalanges]] section. | ||
| − | == | + | ==Vasculature of the Forelimb== |
| − | + | *'''[[Arteries of the Forelimb - Anatomy & Physiology|Arteries of the Forelimb]]''' | |
| + | *'''[[Veins of the Forelimb - Anatomy & Physiology|Veins of the Forelimb]]''' | ||
| + | *'''[[Lymphatics of the Forelimb - Anatomy & Physiology|Lymphatics of the Forelimb]]''' | ||
| − | [[Category:Musculoskeletal System - Anatomy & Physiology]][[Category: | + | [[Category:Musculoskeletal System - Anatomy & Physiology]] |
| − | + | [[Category:To Do - A&P]] | |
Revision as of 16:43, 6 January 2011
This section has been fully reviewed, but still needs its pictures uploading.Structures of the Proximal Forelimb and Shoulder
Scapula
The ox possesses a small tuber scapular, it has an acromion present and has extensive scapular cartilage.
Humerus
The humerus is essentially the same conformation as that of the dog.
Radius and Ulna
These are complete bones in the ox but are entirely fused. There is a proximal and distal interosseous space which are the only two places where the shafts are seperated. The ulna's proximal end is caudal to the radius and it's distal end forms the lateral styloid process, distal to the radius and articulating with the ulnar carpal bone.
Joints of the Proximal Forelimb
Shoulder Joint
The joint capsule attaches a very short distance from the periphery of the articular surfaces. The intertubercular (bicipital) bursa lies between the humeral tubercles cushioning the bicipital tendon. The bursa and tendon are held in place by the transverse humeral retinaculum, running between the greater and lesser tubercles of the humerus.
Elbow Joint
The joint capsule attaches to the articular surface of the condyle, the periphery of the olecranon fossa and the articular cartilage of the trochlear notch of the ulna. It fuses with the collateral ligaments. Paired collateral ligaments attach the epicondyles to the tuberosities of the radius and ulna.
Structures of the Distal Forelimb
Carpal bones
The carpal bones comprise two rows:
Proximally (mediolaterally), radial, intermediate, ulnar and accessory bones.
Distally, 1st is missing, 2 and 3 are fused and there is also a 4th carpal bone.
Metacarpal bones
These are covered in detail in the bovine phalanges section.
Joints of the Distal Forelimb
Carpal Joint
The carpal joint is a compound joint composed of:
1. The antebrachiocarpal joint between the radius/ulna and the proximal carpal bones.
2. The middle carpal joint between the two rows of carpal bones.
3. The carpometacarpal joint between the distal carpal bones and the proximal metacarpals.
The joint is a synovial joint, comprised of a common outer fibrous capsule and three inner synovial pouches, one for each joint. Collateral ligaments extend from the radius to the metacarpal bones on the medial and lateral aspect of the carpus. The carpal canal houses both the deep digital flexor tendon, and the deep branch of the superficial digital flexor.
Muscles of the Forelimb
Extrinsic Musculature
These muscle are responsible for joining the forelimb to the trunk, forming a synsarcosis rather than a conventional joint. Collectively, they act to transfer the weight of the body to the forelimbs as well as stabilize the scapula.
Trapezius: Accessory n.
Origin: mid-dorsal raphe and supraspinous ligament.
Insertion: spine of the scapula.
Body: two parts, cervical and thoracic separated by aponeurosis.
Action: raises scapula against the trunk and swings cranially to advance the limb.
Brachiocephalic m.: Accessory n.
The two parts are separated by the clavicle, where it exists.
Origin: occipital bone, nuchal ligament and the mastoid process.
Insertion: deltoid tuberosity and fascia of the limb.
Actions: advances the limb and extends the shoulder joint when limb is in motion. Draws the head and neck ventrally when the limb is fixed.
Omotransversarius: Accessory n.
Origin: transverse processes of the atlas.
Insertion: acromion and spine of scapula.
Action: advancing the limb.
Latissimus dorsi: local branch of brachial plexus
The broadest muscle of the back.
Origin: thoracolumbar fascia.
Insertion: teres tuberosity of the humerus.
Actions: antagonist to the brachiocephalic m. The cranial fibers strap the scapula to the chest. It retracts the free limb and flexes shoulder joint. It draws the trunk forward over the fixed limb.
Pectoral mm.: brachial plexus
Two superficial parts, cranial and caudal, these aren't very distinct in the ox.
Origin: cranial sternum.
Insertion: 1. cranial (descending), crest of the humerus distal to the deltoid tuberosity. 2. caudal (transverse): covers elbow joint to insert on the medial fascia of the forearm.
Action: adduct the forelimb and assist in protraction and retraction.
Serratis ventralis: branch of the brachial plexus.
Origin: C4 to 10th rib.
Insertion: medial scapula and scapular cartilage.
Action: supporting the weight of the trunk. It is reinforced by strong fascia. The cervical portion can retract the limb and the caudal portion can advance the limb.
Rhomboids: brachial plexus,
Origin: nuchal ligament.
Insertion: dorsal border and adjacent scapula.
Action: retracting the limb, may also raise the limb.
Intrinsic Musculature
Muscles of the Shoulder
These muscles are grouped:
1. Lateral
Supraspinatus and Infraspinatus: Suprascapular n. of the brachial plexus.
Origin: the fossae of the scapula.
Insertion: both tubercles of the humerus.
Action: brace the shoulder.
Clinical significance: bursa between the tendon of the infraspinatus and lateral tubercle of the humerus can be the site of inflammation.
2. Medial
Supscapularis: Subscapular n. from the brachial plexus.
Origin: Deep surface of the scapula.
Insertion: medial tubercle of the humerus.
Action: braces medial shoulder joint, potential adductor.
Coracobrachialis: Musculocutaneous n. of the brachial plexus.
Origin: medial supraglenoid tubercle.
Insertion: proximal shaft of the humerus.
Action: fixator.
Caudal (Flexors)
Deltoids: Axillary n. of the brachial plexus.
Origin: Two heads of origin; the caudal border and spine of the scapula and the acromion.
Insertion: deltoid tuberosity on the humerus.
Action: Flexor of Shoulder.
Teres Major: Axillary n. of the brachial plexus.
Origin: dorsal part of the caudal scapula.
Insertion: teres tuberosity midway down humerus.
Teres Minor: Axillary n. of the brachial plexus.
There are no defined extensors of the shoulder. Those involved (brachiocephalic m., biceps brachii, supraspinatus, and ascending pectorals) have other, more primary roles.
Muscles of the Elbow
Extensors: Radial n. from the brachial plexus
- Triceps brachii: Three heads,the medial branch is the most developed
- Long head: caudal margin of the scapula
- Lateral, medial, and accessory heads: shaft of the humerus
- Insertion: olecranon, proteced by tricipital bursa against the bone and subcutaneous bursa against the skin
- Tensor fasciae antebrachii
- Overlies triceps extending from scapula to olecranon
Flexors: Musculocutaneous n. from the brachial plexus
- Biceps brachii
- Origin: supraglenoid tubercle of the scapula
- Insertion: medial tuberosity of proximal radius and adjacent ulna
- Runs through the intertubercular groove of the humerus
- Brachialis
- Origin: proximocaudal humerus
- Insertion: spirals to insert next to biceps
Muscles of the Carpal and Digital Joints
Extensors: Radial n. from the brachial plexus
- Craniolateral position on the forearm
- Almost all originate from the lateral epicondyle of the humerus
- Extensor carpi radialis: most medial, inserts on 2nd/3rd metacarpal bone
- Ulnaris lateralis: most lateral, inserts on accessory carpal bone
- Extensor carpi obliquus: aka abductor pollicis longus
- Origin: cranial radius
- Insertion: most medial metacarpal bone
- Last two may also serve in medial deviation of the foot
- Common Digital Extensor
- Insertion: extensor process of the distal phalanx of each digit
- Lateral Digital Extensor
- Insertion: dorsal proximal phalanges
- Medial Digital Extensor
- Insertion: middle and distal phalanges
Flexors: Median or Ulnar n. of the brachial plexus
- Caudal position on the forearm
- Originate from the caudal medial epicondyle of the humerus
- Flexor carpi radialis: most medial, inserts on upper 2nd/3rd metacarpal bone
- Flexor carpi ulnaris: most lateral, inserts on the accessory carpal bone
- Superficial Digital Flexor
- Insertion: palmar surface of middle phalanges
- Deep Digital Flexor
- Passes through carpal canal before branching and continues to palmar distal phalanges
Interosseus muscles
- This is covered in more detail in the bovine phalanges section.